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TOMOYO Linux Cross Reference
Linux/mm/slub.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * SLUB: A slab allocator that limits cache line use instead of queuing
  4  * objects in per cpu and per node lists.
  5  *
  6  * The allocator synchronizes using per slab locks or atomic operatios
  7  * and only uses a centralized lock to manage a pool of partial slabs.
  8  *
  9  * (C) 2007 SGI, Christoph Lameter
 10  * (C) 2011 Linux Foundation, Christoph Lameter
 11  */
 12 
 13 #include <linux/mm.h>
 14 #include <linux/swap.h> /* struct reclaim_state */
 15 #include <linux/module.h>
 16 #include <linux/bit_spinlock.h>
 17 #include <linux/interrupt.h>
 18 #include <linux/bitops.h>
 19 #include <linux/slab.h>
 20 #include "slab.h"
 21 #include <linux/proc_fs.h>
 22 #include <linux/seq_file.h>
 23 #include <linux/kasan.h>
 24 #include <linux/cpu.h>
 25 #include <linux/cpuset.h>
 26 #include <linux/mempolicy.h>
 27 #include <linux/ctype.h>
 28 #include <linux/debugobjects.h>
 29 #include <linux/kallsyms.h>
 30 #include <linux/memory.h>
 31 #include <linux/math64.h>
 32 #include <linux/fault-inject.h>
 33 #include <linux/stacktrace.h>
 34 #include <linux/prefetch.h>
 35 #include <linux/memcontrol.h>
 36 #include <linux/random.h>
 37 
 38 #include <trace/events/kmem.h>
 39 
 40 #include "internal.h"
 41 
 42 /*
 43  * Lock order:
 44  *   1. slab_mutex (Global Mutex)
 45  *   2. node->list_lock
 46  *   3. slab_lock(page) (Only on some arches and for debugging)
 47  *
 48  *   slab_mutex
 49  *
 50  *   The role of the slab_mutex is to protect the list of all the slabs
 51  *   and to synchronize major metadata changes to slab cache structures.
 52  *
 53  *   The slab_lock is only used for debugging and on arches that do not
 54  *   have the ability to do a cmpxchg_double. It only protects:
 55  *      A. page->freelist       -> List of object free in a page
 56  *      B. page->inuse          -> Number of objects in use
 57  *      C. page->objects        -> Number of objects in page
 58  *      D. page->frozen         -> frozen state
 59  *
 60  *   If a slab is frozen then it is exempt from list management. It is not
 61  *   on any list. The processor that froze the slab is the one who can
 62  *   perform list operations on the page. Other processors may put objects
 63  *   onto the freelist but the processor that froze the slab is the only
 64  *   one that can retrieve the objects from the page's freelist.
 65  *
 66  *   The list_lock protects the partial and full list on each node and
 67  *   the partial slab counter. If taken then no new slabs may be added or
 68  *   removed from the lists nor make the number of partial slabs be modified.
 69  *   (Note that the total number of slabs is an atomic value that may be
 70  *   modified without taking the list lock).
 71  *
 72  *   The list_lock is a centralized lock and thus we avoid taking it as
 73  *   much as possible. As long as SLUB does not have to handle partial
 74  *   slabs, operations can continue without any centralized lock. F.e.
 75  *   allocating a long series of objects that fill up slabs does not require
 76  *   the list lock.
 77  *   Interrupts are disabled during allocation and deallocation in order to
 78  *   make the slab allocator safe to use in the context of an irq. In addition
 79  *   interrupts are disabled to ensure that the processor does not change
 80  *   while handling per_cpu slabs, due to kernel preemption.
 81  *
 82  * SLUB assigns one slab for allocation to each processor.
 83  * Allocations only occur from these slabs called cpu slabs.
 84  *
 85  * Slabs with free elements are kept on a partial list and during regular
 86  * operations no list for full slabs is used. If an object in a full slab is
 87  * freed then the slab will show up again on the partial lists.
 88  * We track full slabs for debugging purposes though because otherwise we
 89  * cannot scan all objects.
 90  *
 91  * Slabs are freed when they become empty. Teardown and setup is
 92  * minimal so we rely on the page allocators per cpu caches for
 93  * fast frees and allocs.
 94  *
 95  * Overloading of page flags that are otherwise used for LRU management.
 96  *
 97  * PageActive           The slab is frozen and exempt from list processing.
 98  *                      This means that the slab is dedicated to a purpose
 99  *                      such as satisfying allocations for a specific
100  *                      processor. Objects may be freed in the slab while
101  *                      it is frozen but slab_free will then skip the usual
102  *                      list operations. It is up to the processor holding
103  *                      the slab to integrate the slab into the slab lists
104  *                      when the slab is no longer needed.
105  *
106  *                      One use of this flag is to mark slabs that are
107  *                      used for allocations. Then such a slab becomes a cpu
108  *                      slab. The cpu slab may be equipped with an additional
109  *                      freelist that allows lockless access to
110  *                      free objects in addition to the regular freelist
111  *                      that requires the slab lock.
112  *
113  * PageError            Slab requires special handling due to debug
114  *                      options set. This moves slab handling out of
115  *                      the fast path and disables lockless freelists.
116  */
117 
118 static inline int kmem_cache_debug(struct kmem_cache *s)
119 {
120 #ifdef CONFIG_SLUB_DEBUG
121         return unlikely(s->flags & SLAB_DEBUG_FLAGS);
122 #else
123         return 0;
124 #endif
125 }
126 
127 void *fixup_red_left(struct kmem_cache *s, void *p)
128 {
129         if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE)
130                 p += s->red_left_pad;
131 
132         return p;
133 }
134 
135 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
136 {
137 #ifdef CONFIG_SLUB_CPU_PARTIAL
138         return !kmem_cache_debug(s);
139 #else
140         return false;
141 #endif
142 }
143 
144 /*
145  * Issues still to be resolved:
146  *
147  * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
148  *
149  * - Variable sizing of the per node arrays
150  */
151 
152 /* Enable to test recovery from slab corruption on boot */
153 #undef SLUB_RESILIENCY_TEST
154 
155 /* Enable to log cmpxchg failures */
156 #undef SLUB_DEBUG_CMPXCHG
157 
158 /*
159  * Mininum number of partial slabs. These will be left on the partial
160  * lists even if they are empty. kmem_cache_shrink may reclaim them.
161  */
162 #define MIN_PARTIAL 5
163 
164 /*
165  * Maximum number of desirable partial slabs.
166  * The existence of more partial slabs makes kmem_cache_shrink
167  * sort the partial list by the number of objects in use.
168  */
169 #define MAX_PARTIAL 10
170 
171 #define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
172                                 SLAB_POISON | SLAB_STORE_USER)
173 
174 /*
175  * These debug flags cannot use CMPXCHG because there might be consistency
176  * issues when checking or reading debug information
177  */
178 #define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
179                                 SLAB_TRACE)
180 
181 
182 /*
183  * Debugging flags that require metadata to be stored in the slab.  These get
184  * disabled when slub_debug=O is used and a cache's min order increases with
185  * metadata.
186  */
187 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
188 
189 #define OO_SHIFT        16
190 #define OO_MASK         ((1 << OO_SHIFT) - 1)
191 #define MAX_OBJS_PER_PAGE       32767 /* since page.objects is u15 */
192 
193 /* Internal SLUB flags */
194 /* Poison object */
195 #define __OBJECT_POISON         ((slab_flags_t __force)0x80000000U)
196 /* Use cmpxchg_double */
197 #define __CMPXCHG_DOUBLE        ((slab_flags_t __force)0x40000000U)
198 
199 /*
200  * Tracking user of a slab.
201  */
202 #define TRACK_ADDRS_COUNT 16
203 struct track {
204         unsigned long addr;     /* Called from address */
205 #ifdef CONFIG_STACKTRACE
206         unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
207 #endif
208         int cpu;                /* Was running on cpu */
209         int pid;                /* Pid context */
210         unsigned long when;     /* When did the operation occur */
211 };
212 
213 enum track_item { TRACK_ALLOC, TRACK_FREE };
214 
215 #ifdef CONFIG_SYSFS
216 static int sysfs_slab_add(struct kmem_cache *);
217 static int sysfs_slab_alias(struct kmem_cache *, const char *);
218 static void memcg_propagate_slab_attrs(struct kmem_cache *s);
219 static void sysfs_slab_remove(struct kmem_cache *s);
220 #else
221 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
222 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
223                                                         { return 0; }
224 static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
225 static inline void sysfs_slab_remove(struct kmem_cache *s) { }
226 #endif
227 
228 static inline void stat(const struct kmem_cache *s, enum stat_item si)
229 {
230 #ifdef CONFIG_SLUB_STATS
231         /*
232          * The rmw is racy on a preemptible kernel but this is acceptable, so
233          * avoid this_cpu_add()'s irq-disable overhead.
234          */
235         raw_cpu_inc(s->cpu_slab->stat[si]);
236 #endif
237 }
238 
239 /********************************************************************
240  *                      Core slab cache functions
241  *******************************************************************/
242 
243 /*
244  * Returns freelist pointer (ptr). With hardening, this is obfuscated
245  * with an XOR of the address where the pointer is held and a per-cache
246  * random number.
247  */
248 static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr,
249                                  unsigned long ptr_addr)
250 {
251 #ifdef CONFIG_SLAB_FREELIST_HARDENED
252         /*
253          * When CONFIG_KASAN_SW_TAGS is enabled, ptr_addr might be tagged.
254          * Normally, this doesn't cause any issues, as both set_freepointer()
255          * and get_freepointer() are called with a pointer with the same tag.
256          * However, there are some issues with CONFIG_SLUB_DEBUG code. For
257          * example, when __free_slub() iterates over objects in a cache, it
258          * passes untagged pointers to check_object(). check_object() in turns
259          * calls get_freepointer() with an untagged pointer, which causes the
260          * freepointer to be restored incorrectly.
261          */
262         return (void *)((unsigned long)ptr ^ s->random ^
263                         (unsigned long)kasan_reset_tag((void *)ptr_addr));
264 #else
265         return ptr;
266 #endif
267 }
268 
269 /* Returns the freelist pointer recorded at location ptr_addr. */
270 static inline void *freelist_dereference(const struct kmem_cache *s,
271                                          void *ptr_addr)
272 {
273         return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr),
274                             (unsigned long)ptr_addr);
275 }
276 
277 static inline void *get_freepointer(struct kmem_cache *s, void *object)
278 {
279         return freelist_dereference(s, object + s->offset);
280 }
281 
282 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
283 {
284         prefetch(object + s->offset);
285 }
286 
287 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
288 {
289         unsigned long freepointer_addr;
290         void *p;
291 
292         if (!debug_pagealloc_enabled())
293                 return get_freepointer(s, object);
294 
295         freepointer_addr = (unsigned long)object + s->offset;
296         probe_kernel_read(&p, (void **)freepointer_addr, sizeof(p));
297         return freelist_ptr(s, p, freepointer_addr);
298 }
299 
300 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
301 {
302         unsigned long freeptr_addr = (unsigned long)object + s->offset;
303 
304 #ifdef CONFIG_SLAB_FREELIST_HARDENED
305         BUG_ON(object == fp); /* naive detection of double free or corruption */
306 #endif
307 
308         *(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr);
309 }
310 
311 /* Loop over all objects in a slab */
312 #define for_each_object(__p, __s, __addr, __objects) \
313         for (__p = fixup_red_left(__s, __addr); \
314                 __p < (__addr) + (__objects) * (__s)->size; \
315                 __p += (__s)->size)
316 
317 /* Determine object index from a given position */
318 static inline unsigned int slab_index(void *p, struct kmem_cache *s, void *addr)
319 {
320         return (kasan_reset_tag(p) - addr) / s->size;
321 }
322 
323 static inline unsigned int order_objects(unsigned int order, unsigned int size)
324 {
325         return ((unsigned int)PAGE_SIZE << order) / size;
326 }
327 
328 static inline struct kmem_cache_order_objects oo_make(unsigned int order,
329                 unsigned int size)
330 {
331         struct kmem_cache_order_objects x = {
332                 (order << OO_SHIFT) + order_objects(order, size)
333         };
334 
335         return x;
336 }
337 
338 static inline unsigned int oo_order(struct kmem_cache_order_objects x)
339 {
340         return x.x >> OO_SHIFT;
341 }
342 
343 static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
344 {
345         return x.x & OO_MASK;
346 }
347 
348 /*
349  * Per slab locking using the pagelock
350  */
351 static __always_inline void slab_lock(struct page *page)
352 {
353         VM_BUG_ON_PAGE(PageTail(page), page);
354         bit_spin_lock(PG_locked, &page->flags);
355 }
356 
357 static __always_inline void slab_unlock(struct page *page)
358 {
359         VM_BUG_ON_PAGE(PageTail(page), page);
360         __bit_spin_unlock(PG_locked, &page->flags);
361 }
362 
363 /* Interrupts must be disabled (for the fallback code to work right) */
364 static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
365                 void *freelist_old, unsigned long counters_old,
366                 void *freelist_new, unsigned long counters_new,
367                 const char *n)
368 {
369         VM_BUG_ON(!irqs_disabled());
370 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
371     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
372         if (s->flags & __CMPXCHG_DOUBLE) {
373                 if (cmpxchg_double(&page->freelist, &page->counters,
374                                    freelist_old, counters_old,
375                                    freelist_new, counters_new))
376                         return true;
377         } else
378 #endif
379         {
380                 slab_lock(page);
381                 if (page->freelist == freelist_old &&
382                                         page->counters == counters_old) {
383                         page->freelist = freelist_new;
384                         page->counters = counters_new;
385                         slab_unlock(page);
386                         return true;
387                 }
388                 slab_unlock(page);
389         }
390 
391         cpu_relax();
392         stat(s, CMPXCHG_DOUBLE_FAIL);
393 
394 #ifdef SLUB_DEBUG_CMPXCHG
395         pr_info("%s %s: cmpxchg double redo ", n, s->name);
396 #endif
397 
398         return false;
399 }
400 
401 static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
402                 void *freelist_old, unsigned long counters_old,
403                 void *freelist_new, unsigned long counters_new,
404                 const char *n)
405 {
406 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
407     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
408         if (s->flags & __CMPXCHG_DOUBLE) {
409                 if (cmpxchg_double(&page->freelist, &page->counters,
410                                    freelist_old, counters_old,
411                                    freelist_new, counters_new))
412                         return true;
413         } else
414 #endif
415         {
416                 unsigned long flags;
417 
418                 local_irq_save(flags);
419                 slab_lock(page);
420                 if (page->freelist == freelist_old &&
421                                         page->counters == counters_old) {
422                         page->freelist = freelist_new;
423                         page->counters = counters_new;
424                         slab_unlock(page);
425                         local_irq_restore(flags);
426                         return true;
427                 }
428                 slab_unlock(page);
429                 local_irq_restore(flags);
430         }
431 
432         cpu_relax();
433         stat(s, CMPXCHG_DOUBLE_FAIL);
434 
435 #ifdef SLUB_DEBUG_CMPXCHG
436         pr_info("%s %s: cmpxchg double redo ", n, s->name);
437 #endif
438 
439         return false;
440 }
441 
442 #ifdef CONFIG_SLUB_DEBUG
443 /*
444  * Determine a map of object in use on a page.
445  *
446  * Node listlock must be held to guarantee that the page does
447  * not vanish from under us.
448  */
449 static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
450 {
451         void *p;
452         void *addr = page_address(page);
453 
454         for (p = page->freelist; p; p = get_freepointer(s, p))
455                 set_bit(slab_index(p, s, addr), map);
456 }
457 
458 static inline unsigned int size_from_object(struct kmem_cache *s)
459 {
460         if (s->flags & SLAB_RED_ZONE)
461                 return s->size - s->red_left_pad;
462 
463         return s->size;
464 }
465 
466 static inline void *restore_red_left(struct kmem_cache *s, void *p)
467 {
468         if (s->flags & SLAB_RED_ZONE)
469                 p -= s->red_left_pad;
470 
471         return p;
472 }
473 
474 /*
475  * Debug settings:
476  */
477 #if defined(CONFIG_SLUB_DEBUG_ON)
478 static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
479 #else
480 static slab_flags_t slub_debug;
481 #endif
482 
483 static char *slub_debug_slabs;
484 static int disable_higher_order_debug;
485 
486 /*
487  * slub is about to manipulate internal object metadata.  This memory lies
488  * outside the range of the allocated object, so accessing it would normally
489  * be reported by kasan as a bounds error.  metadata_access_enable() is used
490  * to tell kasan that these accesses are OK.
491  */
492 static inline void metadata_access_enable(void)
493 {
494         kasan_disable_current();
495 }
496 
497 static inline void metadata_access_disable(void)
498 {
499         kasan_enable_current();
500 }
501 
502 /*
503  * Object debugging
504  */
505 
506 /* Verify that a pointer has an address that is valid within a slab page */
507 static inline int check_valid_pointer(struct kmem_cache *s,
508                                 struct page *page, void *object)
509 {
510         void *base;
511 
512         if (!object)
513                 return 1;
514 
515         base = page_address(page);
516         object = kasan_reset_tag(object);
517         object = restore_red_left(s, object);
518         if (object < base || object >= base + page->objects * s->size ||
519                 (object - base) % s->size) {
520                 return 0;
521         }
522 
523         return 1;
524 }
525 
526 static void print_section(char *level, char *text, u8 *addr,
527                           unsigned int length)
528 {
529         metadata_access_enable();
530         print_hex_dump(level, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
531                         length, 1);
532         metadata_access_disable();
533 }
534 
535 static struct track *get_track(struct kmem_cache *s, void *object,
536         enum track_item alloc)
537 {
538         struct track *p;
539 
540         if (s->offset)
541                 p = object + s->offset + sizeof(void *);
542         else
543                 p = object + s->inuse;
544 
545         return p + alloc;
546 }
547 
548 static void set_track(struct kmem_cache *s, void *object,
549                         enum track_item alloc, unsigned long addr)
550 {
551         struct track *p = get_track(s, object, alloc);
552 
553         if (addr) {
554 #ifdef CONFIG_STACKTRACE
555                 struct stack_trace trace;
556                 int i;
557 
558                 trace.nr_entries = 0;
559                 trace.max_entries = TRACK_ADDRS_COUNT;
560                 trace.entries = p->addrs;
561                 trace.skip = 3;
562                 metadata_access_enable();
563                 save_stack_trace(&trace);
564                 metadata_access_disable();
565 
566                 /* See rant in lockdep.c */
567                 if (trace.nr_entries != 0 &&
568                     trace.entries[trace.nr_entries - 1] == ULONG_MAX)
569                         trace.nr_entries--;
570 
571                 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
572                         p->addrs[i] = 0;
573 #endif
574                 p->addr = addr;
575                 p->cpu = smp_processor_id();
576                 p->pid = current->pid;
577                 p->when = jiffies;
578         } else
579                 memset(p, 0, sizeof(struct track));
580 }
581 
582 static void init_tracking(struct kmem_cache *s, void *object)
583 {
584         if (!(s->flags & SLAB_STORE_USER))
585                 return;
586 
587         set_track(s, object, TRACK_FREE, 0UL);
588         set_track(s, object, TRACK_ALLOC, 0UL);
589 }
590 
591 static void print_track(const char *s, struct track *t, unsigned long pr_time)
592 {
593         if (!t->addr)
594                 return;
595 
596         pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
597                s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
598 #ifdef CONFIG_STACKTRACE
599         {
600                 int i;
601                 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
602                         if (t->addrs[i])
603                                 pr_err("\t%pS\n", (void *)t->addrs[i]);
604                         else
605                                 break;
606         }
607 #endif
608 }
609 
610 static void print_tracking(struct kmem_cache *s, void *object)
611 {
612         unsigned long pr_time = jiffies;
613         if (!(s->flags & SLAB_STORE_USER))
614                 return;
615 
616         print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
617         print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
618 }
619 
620 static void print_page_info(struct page *page)
621 {
622         pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
623                page, page->objects, page->inuse, page->freelist, page->flags);
624 
625 }
626 
627 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
628 {
629         struct va_format vaf;
630         va_list args;
631 
632         va_start(args, fmt);
633         vaf.fmt = fmt;
634         vaf.va = &args;
635         pr_err("=============================================================================\n");
636         pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
637         pr_err("-----------------------------------------------------------------------------\n\n");
638 
639         add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
640         va_end(args);
641 }
642 
643 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
644 {
645         struct va_format vaf;
646         va_list args;
647 
648         va_start(args, fmt);
649         vaf.fmt = fmt;
650         vaf.va = &args;
651         pr_err("FIX %s: %pV\n", s->name, &vaf);
652         va_end(args);
653 }
654 
655 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
656 {
657         unsigned int off;       /* Offset of last byte */
658         u8 *addr = page_address(page);
659 
660         print_tracking(s, p);
661 
662         print_page_info(page);
663 
664         pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
665                p, p - addr, get_freepointer(s, p));
666 
667         if (s->flags & SLAB_RED_ZONE)
668                 print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
669                               s->red_left_pad);
670         else if (p > addr + 16)
671                 print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
672 
673         print_section(KERN_ERR, "Object ", p,
674                       min_t(unsigned int, s->object_size, PAGE_SIZE));
675         if (s->flags & SLAB_RED_ZONE)
676                 print_section(KERN_ERR, "Redzone ", p + s->object_size,
677                         s->inuse - s->object_size);
678 
679         if (s->offset)
680                 off = s->offset + sizeof(void *);
681         else
682                 off = s->inuse;
683 
684         if (s->flags & SLAB_STORE_USER)
685                 off += 2 * sizeof(struct track);
686 
687         off += kasan_metadata_size(s);
688 
689         if (off != size_from_object(s))
690                 /* Beginning of the filler is the free pointer */
691                 print_section(KERN_ERR, "Padding ", p + off,
692                               size_from_object(s) - off);
693 
694         dump_stack();
695 }
696 
697 void object_err(struct kmem_cache *s, struct page *page,
698                         u8 *object, char *reason)
699 {
700         slab_bug(s, "%s", reason);
701         print_trailer(s, page, object);
702 }
703 
704 static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page,
705                         const char *fmt, ...)
706 {
707         va_list args;
708         char buf[100];
709 
710         va_start(args, fmt);
711         vsnprintf(buf, sizeof(buf), fmt, args);
712         va_end(args);
713         slab_bug(s, "%s", buf);
714         print_page_info(page);
715         dump_stack();
716 }
717 
718 static void init_object(struct kmem_cache *s, void *object, u8 val)
719 {
720         u8 *p = object;
721 
722         if (s->flags & SLAB_RED_ZONE)
723                 memset(p - s->red_left_pad, val, s->red_left_pad);
724 
725         if (s->flags & __OBJECT_POISON) {
726                 memset(p, POISON_FREE, s->object_size - 1);
727                 p[s->object_size - 1] = POISON_END;
728         }
729 
730         if (s->flags & SLAB_RED_ZONE)
731                 memset(p + s->object_size, val, s->inuse - s->object_size);
732 }
733 
734 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
735                                                 void *from, void *to)
736 {
737         slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
738         memset(from, data, to - from);
739 }
740 
741 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
742                         u8 *object, char *what,
743                         u8 *start, unsigned int value, unsigned int bytes)
744 {
745         u8 *fault;
746         u8 *end;
747 
748         metadata_access_enable();
749         fault = memchr_inv(start, value, bytes);
750         metadata_access_disable();
751         if (!fault)
752                 return 1;
753 
754         end = start + bytes;
755         while (end > fault && end[-1] == value)
756                 end--;
757 
758         slab_bug(s, "%s overwritten", what);
759         pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
760                                         fault, end - 1, fault[0], value);
761         print_trailer(s, page, object);
762 
763         restore_bytes(s, what, value, fault, end);
764         return 0;
765 }
766 
767 /*
768  * Object layout:
769  *
770  * object address
771  *      Bytes of the object to be managed.
