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

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