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TOMOYO Linux Cross Reference
Linux/include/linux/slab.h

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  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 /*
  3  * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
  4  *
  5  * (C) SGI 2006, Christoph Lameter
  6  *      Cleaned up and restructured to ease the addition of alternative
  7  *      implementations of SLAB allocators.
  8  * (C) Linux Foundation 2008-2013
  9  *      Unified interface for all slab allocators
 10  */
 11 
 12 #ifndef _LINUX_SLAB_H
 13 #define _LINUX_SLAB_H
 14 
 15 #include <linux/gfp.h>
 16 #include <linux/overflow.h>
 17 #include <linux/types.h>
 18 #include <linux/workqueue.h>
 19 #include <linux/percpu-refcount.h>
 20 
 21 
 22 /*
 23  * Flags to pass to kmem_cache_create().
 24  * The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
 25  */
 26 /* DEBUG: Perform (expensive) checks on alloc/free */
 27 #define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100U)
 28 /* DEBUG: Red zone objs in a cache */
 29 #define SLAB_RED_ZONE           ((slab_flags_t __force)0x00000400U)
 30 /* DEBUG: Poison objects */
 31 #define SLAB_POISON             ((slab_flags_t __force)0x00000800U)
 32 /* Align objs on cache lines */
 33 #define SLAB_HWCACHE_ALIGN      ((slab_flags_t __force)0x00002000U)
 34 /* Use GFP_DMA memory */
 35 #define SLAB_CACHE_DMA          ((slab_flags_t __force)0x00004000U)
 36 /* Use GFP_DMA32 memory */
 37 #define SLAB_CACHE_DMA32        ((slab_flags_t __force)0x00008000U)
 38 /* DEBUG: Store the last owner for bug hunting */
 39 #define SLAB_STORE_USER         ((slab_flags_t __force)0x00010000U)
 40 /* Panic if kmem_cache_create() fails */
 41 #define SLAB_PANIC              ((slab_flags_t __force)0x00040000U)
 42 /*
 43  * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
 44  *
 45  * This delays freeing the SLAB page by a grace period, it does _NOT_
 46  * delay object freeing. This means that if you do kmem_cache_free()
 47  * that memory location is free to be reused at any time. Thus it may
 48  * be possible to see another object there in the same RCU grace period.
 49  *
 50  * This feature only ensures the memory location backing the object
 51  * stays valid, the trick to using this is relying on an independent
 52  * object validation pass. Something like:
 53  *
 54  *  rcu_read_lock()
 55  * again:
 56  *  obj = lockless_lookup(key);
 57  *  if (obj) {
 58  *    if (!try_get_ref(obj)) // might fail for free objects
 59  *      goto again;
 60  *
 61  *    if (obj->key != key) { // not the object we expected
 62  *      put_ref(obj);
 63  *      goto again;
 64  *    }
 65  *  }
 66  *  rcu_read_unlock();
 67  *
 68  * This is useful if we need to approach a kernel structure obliquely,
 69  * from its address obtained without the usual locking. We can lock
 70  * the structure to stabilize it and check it's still at the given address,
 71  * only if we can be sure that the memory has not been meanwhile reused
 72  * for some other kind of object (which our subsystem's lock might corrupt).
 73  *
 74  * rcu_read_lock before reading the address, then rcu_read_unlock after
 75  * taking the spinlock within the structure expected at that address.