772  *      If the freepointer may overlay the object then the free
773  *      pointer is the first word of the object.
774  *
775  *      Poisoning uses 0x6b (POISON_FREE) and the last byte is
776  *      0xa5 (POISON_END)
777  *
778  * object + s->object_size
779  *      Padding to reach word boundary. This is also used for Redzoning.
780  *      Padding is extended by another word if Redzoning is enabled and
781  *      object_size == inuse.
782  *
783  *      We fill with 0xbb (RED_INACTIVE) for inactive objects and with
784  *      0xcc (RED_ACTIVE) for objects in use.
785  *
786  * object + s->inuse
787  *      Meta data starts here.
788  *
789  *      A. Free pointer (if we cannot overwrite object on free)
790  *      B. Tracking data for SLAB_STORE_USER
791  *      C. Padding to reach required alignment boundary or at mininum
792  *              one word if debugging is on to be able to detect writes
793  *              before the word boundary.
794  *
795  *      Padding is done using 0x5a (POISON_INUSE)
796  *
797  * object + s->size
798  *      Nothing is used beyond s->size.
799  *
800  * If slabcaches are merged then the object_size and inuse boundaries are mostly
801  * ignored. And therefore no slab options that rely on these boundaries
802  * may be used with merged slabcaches.
803  */
804 
805 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
806 {
807         unsigned long off = s->inuse;   /* The end of info */
808 
809         if (s->offset)
810                 /* Freepointer is placed after the object. */
811                 off += sizeof(void *);
812 
813         if (s->flags & SLAB_STORE_USER)
814                 /* We also have user information there */
815                 off += 2 * sizeof(struct track);
816 
817         off += kasan_metadata_size(s);
818 
819         if (size_from_object(s) == off)
820                 return 1;
821 
822         return check_bytes_and_report(s, page, p, "Object padding",
823                         p + off, POISON_INUSE, size_from_object(s) - off);
824 }
825 
826 /* Check the pad bytes at the end of a slab page */
827 static int slab_pad_check(struct kmem_cache *s, struct page *page)
828 {
829         u8 *start;
830         u8 *fault;
831         u8 *end;
832         u8 *pad;
833         int length;
834         int remainder;
835 
836         if (!(s->flags & SLAB_POISON))
837                 return 1;
838 
839         start = page_address(page);
840         length = PAGE_SIZE << compound_order(page);
841         end = start + length;
842         remainder = length % s->size;
843         if (!remainder)
844                 return 1;
845 
846         pad = end - remainder;
847         metadata_access_enable();
848         fault = memchr_inv(pad, POISON_INUSE, remainder);
849         metadata_access_disable();
850         if (!fault)
851                 return 1;
852         while (end > fault && end[-1] == POISON_INUSE)
853                 end--;
854 
855         slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
856         print_section(KERN_ERR, "Padding ", pad, remainder);
857 
858         restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
859         return 0;
860 }
861 
862 static int check_object(struct kmem_cache *s, struct page *page,
863                                         void *object, u8 val)
864 {
865         u8 *p = object;
866         u8 *endobject = object + s->object_size;
867 
868         if (s->flags & SLAB_RED_ZONE) {
869                 if (!check_bytes_and_report(s, page, object, "Redzone",
870                         object - s->red_left_pad, val, s->red_left_pad))
871                         return 0;
872 
873                 if (!check_bytes_and_report(s, page, object, "Redzone",
874                         endobject, val, s->inuse - s->object_size))
875                         return 0;
876         } else {
877                 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
878                         check_bytes_and_report(s, page, p, "Alignment padding",
879                                 endobject, POISON_INUSE,
880                                 s->inuse - s->object_size);
881                 }
882         }
883 
884         if (s->flags & SLAB_POISON) {
885                 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
886                         (!check_bytes_and_report(s, page, p, "Poison", p,
887                                         POISON_FREE, s->object_size - 1) ||
888                          !check_bytes_and_report(s, page, p, "Poison",
889                                 p + s->object_size - 1, POISON_END, 1)))
890                         return 0;
891                 /*
892                  * check_pad_bytes cleans up on its own.
893                  */
894                 check_pad_bytes(s, page, p);
895         }
896 
897         if (!s->offset && val == SLUB_RED_ACTIVE)
898                 /*
899                  * Object and freepointer overlap. Cannot check
900                  * freepointer while object is allocated.
901                  */
902                 return 1;
903 
904         /* Check free pointer validity */
905         if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
906                 object_err(s, page, p, "Freepointer corrupt");
907                 /*
908                  * No choice but to zap it and thus lose the remainder
909                  * of the free objects in this slab. May cause
910                  * another error because the object count is now wrong.
911                  */
912                 set_freepointer(s, p, NULL);
913                 return 0;
914         }
915         return 1;
916 }
917 
918 static int check_slab(struct kmem_cache *s, struct page *page)
919 {
920         int maxobj;
921 
922         VM_BUG_ON(!irqs_disabled());
923 
924         if (!PageSlab(page)) {
925                 slab_err(s, page, "Not a valid slab page");
926                 return 0;
927         }
928 
929         maxobj = order_objects(compound_order(page), s->size);
930         if (page->objects > maxobj) {
931                 slab_err(s, page, "objects %u > max %u",
932                         page->objects, maxobj);
933                 return 0;
934         }
935         if (page->inuse > page->objects) {
936                 slab_err(s, page, "inuse %u > max %u",
937                         page->inuse, page->objects);
938                 return 0;
939         }
940         /* Slab_pad_check fixes things up after itself */
941         slab_pad_check(s, page);
942         return 1;
943 }
944 
945 /*
946  * Determine if a certain object on a page is on the freelist. Must hold the
947  * slab lock to guarantee that the chains are in a consistent state.
948  */
949 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
950 {
951         int nr = 0;
952         void *fp;
953         void *object = NULL;
954         int max_objects;
955 
956         fp = page->freelist;
957         while (fp && nr <= page->objects) {
958                 if (fp == search)
959                         return 1;
960                 if (!check_valid_pointer(s, page, fp)) {
961                         if (object) {
962                                 object_err(s, page, object,
963                                         "Freechain corrupt");
964                                 set_freepointer(s, object, NULL);
965                         } else {
966                                 slab_err(s, page, "Freepointer corrupt");
967                                 page->freelist = NULL;
968                                 page->inuse = page->objects;
969                                 slab_fix(s, "Freelist cleared");
970                                 return 0;
971                         }
972                         break;
973                 }
974                 object = fp;
975                 fp = get_freepointer(s, object);
976                 nr++;
977         }
978 
979         max_objects = order_objects(compound_order(page), s->size);
980         if (max_objects > MAX_OBJS_PER_PAGE)
981                 max_objects = MAX_OBJS_PER_PAGE;
982 
983         if (page->objects != max_objects) {
984                 slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
985                          page->objects, max_objects);
986                 page->objects = max_objects;
987                 slab_fix(s, "Number of objects adjusted.");
988         }
989         if (page->inuse != page->objects - nr) {
990                 slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
991                          page->inuse, page->objects - nr);
992                 page->inuse = page->objects - nr;
993                 slab_fix(s, "Object count adjusted.");
994         }
995         return search == NULL;
996 }
997 
998 static void trace(struct kmem_cache *s, struct page *page, void *object,
999                                                                 int alloc)
1000 {
1001         if (s->flags & SLAB_TRACE) {
1002                 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1003                         s->name,
1004                         alloc ? "alloc" : "free",
1005                         object, page->inuse,
1006                         page->freelist);
1007 
1008                 if (!alloc)
1009                         print_section(KERN_INFO, "Object ", (void *)object,
1010                                         s->object_size);
1011 
1012                 dump_stack();
1013         }
1014 }
1015 
1016 /*
1017  * Tracking of fully allocated slabs for debugging purposes.
1018  */
1019 static void add_full(struct kmem_cache *s,
1020         struct kmem_cache_node *n, struct page *page)
1021 {
1022         if (!(s->flags & SLAB_STORE_USER))
1023                 return;
1024 
1025         lockdep_assert_held(&n->list_lock);
1026         list_add(&page->lru, &n->full);
1027 }
1028 
1029 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
1030 {
1031         if (!(s->flags & SLAB_STORE_USER))
1032                 return;
1033 
1034         lockdep_assert_held(&n->list_lock);
1035         list_del(&page->lru);
1036 }
1037 
1038 /* Tracking of the number of slabs for debugging purposes */
1039 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1040 {
1041         struct kmem_cache_node *n = get_node(s, node);
1042 
1043         return atomic_long_read(&n->nr_slabs);
1044 }
1045 
1046 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1047 {
1048         return atomic_long_read(&n->nr_slabs);
1049 }
1050 
1051 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1052 {
1053         struct kmem_cache_node *n = get_node(s, node);
1054 
1055         /*
1056          * May be called early in order to allocate a slab for the
1057          * kmem_cache_node structure. Solve the chicken-egg
1058          * dilemma by deferring the increment of the count during
1059          * bootstrap (see early_kmem_cache_node_alloc).
1060          */
1061         if (likely(n)) {
1062                 atomic_long_inc(&n->nr_slabs);
1063                 atomic_long_add(objects, &n->total_objects);
1064         }
1065 }
1066 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1067 {
1068         struct kmem_cache_node *n = get_node(s, node);
1069 
1070         atomic_long_dec(&n->nr_slabs);
1071         atomic_long_sub(objects, &n->total_objects);
1072 }
1073 
1074 /* Object debug checks for alloc/free paths */
1075 static void setup_object_debug(struct kmem_cache *s, struct page *page,
1076                                                                 void *object)
1077 {
1078         if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1079                 return;
1080 
1081         init_object(s, object, SLUB_RED_INACTIVE);
1082         init_tracking(s, object);
1083 }
1084 
1085 static void setup_page_debug(struct kmem_cache *s, void *addr, int order)
1086 {
1087         if (!(s->flags & SLAB_POISON))
1088                 return;
1089 
1090         metadata_access_enable();
1091         memset(addr, POISON_INUSE, PAGE_SIZE << order);
1092         metadata_access_disable();
1093 }
1094 
1095 static inline int alloc_consistency_checks(struct kmem_cache *s,
1096                                         struct page *page, void *object)
1097 {
1098         if (!check_slab(s, page))
1099                 return 0;
1100 
1101         if (!check_valid_pointer(s, page, object)) {
1102                 object_err(s, page, object, "Freelist Pointer check fails");
1103                 return 0;
1104         }
1105 
1106         if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1107                 return 0;
1108 
1109         return 1;
1110 }
1111 
1112 static noinline int alloc_debug_processing(struct kmem_cache *s,
1113                                         struct page *page,
1114                                         void *object, unsigned long addr)
1115 {
1116         if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1117                 if (!alloc_consistency_checks(s, page, object))
1118                         goto bad;
1119         }
1120 
1121         /* Success perform special debug activities for allocs */
1122         if (s->flags & SLAB_STORE_USER)
1123                 set_track(s, object, TRACK_ALLOC, addr);
1124         trace(s, page, object, 1);
1125         init_object(s, object, SLUB_RED_ACTIVE);
1126         return 1;
1127 
1128 bad:
1129         if (PageSlab(page)) {
1130                 /*
1131                  * If this is a slab page then lets do the best we can
1132                  * to avoid issues in the future. Marking all objects
1133                  * as used avoids touching the remaining objects.
1134                  */
1135                 slab_fix(s, "Marking all objects used");
1136                 page->inuse = page->objects;
1137                 page->freelist = NULL;
1138         }
1139         return 0;
1140 }
1141 
1142 static inline int free_consistency_checks(struct kmem_cache *s,
1143                 struct page *page, void *object, unsigned long addr)
1144 {
1145         if (!check_valid_pointer(s, page, object)) {
1146                 slab_err(s, page, "Invalid object pointer 0x%p", object);
1147                 return 0;
1148         }
1149 
1150         if (on_freelist(s, page, object)) {
1151                 object_err(s, page, object, "Object already free");
1152                 return 0;
1153         }
1154 
1155         if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1156                 return 0;
1157 
1158         if (unlikely(s != page->slab_cache)) {
1159                 if (!PageSlab(page)) {
1160                         slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
1161                                  object);
1162                 } else if (!page->slab_cache) {
1163                         pr_err("SLUB <none>: no slab for object 0x%p.\n",
1164                                object);
1165                         dump_stack();
1166                 } else
1167                         object_err(s, page, object,
1168                                         "page slab pointer corrupt.");
1169                 return 0;
1170         }
1171         return 1;
1172 }
1173 
1174 /* Supports checking bulk free of a constructed freelist */
1175 static noinline int free_debug_processing(
1176         struct kmem_cache *s, struct page *page,
1177         void *head, void *tail, int bulk_cnt,
1178         unsigned long addr)
1179 {
1180         struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1181         void *object = head;
1182         int cnt = 0;
1183         unsigned long uninitialized_var(flags);
1184         int ret = 0;
1185 
1186         spin_lock_irqsave(&n->list_lock, flags);
1187         slab_lock(page);
1188 
1189         if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1190                 if (!check_slab(s, page))
1191                         goto out;
1192         }
1193 
1194 next_object:
1195         cnt++;
1196 
1197         if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1198                 if (!free_consistency_checks(s, page, object, addr))
1199                         goto out;
1200         }
1201 
1202         if (s->flags & SLAB_STORE_USER)
1203                 set_track(s, object, TRACK_FREE, addr);
1204         trace(s, page, object, 0);
1205         /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1206         init_object(s, object, SLUB_RED_INACTIVE);
1207 
1208         /* Reached end of constructed freelist yet? */
1209         if (object != tail) {
1210                 object = get_freepointer(s, object);
1211                 goto next_object;
1212         }
1213         ret = 1;
1214 
1215 out:
1216         if (cnt != bulk_cnt)
1217                 slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
1218                          bulk_cnt, cnt);
1219 
1220         slab_unlock(page);
1221         spin_unlock_irqrestore(&n->list_lock, flags);
1222         if (!ret)
1223                 slab_fix(s, "Object at 0x%p not freed", object);
1224         return ret;
1225 }
1226 
1227 static int __init setup_slub_debug(char *str)
1228 {
1229         slub_debug = DEBUG_DEFAULT_FLAGS;
1230         if (*str++ != '=' || !*str)
1231                 /*
1232                  * No options specified. Switch on full debugging.
1233                  */
1234                 goto out;
1235 
1236         if (*str == ',')
1237                 /*
1238                  * No options but restriction on slabs. This means full
1239                  * debugging for slabs matching a pattern.
1240                  */
1241                 goto check_slabs;
1242 
1243         slub_debug = 0;
1244         if (*str == '-')
1245                 /*
1246                  * Switch off all debugging measures.
1247                  */
1248                 goto out;
1249 
1250         /*
1251          * Determine which debug features should be switched on
1252          */
1253         for (; *str && *str != ','; str++) {
1254                 switch (tolower(*str)) {
1255                 case 'f':
1256                         slub_debug |= SLAB_CONSISTENCY_CHECKS;
1257                         break;
1258                 case 'z':
1259                         slub_debug |= SLAB_RED_ZONE;
1260                         break;
1261                 case 'p':
1262                         slub_debug |= SLAB_POISON;
1263                         break;
1264                 case 'u':
1265                         slub_debug |= SLAB_STORE_USER;
1266                         break;
1267                 case 't':
1268                         slub_debug |= SLAB_TRACE;
1269                         break;
1270                 case 'a':
1271                         slub_debug |= SLAB_FAILSLAB;
1272                         break;
1273                 case 'o':
1274                         /*
1275                          * Avoid enabling debugging on caches if its minimum
1276                          * order would increase as a result.
1277                          */
1278                         disable_higher_order_debug = 1;
1279                         break;
1280                 default:
1281                         pr_err("slub_debug option '%c' unknown. skipped\n",
1282                                *str);
1283                 }
1284         }
1285 
1286 check_slabs:
1287         if (*str == ',')
1288                 slub_debug_slabs = str + 1;
1289 out:
1290         return 1;
1291 }
1292 
1293 __setup("slub_debug", setup_slub_debug);
1294 
1295 /*
1296  * kmem_cache_flags - apply debugging options to the cache
1297  * @object_size:        the size of an object without meta data
1298  * @flags:              flags to set
1299  * @name:               name of the cache
1300  * @ctor:               constructor function
1301  *
1302  * Debug option(s) are applied to @flags. In addition to the debug
1303  * option(s), if a slab name (or multiple) is specified i.e.
1304  * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
1305  * then only the select slabs will receive the debug option(s).
1306  */
1307 slab_flags_t kmem_cache_flags(unsigned int object_size,
1308         slab_flags_t flags, const char *name,
1309         void (*ctor)(void *))
1310 {
1311         char *iter;
1312         size_t len;
1313 
1314         /* If slub_debug = 0, it folds into the if conditional. */
1315         if (!slub_debug_slabs)
1316                 return flags | slub_debug;
1317 
1318         len = strlen(name);
1319         iter = slub_debug_slabs;
1320         while (*iter) {
1321                 char *end, *glob;
1322                 size_t cmplen;
1323 
1324                 end = strchr(iter, ',');
1325                 if (!end)
1326                         end = iter + strlen(iter);
1327 
1328                 glob = strnchr(iter, end - iter, '*');
1329                 if (glob)
1330                         cmplen = glob - iter;
1331                 else
1332                         cmplen = max_t(size_t, len, (end - iter));
1333 
1334                 if (!strncmp(name, iter, cmplen)) {
1335                         flags |= slub_debug;
1336                         break;
1337                 }
1338 
1339                 if (!*end)
1340                         break;
1341                 iter = end + 1;
1342         }
1343 
1344         return flags;
1345 }
1346 #else /* !CONFIG_SLUB_DEBUG */
1347 static inline void setup_object_debug(struct kmem_cache *s,
1348                         struct page *page, void *object) {}
1349 static inline void setup_page_debug(struct kmem_cache *s,
1350                         void *addr, int order) {}
1351 
1352 static inline int alloc_debug_processing(struct kmem_cache *s,
1353         struct page *page, void *object, unsigned long addr) { return 0; }
1354 
1355 static inline int free_debug_processing(
1356         struct kmem_cache *s, struct page *page,
1357         void *head, void *tail, int bulk_cnt,
1358         unsigned long addr) { return 0; }
1359 
1360 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1361                         { return 1; }
1362 static inline int check_object(struct kmem_cache *s, struct page *page,
1363                         void *object, u8 val) { return 1; }
1364 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1365                                         struct page *page) {}
1366 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1367                                         struct page *page) {}
1368 slab_flags_t kmem_cache_flags(unsigned int object_size,
1369         slab_flags_t flags, const char *name,
1370         void (*ctor)(void *))
1371 {
1372         return flags;
1373 }
1374 #define slub_debug 0
1375 
1376 #define disable_higher_order_debug 0
1377 
1378 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1379                                                         { return 0; }
1380 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1381                                                         { return 0; }
1382 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1383                                                         int objects) {}
1384 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1385                                                         int objects) {}
1386 
1387 #endif /* CONFIG_SLUB_DEBUG */
1388 
1389 /*
1390  * Hooks for other subsystems that check memory allocations. In a typical
1391  * production configuration these hooks all should produce no code at all.
1392  */
1393 static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1394 {
1395         ptr = kasan_kmalloc_large(ptr, size, flags);
1396         /* As ptr might get tagged, call kmemleak hook after KASAN. */
1397         kmemleak_alloc(ptr, size, 1, flags);
1398         return ptr;
1399 }
1400 
1401 static __always_inline void kfree_hook(void *x)
1402 {
1403         kmemleak_free(x);
1404         kasan_kfree_large(x, _RET_IP_);
1405 }
1406 
1407 static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x)
1408 {
1409         kmemleak_free_recursive(x, s->flags);
1410 
1411         /*
1412          * Trouble is that we may no longer disable interrupts in the fast path
1413          * So in order to make the debug calls that expect irqs to be
1414          * disabled we need to disable interrupts temporarily.
1415          */
1416 #ifdef CONFIG_LOCKDEP
1417         {
1418                 unsigned long flags;
1419 
1420                 local_irq_save(flags);
1421                 debug_check_no_locks_freed(x, s->object_size);
1422                 local_irq_restore(flags);
1423         }
1424 #endif
1425         if (!(s->flags & SLAB_DEBUG_OBJECTS))
1426                 debug_check_no_obj_freed(x, s->object_size);
1427 
1428         /* KASAN might put x into memory quarantine, delaying its reuse */
1429         return kasan_slab_free(s, x, _RET_IP_);
1430 }
1431 
1432 static inline bool slab_free_freelist_hook(struct kmem_cache *s,
1433                                            void **head, void **tail)
1434 {
1435 /*
1436  * Compiler cannot detect this function can be removed if slab_free_hook()
1437  * evaluates to nothing.  Thus, catch all relevant config debug options here.
1438  */
1439 #if defined(CONFIG_LOCKDEP)     ||              \
1440         defined(CONFIG_DEBUG_KMEMLEAK) ||       \
1441         defined(CONFIG_DEBUG_OBJECTS_FREE) ||   \
1442         defined(CONFIG_KASAN)
1443 
1444         void *object;
1445         void *next = *head;
1446         void *old_tail = *tail ? *tail : *head;
1447 
1448         /* Head and tail of the reconstructed freelist */
1449         *head = NULL;
1450         *tail = NULL;
1451 
1452         do {
1453                 object = next;
1454                 next = get_freepointer(s, object);
1455                 /* If object's reuse doesn't have to be delayed */
1456                 if (!slab_free_hook(s, object)) {
1457                         /* Move object to the new freelist */
1458                         set_freepointer(s, object, *head);
1459                         *head = object;
1460                         if (!*tail)
1461                                 *tail = object;
1462                 }
1463         } while (object != old_tail);
1464 
1465         if (*head == *tail)
1466                 *tail = NULL;
1467 
1468         return *head != NULL;
1469 #else
1470         return true;
1471 #endif
1472 }
1473 
1474 static void *setup_object(struct kmem_cache *s, struct page *page,
1475                                 void *object)
1476 {
1477         setup_object_debug(s, page, object);
1478         object = kasan_init_slab_obj(s, object);
1479         if (unlikely(s->ctor)) {
1480                 kasan_unpoison_object_data(s, object);
1481                 s->ctor(object);
1482                 kasan_poison_object_data(s, object);
1483         }
1484         return object;
1485 }
1486 
1487 /*
1488  * Slab allocation and freeing
1489  */
1490 static inline struct page *alloc_slab_page(struct kmem_cache *s,
1491                 gfp_t flags, int node, struct kmem_cache_order_objects oo)
1492 {
1493         struct page *page;
1494         unsigned int order = oo_order(oo);
1495 
1496         if (node == NUMA_NO_NODE)
1497                 page = alloc_pages(flags, order);
1498         else
1499                 page = __alloc_pages_node(node, flags, order);
1500 
1501         if (page && memcg_charge_slab(page, flags, order, s)) {
1502                 __free_pages(page, order);
1503                 page = NULL;
1504         }
1505 
1506         return page;
1507 }
1508 
1509 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1510 /* Pre-initialize the random sequence cache */
1511 static int init_cache_random_seq(struct kmem_cache *s)
1512 {
1513         unsigned int count = oo_objects(s->oo);
1514         int err;
1515 
1516         /* Bailout if already initialised */
1517         if (s->random_seq)
1518                 return 0;
1519 
1520         err = cache_random_seq_create(s, count, GFP_KERNEL);
1521         if (err) {
1522                 pr_err("SLUB: Unable to initialize free list for %s\n",
1523                         s->name);
1524                 return err;
1525         }
1526 
1527         /* Transform to an offset on the set of pages */
1528         if (s->random_seq) {
1529                 unsigned int i;
1530 
1531                 for (i = 0; i < count; i++)
1532                         s->random_seq[i] *= s->size;
1533         }
1534         return 0;
1535 }
1536 
1537 /* Initialize each random sequence freelist per cache */
1538 static void __init init_freelist_randomization(void)
1539 {
1540         struct kmem_cache *s;
1541 
1542         mutex_lock(&slab_mutex);
1543 
1544         list_for_each_entry(s, &slab_caches, list)
1545                 init_cache_random_seq(s);
1546 
1547         mutex_unlock(&slab_mutex);
1548 }
1549 
1550 /* Get the next entry on the pre-computed freelist randomized */
1551 static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
1552                                 unsigned long *pos, void *start,
1553                                 unsigned long page_limit,
1554                                 unsigned long freelist_count)
1555 {
1556         unsigned int idx;
1557 
1558         /*
1559          * If the target page allocation failed, the number of objects on the
1560          * page might be smaller than the usual size defined by the cache.
1561          */
1562         do {
1563                 idx = s->random_seq[*pos];
1564                 *pos += 1;
1565                 if (*pos >= freelist_count)
1566                         *pos = 0;
1567         } while (unlikely(idx >= page_limit));
1568 
1569         return (char *)start + idx;
1570 }
1571 
1572 /* Shuffle the single linked freelist based on a random pre-computed sequence */
1573 static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1574 {
1575         void *start;
1576         void *cur;
1577         void *next;
1578         unsigned long idx, pos, page_limit, freelist_count;
1579 
1580         if (page->objects < 2 || !s->random_seq)
1581                 return false;
1582 
1583         freelist_count = oo_objects(s->oo);
1584         pos = get_random_int() % freelist_count;
1585 
1586         page_limit = page->objects * s->size;
1587         start = fixup_red_left(s, page_address(page));
1588 
1589         /* First entry is used as the base of the freelist */
1590         cur = next_freelist_entry(s, page, &pos, start, page_limit,
1591                                 freelist_count);
1592         cur = setup_object(s, page, cur);
1593         page->freelist = cur;
1594 
1595         for (idx = 1; idx < page->objects; idx++) {
1596                 next = next_freelist_entry(s, page, &pos, start, page_limit,
1597                         freelist_count);
1598                 next = setup_object(s, page, next);
1599                 set_freepointer(s, cur, next);
1600                 cur = next;
1601         }
1602         set_freepointer(s, cur, NULL);
1603 
1604         return true;
1605 }
1606 #else
1607 static inline int init_cache_random_seq(struct kmem_cache *s)
1608 {
1609         return 0;
1610 }
1611 static inline void init_freelist_randomization(void) { }
1612 static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1613 {
1614         return false;
1615 }
1616 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1617 
1618 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1619 {
1620         struct page *page;
1621         struct kmem_cache_order_objects oo = s->oo;
1622         gfp_t alloc_gfp;
1623         void *start, *p, *next;
1624         int idx, order;
1625         bool shuffle;
1626 
1627         flags &= gfp_allowed_mask;
1628 
1629         if (gfpflags_allow_blocking(flags))
1630                 local_irq_enable();
1631 
1632         flags |= s->allocflags;
1633 
1634         /*
1635          * Let the initial higher-order allocation fail under memory pressure
1636          * so we fall-back to the minimum order allocation.
1637          */
1638         alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1639         if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1640                 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
1641 
1642         page = alloc_slab_page(s, alloc_gfp, node, oo);
1643         if (unlikely(!page)) {
1644                 oo = s->min;
1645                 alloc_gfp = flags;
1646                 /*
1647                  * Allocation may have failed due to fragmentation.
1648                  * Try a lower order alloc if possible
1649                  */
1650                 page = alloc_slab_page(s, alloc_gfp, node, oo);
1651                 if (unlikely(!page))
1652                         goto out;
1653                 stat(s, ORDER_FALLBACK);
1654         }
1655 
1656         page->objects = oo_objects(oo);
1657 
1658         order = compound_order(page);
1659         page->slab_cache = s;
1660         __SetPageSlab(page);
1661         if (page_is_pfmemalloc(page))
1662                 SetPageSlabPfmemalloc(page);
1663 
1664         kasan_poison_slab(page);
1665 
1666         start = page_address(page);
1667 
1668         setup_page_debug(s, start, order);
1669 
1670         shuffle = shuffle_freelist(s, page);
1671 
1672         if (!shuffle) {
1673                 start = fixup_red_left(s, start);
1674                 start = setup_object(s, page, start);
1675                 page->freelist = start;
1676                 for (idx = 0, p = start; idx < page->objects - 1; idx++) {
1677                         next = p + s->size;
1678                         next = setup_object(s, page, next);
1679                         set_freepointer(s, p, next);
1680                         p = next;
1681                 }
1682                 set_freepointer(s, p, NULL);
1683         }
1684 
1685         page->inuse = page->objects;
1686         page->frozen = 1;
1687 
1688 out:
1689         if (gfpflags_allow_blocking(flags))
1690                 local_irq_disable();
1691         if (!page)
1692                 return NULL;
1693 
1694         mod_lruvec_page_state(page,
1695                 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1696                 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1697                 1 << oo_order(oo));
1698 
1699         inc_slabs_node(s, page_to_nid(page), page->objects);
1700 
1701         return page;
1702 }
1703 
1704 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1705 {
1706         if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
1707                 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
1708                 flags &= ~GFP_SLAB_BUG_MASK;
1709                 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
1710                                 invalid_mask, &invalid_mask, flags, &flags);
1711                 dump_stack();
1712         }
1713 
1714         return allocate_slab(s,
1715                 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1716 }
1717 
1718 static void __free_slab(struct kmem_cache *s, struct page *page)
1719 {
1720         int order = compound_order(page);
1721         int pages = 1 << order;
1722 
1723         if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1724                 void *p;
1725 
1726                 slab_pad_check(s, page);
1727                 for_each_object(p, s, page_address(page),
1728                                                 page->objects)
1729                         check_object(s, page, p, SLUB_RED_INACTIVE);
1730         }
1731 
1732         mod_lruvec_page_state(page,
1733                 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1734                 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1735                 -pages);
1736 
1737         __ClearPageSlabPfmemalloc(page);
1738         __ClearPageSlab(page);
1739 
1740         page->mapping = NULL;
1741         if (current->reclaim_state)
1742                 current->reclaim_state->reclaimed_slab += pages;
1743         memcg_uncharge_slab(page, order, s);
1744         __free_pages(page, order);
1745 }
1746 
1747 static void rcu_free_slab(struct rcu_head *h)
1748 {
1749         struct page *page = container_of(h, struct page, rcu_head);
1750 
1751         __free_slab(page->slab_cache, page);
1752 }
1753 
1754 static void free_slab(struct kmem_cache *s, struct page *page)
1755 {
1756         if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
1757                 call_rcu(&page->rcu_head, rcu_free_slab);
1758         } else
1759                 __free_slab(s, page);
1760 }
1761 
1762 static void discard_slab(struct kmem_cache *s, struct page *page)
1763 {
1764         dec_slabs_node(s, page_to_nid(page), page->objects);
1765         free_slab(s, page);
1766 }
1767 
1768 /*
1769  * Management of partially allocated slabs.
1770  */
1771 static inline void
1772 __add_partial(struct kmem_cache_node *n, struct page *page, int tail)
1773 {
1774         n->nr_partial++;
1775         if (tail == DEACTIVATE_TO_TAIL)
1776                 list_add_tail(&page->lru, &n->partial);
1777         else
1778                 list_add(&page->lru, &n->partial);
1779 }
1780 
1781 static inline void add_partial(struct kmem_cache_node *n,
1782                                 struct page *page, int tail)
1783 {
1784         lockdep_assert_held(&n->list_lock);
1785         __add_partial(n, page, tail);
1786 }
1787 
1788 static inline void remove_partial(struct kmem_cache_node *n,
1789                                         struct page *page)
1790 {
1791         lockdep_assert_held(&n->list_lock);
1792         list_del(&page->lru);
1793         n->nr_partial--;
1794 }
1795 
1796 /*
1797  * Remove slab from the partial list, freeze it and
1798  * return the pointer to the freelist.
1799  *
1800  * Returns a list of objects or NULL if it fails.
1801  */
1802 static inline void *acquire_slab(struct kmem_cache *s,
1803                 struct kmem_cache_node *n, struct page *page,
1804                 int mode, int *objects)
1805 {
1806         void *freelist;
1807         unsigned long counters;
1808         struct page new;
1809 
1810         lockdep_assert_held(&n->list_lock);
1811 
1812         /*
1813          * Zap the freelist and set the frozen bit.
1814          * The old freelist is the list of objects for the
1815          * per cpu allocation list.
1816          */
1817         freelist = page->freelist;
1818         counters = page->counters;
1819         new.counters = counters;
1820         *objects = new.objects - new.inuse;
1821         if (mode) {
1822                 new.inuse = page->objects;
1823                 new.freelist = NULL;
1824         } else {
1825                 new.freelist = freelist;
1826         }
1827 
1828         VM_BUG_ON(new.frozen);
1829         new.frozen = 1;
1830 
1831         if (!__cmpxchg_double_slab(s, page,
1832                         freelist, counters,
1833                         new.freelist, new.counters,
1834                         "acquire_slab"))
1835                 return NULL;
1836 
1837         remove_partial(n, page);
1838         WARN_ON(!freelist);
1839         return freelist;
1840 }
1841 
1842 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1843 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1844 
1845 /*
1846  * Try to allocate a partial slab from a specific node.
1847  */
1848 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1849                                 struct kmem_cache_cpu *c, gfp_t flags)
1850 {
1851         struct page *page, *page2;
1852         void *object = NULL;
1853         unsigned int available = 0;
1854         int objects;
1855 
1856         /*
1857          * Racy check. If we mistakenly see no partial slabs then we
1858          * just allocate an empty slab. If we mistakenly try to get a
1859          * partial slab and there is none available then get_partials()
1860          * will return NULL.
1861          */
1862         if (!n || !n->nr_partial)
1863                 return NULL;
1864 
1865         spin_lock(&n->list_lock);
1866         list_for_each_entry_safe(page, page2, &n->partial, lru) {
1867                 void *t;
1868 
1869                 if (!pfmemalloc_match(page, flags))
1870                         continue;
1871 
1872                 t = acquire_slab(s, n, page, object == NULL, &objects);
1873                 if (!t)
1874                         break;
1875 
1876                 available += objects;
1877                 if (!object) {
1878                         c->page = page;
1879                         stat(s, ALLOC_FROM_PARTIAL);
1880                         object = t;
1881                 } else {
1882                         put_cpu_partial(s, page, 0);
1883                         stat(s, CPU_PARTIAL_NODE);
1884                 }
1885                 if (!kmem_cache_has_cpu_partial(s)
1886                         || available > slub_cpu_partial(s) / 2)
1887                         break;
1888 
1889         }
1890         spin_unlock(&n->list_lock);
1891         return object;
1892 }
1893 
1894 /*
1895  * Get a page from somewhere. Search in increasing NUMA distances.
1896  */
1897 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1898                 struct kmem_cache_cpu *c)
1899 {
1900 #ifdef CONFIG_NUMA
1901         struct zonelist *zonelist;
1902         struct zoneref *z;
1903         struct zone *zone;
1904         enum zone_type high_zoneidx = gfp_zone(flags);
1905         void *object;
1906         unsigned int cpuset_mems_cookie;
1907 
1908         /*
1909          * The defrag ratio allows a configuration of the tradeoffs between
1910          * inter node defragmentation and node local allocations. A lower
1911          * defrag_ratio increases the tendency to do local allocations
1912          * instead of attempting to obtain partial slabs from other nodes.
1913          *
1914          * If the defrag_ratio is set to 0 then kmalloc() always
1915          * returns node local objects. If the ratio is higher then kmalloc()
1916          * may return off node objects because partial slabs are obtained
1917          * from other nodes and filled up.
1918          *
1919          * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
1920          * (which makes defrag_ratio = 1000) then every (well almost)
1921          * allocation will first attempt to defrag slab caches on other nodes.
1922          * This means scanning over all nodes to look for partial slabs which
1923          * may be expensive if we do it every time we are trying to find a slab
1924          * with available objects.
1925          */
1926         if (!s->remote_node_defrag_ratio ||
1927                         get_cycles() % 1024 > s->remote_node_defrag_ratio)
1928                 return NULL;
1929 
1930         do {
1931                 cpuset_mems_cookie = read_mems_allowed_begin();
1932                 zonelist = node_zonelist(mempolicy_slab_node(), flags);
1933                 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1934                         struct kmem_cache_node *n;
1935 
1936                         n = get_node(s, zone_to_nid(zone));
1937 
1938                         if (n && cpuset_zone_allowed(zone, flags) &&
1939                                         n->nr_partial > s->min_partial) {
1940                                 object = get_partial_node(s, n, c, flags);
1941                                 if (object) {
1942                                         /*
1943                                          * Don't check read_mems_allowed_retry()
1944                                          * here - if mems_allowed was updated in
1945                                          * parallel, that was a harmless race
1946                                          * between allocation and the cpuset
1947                                          * update
1948                                          */
1949                                         return object;
1950                                 }
1951                         }
1952                 }
1953         } while (read_mems_allowed_retry(cpuset_mems_cookie));
1954 #endif
1955         return NULL;
1956 }
1957 
1958 /*
1959  * Get a partial page, lock it and return it.
1960  */
1961 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1962                 struct kmem_cache_cpu *c)
1963 {
1964         void *object;
1965         int searchnode = node;
1966 
1967         if (node == NUMA_NO_NODE)
1968                 searchnode = numa_mem_id();
1969         else if (!node_present_pages(node))
1970                 searchnode = node_to_mem_node(node);
1971 
1972         object = get_partial_node(s, get_node(s, searchnode), c, flags);
1973         if (object || node != NUMA_NO_NODE)
1974                 return object;
1975 
1976         return get_any_partial(s, flags, c);
1977 }
1978 
1979 #ifdef CONFIG_PREEMPT
1980 /*
1981  * Calculate the next globally unique transaction for disambiguiation
1982  * during cmpxchg. The transactions start with the cpu number and are then
1983  * incremented by CONFIG_NR_CPUS.
1984  */
1985 #define TID_STEP  roundup_pow_of_two(CONFIG_NR_CPUS)
1986 #else
1987 /*
1988  * No preemption supported therefore also no need to check for
1989  * different cpus.
1990  */
1991 #define TID_STEP 1
1992 #endif
1993 
1994 static inline unsigned long next_tid(unsigned long tid)
1995 {
1996         return tid + TID_STEP;
1997 }
1998 
1999 static inline unsigned int tid_to_cpu(unsigned long tid)
2000 {
2001         return tid % TID_STEP;
2002 }
2003 
2004 static inline unsigned long tid_to_event(unsigned long tid)
2005 {
2006         return tid / TID_STEP;
2007 }
2008 
2009 static inline unsigned int init_tid(int cpu)
2010 {
2011         return cpu;
2012 }
2013 
2014 static inline void note_cmpxchg_failure(const char *n,
2015                 const struct kmem_cache *s, unsigned long tid)
2016 {
2017 #ifdef SLUB_DEBUG_CMPXCHG
2018         unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
2019 
2020         pr_info("%s %s: cmpxchg redo ", n, s->name);
2021 
2022 #ifdef CONFIG_PREEMPT
2023         if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
2024                 pr_warn("due to cpu change %d -> %d\n",
2025                         tid_to_cpu(tid), tid_to_cpu(actual_tid));
2026         else
2027 #endif
2028         if (tid_to_event(tid) != tid_to_event(actual_tid))
2029                 pr_warn("due to cpu running other code. Event %ld->%ld\n",
2030                         tid_to_event(tid), tid_to_event(actual_tid));
2031         else
2032                 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2033                         actual_tid, tid, next_tid(tid));
2034 #endif
2035         stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2036 }
2037 
2038 static void init_kmem_cache_cpus(struct kmem_cache *s)
2039 {
2040         int cpu;
2041 
2042         for_each_possible_cpu(cpu)
2043                 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
2044 }
2045 
2046 /*
2047  * Remove the cpu slab
2048  */
2049 static void deactivate_slab(struct kmem_cache *s, struct page *page,
2050                                 void *freelist, struct kmem_cache_cpu *c)
2051 {
2052         enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
2053         struct kmem_cache_node *n = get_node(s, page_to_nid(page));
2054         int lock = 0;
2055         enum slab_modes l = M_NONE, m = M_NONE;
2056         void *nextfree;
2057         int tail = DEACTIVATE_TO_HEAD;
2058         struct page new;
2059         struct page old;
2060 
2061         if (page->freelist) {
2062                 stat(s, DEACTIVATE_REMOTE_FREES);
2063                 tail = DEACTIVATE_TO_TAIL;
2064         }
2065 
2066         /*
2067          * Stage one: Free all available per cpu objects back
2068          * to the page freelist while it is still frozen. Leave the
2069          * last one.
2070          *
2071          * There is no need to take the list->lock because the page
2072          * is still frozen.
2073          */
2074         while (freelist && (nextfree = get_freepointer(s, freelist))) {
2075                 void *prior;
2076                 unsigned long counters;
2077 
2078                 do {
2079                         prior = page->freelist;
2080                         counters = page->counters;
2081                         set_freepointer(s, freelist, prior);
2082                         new.counters = counters;
2083                         new.inuse--;
2084                         VM_BUG_ON(!new.frozen);
2085 
2086                 } while (!__cmpxchg_double_slab(s, page,
2087                         prior, counters,
2088                         freelist, new.counters,
2089                         "drain percpu freelist"));
2090 
2091                 freelist = nextfree;
2092         }
2093 
2094         /*
2095          * Stage two: Ensure that the page is unfrozen while the
2096          * list presence reflects the actual number of objects
2097          * during unfreeze.
2098          *
2099          * We setup the list membership and then perform a cmpxchg
2100          * with the count. If there is a mismatch then the page
2101          * is not unfrozen but the page is on the wrong list.
2102          *
2103          * Then we restart the process which may have to remove
2104          * the page from the list that we just put it on again
2105          * because the number of objects in the slab may have
2106          * changed.
2107          */
2108 redo:
2109 
2110         old.freelist = page->freelist;
2111         old.counters = page->counters;
2112         VM_BUG_ON(!old.frozen);
2113 
2114         /* Determine target state of the slab */
2115         new.counters = old.counters;
2116         if (freelist) {
2117                 new.inuse--;
2118                 set_freepointer(s, freelist, old.freelist);
2119                 new.freelist = freelist;
2120         } else
2121                 new.freelist = old.freelist;
2122 
2123         new.frozen = 0;
2124 
2125         if (!new.inuse && n->nr_partial >= s->min_partial)
2126                 m = M_FREE;
2127         else if (new.freelist) {
2128                 m = M_PARTIAL;
2129                 if (!lock) {
2130                         lock = 1;
2131                         /*
2132                          * Taking the spinlock removes the possibility
2133                          * that acquire_slab() will see a slab page that
2134                          * is frozen
2135                          */
2136                         spin_lock(&n->list_lock);
2137                 }
2138         } else {
2139                 m = M_FULL;
2140                 if (kmem_cache_debug(s) && !lock) {
2141                         lock = 1;
2142                         /*
2143                          * This also ensures that the scanning of full
2144                          * slabs from diagnostic functions will not see
2145                          * any frozen slabs.
2146                          */
2147                         spin_lock(&n->list_lock);
2148                 }
2149         }
2150 
2151         if (l != m) {
2152                 if (l == M_PARTIAL)
2153                         remove_partial(n, page);
2154                 else if (l == M_FULL)
2155                         remove_full(s, n, page);
2156 
2157                 if (m == M_PARTIAL)
2158                         add_partial(n, page, tail);
2159                 else if (m == M_FULL)
2160                         add_full(s, n, page);
2161         }
2162 
2163         l = m;
2164         if (!__cmpxchg_double_slab(s, page,
2165                                 old.freelist, old.counters,
2166                                 new.freelist, new.counters,
2167                                 "unfreezing slab"))
2168                 goto redo;
2169 
2170         if (lock)
2171                 spin_unlock(&n->list_lock);
2172 
2173         if (m == M_PARTIAL)
2174                 stat(s, tail);
2175         else if (m == M_FULL)
2176                 stat(s, DEACTIVATE_FULL);
2177         else if (m == M_FREE) {
2178                 stat(s, DEACTIVATE_EMPTY);
2179                 discard_slab(s, page);
2180                 stat(s, FREE_SLAB);
2181         }
2182 
2183         c->page = NULL;
2184         c->freelist = NULL;
2185 }
2186 
2187 /*
2188  * Unfreeze all the cpu partial slabs.
2189  *
2190  * This function must be called with interrupts disabled
2191  * for the cpu using c (or some other guarantee must be there
2192  * to guarantee no concurrent accesses).
2193  */
2194 static void unfreeze_partials(struct kmem_cache *s,
2195                 struct kmem_cache_cpu *c)
2196 {
2197 #ifdef CONFIG_SLUB_CPU_PARTIAL
2198         struct kmem_cache_node *n = NULL, *n2 = NULL;
2199         struct page *page, *discard_page = NULL;
2200 
2201         while ((page = c->partial)) {
2202                 struct page new;
2203                 struct page old;
2204 
2205                 c->partial = page->next;
2206 
2207                 n2 = get_node(s, page_to_nid(page));
2208                 if (n != n2) {
2209                         if (n)
2210                                 spin_unlock(&n->list_lock);
2211 
2212                         n = n2;
2213                         spin_lock(&n->list_lock);
2214                 }
2215 
2216                 do {
2217 
2218                         old.freelist = page->freelist;
2219                         old.counters = page->counters;
2220                         VM_BUG_ON(!old.frozen);
2221 
2222                         new.counters = old.counters;
2223                         new.freelist = old.freelist;
2224 
2225                         new.frozen = 0;
2226 
2227                 } while (!__cmpxchg_double_slab(s, page,
2228                                 old.freelist, old.counters,
2229                                 new.freelist, new.counters,
2230                                 "unfreezing slab"));
2231 
2232                 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2233                         page->next = discard_page;
2234                         discard_page = page;
2235                 } else {
2236                         add_partial(n, page, DEACTIVATE_TO_TAIL);
2237                         stat(s, FREE_ADD_PARTIAL);
2238                 }
2239         }
2240 
2241         if (n)
2242                 spin_unlock(&n->list_lock);
2243 
2244         while (discard_page) {
2245                 page = discard_page;
2246                 discard_page = discard_page->next;
2247 
2248                 stat(s, DEACTIVATE_EMPTY);
2249                 discard_slab(s, page);
2250                 stat(s, FREE_SLAB);
2251         }
2252 #endif
2253 }
2254 
2255 /*
2256  * Put a page that was just frozen (in __slab_free|get_partial_node) into a
2257  * partial page slot if available.