 76  *
 77  * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
 78  */
 79 /* Defer freeing slabs to RCU */
 80 #define SLAB_TYPESAFE_BY_RCU    ((slab_flags_t __force)0x00080000U)
 81 /* Spread some memory over cpuset */
 82 #define SLAB_MEM_SPREAD         ((slab_flags_t __force)0x00100000U)
 83 /* Trace allocations and frees */
 84 #define SLAB_TRACE              ((slab_flags_t __force)0x00200000U)
 85 
 86 /* Flag to prevent checks on free */
 87 #ifdef CONFIG_DEBUG_OBJECTS
 88 # define SLAB_DEBUG_OBJECTS     ((slab_flags_t __force)0x00400000U)
 89 #else
 90 # define SLAB_DEBUG_OBJECTS     0
 91 #endif
 92 
 93 /* Avoid kmemleak tracing */
 94 #define SLAB_NOLEAKTRACE        ((slab_flags_t __force)0x00800000U)
 95 
 96 /* Fault injection mark */
 97 #ifdef CONFIG_FAILSLAB
 98 # define SLAB_FAILSLAB          ((slab_flags_t __force)0x02000000U)
 99 #else
100 # define SLAB_FAILSLAB          0
101 #endif
102 /* Account to memcg */
103 #ifdef CONFIG_MEMCG_KMEM
104 # define SLAB_ACCOUNT           ((slab_flags_t __force)0x04000000U)
105 #else
106 # define SLAB_ACCOUNT           0
107 #endif
108 
109 #ifdef CONFIG_KASAN
110 #define SLAB_KASAN              ((slab_flags_t __force)0x08000000U)
111 #else
112 #define SLAB_KASAN              0
113 #endif
114 
115 /* The following flags affect the page allocator grouping pages by mobility */
116 /* Objects are reclaimable */
117 #define SLAB_RECLAIM_ACCOUNT    ((slab_flags_t __force)0x00020000U)
118 #define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
119 
120 /* Slab deactivation flag */
121 #define SLAB_DEACTIVATED        ((slab_flags_t __force)0x10000000U)
122 
123 /*
124  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
125  *
126  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
127  *
128  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
129  * Both make kfree a no-op.
130  */
131 #define ZERO_SIZE_PTR ((void *)16)
132 
133 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
134                                 (unsigned long)ZERO_SIZE_PTR)
135 
136 #include <linux/kasan.h>
137 
138 struct mem_cgroup;
139 /*
140  * struct kmem_cache related prototypes
141  */
142 void __init kmem_cache_init(void);
143 bool slab_is_available(void);
144 
145 extern bool usercopy_fallback;
146 
147 struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
148                         unsigned int align, slab_flags_t flags,
149                         void (*ctor)(void *));
150 struct kmem_cache *kmem_cache_create_usercopy(const char *name,
151                         unsigned int size, unsigned int align,
152                         slab_flags_t flags,
153                         unsigned int useroffset, unsigned int usersize,
154                         void (*ctor)(void *));
155 void kmem_cache_destroy(struct kmem_cache *);
156 int kmem_cache_shrink(struct kmem_cache *);
157 
158 void memcg_create_kmem_cache(struct mem_cgroup *, struct kmem_cache *);
159 void memcg_deactivate_kmem_caches(struct mem_cgroup *, struct mem_cgroup *);
160 
161 /*
162  * Please use this macro to create slab caches. Simply specify the
163  * name of the structure and maybe some flags that are listed above.
164  *
165  * The alignment of the struct determines object alignment. If you
166  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
167  * then the objects will be properly aligned in SMP configurations.
168  */
169 #define KMEM_CACHE(__struct, __flags)                                   \
170                 kmem_cache_create(#__struct, sizeof(struct __struct),   \
171                         __alignof__(struct __struct), (__flags), NULL)
172 
173 /*
174  * To whitelist a single field for copying to/from usercopy, use this
175  * macro instead for KMEM_CACHE() above.