2258  *
2259  * If we did not find a slot then simply move all the partials to the
2260  * per node partial list.
2261  */
2262 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
2263 {
2264 #ifdef CONFIG_SLUB_CPU_PARTIAL
2265         struct page *oldpage;
2266         int pages;
2267         int pobjects;
2268 
2269         preempt_disable();
2270         do {
2271                 pages = 0;
2272                 pobjects = 0;
2273                 oldpage = this_cpu_read(s->cpu_slab->partial);
2274 
2275                 if (oldpage) {
2276                         pobjects = oldpage->pobjects;
2277                         pages = oldpage->pages;
2278                         if (drain && pobjects > s->cpu_partial) {
2279                                 unsigned long flags;
2280                                 /*
2281                                  * partial array is full. Move the existing
2282                                  * set to the per node partial list.
2283                                  */
2284                                 local_irq_save(flags);
2285                                 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2286                                 local_irq_restore(flags);
2287                                 oldpage = NULL;
2288                                 pobjects = 0;
2289                                 pages = 0;
2290                                 stat(s, CPU_PARTIAL_DRAIN);
2291                         }
2292                 }
2293 
2294                 pages++;
2295                 pobjects += page->objects - page->inuse;
2296 
2297                 page->pages = pages;
2298                 page->pobjects = pobjects;
2299                 page->next = oldpage;
2300 
2301         } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2302                                                                 != oldpage);
2303         if (unlikely(!s->cpu_partial)) {
2304                 unsigned long flags;
2305 
2306                 local_irq_save(flags);
2307                 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2308                 local_irq_restore(flags);
2309         }
2310         preempt_enable();
2311 #endif
2312 }
2313 
2314 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2315 {
2316         stat(s, CPUSLAB_FLUSH);
2317         deactivate_slab(s, c->page, c->freelist, c);
2318 
2319         c->tid = next_tid(c->tid);
2320 }
2321 
2322 /*
2323  * Flush cpu slab.
2324  *
2325  * Called from IPI handler with interrupts disabled.
2326  */
2327 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2328 {
2329         struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2330 
2331         if (c->page)
2332                 flush_slab(s, c);
2333 
2334         unfreeze_partials(s, c);
2335 }
2336 
2337 static void flush_cpu_slab(void *d)
2338 {
2339         struct kmem_cache *s = d;
2340 
2341         __flush_cpu_slab(s, smp_processor_id());
2342 }
2343 
2344 static bool has_cpu_slab(int cpu, void *info)
2345 {
2346         struct kmem_cache *s = info;
2347         struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2348 
2349         return c->page || slub_percpu_partial(c);
2350 }
2351 
2352 static void flush_all(struct kmem_cache *s)
2353 {
2354         on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2355 }
2356 
2357 /*
2358  * Use the cpu notifier to insure that the cpu slabs are flushed when
2359  * necessary.
2360  */
2361 static int slub_cpu_dead(unsigned int cpu)
2362 {
2363         struct kmem_cache *s;
2364         unsigned long flags;
2365 
2366         mutex_lock(&slab_mutex);
2367         list_for_each_entry(s, &slab_caches, list) {
2368                 local_irq_save(flags);
2369                 __flush_cpu_slab(s, cpu);
2370                 local_irq_restore(flags);
2371         }
2372         mutex_unlock(&slab_mutex);
2373         return 0;
2374 }
2375 
2376 /*
2377  * Check if the objects in a per cpu structure fit numa
2378  * locality expectations.
2379  */
2380 static inline int node_match(struct page *page, int node)
2381 {
2382 #ifdef CONFIG_NUMA
2383         if (node != NUMA_NO_NODE && page_to_nid(page) != node)
2384                 return 0;
2385 #endif
2386         return 1;
2387 }
2388 
2389 #ifdef CONFIG_SLUB_DEBUG
2390 static int count_free(struct page *page)
2391 {
2392         return page->objects - page->inuse;
2393 }
2394 
2395 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2396 {
2397         return atomic_long_read(&n->total_objects);
2398 }
2399 #endif /* CONFIG_SLUB_DEBUG */
2400 
2401 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2402 static unsigned long count_partial(struct kmem_cache_node *n,
2403                                         int (*get_count)(struct page *))
2404 {
2405         unsigned long flags;
2406         unsigned long x = 0;
2407         struct page *page;
2408 
2409         spin_lock_irqsave(&n->list_lock, flags);
2410         list_for_each_entry(page, &n->partial, lru)
2411                 x += get_count(page);
2412         spin_unlock_irqrestore(&n->list_lock, flags);
2413         return x;
2414 }
2415 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2416 
2417 static noinline void
2418 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2419 {
2420 #ifdef CONFIG_SLUB_DEBUG
2421         static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2422                                       DEFAULT_RATELIMIT_BURST);
2423         int node;
2424         struct kmem_cache_node *n;
2425 
2426         if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2427                 return;
2428 
2429         pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2430                 nid, gfpflags, &gfpflags);
2431         pr_warn("  cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
2432                 s->name, s->object_size, s->size, oo_order(s->oo),
2433                 oo_order(s->min));
2434 
2435         if (oo_order(s->min) > get_order(s->object_size))
2436                 pr_warn("  %s debugging increased min order, use slub_debug=O to disable.\n",
2437                         s->name);
2438 
2439         for_each_kmem_cache_node(s, node, n) {
2440                 unsigned long nr_slabs;
2441                 unsigned long nr_objs;
2442                 unsigned long nr_free;
2443 
2444                 nr_free  = count_partial(n, count_free);
2445                 nr_slabs = node_nr_slabs(n);
2446                 nr_objs  = node_nr_objs(n);
2447 
2448                 pr_warn("  node %d: slabs: %ld, objs: %ld, free: %ld\n",
2449                         node, nr_slabs, nr_objs, nr_free);
2450         }
2451 #endif
2452 }
2453 
2454 static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2455                         int node, struct kmem_cache_cpu **pc)
2456 {
2457         void *freelist;
2458         struct kmem_cache_cpu *c = *pc;
2459         struct page *page;
2460 
2461         WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
2462 
2463         freelist = get_partial(s, flags, node, c);
2464 
2465         if (freelist)
2466                 return freelist;
2467 
2468         page = new_slab(s, flags, node);
2469         if (page) {
2470                 c = raw_cpu_ptr(s->cpu_slab);
2471                 if (c->page)
2472                         flush_slab(s, c);
2473 
2474                 /*
2475                  * No other reference to the page yet so we can
2476                  * muck around with it freely without cmpxchg
2477                  */
2478                 freelist = page->freelist;
2479                 page->freelist = NULL;
2480 
2481                 stat(s, ALLOC_SLAB);
2482                 c->page = page;
2483                 *pc = c;
2484         }
2485 
2486         return freelist;
2487 }
2488 
2489 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2490 {
2491         if (unlikely(PageSlabPfmemalloc(page)))
2492                 return gfp_pfmemalloc_allowed(gfpflags);
2493 
2494         return true;
2495 }
2496 
2497 /*
2498  * Check the page->freelist of a page and either transfer the freelist to the
2499  * per cpu freelist or deactivate the page.
2500  *
2501  * The page is still frozen if the return value is not NULL.
2502  *
2503  * If this function returns NULL then the page has been unfrozen.
2504  *
2505  * This function must be called with interrupt disabled.
2506  */
2507 static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2508 {
2509         struct page new;
2510         unsigned long counters;
2511         void *freelist;
2512 
2513         do {
2514                 freelist = page->freelist;
2515                 counters = page->counters;
2516 
2517                 new.counters = counters;
2518                 VM_BUG_ON(!new.frozen);
2519 
2520                 new.inuse = page->objects;
2521                 new.frozen = freelist != NULL;
2522 
2523         } while (!__cmpxchg_double_slab(s, page,
2524                 freelist, counters,
2525                 NULL, new.counters,
2526                 "get_freelist"));
2527 
2528         return freelist;
2529 }
2530 
2531 /*
2532  * Slow path. The lockless freelist is empty or we need to perform
2533  * debugging duties.
2534  *
2535  * Processing is still very fast if new objects have been freed to the
2536  * regular freelist. In that case we simply take over the regular freelist
2537  * as the lockless freelist and zap the regular freelist.
2538  *
2539  * If that is not working then we fall back to the partial lists. We take the
2540  * first element of the freelist as the object to allocate now and move the
2541  * rest of the freelist to the lockless freelist.
2542  *
2543  * And if we were unable to get a new slab from the partial slab lists then
2544  * we need to allocate a new slab. This is the slowest path since it involves
2545  * a call to the page allocator and the setup of a new slab.
2546  *
2547  * Version of __slab_alloc to use when we know that interrupts are
2548  * already disabled (which is the case for bulk allocation).
2549  */
2550 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2551                           unsigned long addr, struct kmem_cache_cpu *c)
2552 {
2553         void *freelist;
2554         struct page *page;
2555 
2556         page = c->page;
2557         if (!page)
2558                 goto new_slab;
2559 redo:
2560 
2561         if (unlikely(!node_match(page, node))) {
2562                 int searchnode = node;
2563 
2564                 if (node != NUMA_NO_NODE && !node_present_pages(node))
2565                         searchnode = node_to_mem_node(node);
2566 
2567                 if (unlikely(!node_match(page, searchnode))) {
2568                         stat(s, ALLOC_NODE_MISMATCH);
2569                         deactivate_slab(s, page, c->freelist, c);
2570                         goto new_slab;
2571                 }
2572         }
2573 
2574         /*
2575          * By rights, we should be searching for a slab page that was
2576          * PFMEMALLOC but right now, we are losing the pfmemalloc
2577          * information when the page leaves the per-cpu allocator
2578          */
2579         if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2580                 deactivate_slab(s, page, c->freelist, c);
2581                 goto new_slab;
2582         }
2583 
2584         /* must check again c->freelist in case of cpu migration or IRQ */
2585         freelist = c->freelist;
2586         if (freelist)
2587                 goto load_freelist;
2588 
2589         freelist = get_freelist(s, page);
2590 
2591         if (!freelist) {
2592                 c->page = NULL;
2593                 stat(s, DEACTIVATE_BYPASS);
2594                 goto new_slab;
2595         }
2596 
2597         stat(s, ALLOC_REFILL);
2598 
2599 load_freelist:
2600         /*
2601          * freelist is pointing to the list of objects to be used.
2602          * page is pointing to the page from which the objects are obtained.
2603          * That page must be frozen for per cpu allocations to work.
2604          */
2605         VM_BUG_ON(!c->page->frozen);
2606         c->freelist = get_freepointer(s, freelist);
2607         c->tid = next_tid(c->tid);
2608         return freelist;
2609 
2610 new_slab:
2611 
2612         if (slub_percpu_partial(c)) {
2613                 page = c->page = slub_percpu_partial(c);
2614                 slub_set_percpu_partial(c, page);
2615                 stat(s, CPU_PARTIAL_ALLOC);
2616                 goto redo;
2617         }
2618 
2619         freelist = new_slab_objects(s, gfpflags, node, &c);
2620 
2621         if (unlikely(!freelist)) {
2622                 slab_out_of_memory(s, gfpflags, node);
2623                 return NULL;
2624         }
2625 
2626         page = c->page;
2627         if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2628                 goto load_freelist;
2629 
2630         /* Only entered in the debug case */
2631         if (kmem_cache_debug(s) &&
2632                         !alloc_debug_processing(s, page, freelist, addr))
2633                 goto new_slab;  /* Slab failed checks. Next slab needed */
2634 
2635         deactivate_slab(s, page, get_freepointer(s, freelist), c);
2636         return freelist;
2637 }
2638 
2639 /*
2640  * Another one that disabled interrupt and compensates for possible
2641  * cpu changes by refetching the per cpu area pointer.
2642  */
2643 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2644                           unsigned long addr, struct kmem_cache_cpu *c)
2645 {
2646         void *p;
2647         unsigned long flags;
2648 
2649         local_irq_save(flags);
2650 #ifdef CONFIG_PREEMPT
2651         /*
2652          * We may have been preempted and rescheduled on a different
2653          * cpu before disabling interrupts. Need to reload cpu area
2654          * pointer.
2655          */
2656         c = this_cpu_ptr(s->cpu_slab);
2657 #endif
2658 
2659         p = ___slab_alloc(s, gfpflags, node, addr, c);
2660         local_irq_restore(flags);
2661         return p;
2662 }
2663 
2664 /*
2665  * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2666  * have the fastpath folded into their functions. So no function call
2667  * overhead for requests that can be satisfied on the fastpath.
2668  *
2669  * The fastpath works by first checking if the lockless freelist can be used.
2670  * If not then __slab_alloc is called for slow processing.
2671  *
2672  * Otherwise we can simply pick the next object from the lockless free list.
2673  */
2674 static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2675                 gfp_t gfpflags, int node, unsigned long addr)
2676 {
2677         void *object;
2678         struct kmem_cache_cpu *c;
2679         struct page *page;
2680         unsigned long tid;
2681 
2682         s = slab_pre_alloc_hook(s, gfpflags);
2683         if (!s)
2684                 return NULL;
2685 redo:
2686         /*
2687          * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2688          * enabled. We may switch back and forth between cpus while
2689          * reading from one cpu area. That does not matter as long
2690          * as we end up on the original cpu again when doing the cmpxchg.
2691          *
2692          * We should guarantee that tid and kmem_cache are retrieved on
2693          * the same cpu. It could be different if CONFIG_PREEMPT so we need
2694          * to check if it is matched or not.
2695          */
2696         do {
2697                 tid = this_cpu_read(s->cpu_slab->tid);
2698                 c = raw_cpu_ptr(s->cpu_slab);
2699         } while (IS_ENABLED(CONFIG_PREEMPT) &&
2700                  unlikely(tid != READ_ONCE(c->tid)));
2701 
2702         /*
2703          * Irqless object alloc/free algorithm used here depends on sequence
2704          * of fetching cpu_slab's data. tid should be fetched before anything
2705          * on c to guarantee that object and page associated with previous tid
2706          * won't be used with current tid. If we fetch tid first, object and
2707          * page could be one associated with next tid and our alloc/free
2708          * request will be failed. In this case, we will retry. So, no problem.
2709          */
2710         barrier();
2711 
2712         /*
2713          * The transaction ids are globally unique per cpu and per operation on
2714          * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2715          * occurs on the right processor and that there was no operation on the
2716          * linked list in between.
2717          */
2718 
2719         object = c->freelist;
2720         page = c->page;
2721         if (unlikely(!object || !node_match(page, node))) {
2722                 object = __slab_alloc(s, gfpflags, node, addr, c);
2723                 stat(s, ALLOC_SLOWPATH);
2724         } else {
2725                 void *next_object = get_freepointer_safe(s, object);
2726 
2727                 /*
2728                  * The cmpxchg will only match if there was no additional
2729                  * operation and if we are on the right processor.
2730                  *
2731                  * The cmpxchg does the following atomically (without lock
2732                  * semantics!)
2733                  * 1. Relocate first pointer to the current per cpu area.
2734                  * 2. Verify that tid and freelist have not been changed
2735                  * 3. If they were not changed replace tid and freelist
2736                  *
2737                  * Since this is without lock semantics the protection is only
2738                  * against code executing on this cpu *not* from access by
2739                  * other cpus.
2740                  */
2741                 if (unlikely(!this_cpu_cmpxchg_double(
2742                                 s->cpu_slab->freelist, s->cpu_slab->tid,
2743                                 object, tid,
2744                                 next_object, next_tid(tid)))) {
2745 
2746                         note_cmpxchg_failure("slab_alloc", s, tid);
2747                         goto redo;
2748                 }
2749                 prefetch_freepointer(s, next_object);
2750                 stat(s, ALLOC_FASTPATH);
2751         }
2752 
2753         if (unlikely(gfpflags & __GFP_ZERO) && object)
2754                 memset(object, 0, s->object_size);
2755 
2756         slab_post_alloc_hook(s, gfpflags, 1, &object);
2757 
2758         return object;
2759 }
2760 
2761 static __always_inline void *slab_alloc(struct kmem_cache *s,
2762                 gfp_t gfpflags, unsigned long addr)
2763 {
2764         return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2765 }
2766 
2767 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2768 {
2769         void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2770 
2771         trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2772                                 s->size, gfpflags);
2773 
2774         return ret;
2775 }
2776 EXPORT_SYMBOL(kmem_cache_alloc);
2777 
2778 #ifdef CONFIG_TRACING
2779 void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2780 {
2781         void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2782         trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2783         ret = kasan_kmalloc(s, ret, size, gfpflags);
2784         return ret;
2785 }
2786 EXPORT_SYMBOL(kmem_cache_alloc_trace);
2787 #endif
2788 
2789 #ifdef CONFIG_NUMA
2790 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2791 {
2792         void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2793 
2794         trace_kmem_cache_alloc_node(_RET_IP_, ret,
2795                                     s->object_size, s->size, gfpflags, node);
2796 
2797         return ret;
2798 }
2799 EXPORT_SYMBOL(kmem_cache_alloc_node);
2800 
2801 #ifdef CONFIG_TRACING
2802 void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2803                                     gfp_t gfpflags,
2804                                     int node, size_t size)
2805 {
2806         void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2807 
2808         trace_kmalloc_node(_RET_IP_, ret,
2809                            size, s->size, gfpflags, node);
2810 
2811         ret = kasan_kmalloc(s, ret, size, gfpflags);
2812         return ret;
2813 }
2814 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2815 #endif
2816 #endif
2817 
2818 /*
2819  * Slow path handling. This may still be called frequently since objects
2820  * have a longer lifetime than the cpu slabs in most processing loads.
2821  *
2822  * So we still attempt to reduce cache line usage. Just take the slab
2823  * lock and free the item. If there is no additional partial page
2824  * handling required then we can return immediately.
2825  */
2826 static void __slab_free(struct kmem_cache *s, struct page *page,
2827                         void *head, void *tail, int cnt,
2828                         unsigned long addr)
2829 
2830 {
2831         void *prior;
2832         int was_frozen;
2833         struct page new;
2834         unsigned long counters;
2835         struct kmem_cache_node *n = NULL;
2836         unsigned long uninitialized_var(flags);
2837 
2838         stat(s, FREE_SLOWPATH);
2839 
2840         if (kmem_cache_debug(s) &&
2841             !free_debug_processing(s, page, head, tail, cnt, addr))
2842                 return;
2843 
2844         do {
2845                 if (unlikely(n)) {
2846                         spin_unlock_irqrestore(&n->list_lock, flags);
2847                         n = NULL;
2848                 }
2849                 prior = page->freelist;
2850                 counters = page->counters;
2851                 set_freepointer(s, tail, prior);
2852                 new.counters = counters;
2853                 was_frozen = new.frozen;
2854                 new.inuse -= cnt;
2855                 if ((!new.inuse || !prior) && !was_frozen) {
2856 
2857                         if (kmem_cache_has_cpu_partial(s) && !prior) {
2858 
2859                                 /*
2860                                  * Slab was on no list before and will be
2861                                  * partially empty
2862                                  * We can defer the list move and instead
2863                                  * freeze it.
2864                                  */
2865                                 new.frozen = 1;
2866 
2867                         } else { /* Needs to be taken off a list */
2868 
2869                                 n = get_node(s, page_to_nid(page));
2870                                 /*
2871                                  * Speculatively acquire the list_lock.
2872                                  * If the cmpxchg does not succeed then we may
2873                                  * drop the list_lock without any processing.
2874                                  *
2875                                  * Otherwise the list_lock will synchronize with
2876                                  * other processors updating the list of slabs.
2877                                  */
2878                                 spin_lock_irqsave(&n->list_lock, flags);
2879 
2880                         }
2881                 }
2882 
2883         } while (!cmpxchg_double_slab(s, page,
2884                 prior, counters,
2885                 head, new.counters,
2886                 "__slab_free"));
2887 
2888         if (likely(!n)) {
2889 
2890                 /*
2891                  * If we just froze the page then put it onto the
2892                  * per cpu partial list.
2893                  */
2894                 if (new.frozen && !was_frozen) {
2895                         put_cpu_partial(s, page, 1);
2896                         stat(s, CPU_PARTIAL_FREE);
2897                 }
2898                 /*
2899                  * The list lock was not taken therefore no list
2900                  * activity can be necessary.
2901                  */
2902                 if (was_frozen)
2903                         stat(s, FREE_FROZEN);
2904                 return;
2905         }
2906 
2907         if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
2908                 goto slab_empty;
2909 
2910         /*
2911          * Objects left in the slab. If it was not on the partial list before
2912          * then add it.
2913          */
2914         if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
2915                 if (kmem_cache_debug(s))
2916                         remove_full(s, n, page);
2917                 add_partial(n, page, DEACTIVATE_TO_TAIL);
2918                 stat(s, FREE_ADD_PARTIAL);
2919         }
2920         spin_unlock_irqrestore(&n->list_lock, flags);
2921         return;
2922 
2923 slab_empty:
2924         if (prior) {
2925                 /*
2926                  * Slab on the partial list.
2927                  */
2928                 remove_partial(n, page);
2929                 stat(s, FREE_REMOVE_PARTIAL);
2930         } else {
2931                 /* Slab must be on the full list */
2932                 remove_full(s, n, page);
2933         }
2934 
2935         spin_unlock_irqrestore(&n->list_lock, flags);
2936         stat(s, FREE_SLAB);
2937         discard_slab(s, page);
2938 }
2939 
2940 /*
2941  * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2942  * can perform fastpath freeing without additional function calls.
2943  *
2944  * The fastpath is only possible if we are freeing to the current cpu slab
2945  * of this processor. This typically the case if we have just allocated
2946  * the item before.
2947  *
2948  * If fastpath is not possible then fall back to __slab_free where we deal
2949  * with all sorts of special processing.
2950  *
2951  * Bulk free of a freelist with several objects (all pointing to the
2952  * same page) possible by specifying head and tail ptr, plus objects
2953  * count (cnt). Bulk free indicated by tail pointer being set.
2954  */
2955 static __always_inline void do_slab_free(struct kmem_cache *s,
2956                                 struct page *page, void *head, void *tail,
2957                                 int cnt, unsigned long addr)
2958 {
2959         void *tail_obj = tail ? : head;
2960         struct kmem_cache_cpu *c;
2961         unsigned long tid;
2962 redo:
2963         /*
2964          * Determine the currently cpus per cpu slab.