176  */
177 #define KMEM_CACHE_USERCOPY(__struct, __flags, __field)                 \
178                 kmem_cache_create_usercopy(#__struct,                   \
179                         sizeof(struct __struct),                        \
180                         __alignof__(struct __struct), (__flags),        \
181                         offsetof(struct __struct, __field),             \
182                         sizeof_field(struct __struct, __field), NULL)
183 
184 /*
185  * Common kmalloc functions provided by all allocators
186  */
187 void * __must_check __krealloc(const void *, size_t, gfp_t);
188 void * __must_check krealloc(const void *, size_t, gfp_t);
189 void kfree(const void *);
190 void kzfree(const void *);
191 size_t __ksize(const void *);
192 size_t ksize(const void *);
193 
194 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
195 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
196                         bool to_user);
197 #else
198 static inline void __check_heap_object(const void *ptr, unsigned long n,
199                                        struct page *page, bool to_user) { }
200 #endif
201 
202 /*
203  * Some archs want to perform DMA into kmalloc caches and need a guaranteed
204  * alignment larger than the alignment of a 64-bit integer.
205  * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
206  */
207 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
208 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
209 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
210 #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
211 #else
212 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
213 #endif
214 
215 /*
216  * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
217  * Intended for arches that get misalignment faults even for 64 bit integer
218  * aligned buffers.
219  */
220 #ifndef ARCH_SLAB_MINALIGN
221 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
222 #endif
223 
224 /*
225  * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
226  * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
227  * aligned pointers.
228  */
229 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
230 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
231 #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
232 
233 /*
234  * Kmalloc array related definitions
235  */
236 
237 #ifdef CONFIG_SLAB
238 /*
239  * The largest kmalloc size supported by the SLAB allocators is
240  * 32 megabyte (2^25) or the maximum allocatable page order if that is
241  * less than 32 MB.
242  *
243  * WARNING: Its not easy to increase this value since the allocators have
244  * to do various tricks to work around compiler limitations in order to
245  * ensure proper constant folding.
246  */
247 #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
248                                 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
249 #define KMALLOC_SHIFT_MAX       KMALLOC_SHIFT_HIGH
250 #ifndef KMALLOC_SHIFT_LOW
251 #define KMALLOC_SHIFT_LOW       5
252 #endif
253 #endif
254 
255 #ifdef CONFIG_SLUB
256 /*
257  * SLUB directly allocates requests fitting in to an order-1 page
258  * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
259  */
260 #define KMALLOC_SHIFT_HIGH      (PAGE_SHIFT + 1)
261 #define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
262 #ifndef KMALLOC_SHIFT_LOW
263 #define KMALLOC_SHIFT_LOW       3
264 #endif
265 #endif
266 
267 #ifdef CONFIG_SLOB
268 /*
269  * SLOB passes all requests larger than one page to the page allocator.
270  * No kmalloc array is necessary since objects of different sizes can
271  * be allocated from the same page.
272  */
273 #define KMALLOC_SHIFT_HIGH      PAGE_SHIFT
274 #define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
275 #ifndef KMALLOC_SHIFT_LOW
276 #define KMALLOC_SHIFT_LOW       3
277 #endif
278 #endif
279 
280 /* Maximum allocatable size */
281 #define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_MAX)
282 /* Maximum size for which we actually use a slab cache */
283 #define KMALLOC_MAX_CACHE_SIZE  (1UL << KMALLOC_SHIFT_HIGH)
284 /* Maximum order allocatable via the slab allocagtor */
285 #define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
286 
287 /*
288  * Kmalloc subsystem.
289  */
290 #ifndef KMALLOC_MIN_SIZE
291 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
292 #endif
293 
294 /*
295  * This restriction comes from byte sized index implementation.
296  * Page size is normally 2^12 bytes and, in this case, if we want to use
297  * byte sized index which can represent 2^8 entries, the size of the object
298  * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
299  * If minimum size of kmalloc is less than 16, we use it as minimum object
300  * size and give up to use byte sized index.
301  */
302 #define SLAB_OBJ_MIN_SIZE      (KMALLOC_MIN_SIZE < 16 ? \
303                                (KMALLOC_MIN_SIZE) : 16)
304 
305 /*
306  * Whenever changing this, take care of that kmalloc_type() and
307  * create_kmalloc_caches() still work as intended.