2965          * The cpu may change afterward. However that does not matter since
2966          * data is retrieved via this pointer. If we are on the same cpu
2967          * during the cmpxchg then the free will succeed.
2968          */
2969         do {
2970                 tid = this_cpu_read(s->cpu_slab->tid);
2971                 c = raw_cpu_ptr(s->cpu_slab);
2972         } while (IS_ENABLED(CONFIG_PREEMPT) &&
2973                  unlikely(tid != READ_ONCE(c->tid)));
2974 
2975         /* Same with comment on barrier() in slab_alloc_node() */
2976         barrier();
2977 
2978         if (likely(page == c->page)) {
2979                 set_freepointer(s, tail_obj, c->freelist);
2980 
2981                 if (unlikely(!this_cpu_cmpxchg_double(
2982                                 s->cpu_slab->freelist, s->cpu_slab->tid,
2983                                 c->freelist, tid,
2984                                 head, next_tid(tid)))) {
2985 
2986                         note_cmpxchg_failure("slab_free", s, tid);
2987                         goto redo;
2988                 }
2989                 stat(s, FREE_FASTPATH);
2990         } else
2991                 __slab_free(s, page, head, tail_obj, cnt, addr);
2992 
2993 }
2994 
2995 static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
2996                                       void *head, void *tail, int cnt,
2997                                       unsigned long addr)
2998 {
2999         /*
3000          * With KASAN enabled slab_free_freelist_hook modifies the freelist
3001          * to remove objects, whose reuse must be delayed.
3002          */
3003         if (slab_free_freelist_hook(s, &head, &tail))
3004                 do_slab_free(s, page, head, tail, cnt, addr);
3005 }
3006 
3007 #ifdef CONFIG_KASAN_GENERIC
3008 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
3009 {
3010         do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
3011 }
3012 #endif
3013 
3014 void kmem_cache_free(struct kmem_cache *s, void *x)
3015 {
3016         s = cache_from_obj(s, x);
3017         if (!s)
3018                 return;
3019         slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
3020         trace_kmem_cache_free(_RET_IP_, x);
3021 }
3022 EXPORT_SYMBOL(kmem_cache_free);
3023 
3024 struct detached_freelist {
3025         struct page *page;
3026         void *tail;
3027         void *freelist;
3028         int cnt;
3029         struct kmem_cache *s;
3030 };
3031 
3032 /*
3033  * This function progressively scans the array with free objects (with
3034  * a limited look ahead) and extract objects belonging to the same
3035  * page.  It builds a detached freelist directly within the given
3036  * page/objects.  This can happen without any need for
3037  * synchronization, because the objects are owned by running process.
3038  * The freelist is build up as a single linked list in the objects.
3039  * The idea is, that this detached freelist can then be bulk
3040  * transferred to the real freelist(s), but only requiring a single
3041  * synchronization primitive.  Look ahead in the array is limited due
3042  * to performance reasons.
3043  */
3044 static inline
3045 int build_detached_freelist(struct kmem_cache *s, size_t size,
3046                             void **p, struct detached_freelist *df)
3047 {
3048         size_t first_skipped_index = 0;
3049         int lookahead = 3;
3050         void *object;
3051         struct page *page;
3052 
3053         /* Always re-init detached_freelist */
3054         df->page = NULL;
3055 
3056         do {
3057                 object = p[--size];
3058                 /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
3059         } while (!object && size);
3060 
3061         if (!object)
3062                 return 0;
3063 
3064         page = virt_to_head_page(object);
3065         if (!s) {
3066                 /* Handle kalloc'ed objects */
3067                 if (unlikely(!PageSlab(page))) {
3068                         BUG_ON(!PageCompound(page));
3069                         kfree_hook(object);
3070                         __free_pages(page, compound_order(page));
3071                         p[size] = NULL; /* mark object processed */
3072                         return size;
3073                 }
3074                 /* Derive kmem_cache from object */
3075                 df->s = page->slab_cache;
3076         } else {
3077                 df->s = cache_from_obj(s, object); /* Support for memcg */
3078         }
3079 
3080         /* Start new detached freelist */
3081         df->page = page;
3082         set_freepointer(df->s, object, NULL);
3083         df->tail = object;
3084         df->freelist = object;
3085         p[size] = NULL; /* mark object processed */
3086         df->cnt = 1;
3087 
3088         while (size) {
3089                 object = p[--size];
3090                 if (!object)
3091                         continue; /* Skip processed objects */
3092 
3093                 /* df->page is always set at this point */
3094                 if (df->page == virt_to_head_page(object)) {
3095                         /* Opportunity build freelist */
3096                         set_freepointer(df->s, object, df->freelist);
3097                         df->freelist = object;
3098                         df->cnt++;
3099                         p[size] = NULL; /* mark object processed */
3100 
3101                         continue;
3102                 }
3103 
3104                 /* Limit look ahead search */
3105                 if (!--lookahead)
3106                         break;
3107 
3108                 if (!first_skipped_index)
3109                         first_skipped_index = size + 1;
3110         }
3111 
3112         return first_skipped_index;
3113 }
3114 
3115 /* Note that interrupts must be enabled when calling this function. */
3116 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3117 {
3118         if (WARN_ON(!size))
3119                 return;
3120 
3121         do {
3122                 struct detached_freelist df;
3123 
3124                 size = build_detached_freelist(s, size, p, &df);
3125                 if (!df.page)
3126                         continue;
3127 
3128                 slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);
3129         } while (likely(size));
3130 }
3131 EXPORT_SYMBOL(kmem_cache_free_bulk);
3132 
3133 /* Note that interrupts must be enabled when calling this function. */
3134 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3135                           void **p)
3136 {
3137         struct kmem_cache_cpu *c;
3138         int i;
3139 
3140         /* memcg and kmem_cache debug support */
3141         s = slab_pre_alloc_hook(s, flags);
3142         if (unlikely(!s))
3143                 return false;
3144         /*
3145          * Drain objects in the per cpu slab, while disabling local
3146          * IRQs, which protects against PREEMPT and interrupts
3147          * handlers invoking normal fastpath.
3148          */
3149         local_irq_disable();
3150         c = this_cpu_ptr(s->cpu_slab);
3151 
3152         for (i = 0; i < size; i++) {
3153                 void *object = c->freelist;
3154 
3155                 if (unlikely(!object)) {
3156                         /*
3157                          * Invoking slow path likely have side-effect
3158                          * of re-populating per CPU c->freelist
3159                          */
3160                         p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3161                                             _RET_IP_, c);
3162                         if (unlikely(!p[i]))
3163                                 goto error;
3164 
3165                         c = this_cpu_ptr(s->cpu_slab);
3166                         continue; /* goto for-loop */
3167                 }
3168                 c->freelist = get_freepointer(s, object);
3169                 p[i] = object;
3170         }
3171         c->tid = next_tid(c->tid);
3172         local_irq_enable();
3173 
3174         /* Clear memory outside IRQ disabled fastpath loop */
3175         if (unlikely(flags & __GFP_ZERO)) {
3176                 int j;
3177 
3178                 for (j = 0; j < i; j++)
3179                         memset(p[j], 0, s->object_size);
3180         }
3181 
3182         /* memcg and kmem_cache debug support */
3183         slab_post_alloc_hook(s, flags, size, p);
3184         return i;
3185 error:
3186         local_irq_enable();
3187         slab_post_alloc_hook(s, flags, i, p);
3188         __kmem_cache_free_bulk(s, i, p);
3189         return 0;
3190 }
3191 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3192 
3193 
3194 /*
3195  * Object placement in a slab is made very easy because we always start at
3196  * offset 0. If we tune the size of the object to the alignment then we can
3197  * get the required alignment by putting one properly sized object after
3198  * another.
3199  *
3200  * Notice that the allocation order determines the sizes of the per cpu
3201  * caches. Each processor has always one slab available for allocations.
3202  * Increasing the allocation order reduces the number of times that slabs
3203  * must be moved on and off the partial lists and is therefore a factor in
3204  * locking overhead.
3205  */
3206 
3207 /*
3208  * Mininum / Maximum order of slab pages. This influences locking overhead
3209  * and slab fragmentation. A higher order reduces the number of partial slabs
3210  * and increases the number of allocations possible without having to
3211  * take the list_lock.
3212  */
3213 static unsigned int slub_min_order;
3214 static unsigned int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3215 static unsigned int slub_min_objects;
3216 
3217 /*
3218  * Calculate the order of allocation given an slab object size.
3219  *
3220  * The order of allocation has significant impact on performance and other
3221  * system components. Generally order 0 allocations should be preferred since
3222  * order 0 does not cause fragmentation in the page allocator. Larger objects
3223  * be problematic to put into order 0 slabs because there may be too much
3224  * unused space left. We go to a higher order if more than 1/16th of the slab
3225  * would be wasted.
3226  *
3227  * In order to reach satisfactory performance we must ensure that a minimum
3228  * number of objects is in one slab. Otherwise we may generate too much
3229  * activity on the partial lists which requires taking the list_lock. This is
3230  * less a concern for large slabs though which are rarely used.
3231  *
3232  * slub_max_order specifies the order where we begin to stop considering the
3233  * number of objects in a slab as critical. If we reach slub_max_order then
3234  * we try to keep the page order as low as possible. So we accept more waste
3235  * of space in favor of a small page order.
3236  *
3237  * Higher order allocations also allow the placement of more objects in a
3238  * slab and thereby reduce object handling overhead. If the user has
3239  * requested a higher mininum order then we start with that one instead of
3240  * the smallest order which will fit the object.
3241  */
3242 static inline unsigned int slab_order(unsigned int size,
3243                 unsigned int min_objects, unsigned int max_order,
3244                 unsigned int fract_leftover)
3245 {
3246         unsigned int min_order = slub_min_order;
3247         unsigned int order;
3248 
3249         if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
3250                 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3251 
3252         for (order = max(min_order, (unsigned int)get_order(min_objects * size));
3253                         order <= max_order; order++) {
3254 
3255                 unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
3256                 unsigned int rem;
3257 
3258                 rem = slab_size % size;
3259 
3260                 if (rem <= slab_size / fract_leftover)
3261                         break;
3262         }
3263 
3264         return order;
3265 }
3266 
3267 static inline int calculate_order(unsigned int size)
3268 {
3269         unsigned int order;
3270         unsigned int min_objects;
3271         unsigned int max_objects;
3272 
3273         /*
3274          * Attempt to find best configuration for a slab. This
3275          * works by first attempting to generate a layout with
3276          * the best configuration and backing off gradually.
3277          *
3278          * First we increase the acceptable waste in a slab. Then
3279          * we reduce the minimum objects required in a slab.
3280          */
3281         min_objects = slub_min_objects;
3282         if (!min_objects)
3283                 min_objects = 4 * (fls(nr_cpu_ids) + 1);
3284         max_objects = order_objects(slub_max_order, size);
3285         min_objects = min(min_objects, max_objects);
3286 
3287         while (min_objects > 1) {
3288                 unsigned int fraction;
3289 
3290                 fraction = 16;
3291                 while (fraction >= 4) {
3292                         order = slab_order(size, min_objects,
3293                                         slub_max_order, fraction);
3294                         if (order <= slub_max_order)
3295                                 return order;
3296                         fraction /= 2;
3297                 }
3298                 min_objects--;
3299         }
3300 
3301         /*
3302          * We were unable to place multiple objects in a slab. Now
3303          * lets see if we can place a single object there.
3304          */
3305         order = slab_order(size, 1, slub_max_order, 1);
3306         if (order <= slub_max_order)
3307                 return order;
3308 
3309         /*
3310          * Doh this slab cannot be placed using slub_max_order.
3311          */
3312         order = slab_order(size, 1, MAX_ORDER, 1);
3313         if (order < MAX_ORDER)
3314                 return order;
3315         return -ENOSYS;
3316 }
3317 
3318 static void
3319 init_kmem_cache_node(struct kmem_cache_node *n)
3320 {
3321         n->nr_partial = 0;
3322         spin_lock_init(&n->list_lock);
3323         INIT_LIST_HEAD(&n->partial);
3324 #ifdef CONFIG_SLUB_DEBUG
3325         atomic_long_set(&n->nr_slabs, 0);
3326         atomic_long_set(&n->total_objects, 0);
3327         INIT_LIST_HEAD(&n->full);
3328 #endif
3329 }
3330 
3331 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3332 {
3333         BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3334                         KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3335 
3336         /*
3337          * Must align to double word boundary for the double cmpxchg
3338          * instructions to work; see __pcpu_double_call_return_bool().
3339          */
3340         s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3341                                      2 * sizeof(void *));
3342 
3343         if (!s->cpu_slab)
3344                 return 0;
3345 
3346         init_kmem_cache_cpus(s);
3347 
3348         return 1;
3349 }
3350 
3351 static struct kmem_cache *kmem_cache_node;
3352 
3353 /*
3354  * No kmalloc_node yet so do it by hand. We know that this is the first
3355  * slab on the node for this slabcache. There are no concurrent accesses
3356  * possible.
3357  *
3358  * Note that this function only works on the kmem_cache_node
3359  * when allocating for the kmem_cache_node. This is used for bootstrapping
3360  * memory on a fresh node that has no slab structures yet.
3361  */
3362 static void early_kmem_cache_node_alloc(int node)
3363 {
3364         struct page *page;
3365         struct kmem_cache_node *n;
3366 
3367         BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3368 
3369         page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3370 
3371         BUG_ON(!page);
3372         if (page_to_nid(page) != node) {
3373                 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3374                 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3375         }
3376 
3377         n = page->freelist;
3378         BUG_ON(!n);
3379 #ifdef CONFIG_SLUB_DEBUG
3380         init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3381         init_tracking(kmem_cache_node, n);
3382 #endif
3383         n = kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node),
3384                       GFP_KERNEL);
3385         page->freelist = get_freepointer(kmem_cache_node, n);
3386         page->inuse = 1;
3387         page->frozen = 0;
3388         kmem_cache_node->node[node] = n;
3389         init_kmem_cache_node(n);
3390         inc_slabs_node(kmem_cache_node, node, page->objects);
3391 
3392         /*
3393          * No locks need to be taken here as it has just been
3394          * initialized and there is no concurrent access.
3395          */
3396         __add_partial(n, page, DEACTIVATE_TO_HEAD);
3397 }
3398 
3399 static void free_kmem_cache_nodes(struct kmem_cache *s)
3400 {
3401         int node;
3402         struct kmem_cache_node *n;
3403 
3404         for_each_kmem_cache_node(s, node, n) {
3405                 s->node[node] = NULL;
3406                 kmem_cache_free(kmem_cache_node, n);
3407         }
3408 }
3409 
3410 void __kmem_cache_release(struct kmem_cache *s)
3411 {
3412         cache_random_seq_destroy(s);
3413         free_percpu(s->cpu_slab);
3414         free_kmem_cache_nodes(s);
3415 }
3416 
3417 static int init_kmem_cache_nodes(struct kmem_cache *s)
3418 {
3419         int node;
3420 
3421         for_each_node_state(node, N_NORMAL_MEMORY) {
3422                 struct kmem_cache_node *n;
3423 
3424                 if (slab_state == DOWN) {
3425                         early_kmem_cache_node_alloc(node);
3426                         continue;
3427                 }
3428                 n = kmem_cache_alloc_node(kmem_cache_node,
3429                                                 GFP_KERNEL, node);
3430 
3431                 if (!n) {
3432                         free_kmem_cache_nodes(s);
3433                         return 0;
3434                 }
3435 
3436                 init_kmem_cache_node(n);
3437                 s->node[node] = n;
3438         }
3439         return 1;
3440 }
3441 
3442 static void set_min_partial(struct kmem_cache *s, unsigned long min)
3443 {
3444         if (min < MIN_PARTIAL)
3445                 min = MIN_PARTIAL;
3446         else if (min > MAX_PARTIAL)
3447                 min = MAX_PARTIAL;
3448         s->min_partial = min;
3449 }
3450 
3451 static void set_cpu_partial(struct kmem_cache *s)
3452 {
3453 #ifdef CONFIG_SLUB_CPU_PARTIAL
3454         /*
3455          * cpu_partial determined the maximum number of objects kept in the
3456          * per cpu partial lists of a processor.
3457          *
3458          * Per cpu partial lists mainly contain slabs that just have one
3459          * object freed. If they are used for allocation then they can be
3460          * filled up again with minimal effort. The slab will never hit the
3461          * per node partial lists and therefore no locking will be required.
3462          *
3463          * This setting also determines
3464          *
3465          * A) The number of objects from per cpu partial slabs dumped to the
3466          *    per node list when we reach the limit.
3467          * B) The number of objects in cpu partial slabs to extract from the
3468          *    per node list when we run out of per cpu objects. We only fetch
3469          *    50% to keep some capacity around for frees.
3470          */
3471         if (!kmem_cache_has_cpu_partial(s))
3472                 s->cpu_partial = 0;
3473         else if (s->size >= PAGE_SIZE)
3474                 s->cpu_partial = 2;
3475         else if (s->size >= 1024)
3476                 s->cpu_partial = 6;
3477         else if (s->size >= 256)
3478                 s->cpu_partial = 13;
3479         else
3480                 s->cpu_partial = 30;
3481 #endif
3482 }
3483 
3484 /*
3485  * calculate_sizes() determines the order and the distribution of data within
3486  * a slab object.
3487  */
3488 static int calculate_sizes(struct kmem_cache *s, int forced_order)
3489 {
3490         slab_flags_t flags = s->flags;
3491         unsigned int size = s->object_size;
3492         unsigned int order;
3493 
3494         /*
3495          * Round up object size to the next word boundary. We can only
3496          * place the free pointer at word boundaries and this determines
3497          * the possible location of the free pointer.
3498          */
3499         size = ALIGN(size, sizeof(void *));
3500 
3501 #ifdef CONFIG_SLUB_DEBUG
3502         /*
3503          * Determine if we can poison the object itself. If the user of
3504          * the slab may touch the object after free or before allocation
3505          * then we should never poison the object itself.
3506          */
3507         if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
3508                         !s->ctor)
3509                 s->flags |= __OBJECT_POISON;
3510         else
3511                 s->flags &= ~__OBJECT_POISON;
3512 
3513 
3514         /*
3515          * If we are Redzoning then check if there is some space between the
3516          * end of the object and the free pointer. If not then add an
3517          * additional word to have some bytes to store Redzone information.
3518          */
3519         if ((flags & SLAB_RED_ZONE) && size == s->object_size)
3520                 size += sizeof(void *);
3521 #endif
3522 
3523         /*
3524          * With that we have determined the number of bytes in actual use
3525          * by the object. This is the potential offset to the free pointer.
3526          */
3527         s->inuse = size;
3528 
3529         if (((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
3530                 s->ctor)) {
3531                 /*
3532                  * Relocate free pointer after the object if it is not
3533                  * permitted to overwrite the first word of the object on
3534                  * kmem_cache_free.
3535                  *
3536                  * This is the case if we do RCU, have a constructor or
3537                  * destructor or are poisoning the objects.
3538                  */
3539                 s->offset = size;
3540                 size += sizeof(void *);
3541         }
3542 
3543 #ifdef CONFIG_SLUB_DEBUG
3544         if (flags & SLAB_STORE_USER)
3545                 /*
3546                  * Need to store information about allocs and frees after
3547                  * the object.
3548                  */
3549                 size += 2 * sizeof(struct track);
3550 #endif
3551 
3552         kasan_cache_create(s, &size, &s->flags);
3553 #ifdef CONFIG_SLUB_DEBUG
3554         if (flags & SLAB_RED_ZONE) {
3555                 /*
3556                  * Add some empty padding so that we can catch
3557                  * overwrites from earlier objects rather than let
3558                  * tracking information or the free pointer be
3559                  * corrupted if a user writes before the start
3560                  * of the object.
3561                  */
3562                 size += sizeof(void *);
3563 
3564                 s->red_left_pad = sizeof(void *);
3565                 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
3566                 size += s->red_left_pad;
3567         }
3568 #endif
3569 
3570         /*
3571          * SLUB stores one object immediately after another beginning from
3572          * offset 0. In order to align the objects we have to simply size
3573          * each object to conform to the alignment.
3574          */
3575         size = ALIGN(size, s->align);
3576         s->size = size;
3577         if (forced_order >= 0)
3578                 order = forced_order;
3579         else
3580                 order = calculate_order(size);
3581 
3582         if ((int)order < 0)
3583                 return 0;
3584 
3585         s->allocflags = 0;
3586         if (order)
3587                 s->allocflags |= __GFP_COMP;
3588 
3589         if (s->flags & SLAB_CACHE_DMA)
3590                 s->allocflags |= GFP_DMA;
3591 
3592         if (s->flags & SLAB_RECLAIM_ACCOUNT)
3593                 s->allocflags |= __GFP_RECLAIMABLE;
3594 
3595         /*
3596          * Determine the number of objects per slab
3597          */
3598         s->oo = oo_make(order, size);
3599         s->min = oo_make(get_order(size), size);
3600         if (oo_objects(s->oo) > oo_objects(s->max))
3601                 s->max = s->oo;
3602 
3603         return !!oo_objects(s->oo);
3604 }
3605 
3606 static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
3607 {
3608         s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3609 #ifdef CONFIG_SLAB_FREELIST_HARDENED
3610         s->random = get_random_long();
3611 #endif
3612 
3613         if (!calculate_sizes(s, -1))
3614                 goto error;
3615         if (disable_higher_order_debug) {
3616                 /*
3617                  * Disable debugging flags that store metadata if the min slab
3618                  * order increased.
3619                  */
3620                 if (get_order(s->size) > get_order(s->object_size)) {
3621                         s->flags &= ~DEBUG_METADATA_FLAGS;
3622                         s->offset = 0;
3623                         if (!calculate_sizes(s, -1))
3624                                 goto error;
3625                 }
3626         }
3627 
3628 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3629     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3630         if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
3631                 /* Enable fast mode */
3632                 s->flags |= __CMPXCHG_DOUBLE;
3633 #endif
3634 
3635         /*
3636          * The larger the object size is, the more pages we want on the partial
3637          * list to avoid pounding the page allocator excessively.
3638          */
3639         set_min_partial(s, ilog2(s->size) / 2);
3640 
3641         set_cpu_partial(s);
3642 
3643 #ifdef CONFIG_NUMA
3644         s->remote_node_defrag_ratio = 1000;
3645 #endif
3646 
3647         /* Initialize the pre-computed randomized freelist if slab is up */
3648         if (slab_state >= UP) {
3649                 if (init_cache_random_seq(s))
3650                         goto error;
3651         }
3652 
3653         if (!init_kmem_cache_nodes(s))
3654                 goto error;
3655 
3656         if (alloc_kmem_cache_cpus(s))
3657                 return 0;
3658 
3659         free_kmem_cache_nodes(s);
3660 error:
3661         if (flags & SLAB_PANIC)
3662                 panic("Cannot create slab %s size=%u realsize=%u order=%u offset=%u flags=%lx\n",
3663                       s->name, s->size, s->size,
3664                       oo_order(s->oo), s->offset, (unsigned long)flags);
3665         return -EINVAL;
3666 }
3667 
3668 static void list_slab_objects(struct kmem_cache *s, struct page *page,
3669                                                         const char *text)
3670 {
3671 #ifdef CONFIG_SLUB_DEBUG
3672         void *addr = page_address(page);
3673         void *p;
3674         unsigned long *map = bitmap_zalloc(page->objects, GFP_ATOMIC);
3675         if (!map)
3676                 return;
3677         slab_err(s, page, text, s->name);
3678         slab_lock(page);
3679 
3680         get_map(s, page, map);
3681         for_each_object(p, s, addr, page->objects) {
3682 
3683                 if (!test_bit(slab_index(p, s, addr), map)) {
3684                         pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
3685                         print_tracking(s, p);
3686                 }
3687         }
3688         slab_unlock(page);
3689         bitmap_free(map);
3690 #endif
3691 }
3692 
3693 /*
3694  * Attempt to free all partial slabs on a node.
3695  * This is called from __kmem_cache_shutdown(). We must take list_lock
3696  * because sysfs file might still access partial list after the shutdowning.
3697  */
3698 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3699 {
3700         LIST_HEAD(discard);
3701         struct page *page, *h;
3702 
3703         BUG_ON(irqs_disabled());
3704         spin_lock_irq(&n->list_lock);
3705         list_for_each_entry_safe(page, h, &n->partial, lru) {
3706                 if (!page->inuse) {
3707                         remove_partial(n, page);
3708                         list_add(&page->lru, &discard);
3709                 } else {
3710                         list_slab_objects(s, page,
3711                         "Objects remaining in %s on __kmem_cache_shutdown()");
3712                 }
3713         }
3714         spin_unlock_irq(&n->list_lock);
3715 
3716         list_for_each_entry_safe(page, h, &discard, lru)
3717                 discard_slab(s, page);
3718 }
3719 
3720 bool __kmem_cache_empty(struct kmem_cache *s)
3721 {
3722         int node;
3723         struct kmem_cache_node *n;
3724 
3725         for_each_kmem_cache_node(s, node, n)
3726                 if (n->nr_partial || slabs_node(s, node))
3727                         return false;
3728         return true;
3729 }
3730 
3731 /*
3732  * Release all resources used by a slab cache.
3733  */
3734 int __kmem_cache_shutdown(struct kmem_cache *s)
3735 {
3736         int node;
3737         struct kmem_cache_node *n;
3738 
3739         flush_all(s);
3740         /* Attempt to free all objects */
3741         for_each_kmem_cache_node(s, node, n) {
3742                 free_partial(s, n);
3743                 if (n->nr_partial || slabs_node(s, node))
3744                         return 1;
3745         }
3746         sysfs_slab_remove(s);
3747         return 0;
3748 }
3749 
3750 /********************************************************************
3751  *              Kmalloc subsystem
3752  *******************************************************************/
3753 
3754 static int __init setup_slub_min_order(char *str)
3755 {
3756         get_option(&str, (int *)&slub_min_order);
3757 
3758         return 1;
3759 }
3760 
3761 __setup("slub_min_order=", setup_slub_min_order);
3762 
3763 static int __init setup_slub_max_order(char *str)
3764 {
3765         get_option(&str, (int *)&slub_max_order);
3766         slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
3767 
3768         return 1;
3769 }
3770 
3771 __setup("slub_max_order=", setup_slub_max_order);
3772 
3773 static int __init setup_slub_min_objects(char *str)
3774 {
3775         get_option(&str, (int *)&slub_min_objects);
3776 
3777         return 1;
3778 }
3779 
3780 __setup("slub_min_objects=", setup_slub_min_objects);
3781 
3782 void *__kmalloc(size_t size, gfp_t flags)
3783 {
3784         struct kmem_cache *s;
3785         void *ret;
3786 
3787         if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3788                 return kmalloc_large(size, flags);
3789 
3790         s = kmalloc_slab(size, flags);
3791 
3792         if (unlikely(ZERO_OR_NULL_PTR(s)))
3793                 return s;
3794 
3795         ret = slab_alloc(s, flags, _RET_IP_);
3796 
3797         trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3798 
3799         ret = kasan_kmalloc(s, ret, size, flags);
3800 
3801         return ret;
3802 }
3803 EXPORT_SYMBOL(__kmalloc);
3804 
3805 #ifdef CONFIG_NUMA
3806 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3807 {
3808         struct page *page;
3809         void *ptr = NULL;
3810 
3811         flags |= __GFP_COMP;
3812         page = alloc_pages_node(node, flags, get_order(size));
3813         if (page)
3814                 ptr = page_address(page);
3815 
3816         return kmalloc_large_node_hook(ptr, size, flags);
3817 }
3818 
3819 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3820 {
3821         struct kmem_cache *s;
3822         void *ret;
3823 
3824         if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3825                 ret = kmalloc_large_node(size, flags, node);
3826 
3827                 trace_kmalloc_node(_RET_IP_, ret,
3828                                    size, PAGE_SIZE << get_order(size),
3829                                    flags, node);
3830 
3831                 return ret;
3832         }
3833 
3834         s = kmalloc_slab(size, flags);
3835 
3836         if (unlikely(ZERO_OR_NULL_PTR(s)))
3837                 return s;
3838 
3839         ret = slab_alloc_node(s, flags, node, _RET_IP_);
3840 
3841         trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3842 
3843         ret = kasan_kmalloc(s, ret, size, flags);
3844 
3845         return ret;
3846 }
3847 EXPORT_SYMBOL(__kmalloc_node);
3848 #endif
3849 
3850 #ifdef CONFIG_HARDENED_USERCOPY
3851 /*
3852  * Rejects incorrectly sized objects and objects that are to be copied
3853  * to/from userspace but do not fall entirely within the containing slab
3854  * cache's usercopy region.
3855  *
3856  * Returns NULL if check passes, otherwise const char * to name of cache
3857  * to indicate an error.
3858  */
3859 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
3860                          bool to_user)
3861 {
3862         struct kmem_cache *s;
3863         unsigned int offset;
3864         size_t object_size;
3865 
3866         ptr = kasan_reset_tag(ptr);
3867 
3868         /* Find object and usable object size. */
3869         s = page->slab_cache;
3870 
3871         /* Reject impossible pointers. */
3872         if (ptr < page_address(page))
3873                 usercopy_abort("SLUB object not in SLUB page?!", NULL,
3874                                to_user, 0, n);
3875 
3876         /* Find offset within object. */
3877         offset = (ptr - page_address(page)) % s->size;
3878 
3879         /* Adjust for redzone and reject if within the redzone. */
3880         if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) {
3881                 if (offset < s->red_left_pad)
3882                         usercopy_abort("SLUB object in left red zone",
3883                                        s->name, to_user, offset, n);
3884                 offset -= s->red_left_pad;
3885         }
3886 
3887         /* Allow address range falling entirely within usercopy region. */
3888         if (offset >= s->useroffset &&
3889             offset - s->useroffset <= s->usersize &&
3890             n <= s->useroffset - offset + s->usersize)
3891                 return;
3892 
3893         /*
3894          * If the copy is still within the allocated object, produce
3895          * a warning instead of rejecting the copy. This is intended
3896          * to be a temporary method to find any missing usercopy
3897          * whitelists.
3898          */
3899         object_size = slab_ksize(s);
3900         if (usercopy_fallback &&
3901             offset <= object_size && n <= object_size - offset) {
3902                 usercopy_warn("SLUB object", s->name, to_user, offset, n);
3903                 return;
3904         }
3905 
3906         usercopy_abort("SLUB object", s->name, to_user, offset, n);
3907 }
3908 #endif /* CONFIG_HARDENED_USERCOPY */
3909 
3910 static size_t __ksize(const void *object)
3911 {
3912         struct page *page;
3913 
3914         if (unlikely(object == ZERO_SIZE_PTR))
3915                 return 0;
3916 
3917         page = virt_to_head_page(object);
3918 
3919         if (unlikely(!PageSlab(page))) {
3920                 WARN_ON(!PageCompound(page));
3921                 return PAGE_SIZE << compound_order(page);
3922         }
3923 
3924         return slab_ksize(page->slab_cache);
3925 }
3926 
3927 size_t ksize(const void *object)
3928 {
3929         size_t size = __ksize(object);
3930         /* We assume that ksize callers could use whole allocated area,
3931          * so we need to unpoison this area.
3932          */
3933         kasan_unpoison_shadow(object, size);
3934         return size;
3935 }
3936 EXPORT_SYMBOL(ksize);
3937 
3938 void kfree(const void *x)
3939 {
3940         struct page *page;
3941         void *object = (void *)x;
3942 
3943         trace_kfree(_RET_IP_, x);
3944 
3945         if (unlikely(ZERO_OR_NULL_PTR(x)))
3946                 return;
3947 
3948         page = virt_to_head_page(x);
3949         if (unlikely(!PageSlab(page))) {
3950                 BUG_ON(!PageCompound(page));
3951                 kfree_hook(object);
3952                 __free_pages(page, compound_order(page));
3953                 return;
3954         }
3955         slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
3956 }
3957 EXPORT_SYMBOL(kfree);
3958 
3959 #define SHRINK_PROMOTE_MAX 32
3960 
3961 /*
3962  * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3963  * up most to the head of the partial lists. New allocations will then
3964  * fill those up and thus they can be removed from the partial lists.
3965  *
3966  * The slabs with the least items are placed last. This results in them
3967  * being allocated from last increasing the chance that the last objects
3968  * are freed in them.
3969  */
3970 int __kmem_cache_shrink(struct kmem_cache *s)
3971 {
3972         int node;
3973         int i;
3974         struct kmem_cache_node *n;
3975         struct page *page;
3976         struct page *t;
3977         struct list_head discard;
3978         struct list_head promote[SHRINK_PROMOTE_MAX];
3979         unsigned long flags;
3980         int ret = 0;
3981 
3982         flush_all(s);
3983         for_each_kmem_cache_node(s, node, n) {
3984                 INIT_LIST_HEAD(&discard);
3985                 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
3986                         INIT_LIST_HEAD(promote + i);
3987 
3988                 spin_lock_irqsave(&n->list_lock, flags);
3989 
3990                 /*
3991                  * Build lists of slabs to discard or promote.
3992                  *
3993                  * Note that concurrent frees may occur while we hold the
3994                  * list_lock. page->inuse here is the upper limit.
3995                  */
3996                 list_for_each_entry_safe(page, t, &n->partial, lru) {
3997                         int free = page->objects - page->inuse;
3998 
3999                         /* Do not reread page->inuse */
4000                         barrier();
4001 
4002                         /* We do not keep full slabs on the list */
4003                         BUG_ON(free <= 0);
4004 
4005                         if (free == page->objects) {
4006                                 list_move(&page->lru, &discard);
4007                                 n->nr_partial--;
4008                         } else if (free <= SHRINK_PROMOTE_MAX)
4009                                 list_move(&page->lru, promote + free - 1);
4010                 }
4011 
4012                 /*
4013                  * Promote the slabs filled up most to the head of the
4014                  * partial list.
4015                  */
4016                 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
4017                         list_splice(promote + i, &n->partial);
4018 
4019                 spin_unlock_irqrestore(&n->list_lock, flags);
4020 
4021                 /* Release empty slabs */
4022                 list_for_each_entry_safe(page, t, &discard, lru)
4023                         discard_slab(s, page);
4024 
4025                 if (slabs_node(s, node))
4026                         ret = 1;
4027         }
4028 
4029         return ret;
4030 }
4031 
4032 #ifdef CONFIG_MEMCG
4033 static void kmemcg_cache_deact_after_rcu(struct kmem_cache *s)
4034 {
4035         /*
4036          * Called with all the locks held after a sched RCU grace period.
4037          * Even if @s becomes empty after shrinking, we can't know that @s
4038          * doesn't have allocations already in-flight and thus can't
4039          * destroy @s until the associated memcg is released.
4040          *
4041          * However, let's remove the sysfs files for empty caches here.
4042          * Each cache has a lot of interface files which aren't
4043          * particularly useful for empty draining caches; otherwise, we can
4044          * easily end up with millions of unnecessary sysfs files on
4045          * systems which have a lot of memory and transient cgroups.
4046          */
4047         if (!__kmem_cache_shrink(s))
4048                 sysfs_slab_remove(s);
4049 }
4050 
4051 void __kmemcg_cache_deactivate(struct kmem_cache *s)
4052 {
4053         /*
4054          * Disable empty slabs caching. Used to avoid pinning offline
4055          * memory cgroups by kmem pages that can be freed.
4056          */
4057         slub_set_cpu_partial(s, 0);
4058         s->min_partial = 0;
4059 
4060         /*
4061          * s->cpu_partial is checked locklessly (see put_cpu_partial), so
4062          * we have to make sure the change is visible before shrinking.
4063          */
4064         slab_deactivate_memcg_cache_rcu_sched(s, kmemcg_cache_deact_after_rcu);
4065 }
4066 #endif
4067 
4068 static int slab_mem_going_offline_callback(void *arg)
4069 {
4070         struct kmem_cache *s;
4071 
4072         mutex_lock(&slab_mutex);
4073         list_for_each_entry(s, &slab_caches, list)
4074                 __kmem_cache_shrink(s);
4075         mutex_unlock(&slab_mutex);
4076 
4077         return 0;
4078 }
4079 
4080 static void slab_mem_offline_callback(void *arg)
4081 {
4082         struct kmem_cache_node *n;
4083         struct kmem_cache *s;
4084         struct memory_notify *marg = arg;
4085         int offline_node;
4086 
4087         offline_node = marg->status_change_nid_normal;
4088 
4089         /*
4090          * If the node still has available memory. we need kmem_cache_node
4091          * for it yet.
4092          */
4093         if (offline_node < 0)
4094                 return;
4095 
4096         mutex_lock(&slab_mutex);
4097         list_for_each_entry(s, &slab_caches, list) {
4098                 n = get_node(s, offline_node);
4099                 if (n) {
4100                         /*
4101                          * if n->nr_slabs > 0, slabs still exist on the node
4102                          * that is going down. We were unable to free them,
4103                          * and offline_pages() function shouldn't call this
4104                          * callback. So, we must fail.
4105                          */
4106                         BUG_ON(slabs_node(s, offline_node));
4107 
4108                         s->node[offline_node] = NULL;
4109                         kmem_cache_free(kmem_cache_node, n);
4110                 }
4111         }
4112         mutex_unlock(&slab_mutex);
4113 }
4114 
4115 static int slab_mem_going_online_callback(void *arg)
4116 {
4117         struct kmem_cache_node *n;
4118         struct kmem_cache *s;
4119         struct memory_notify *marg = arg;
4120         int nid = marg->status_change_nid_normal;
4121         int ret = 0;
4122 
4123         /*
4124          * If the node's memory is already available, then kmem_cache_node is
4125          * already created. Nothing to do.
4126          */
4127         if (nid < 0)
4128                 return 0;
4129 
4130         /*
4131          * We are bringing a node online. No memory is available yet. We must
4132          * allocate a kmem_cache_node structure in order to bring the node
4133          * online.
4134          */
4135         mutex_lock(&slab_mutex);
4136         list_for_each_entry(s, &slab_caches, list) {
4137                 /*
4138                  * XXX: kmem_cache_alloc_node will fallback to other nodes
4139                  *      since memory is not yet available from the node that
4140                  *      is brought up.
4141                  */
4142                 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
4143                 if (!n) {
4144                         ret = -ENOMEM;
4145                         goto out;
4146                 }
4147                 init_kmem_cache_node(n);
4148                 s->node[nid] = n;
4149         }
4150 out:
4151         mutex_unlock(&slab_mutex);
4152         return ret;
4153 }
4154 
4155 static int slab_memory_callback(struct notifier_block *self,
4156                                 unsigned long action, void *arg)
4157 {
4158         int ret = 0;
4159 
4160         switch (action) {
4161         case MEM_GOING_ONLINE:
4162                 ret = slab_mem_going_online_callback(arg);
4163                 break;
4164         case MEM_GOING_OFFLINE:
4165                 ret = slab_mem_going_offline_callback(arg);
4166                 break;
4167         case MEM_OFFLINE:
4168         case MEM_CANCEL_ONLINE:
4169                 slab_mem_offline_callback(arg);
4170                 break;
4171         case MEM_ONLINE:
4172         case MEM_CANCEL_OFFLINE:
4173                 break;
4174         }
4175         if (ret)
4176                 ret = notifier_from_errno(ret);
4177         else
4178                 ret = NOTIFY_OK;
4179         return ret;
4180 }
4181 
4182 static struct notifier_block slab_memory_callback_nb = {
4183         .notifier_call = slab_memory_callback,
4184         .priority = SLAB_CALLBACK_PRI,
4185 };
4186 
4187 /********************************************************************
4188  *                      Basic setup of slabs
4189  *******************************************************************/
4190 
4191 /*
4192  * Used for early kmem_cache structures that were allocated using
4193  * the page allocator. Allocate them properly then fix up the pointers
4194  * that may be pointing to the wrong kmem_cache structure.
4195  */
4196 
4197 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4198 {
4199         int node;
4200         struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4201         struct kmem_cache_node *n;
4202 
4203         memcpy(s, static_cache, kmem_cache->object_size);
4204 
4205         /*
4206          * This runs very early, and only the boot processor is supposed to be
4207          * up.  Even if it weren't true, IRQs are not up so we couldn't fire
4208          * IPIs around.
4209          */
4210         __flush_cpu_slab(s, smp_processor_id());
4211         for_each_kmem_cache_node(s, node, n) {
4212                 struct page *p;
4213 
4214                 list_for_each_entry(p, &n->partial, lru)
4215                         p->slab_cache = s;
4216 
4217 #ifdef CONFIG_SLUB_DEBUG
4218                 list_for_each_entry(p, &n->full, lru)
4219                         p->slab_cache = s;
4220 #endif
4221         }
4222         slab_init_memcg_params(s);
4223         list_add(&s->list, &slab_caches);
4224         memcg_link_cache(s);
4225         return s;
4226 }
4227 
4228 void __init kmem_cache_init(void)
4229 {
4230         static __initdata struct kmem_cache boot_kmem_cache,
4231                 boot_kmem_cache_node;
4232 
4233         if (debug_guardpage_minorder())
4234                 slub_max_order = 0;
4235 
4236         kmem_cache_node = &boot_kmem_cache_node;
4237         kmem_cache = &boot_kmem_cache;
4238 
4239         create_boot_cache(kmem_cache_node, "kmem_cache_node",
4240                 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
4241 
4242         register_hotmemory_notifier(&slab_memory_callback_nb);
4243 
4244         /* Able to allocate the per node structures */
4245         slab_state = PARTIAL;
4246 
4247         create_boot_cache(kmem_cache, "kmem_cache",
4248                         offsetof(struct kmem_cache, node) +
4249                                 nr_node_ids * sizeof(struct kmem_cache_node *),
4250                        SLAB_HWCACHE_ALIGN, 0, 0);
4251 
4252         kmem_cache = bootstrap(&boot_kmem_cache);
4253         kmem_cache_node = bootstrap(&boot_kmem_cache_node);
4254 
4255         /* Now we can use the kmem_cache to allocate kmalloc slabs */
4256         setup_kmalloc_cache_index_table();
4257         create_kmalloc_caches(0);
4258 
4259         /* Setup random freelists for each cache */
4260         init_freelist_randomization();
4261 
4262         cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
4263                                   slub_cpu_dead);
4264 
4265         pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
4266                 cache_line_size(),
4267                 slub_min_order, slub_max_order, slub_min_objects,
4268                 nr_cpu_ids, nr_node_ids);
4269 }
4270 
4271 void __init kmem_cache_init_late(void)
4272 {
4273 }
4274 
4275 struct kmem_cache *
4276 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
4277                    slab_flags_t flags, void (*ctor)(void *))
4278 {
4279         struct kmem_cache *s, *c;
4280 
4281         s = find_mergeable(size, align, flags, name, ctor);
4282         if (s) {
4283                 s->refcount++;
4284 
4285                 /*
4286                  * Adjust the object sizes so that we clear
4287                  * the complete object on kzalloc.
4288                  */
4289                 s->object_size = max(s->object_size, size);
4290                 s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
4291 
4292                 for_each_memcg_cache(c, s) {
4293                         c->object_size = s->object_size;
4294                         c->inuse = max(c->inuse, ALIGN(size, sizeof(void *)));
4295                 }
4296 
4297                 if (sysfs_slab_alias(s, name)) {
4298                         s->refcount--;
4299                         s = NULL;
4300                 }
4301         }
4302 
4303         return s;
4304 }
4305 
4306 int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
4307 {
4308         int err;
4309 
4310         err = kmem_cache_open(s, flags);
4311         if (err)
4312                 return err;
4313 
4314         /* Mutex is not taken during early boot */
4315         if (slab_state <= UP)
4316                 return 0;
4317 
4318         memcg_propagate_slab_attrs(s);
4319         err = sysfs_slab_add(s);
4320         if (err)
4321                 __kmem_cache_release(s);
4322 
4323         return err;
4324 }
4325 
4326 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4327 {
4328         struct kmem_cache *s;
4329         void *ret;
4330 
4331         if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4332                 return kmalloc_large(size, gfpflags);
4333 
4334         s = kmalloc_slab(size, gfpflags);
4335 
4336         if (unlikely(ZERO_OR_NULL_PTR(s)))
4337                 return s;
4338 
4339         ret = slab_alloc(s, gfpflags, caller);
4340 
4341         /* Honor the call site pointer we received. */
4342         trace_kmalloc(caller, ret, size, s->size, gfpflags);
4343 
4344         return ret;
4345 }
4346 
4347 #ifdef CONFIG_NUMA
4348 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4349                                         int node, unsigned long caller)
4350 {
4351         struct kmem_cache *s;
4352         void *ret;
4353 
4354         if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4355                 ret = kmalloc_large_node(size, gfpflags, node);
4356 
4357                 trace_kmalloc_node(caller, ret,
4358                                    size, PAGE_SIZE << get_order(size),
4359                                    gfpflags, node);
4360 
4361                 return ret;
4362         }
4363 
4364         s = kmalloc_slab(size, gfpflags);
4365 
4366         if (unlikely(ZERO_OR_NULL_PTR(s)))
4367                 return s;
4368 
4369         ret = slab_alloc_node(s, gfpflags, node, caller);
4370 
4371         /* Honor the call site pointer we received. */
4372         trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4373 
4374         return ret;
4375 }
4376 #endif
4377 
4378 #ifdef CONFIG_SYSFS
4379 static int count_inuse(struct page *page)
4380 {
4381         return page->inuse;
4382 }
4383 
4384 static int count_total(struct page *page)
4385 {
4386         return page->objects;
4387 }
4388 #endif
4389 
4390 #ifdef CONFIG_SLUB_DEBUG
4391 static int validate_slab(struct kmem_cache *s, struct page *page,
4392                                                 unsigned long *map)
4393 {
4394         void *p;
4395         void *addr = page_address(page);
4396 
4397         if (!check_slab(s, page) ||
4398                         !on_freelist(s, page, NULL))
4399                 return 0;
4400 
4401         /* Now we know that a valid freelist exists */
4402         bitmap_zero(map, page->objects);
4403 
4404         get_map(s, page, map);
4405         for_each_object(p, s, addr, page->objects) {
4406                 if (test_bit(slab_index(p, s, addr), map))
4407                         if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4408                                 return 0;
4409         }
4410 
4411         for_each_object(p, s, addr, page->objects)
4412                 if (!test_bit(slab_index(p, s, addr), map))
4413                         if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4414                                 return 0;
4415         return 1;
4416 }
4417 
4418 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4419                                                 unsigned long *map)
4420 {
4421         slab_lock(page);
4422         validate_slab(s, page, map);
4423         slab_unlock(page);
4424 }
4425 
4426 static int validate_slab_node(struct kmem_cache *s,
4427                 struct kmem_cache_node *n, unsigned long *map)
4428 {
4429         unsigned long count = 0;
4430         struct page *page;
4431         unsigned long flags;
4432 
4433         spin_lock_irqsave(&n->list_lock, flags);
4434 
4435         list_for_each_entry(page, &n->partial, lru) {
4436                 validate_slab_slab(s, page, map);
4437                 count++;
4438         }
4439         if (count != n->nr_partial)
4440                 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4441                        s->name, count, n->nr_partial);
4442 
4443         if (!(s->flags & SLAB_STORE_USER))
4444                 goto out;
4445 
4446         list_for_each_entry(page, &n->full, lru) {
4447                 validate_slab_slab(s, page, map);
4448                 count++;
4449         }
4450         if (count != atomic_long_read(&n->nr_slabs))
4451                 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4452                        s->name, count, atomic_long_read(&n->nr_slabs));
4453 
4454 out:
4455         spin_unlock_irqrestore(&n->list_lock, flags);
4456         return count;
4457 }
4458 
4459 static long validate_slab_cache(struct kmem_cache *s)
4460 {
4461         int node;
4462         unsigned long count = 0;
4463         struct kmem_cache_node *n;
4464         unsigned long *map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL);
4465 
4466         if (!map)
4467                 return -ENOMEM;
4468 
4469         flush_all(s);
4470         for_each_kmem_cache_node(s, node, n)
4471                 count += validate_slab_node(s, n, map);
4472         bitmap_free(map);
4473         return count;
4474 }
4475 /*
4476  * Generate lists of code addresses where slabcache objects are allocated
4477  * and freed.