308  */
309 enum kmalloc_cache_type {
310         KMALLOC_NORMAL = 0,
311         KMALLOC_RECLAIM,
312 #ifdef CONFIG_ZONE_DMA
313         KMALLOC_DMA,
314 #endif
315         NR_KMALLOC_TYPES
316 };
317 
318 #ifndef CONFIG_SLOB
319 extern struct kmem_cache *
320 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
321 
322 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
323 {
324 #ifdef CONFIG_ZONE_DMA
325         /*
326          * The most common case is KMALLOC_NORMAL, so test for it
327          * with a single branch for both flags.
328          */
329         if (likely((flags & (__GFP_DMA | __GFP_RECLAIMABLE)) == 0))
330                 return KMALLOC_NORMAL;
331 
332         /*
333          * At least one of the flags has to be set. If both are, __GFP_DMA
334          * is more important.
335          */
336         return flags & __GFP_DMA ? KMALLOC_DMA : KMALLOC_RECLAIM;
337 #else
338         return flags & __GFP_RECLAIMABLE ? KMALLOC_RECLAIM : KMALLOC_NORMAL;
339 #endif
340 }
341 
342 /*
343  * Figure out which kmalloc slab an allocation of a certain size
344  * belongs to.
345  * 0 = zero alloc
346  * 1 =  65 .. 96 bytes
347  * 2 = 129 .. 192 bytes
348  * n = 2^(n-1)+1 .. 2^n
349  */
350 static __always_inline unsigned int kmalloc_index(size_t size)
351 {
352         if (!size)
353                 return 0;
354 
355         if (size <= KMALLOC_MIN_SIZE)
356                 return KMALLOC_SHIFT_LOW;
357 
358         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
359                 return 1;
360         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
361                 return 2;
362         if (size <=          8) return 3;
363         if (size <=         16) return 4;
364         if (size <=         32) return 5;
365         if (size <=         64) return 6;
366         if (size <=        128) return 7;
367         if (size <=        256) return 8;
368         if (size <=        512) return 9;
369         if (size <=       1024) return 10;
370         if (size <=   2 * 1024) return 11;
371         if (size <=   4 * 1024) return 12;
372         if (size <=   8 * 1024) return 13;
373         if (size <=  16 * 1024) return 14;
374         if (size <=  32 * 1024) return 15;
375         if (size <=  64 * 1024) return 16;
376         if (size <= 128 * 1024) return 17;
377         if (size <= 256 * 1024) return 18;
378         if (size <= 512 * 1024) return 19;
379         if (size <= 1024 * 1024) return 20;
380         if (size <=  2 * 1024 * 1024) return 21;
381         if (size <=  4 * 1024 * 1024) return 22;
382         if (size <=  8 * 1024 * 1024) return 23;
383         if (size <=  16 * 1024 * 1024) return 24;
384         if (size <=  32 * 1024 * 1024) return 25;
385         if (size <=  64 * 1024 * 1024) return 26;
386         BUG();
387 
388         /* Will never be reached. Needed because the compiler may complain */
389         return -1;
390 }
391 #endif /* !CONFIG_SLOB */
392 
393 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
394 void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __assume_slab_alignment __malloc;
395 void kmem_cache_free(struct kmem_cache *, void *);
396 
397 /*
398  * Bulk allocation and freeing operations. These are accelerated in an
399  * allocator specific way to avoid taking locks repeatedly or building
400  * metadata structures unnecessarily.
401  *
402  * Note that interrupts must be enabled when calling these functions.
403  */
404 void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
405 int kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
406 
407 /*
408  * Caller must not use kfree_bulk() on memory not originally allocated
409  * by kmalloc(), because the SLOB allocator cannot handle this.