4478  */
4479 
4480 struct location {
4481         unsigned long count;
4482         unsigned long addr;
4483         long long sum_time;
4484         long min_time;
4485         long max_time;
4486         long min_pid;
4487         long max_pid;
4488         DECLARE_BITMAP(cpus, NR_CPUS);
4489         nodemask_t nodes;
4490 };
4491 
4492 struct loc_track {
4493         unsigned long max;
4494         unsigned long count;
4495         struct location *loc;
4496 };
4497 
4498 static void free_loc_track(struct loc_track *t)
4499 {
4500         if (t->max)
4501                 free_pages((unsigned long)t->loc,
4502                         get_order(sizeof(struct location) * t->max));
4503 }
4504 
4505 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4506 {
4507         struct location *l;
4508         int order;
4509 
4510         order = get_order(sizeof(struct location) * max);
4511 
4512         l = (void *)__get_free_pages(flags, order);
4513         if (!l)
4514                 return 0;
4515 
4516         if (t->count) {
4517                 memcpy(l, t->loc, sizeof(struct location) * t->count);
4518                 free_loc_track(t);
4519         }
4520         t->max = max;
4521         t->loc = l;
4522         return 1;
4523 }
4524 
4525 static int add_location(struct loc_track *t, struct kmem_cache *s,
4526                                 const struct track *track)
4527 {
4528         long start, end, pos;
4529         struct location *l;
4530         unsigned long caddr;
4531         unsigned long age = jiffies - track->when;
4532 
4533         start = -1;
4534         end = t->count;
4535 
4536         for ( ; ; ) {
4537                 pos = start + (end - start + 1) / 2;
4538 
4539                 /*
4540                  * There is nothing at "end". If we end up there
4541                  * we need to add something to before end.
4542                  */
4543                 if (pos == end)
4544                         break;
4545 
4546                 caddr = t->loc[pos].addr;
4547                 if (track->addr == caddr) {
4548 
4549                         l = &t->loc[pos];
4550                         l->count++;
4551                         if (track->when) {
4552                                 l->sum_time += age;
4553                                 if (age < l->min_time)
4554                                         l->min_time = age;
4555                                 if (age > l->max_time)
4556                                         l->max_time = age;
4557 
4558                                 if (track->pid < l->min_pid)
4559                                         l->min_pid = track->pid;
4560                                 if (track->pid > l->max_pid)
4561                                         l->max_pid = track->pid;
4562 
4563                                 cpumask_set_cpu(track->cpu,
4564                                                 to_cpumask(l->cpus));
4565                         }
4566                         node_set(page_to_nid(virt_to_page(track)), l->nodes);
4567                         return 1;
4568                 }
4569 
4570                 if (track->addr < caddr)
4571                         end = pos;
4572                 else
4573                         start = pos;
4574         }
4575 
4576         /*
4577          * Not found. Insert new tracking element.
4578          */
4579         if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4580                 return 0;
4581 
4582         l = t->loc + pos;
4583         if (pos < t->count)
4584                 memmove(l + 1, l,
4585                         (t->count - pos) * sizeof(struct location));
4586         t->count++;
4587         l->count = 1;
4588         l->addr = track->addr;
4589         l->sum_time = age;
4590         l->min_time = age;
4591         l->max_time = age;
4592         l->min_pid = track->pid;
4593         l->max_pid = track->pid;
4594         cpumask_clear(to_cpumask(l->cpus));
4595         cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4596         nodes_clear(l->nodes);
4597         node_set(page_to_nid(virt_to_page(track)), l->nodes);
4598         return 1;
4599 }
4600 
4601 static void process_slab(struct loc_track *t, struct kmem_cache *s,
4602                 struct page *page, enum track_item alloc,
4603                 unsigned long *map)
4604 {
4605         void *addr = page_address(page);
4606         void *p;
4607 
4608         bitmap_zero(map, page->objects);
4609         get_map(s, page, map);
4610 
4611         for_each_object(p, s, addr, page->objects)
4612                 if (!test_bit(slab_index(p, s, addr), map))
4613                         add_location(t, s, get_track(s, p, alloc));
4614 }
4615 
4616 static int list_locations(struct kmem_cache *s, char *buf,
4617                                         enum track_item alloc)
4618 {
4619         int len = 0;
4620         unsigned long i;
4621         struct loc_track t = { 0, 0, NULL };
4622         int node;
4623         struct kmem_cache_node *n;
4624         unsigned long *map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL);
4625 
4626         if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4627                                      GFP_KERNEL)) {
4628                 bitmap_free(map);
4629                 return sprintf(buf, "Out of memory\n");
4630         }
4631         /* Push back cpu slabs */
4632         flush_all(s);
4633 
4634         for_each_kmem_cache_node(s, node, n) {
4635                 unsigned long flags;
4636                 struct page *page;
4637 
4638                 if (!atomic_long_read(&n->nr_slabs))
4639                         continue;
4640 
4641                 spin_lock_irqsave(&n->list_lock, flags);
4642                 list_for_each_entry(page, &n->partial, lru)
4643                         process_slab(&t, s, page, alloc, map);
4644                 list_for_each_entry(page, &n->full, lru)
4645                         process_slab(&t, s, page, alloc, map);
4646                 spin_unlock_irqrestore(&n->list_lock, flags);
4647         }
4648 
4649         for (i = 0; i < t.count; i++) {
4650                 struct location *l = &t.loc[i];
4651 
4652                 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4653                         break;
4654                 len += sprintf(buf + len, "%7ld ", l->count);
4655 
4656                 if (l->addr)
4657                         len += sprintf(buf + len, "%pS", (void *)l->addr);
4658                 else
4659                         len += sprintf(buf + len, "<not-available>");
4660 
4661                 if (l->sum_time != l->min_time) {
4662                         len += sprintf(buf + len, " age=%ld/%ld/%ld",
4663                                 l->min_time,
4664                                 (long)div_u64(l->sum_time, l->count),
4665                                 l->max_time);
4666                 } else
4667                         len += sprintf(buf + len, " age=%ld",
4668                                 l->min_time);
4669 
4670                 if (l->min_pid != l->max_pid)
4671                         len += sprintf(buf + len, " pid=%ld-%ld",
4672                                 l->min_pid, l->max_pid);
4673                 else
4674                         len += sprintf(buf + len, " pid=%ld",
4675                                 l->min_pid);
4676 
4677                 if (num_online_cpus() > 1 &&
4678                                 !cpumask_empty(to_cpumask(l->cpus)) &&
4679                                 len < PAGE_SIZE - 60)
4680                         len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4681                                          " cpus=%*pbl",
4682                                          cpumask_pr_args(to_cpumask(l->cpus)));
4683 
4684                 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4685                                 len < PAGE_SIZE - 60)
4686                         len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4687                                          " nodes=%*pbl",
4688                                          nodemask_pr_args(&l->nodes));
4689 
4690                 len += sprintf(buf + len, "\n");
4691         }
4692 
4693         free_loc_track(&t);
4694         bitmap_free(map);
4695         if (!t.count)
4696                 len += sprintf(buf, "No data\n");
4697         return len;
4698 }
4699 #endif
4700 
4701 #ifdef SLUB_RESILIENCY_TEST
4702 static void __init resiliency_test(void)
4703 {
4704         u8 *p;
4705         int type = KMALLOC_NORMAL;
4706 
4707         BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4708 
4709         pr_err("SLUB resiliency testing\n");
4710         pr_err("-----------------------\n");
4711         pr_err("A. Corruption after allocation\n");
4712 
4713         p = kzalloc(16, GFP_KERNEL);
4714         p[16] = 0x12;
4715         pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4716                p + 16);
4717 
4718         validate_slab_cache(kmalloc_caches[type][4]);
4719 
4720         /* Hmmm... The next two are dangerous */
4721         p = kzalloc(32, GFP_KERNEL);
4722         p[32 + sizeof(void *)] = 0x34;
4723         pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4724                p);
4725         pr_err("If allocated object is overwritten then not detectable\n\n");
4726 
4727         validate_slab_cache(kmalloc_caches[type][5]);
4728         p = kzalloc(64, GFP_KERNEL);
4729         p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4730         *p = 0x56;
4731         pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4732                p);
4733         pr_err("If allocated object is overwritten then not detectable\n\n");
4734         validate_slab_cache(kmalloc_caches[type][6]);
4735 
4736         pr_err("\nB. Corruption after free\n");
4737         p = kzalloc(128, GFP_KERNEL);
4738         kfree(p);
4739         *p = 0x78;
4740         pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4741         validate_slab_cache(kmalloc_caches[type][7]);
4742 
4743         p = kzalloc(256, GFP_KERNEL);
4744         kfree(p);
4745         p[50] = 0x9a;
4746         pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
4747         validate_slab_cache(kmalloc_caches[type][8]);
4748 
4749         p = kzalloc(512, GFP_KERNEL);
4750         kfree(p);
4751         p[512] = 0xab;
4752         pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4753         validate_slab_cache(kmalloc_caches[type][9]);
4754 }
4755 #else
4756 #ifdef CONFIG_SYSFS
4757 static void resiliency_test(void) {};
4758 #endif
4759 #endif
4760 
4761 #ifdef CONFIG_SYSFS
4762 enum slab_stat_type {
4763         SL_ALL,                 /* All slabs */
4764         SL_PARTIAL,             /* Only partially allocated slabs */
4765         SL_CPU,                 /* Only slabs used for cpu caches */
4766         SL_OBJECTS,             /* Determine allocated objects not slabs */
4767         SL_TOTAL                /* Determine object capacity not slabs */
4768 };
4769 
4770 #define SO_ALL          (1 << SL_ALL)
4771 #define SO_PARTIAL      (1 << SL_PARTIAL)
4772 #define SO_CPU          (1 << SL_CPU)
4773 #define SO_OBJECTS      (1 << SL_OBJECTS)
4774 #define SO_TOTAL        (1 << SL_TOTAL)
4775 
4776 #ifdef CONFIG_MEMCG
4777 static bool memcg_sysfs_enabled = IS_ENABLED(CONFIG_SLUB_MEMCG_SYSFS_ON);
4778 
4779 static int __init setup_slub_memcg_sysfs(char *str)
4780 {
4781         int v;
4782 
4783         if (get_option(&str, &v) > 0)
4784                 memcg_sysfs_enabled = v;
4785 
4786         return 1;
4787 }
4788 
4789 __setup("slub_memcg_sysfs=", setup_slub_memcg_sysfs);
4790 #endif
4791 
4792 static ssize_t show_slab_objects(struct kmem_cache *s,
4793                             char *buf, unsigned long flags)
4794 {
4795         unsigned long total = 0;
4796         int node;
4797         int x;
4798         unsigned long *nodes;
4799 
4800         nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
4801         if (!nodes)
4802                 return -ENOMEM;
4803 
4804         if (flags & SO_CPU) {
4805                 int cpu;
4806 
4807                 for_each_possible_cpu(cpu) {
4808                         struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4809                                                                cpu);
4810                         int node;
4811                         struct page *page;
4812 
4813                         page = READ_ONCE(c->page);
4814                         if (!page)
4815                                 continue;
4816 
4817                         node = page_to_nid(page);
4818                         if (flags & SO_TOTAL)
4819                                 x = page->objects;
4820                         else if (flags & SO_OBJECTS)
4821                                 x = page->inuse;
4822                         else
4823                                 x = 1;
4824 
4825                         total += x;
4826                         nodes[node] += x;
4827 
4828                         page = slub_percpu_partial_read_once(c);
4829                         if (page) {
4830                                 node = page_to_nid(page);
4831                                 if (flags & SO_TOTAL)
4832                                         WARN_ON_ONCE(1);
4833                                 else if (flags & SO_OBJECTS)
4834                                         WARN_ON_ONCE(1);
4835                                 else
4836                                         x = page->pages;
4837                                 total += x;
4838                                 nodes[node] += x;
4839                         }
4840                 }
4841         }
4842 
4843         get_online_mems();
4844 #ifdef CONFIG_SLUB_DEBUG
4845         if (flags & SO_ALL) {
4846                 struct kmem_cache_node *n;
4847 
4848                 for_each_kmem_cache_node(s, node, n) {
4849 
4850                         if (flags & SO_TOTAL)
4851                                 x = atomic_long_read(&n->total_objects);
4852                         else if (flags & SO_OBJECTS)
4853                                 x = atomic_long_read(&n->total_objects) -
4854                                         count_partial(n, count_free);
4855                         else
4856                                 x = atomic_long_read(&n->nr_slabs);
4857                         total += x;
4858                         nodes[node] += x;
4859                 }
4860 
4861         } else
4862 #endif
4863         if (flags & SO_PARTIAL) {
4864                 struct kmem_cache_node *n;
4865 
4866                 for_each_kmem_cache_node(s, node, n) {
4867                         if (flags & SO_TOTAL)
4868                                 x = count_partial(n, count_total);
4869                         else if (flags & SO_OBJECTS)
4870                                 x = count_partial(n, count_inuse);
4871                         else
4872                                 x = n->nr_partial;
4873                         total += x;
4874                         nodes[node] += x;
4875                 }
4876         }
4877         x = sprintf(buf, "%lu", total);
4878 #ifdef CONFIG_NUMA
4879         for (node = 0; node < nr_node_ids; node++)
4880                 if (nodes[node])
4881                         x += sprintf(buf + x, " N%d=%lu",
4882                                         node, nodes[node]);
4883 #endif
4884         put_online_mems();
4885         kfree(nodes);
4886         return x + sprintf(buf + x, "\n");
4887 }
4888 
4889 #ifdef CONFIG_SLUB_DEBUG
4890 static int any_slab_objects(struct kmem_cache *s)
4891 {
4892         int node;
4893         struct kmem_cache_node *n;
4894 
4895         for_each_kmem_cache_node(s, node, n)
4896                 if (atomic_long_read(&n->total_objects))
4897                         return 1;
4898 
4899         return 0;
4900 }
4901 #endif
4902 
4903 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4904 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4905 
4906 struct slab_attribute {
4907         struct attribute attr;
4908         ssize_t (*show)(struct kmem_cache *s, char *buf);
4909         ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4910 };
4911 
4912 #define SLAB_ATTR_RO(_name) \
4913         static struct slab_attribute _name##_attr = \
4914         __ATTR(_name, 0400, _name##_show, NULL)
4915 
4916 #define SLAB_ATTR(_name) \
4917         static struct slab_attribute _name##_attr =  \
4918         __ATTR(_name, 0600, _name##_show, _name##_store)
4919 
4920 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4921 {
4922         return sprintf(buf, "%u\n", s->size);
4923 }
4924 SLAB_ATTR_RO(slab_size);
4925 
4926 static ssize_t align_show(struct kmem_cache *s, char *buf)
4927 {
4928         return sprintf(buf, "%u\n", s->align);
4929 }
4930 SLAB_ATTR_RO(align);
4931 
4932 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4933 {
4934         return sprintf(buf, "%u\n", s->object_size);
4935 }
4936 SLAB_ATTR_RO(object_size);
4937 
4938 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4939 {
4940         return sprintf(buf, "%u\n", oo_objects(s->oo));
4941 }
4942 SLAB_ATTR_RO(objs_per_slab);
4943 
4944 static ssize_t order_store(struct kmem_cache *s,
4945                                 const char *buf, size_t length)
4946 {
4947         unsigned int order;
4948         int err;
4949 
4950         err = kstrtouint(buf, 10, &order);
4951         if (err)
4952                 return err;
4953 
4954         if (order > slub_max_order || order < slub_min_order)
4955                 return -EINVAL;
4956 
4957         calculate_sizes(s, order);
4958         return length;
4959 }
4960 
4961 static ssize_t order_show(struct kmem_cache *s, char *buf)
4962 {
4963         return sprintf(buf, "%u\n", oo_order(s->oo));
4964 }
4965 SLAB_ATTR(order);
4966 
4967 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4968 {
4969         return sprintf(buf, "%lu\n", s->min_partial);
4970 }
4971 
4972 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4973                                  size_t length)
4974 {
4975         unsigned long min;
4976         int err;
4977 
4978         err = kstrtoul(buf, 10, &min);
4979         if (err)
4980                 return err;
4981 
4982         set_min_partial(s, min);
4983         return length;
4984 }
4985 SLAB_ATTR(min_partial);
4986 
4987 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4988 {
4989         return sprintf(buf, "%u\n", slub_cpu_partial(s));
4990 }
4991 
4992 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4993                                  size_t length)
4994 {
4995         unsigned int objects;
4996         int err;
4997 
4998         err = kstrtouint(buf, 10, &objects);
4999         if (err)
5000                 return err;
5001         if (objects && !kmem_cache_has_cpu_partial(s))
5002                 return -EINVAL;
5003 
5004         slub_set_cpu_partial(s, objects);
5005         flush_all(s);
5006         return length;
5007 }
5008 SLAB_ATTR(cpu_partial);
5009 
5010 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
5011 {
5012         if (!s->ctor)
5013                 return 0;
5014         return sprintf(buf, "%pS\n", s->ctor);
5015 }
5016 SLAB_ATTR_RO(ctor);
5017 
5018 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
5019 {
5020         return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
5021 }
5022 SLAB_ATTR_RO(aliases);
5023 
5024 static ssize_t partial_show(struct kmem_cache *s, char *buf)
5025 {
5026         return show_slab_objects(s, buf, SO_PARTIAL);
5027 }
5028 SLAB_ATTR_RO(partial);
5029 
5030 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
5031 {
5032         return show_slab_objects(s, buf, SO_CPU);
5033 }
5034 SLAB_ATTR_RO(cpu_slabs);
5035 
5036 static ssize_t objects_show(struct kmem_cache *s, char *buf)
5037 {
5038         return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
5039 }
5040 SLAB_ATTR_RO(objects);
5041 
5042 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
5043 {
5044         return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
5045 }
5046 SLAB_ATTR_RO(objects_partial);
5047 
5048 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
5049 {
5050         int objects = 0;
5051         int pages = 0;
5052         int cpu;
5053         int len;
5054 
5055         for_each_online_cpu(cpu) {
5056                 struct page *page;
5057 
5058                 page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5059 
5060                 if (page) {
5061                         pages += page->pages;
5062                         objects += page->pobjects;
5063                 }
5064         }
5065 
5066         len = sprintf(buf, "%d(%d)", objects, pages);
5067 
5068 #ifdef CONFIG_SMP
5069         for_each_online_cpu(cpu) {
5070                 struct page *page;
5071 
5072                 page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5073 
5074                 if (page && len < PAGE_SIZE - 20)
5075                         len += sprintf(buf + len, " C%d=%d(%d)", cpu,
5076                                 page->pobjects, page->pages);
5077         }
5078 #endif
5079         return len + sprintf(buf + len, "\n");
5080 }
5081 SLAB_ATTR_RO(slabs_cpu_partial);
5082 
5083 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
5084 {
5085         return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
5086 }
5087 
5088 static ssize_t reclaim_account_store(struct kmem_cache *s,
5089                                 const char *buf, size_t length)
5090 {
5091         s->flags &= ~SLAB_RECLAIM_ACCOUNT;
5092         if (buf[0] == '1')
5093                 s->flags |= SLAB_RECLAIM_ACCOUNT;
5094         return length;
5095 }
5096 SLAB_ATTR(reclaim_account);
5097 
5098 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
5099 {
5100         return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
5101 }
5102 SLAB_ATTR_RO(hwcache_align);
5103 
5104 #ifdef CONFIG_ZONE_DMA
5105 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
5106 {
5107         return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
5108 }
5109 SLAB_ATTR_RO(cache_dma);
5110 #endif
5111 
5112 static ssize_t usersize_show(struct kmem_cache *s, char *buf)
5113 {
5114         return sprintf(buf, "%u\n", s->usersize);
5115 }
5116 SLAB_ATTR_RO(usersize);
5117 
5118 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
5119 {
5120         return sprintf(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
5121 }
5122 SLAB_ATTR_RO(destroy_by_rcu);
5123 
5124 #ifdef CONFIG_SLUB_DEBUG
5125 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
5126 {
5127         return show_slab_objects(s, buf, SO_ALL);
5128 }
5129 SLAB_ATTR_RO(slabs);
5130 
5131 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
5132 {
5133         return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
5134 }
5135 SLAB_ATTR_RO(total_objects);
5136 
5137 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
5138 {
5139         return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
5140 }
5141 
5142 static ssize_t sanity_checks_store(struct kmem_cache *s,
5143                                 const char *buf, size_t length)
5144 {
5145         s->flags &= ~SLAB_CONSISTENCY_CHECKS;
5146         if (buf[0] == '1') {
5147                 s->flags &= ~__CMPXCHG_DOUBLE;
5148                 s->flags |= SLAB_CONSISTENCY_CHECKS;
5149         }
5150         return length;
5151 }
5152 SLAB_ATTR(sanity_checks);
5153 
5154 static ssize_t trace_show(struct kmem_cache *s, char *buf)
5155 {
5156         return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
5157 }
5158 
5159 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
5160                                                         size_t length)
5161 {
5162         /*
5163          * Tracing a merged cache is going to give confusing results
5164          * as well as cause other issues like converting a mergeable
5165          * cache into an umergeable one.
5166          */
5167         if (s->refcount > 1)
5168                 return -EINVAL;
5169 
5170         s->flags &= ~SLAB_TRACE;
5171         if (buf[0] == '1') {
5172                 s->flags &= ~__CMPXCHG_DOUBLE;
5173                 s->flags |= SLAB_TRACE;
5174         }
5175         return length;
5176 }
5177 SLAB_ATTR(trace);
5178 
5179 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5180 {
5181         return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5182 }
5183 
5184 static ssize_t red_zone_store(struct kmem_cache *s,
5185                                 const char *buf, size_t length)
5186 {
5187         if (any_slab_objects(s))
5188                 return -EBUSY;
5189 
5190         s->flags &= ~SLAB_RED_ZONE;
5191         if (buf[0] == '1') {
5192                 s->flags |= SLAB_RED_ZONE;
5193         }
5194         calculate_sizes(s, -1);
5195         return length;
5196 }
5197 SLAB_ATTR(red_zone);
5198 
5199 static ssize_t poison_show(struct kmem_cache *s, char *buf)
5200 {
5201         return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
5202 }
5203 
5204 static ssize_t poison_store(struct kmem_cache *s,
5205                                 const char *buf, size_t length)
5206 {
5207         if (any_slab_objects(s))
5208                 return -EBUSY;
5209 
5210         s->flags &= ~SLAB_POISON;
5211         if (buf[0] == '1') {
5212                 s->flags |= SLAB_POISON;
5213         }
5214         calculate_sizes(s, -1);
5215         return length;
5216 }
5217 SLAB_ATTR(poison);
5218 
5219 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5220 {
5221         return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5222 }
5223 
5224 static ssize_t store_user_store(struct kmem_cache *s,
5225                                 const char *buf, size_t length)
5226 {
5227         if (any_slab_objects(s))
5228                 return -EBUSY;
5229 
5230         s->flags &= ~SLAB_STORE_USER;
5231         if (buf[0] == '1') {
5232                 s->flags &= ~__CMPXCHG_DOUBLE;
5233                 s->flags |= SLAB_STORE_USER;
5234         }
5235         calculate_sizes(s, -1);
5236         return length;
5237 }
5238 SLAB_ATTR(store_user);
5239 
5240 static ssize_t validate_show(struct kmem_cache *s, char *buf)
5241 {
5242         return 0;
5243 }
5244 
5245 static ssize_t validate_store(struct kmem_cache *s,
5246                         const char *buf, size_t length)
5247 {
5248         int ret = -EINVAL;
5249 
5250         if (buf[0] == '1') {
5251                 ret = validate_slab_cache(s);
5252                 if (ret >= 0)
5253                         ret = length;
5254         }
5255         return ret;
5256 }
5257 SLAB_ATTR(validate);
5258 
5259 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
5260 {
5261         if (!(s->flags & SLAB_STORE_USER))
5262                 return -ENOSYS;
5263         return list_locations(s, buf, TRACK_ALLOC);
5264 }
5265 SLAB_ATTR_RO(alloc_calls);
5266 
5267 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
5268 {
5269         if (!(s->flags & SLAB_STORE_USER))
5270                 return -ENOSYS;
5271         return list_locations(s, buf, TRACK_FREE);
5272 }
5273 SLAB_ATTR_RO(free_calls);
5274 #endif /* CONFIG_SLUB_DEBUG */
5275 
5276 #ifdef CONFIG_FAILSLAB
5277 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5278 {
5279         return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5280 }
5281 
5282 static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
5283                                                         size_t length)
5284 {
5285         if (s->refcount > 1)
5286                 return -EINVAL;
5287 
5288         s->flags &= ~SLAB_FAILSLAB;
5289         if (buf[0] == '1')
5290                 s->flags |= SLAB_FAILSLAB;
5291         return length;
5292 }
5293 SLAB_ATTR(failslab);
5294 #endif
5295 
5296 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5297 {
5298         return 0;
5299 }
5300 
5301 static ssize_t shrink_store(struct kmem_cache *s,
5302                         const char *buf, size_t length)
5303 {
5304         if (buf[0] == '1')
5305                 kmem_cache_shrink(s);
5306         else
5307                 return -EINVAL;
5308         return length;
5309 }
5310 SLAB_ATTR(shrink);
5311 
5312 #ifdef CONFIG_NUMA
5313 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5314 {
5315         return sprintf(buf, "%u\n", s->remote_node_defrag_ratio / 10);
5316 }
5317 
5318 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5319                                 const char *buf, size_t length)
5320 {
5321         unsigned int ratio;
5322         int err;
5323 
5324         err = kstrtouint(buf, 10, &ratio);
5325         if (err)
5326                 return err;
5327         if (ratio > 100)
5328                 return -ERANGE;
5329 
5330         s->remote_node_defrag_ratio = ratio * 10;
5331 
5332         return length;
5333 }
5334 SLAB_ATTR(remote_node_defrag_ratio);
5335 #endif
5336 
5337 #ifdef CONFIG_SLUB_STATS
5338 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5339 {
5340         unsigned long sum  = 0;
5341         int cpu;
5342         int len;
5343         int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
5344 
5345         if (!data)
5346                 return -ENOMEM;
5347 
5348         for_each_online_cpu(cpu) {
5349                 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5350 
5351                 data[cpu] = x;
5352                 sum += x;
5353         }
5354 
5355         len = sprintf(buf, "%lu", sum);
5356 
5357 #ifdef CONFIG_SMP
5358         for_each_online_cpu(cpu) {
5359                 if (data[cpu] && len < PAGE_SIZE - 20)
5360                         len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
5361         }
5362 #endif
5363         kfree(data);
5364         return len + sprintf(buf + len, "\n");
5365 }
5366 
5367 static void clear_stat(struct kmem_cache *s, enum stat_item si)
5368 {
5369         int cpu;
5370 
5371         for_each_online_cpu(cpu)
5372                 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5373 }
5374 
5375 #define STAT_ATTR(si, text)                                     \
5376 static ssize_t text##_show(struct kmem_cache *s, char *buf)     \
5377 {                                                               \
5378         return show_stat(s, buf, si);                           \
5379 }                                                               \
5380 static ssize_t text##_store(struct kmem_cache *s,               \
5381                                 const char *buf, size_t length) \
5382 {                                                               \
5383         if (buf[0] != '')                                      \
5384                 return -EINVAL;                                 \
5385         clear_stat(s, si);                                      \
5386         return length;                                          \
5387 }                                                               \
5388 SLAB_ATTR(text);                                                \
5389 
5390 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5391 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5392 STAT_ATTR(FREE_FASTPATH, free_fastpath);
5393 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5394 STAT_ATTR(FREE_FROZEN, free_frozen);
5395 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5396 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5397 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5398 STAT_ATTR(ALLOC_SLAB, alloc_slab);
5399 STAT_ATTR(ALLOC_REFILL, alloc_refill);
5400 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5401 STAT_ATTR(FREE_SLAB, free_slab);
5402 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5403 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5404 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5405 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5406 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5407 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5408 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5409 STAT_ATTR(ORDER_FALLBACK, order_fallback);
5410 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5411 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5412 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5413 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5414 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5415 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5416 #endif
5417 
5418 static struct attribute *slab_attrs[] = {
5419         &slab_size_attr.attr,
5420         &object_size_attr.attr,
5421         &objs_per_slab_attr.attr,
5422         &order_attr.attr,
5423         &min_partial_attr.attr,
5424         &cpu_partial_attr.attr,
5425         &objects_attr.attr,
5426         &objects_partial_attr.attr,
5427         &partial_attr.attr,
5428         &cpu_slabs_attr.attr,
5429         &ctor_attr.attr,
5430         &aliases_attr.attr,
5431         &align_attr.attr,
5432         &hwcache_align_attr.attr,
5433         &reclaim_account_attr.attr,
5434         &destroy_by_rcu_attr.attr,
5435         &shrink_attr.attr,
5436         &slabs_cpu_partial_attr.attr,
5437 #ifdef CONFIG_SLUB_DEBUG
5438         &total_objects_attr.attr,
5439         &slabs_attr.attr,
5440         &sanity_checks_attr.attr,
5441         &trace_attr.attr,
5442         &red_zone_attr.attr,
5443         &poison_attr.attr,
5444         &store_user_attr.attr,
5445         &validate_attr.attr,
5446         &alloc_calls_attr.attr,
5447         &free_calls_attr.attr,
5448 #endif
5449 #ifdef CONFIG_ZONE_DMA
5450         &cache_dma_attr.attr,
5451 #endif
5452 #ifdef CONFIG_NUMA
5453         &remote_node_defrag_ratio_attr.attr,
5454 #endif
5455 #ifdef CONFIG_SLUB_STATS
5456         &alloc_fastpath_attr.attr,
5457         &alloc_slowpath_attr.attr,
5458         &free_fastpath_attr.attr,
5459         &free_slowpath_attr.attr,
5460         &free_frozen_attr.attr,
5461         &free_add_partial_attr.attr,
5462         &free_remove_partial_attr.attr,
5463         &alloc_from_partial_attr.attr,
5464         &alloc_slab_attr.attr,
5465         &alloc_refill_attr.attr,
5466         &alloc_node_mismatch_attr.attr,
5467         &free_slab_attr.attr,
5468         &cpuslab_flush_attr.attr,
5469         &deactivate_full_attr.attr,
5470         &deactivate_empty_attr.attr,
5471         &deactivate_to_head_attr.attr,
5472         &deactivate_to_tail_attr.attr,
5473         &deactivate_remote_frees_attr.attr,
5474         &deactivate_bypass_attr.attr,
5475         &order_fallback_attr.attr,
5476         &cmpxchg_double_fail_attr.attr,
5477         &cmpxchg_double_cpu_fail_attr.attr,
5478         &cpu_partial_alloc_attr.attr,
5479         &cpu_partial_free_attr.attr,
5480         &cpu_partial_node_attr.attr,
5481         &cpu_partial_drain_attr.attr,
5482 #endif
5483 #ifdef CONFIG_FAILSLAB
5484         &failslab_attr.attr,
5485 #endif
5486         &usersize_attr.attr,
5487 
5488         NULL
5489 };
5490 
5491 static const struct attribute_group slab_attr_group = {
5492         .attrs = slab_attrs,
5493 };
5494 
5495 static ssize_t slab_attr_show(struct kobject *kobj,
5496                                 struct attribute *attr,
5497                                 char *buf)
5498 {
5499         struct slab_attribute *attribute;
5500         struct kmem_cache *s;
5501         int err;
5502 
5503         attribute = to_slab_attr(attr);
5504         s = to_slab(kobj);
5505 
5506         if (!attribute->show)
5507                 return -EIO;
5508 
5509         err = attribute->show(s, buf);
5510 
5511         return err;
5512 }
5513 
5514 static ssize_t slab_attr_store(struct kobject *kobj,
5515                                 struct attribute *attr,
5516                                 const char *buf, size_t len)
5517 {
5518         struct slab_attribute *attribute;
5519         struct kmem_cache *s;
5520         int err;
5521 
5522         attribute = to_slab_attr(attr);
5523         s = to_slab(kobj);
5524 
5525         if (!attribute->store)
5526                 return -EIO;
5527 
5528         err = attribute->store(s, buf, len);
5529 #ifdef CONFIG_MEMCG
5530         if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
5531                 struct kmem_cache *c;
5532 
5533                 mutex_lock(&slab_mutex);
5534                 if (s->max_attr_size < len)
5535                         s->max_attr_size = len;
5536 
5537                 /*
5538                  * This is a best effort propagation, so this function's return
5539                  * value will be determined by the parent cache only. This is
5540                  * basically because not all attributes will have a well
5541                  * defined semantics for rollbacks - most of the actions will
5542                  * have permanent effects.
5543                  *
5544                  * Returning the error value of any of the children that fail
5545                  * is not 100 % defined, in the sense that users seeing the
5546                  * error code won't be able to know anything about the state of
5547                  * the cache.
5548                  *
5549                  * Only returning the error code for the parent cache at least
5550                  * has well defined semantics. The cache being written to
5551                  * directly either failed or succeeded, in which case we loop
5552                  * through the descendants with best-effort propagation.
5553                  */
5554                 for_each_memcg_cache(c, s)
5555                         attribute->store(c, buf, len);
5556                 mutex_unlock(&slab_mutex);
5557         }
5558 #endif
5559         return err;
5560 }
5561 
5562 static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5563 {
5564 #ifdef CONFIG_MEMCG
5565         int i;
5566         char *buffer = NULL;
5567         struct kmem_cache *root_cache;
5568 
5569         if (is_root_cache(s))
5570                 return;
5571 
5572         root_cache = s->memcg_params.root_cache;
5573 
5574         /*
5575          * This mean this cache had no attribute written. Therefore, no point
5576          * in copying default values around
5577          */
5578         if (!root_cache->max_attr_size)
5579                 return;
5580 
5581         for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5582                 char mbuf[64];
5583                 char *buf;
5584                 struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5585                 ssize_t len;
5586 
5587                 if (!attr || !attr->store || !attr->show)
5588                         continue;
5589 
5590                 /*
5591                  * It is really bad that we have to allocate here, so we will
5592                  * do it only as a fallback. If we actually allocate, though,
5593                  * we can just use the allocated buffer until the end.
5594                  *
5595                  * Most of the slub attributes will tend to be very small in
5596                  * size, but sysfs allows buffers up to a page, so they can
5597                  * theoretically happen.
5598                  */
5599                 if (buffer)
5600                         buf = buffer;
5601                 else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
5602                         buf = mbuf;
5603                 else {
5604                         buffer = (char *) get_zeroed_page(GFP_KERNEL);
5605                         if (WARN_ON(!buffer))
5606                                 continue;
5607                         buf = buffer;
5608                 }
5609 
5610                 len = attr->show(root_cache, buf);
5611                 if (len > 0)
5612                         attr->store(s, buf, len);
5613         }
5614 
5615         if (buffer)
5616                 free_page((unsigned long)buffer);
5617 #endif
5618 }
5619 
5620 static void kmem_cache_release(struct kobject *k)
5621 {
5622         slab_kmem_cache_release(to_slab(k));
5623 }
5624 
5625 static const struct sysfs_ops slab_sysfs_ops = {
5626         .show = slab_attr_show,
5627         .store = slab_attr_store,
5628 };
5629 
5630 static struct kobj_type slab_ktype = {
5631         .sysfs_ops = &slab_sysfs_ops,
5632         .release = kmem_cache_release,
5633 };
5634 
5635 static int uevent_filter(struct kset *kset, struct kobject *kobj)
5636 {
5637         struct kobj_type *ktype = get_ktype(kobj);
5638 
5639         if (ktype == &slab_ktype)
5640                 return 1;
5641         return 0;
5642 }
5643 
5644 static const struct kset_uevent_ops slab_uevent_ops = {
5645         .filter = uevent_filter,
5646 };
5647 
5648 static struct kset *slab_kset;
5649 
5650 static inline struct kset *cache_kset(struct kmem_cache *s)
5651 {
5652 #ifdef CONFIG_MEMCG
5653         if (!is_root_cache(s))
5654                 return s->memcg_params.root_cache->memcg_kset;
5655 #endif
5656         return slab_kset;
5657 }
5658 
5659 #define ID_STR_LENGTH 64
5660 
5661 /* Create a unique string id for a slab cache:
5662  *
5663  * Format       :[flags-]size
5664  */
5665 static char *create_unique_id(struct kmem_cache *s)
5666 {
5667         char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5668         char *p = name;
5669 
5670         BUG_ON(!name);
5671 
5672         *p++ = ':';
5673         /*
5674          * First flags affecting slabcache operations. We will only
5675          * get here for aliasable slabs so we do not need to support
5676          * too many flags. The flags here must cover all flags that
5677          * are matched during merging to guarantee that the id is
5678          * unique.
5679          */
5680         if (s->flags & SLAB_CACHE_DMA)
5681                 *p++ = 'd';
5682         if (s->flags & SLAB_RECLAIM_ACCOUNT)
5683                 *p++ = 'a';
5684         if (s->flags & SLAB_CONSISTENCY_CHECKS)
5685                 *p++ = 'F';
5686         if (s->flags & SLAB_ACCOUNT)
5687                 *p++ = 'A';
5688         if (p != name + 1)
5689                 *p++ = '-';
5690         p += sprintf(p, "%07u", s->size);
5691 
5692         BUG_ON(p > name + ID_STR_LENGTH - 1);
5693         return name;
5694 }
5695 
5696 static void sysfs_slab_remove_workfn(struct work_struct *work)
5697 {
5698         struct kmem_cache *s =
5699                 container_of(work, struct kmem_cache, kobj_remove_work);
5700 
5701         if (!s->kobj.state_in_sysfs)
5702                 /*
5703                  * For a memcg cache, this may be called during
5704                  * deactivation and again on shutdown.  Remove only once.
5705                  * A cache is never shut down before deactivation is
5706                  * complete, so no need to worry about synchronization.
5707                  */
5708                 goto out;
5709 
5710 #ifdef CONFIG_MEMCG
5711         kset_unregister(s->memcg_kset);
5712 #endif
5713         kobject_uevent(&s->kobj, KOBJ_REMOVE);
5714 out:
5715         kobject_put(&s->kobj);
5716 }
5717 
5718 static int sysfs_slab_add(struct kmem_cache *s)
5719 {
5720         int err;
5721         const char *name;
5722         struct kset *kset = cache_kset(s);
5723         int unmergeable = slab_unmergeable(s);
5724 
5725         INIT_WORK(&s->kobj_remove_work, sysfs_slab_remove_workfn);
5726 
5727         if (!kset) {
5728                 kobject_init(&s->kobj, &slab_ktype);
5729                 return 0;
5730         }
5731 
5732         if (!unmergeable && disable_higher_order_debug &&
5733                         (slub_debug & DEBUG_METADATA_FLAGS))
5734                 unmergeable = 1;
5735 
5736         if (unmergeable) {
5737                 /*
5738                  * Slabcache can never be merged so we can use the name proper.
5739                  * This is typically the case for debug situations. In that
5740                  * case we can catch duplicate names easily.
5741                  */
5742                 sysfs_remove_link(&slab_kset->kobj, s->name);
5743                 name = s->name;
5744         } else {
5745                 /*
5746                  * Create a unique name for the slab as a target
5747                  * for the symlinks.
5748                  */
5749                 name = create_unique_id(s);
5750         }
5751 
5752         s->kobj.kset = kset;
5753         err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5754         if (err)
5755                 goto out;
5756 
5757         err = sysfs_create_group(&s->kobj, &slab_attr_group);
5758         if (err)
5759                 goto out_del_kobj;
5760 
5761 #ifdef CONFIG_MEMCG
5762         if (is_root_cache(s) && memcg_sysfs_enabled) {
5763                 s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj);
5764                 if (!s->memcg_kset) {
5765                         err = -ENOMEM;
5766                         goto out_del_kobj;
5767                 }
5768         }
5769 #endif
5770 
5771         kobject_uevent(&s->kobj, KOBJ_ADD);
5772         if (!unmergeable) {
5773                 /* Setup first alias */
5774                 sysfs_slab_alias(s, s->name);
5775         }
5776 out:
5777         if (!unmergeable)
5778                 kfree(name);
5779         return err;
5780 out_del_kobj:
5781         kobject_del(&s->kobj);
5782         goto out;
5783 }
5784 
5785 static void sysfs_slab_remove(struct kmem_cache *s)
5786 {
5787         if (slab_state < FULL)
5788                 /*
5789                  * Sysfs has not been setup yet so no need to remove the
5790                  * cache from sysfs.
5791                  */
5792                 return;
5793 
5794         kobject_get(&s->kobj);
5795         schedule_work(&s->kobj_remove_work);
5796 }
5797 
5798 void sysfs_slab_unlink(struct kmem_cache *s)
5799 {
5800         if (slab_state >= FULL)
5801                 kobject_del(&s->kobj);
5802 }
5803 
5804 void sysfs_slab_release(struct kmem_cache *s)
5805 {
5806         if (slab_state >= FULL)
5807                 kobject_put(&s->kobj);
5808 }
5809 
5810 /*
5811  * Need to buffer aliases during bootup until sysfs becomes
5812  * available lest we lose that information.
5813  */
5814 struct saved_alias {
5815         struct kmem_cache *s;
5816         const char *name;
5817         struct saved_alias *next;
5818 };
5819 
5820 static struct saved_alias *alias_list;
5821 
5822 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5823 {
5824         struct saved_alias *al;
5825 
5826         if (slab_state == FULL) {
5827                 /*
5828                  * If we have a leftover link then remove it.
5829                  */
5830                 sysfs_remove_link(&slab_kset->kobj, name);
5831                 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5832         }
5833 
5834         al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5835         if (!al)
5836                 return -ENOMEM;
5837 
5838         al->s = s;
5839         al->name = name;
5840         al->next = alias_list;
5841         alias_list = al;
5842         return 0;
5843 }
5844 
5845 static int __init slab_sysfs_init(void)
5846 {
5847         struct kmem_cache *s;
5848         int err;
5849 
5850         mutex_lock(&slab_mutex);
5851 
5852         slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5853         if (!slab_kset) {
5854                 mutex_unlock(&slab_mutex);
5855                 pr_err("Cannot register slab subsystem.\n");
5856                 return -ENOSYS;
5857         }
5858 
5859         slab_state = FULL;
5860 
5861         list_for_each_entry(s, &slab_caches, list) {
5862                 err = sysfs_slab_add(s);
5863                 if (err)
5864                         pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5865                                s->name);
5866         }
5867 
5868         while (alias_list) {
5869                 struct saved_alias *al = alias_list;
5870 
5871                 alias_list = alias_list->next;
5872                 err = sysfs_slab_alias(al->s, al->name);
5873                 if (err)
5874                         pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5875                                al->name);
5876                 kfree(al);
5877         }
5878 
5879         mutex_unlock(&slab_mutex);
5880         resiliency_test();
5881         return 0;
5882 }
5883 
5884 __initcall(slab_sysfs_init);
5885 #endif /* CONFIG_SYSFS */
5886 
5887 /*
5888  * The /proc/slabinfo ABI
5889  */
5890 #ifdef CONFIG_SLUB_DEBUG
5891 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5892 {
5893         unsigned long nr_slabs = 0;
5894         unsigned long nr_objs = 0;
5895         unsigned long nr_free = 0;
5896         int node;
5897         struct kmem_cache_node *n;
5898 
5899         for_each_kmem_cache_node(s, node, n) {
5900                 nr_slabs += node_nr_slabs(n);
5901                 nr_objs += node_nr_objs(n);
5902                 nr_free += count_partial(n, count_free);
5903         }
5904 
5905         sinfo->active_objs = nr_objs - nr_free;
5906         sinfo->num_objs = nr_objs;
5907         sinfo->active_slabs = nr_slabs;
5908         sinfo->num_slabs = nr_slabs;
5909         sinfo->objects_per_slab = oo_objects(s->oo);
5910         sinfo->cache_order = oo_order(s->oo);
5911 }
5912 
5913 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5914 {
5915 }
5916 
5917 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5918                        size_t count, loff_t *ppos)
5919 {
5920         return -EIO;
5921 }
5922 #endif /* CONFIG_SLUB_DEBUG */
5923 

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