410  */
411 static __always_inline void kfree_bulk(size_t size, void **p)
412 {
413         kmem_cache_free_bulk(NULL, size, p);
414 }
415 
416 #ifdef CONFIG_NUMA
417 void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
418 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node) __assume_slab_alignment __malloc;
419 #else
420 static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
421 {
422         return __kmalloc(size, flags);
423 }
424 
425 static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
426 {
427         return kmem_cache_alloc(s, flags);
428 }
429 #endif
430 
431 #ifdef CONFIG_TRACING
432 extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t) __assume_slab_alignment __malloc;
433 
434 #ifdef CONFIG_NUMA
435 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
436                                            gfp_t gfpflags,
437                                            int node, size_t size) __assume_slab_alignment __malloc;
438 #else
439 static __always_inline void *
440 kmem_cache_alloc_node_trace(struct kmem_cache *s,
441                               gfp_t gfpflags,
442                               int node, size_t size)
443 {
444         return kmem_cache_alloc_trace(s, gfpflags, size);
445 }
446 #endif /* CONFIG_NUMA */
447 
448 #else /* CONFIG_TRACING */
449 static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
450                 gfp_t flags, size_t size)
451 {
452         void *ret = kmem_cache_alloc(s, flags);
453 
454         ret = kasan_kmalloc(s, ret, size, flags);
455         return ret;
456 }
457 
458 static __always_inline void *
459 kmem_cache_alloc_node_trace(struct kmem_cache *s,
460                               gfp_t gfpflags,
461                               int node, size_t size)
462 {
463         void *ret = kmem_cache_alloc_node(s, gfpflags, node);
464 
465         ret = kasan_kmalloc(s, ret, size, gfpflags);
466         return ret;
467 }
468 #endif /* CONFIG_TRACING */
469 
470 extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
471 
472 #ifdef CONFIG_TRACING
473 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
474 #else
475 static __always_inline void *
476 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
477 {
478         return kmalloc_order(size, flags, order);
479 }
480 #endif
481 
482 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
483 {
484         unsigned int order = get_order(size);
485         return kmalloc_order_trace(size, flags, order);
486 }
487 
488 /**
489  * kmalloc - allocate memory
490  * @size: how many bytes of memory are required.
491  * @flags: the type of memory to allocate.
492  *
493  * kmalloc is the normal method of allocating memory
494  * for objects smaller than page size in the kernel.
495  *
496  * The @flags argument may be one of the GFP flags defined at
497  * include/linux/gfp.h and described at
498  * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
499  *
500  * The recommended usage of the @flags is described at
501  * :ref:`Documentation/core-api/memory-allocation.rst <memory-allocation>`
502  *
503  * Below is a brief outline of the most useful GFP flags
504  *
505  * %GFP_KERNEL
506  *      Allocate normal kernel ram. May sleep.
507  *
508  * %GFP_NOWAIT
509  *      Allocation will not sleep.
510  *
511  * %GFP_ATOMIC
512  *      Allocation will not sleep.  May use emergency pools.
513  *
514  * %GFP_HIGHUSER
515  *      Allocate memory from high memory on behalf of user.
516  *
517  * Also it is possible to set different flags by OR'ing
518  * in one or more of the following additional @flags:
519  *
520  * %__GFP_HIGH
521  *      This allocation has high priority and may use emergency pools.
522  *
523  * %__GFP_NOFAIL
524  *      Indicate that this allocation is in no way allowed to fail
525  *      (think twice before using).
526  *
527  * %__GFP_NORETRY
528  *      If memory is not immediately available,
529  *      then give up at once.
530  *
531  * %__GFP_NOWARN
532  *      If allocation fails, don't issue any warnings.
533  *
534  * %__GFP_RETRY_MAYFAIL
535  *      Try really hard to succeed the allocation but fail
536  *      eventually.
537  */
538 static __always_inline void *kmalloc(size_t size, gfp_t flags)
539 {
540         if (__builtin_constant_p(size)) {
541 #ifndef CONFIG_SLOB
542                 unsigned int index;
543 #endif
544                 if (size > KMALLOC_MAX_CACHE_SIZE)
545                         return kmalloc_large(size, flags);
546 #ifndef CONFIG_SLOB
547                 index = kmalloc_index(size);
548 
549                 if (!index)
550                         return ZERO_SIZE_PTR;
551 
552                 return kmem_cache_alloc_trace(
553                                 kmalloc_caches[kmalloc_type(flags)][index],
554                                 flags, size);
555 #endif
556         }
557         return __kmalloc(size, flags);
558 }
559 
560 /*
561  * Determine size used for the nth kmalloc cache.
562  * return size or 0 if a kmalloc cache for that
563  * size does not exist
564  */
565 static __always_inline unsigned int kmalloc_size(unsigned int n)
566 {
567 #ifndef CONFIG_SLOB
568         if (n > 2)
569                 return 1U << n;
570 
571         if (n == 1 && KMALLOC_MIN_SIZE <= 32)
572                 return 96;
573 
574         if (n == 2 && KMALLOC_MIN_SIZE <= 64)
575                 return 192;
576 #endif
577         return 0;
578 }
579 
580 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
581 {
582 #ifndef CONFIG_SLOB
583         if (__builtin_constant_p(size) &&
584                 size <= KMALLOC_MAX_CACHE_SIZE) {
585                 unsigned int i = kmalloc_index(size);
586 
587                 if (!i)
588                         return ZERO_SIZE_PTR;
589 
590                 return kmem_cache_alloc_node_trace(
591                                 kmalloc_caches[kmalloc_type(flags)][i],
592                                                 flags, node, size);
593         }
594 #endif
595         return __kmalloc_node(size, flags, node);
596 }
597 
598 struct memcg_cache_array {
599         struct rcu_head rcu;
600         struct kmem_cache *entries[0];
601 };
602 
603 /*
604  * This is the main placeholder for memcg-related information in kmem caches.
605  * Both the root cache and the child caches will have it. For the root cache,
606  * this will hold a dynamically allocated array large enough to hold
607  * information about the currently limited memcgs in the system. To allow the
608  * array to be accessed without taking any locks, on relocation we free the old
609  * version only after a grace period.
610  *
611  * Root and child caches hold different metadata.
612  *
613  * @root_cache: Common to root and child caches.  NULL for root, pointer to
614  *              the root cache for children.
615  *
616  * The following fields are specific to root caches.
617  *
618  * @memcg_caches: kmemcg ID indexed table of child caches.  This table is
619  *              used to index child cachces during allocation and cleared
620  *              early during shutdown.
621  *
622  * @root_caches_node: List node for slab_root_caches list.
623  *
624  * @children:   List of all child caches.  While the child caches are also
625  *              reachable through @memcg_caches, a child cache remains on
626  *              this list until it is actually destroyed.
627  *
628  * The following fields are specific to child caches.
629  *
630  * @memcg:      Pointer to the memcg this cache belongs to.
631  *
632  * @children_node: List node for @root_cache->children list.
633  *
634  * @kmem_caches_node: List node for @memcg->kmem_caches list.
635  */
636 struct memcg_cache_params {
637         struct kmem_cache *root_cache;
638         union {
639                 struct {
640                         struct memcg_cache_array __rcu *memcg_caches;
641                         struct list_head __root_caches_node;
642                         struct list_head children;
643                         bool dying;
644                 };
645                 struct {
646                         struct mem_cgroup *memcg;
647                         struct list_head children_node;
648                         struct list_head kmem_caches_node;
649                         struct percpu_ref refcnt;
650 
651                         void (*work_fn)(struct kmem_cache *);
652                         union {
653                                 struct rcu_head rcu_head;
654                                 struct work_struct work;
655                         };
656                 };
657         };
658 };
659 
660 int memcg_update_all_caches(int num_memcgs);
661 
662 /**
663  * kmalloc_array - allocate memory for an array.
664  * @n: number of elements.
665  * @size: element size.
666  * @flags: the type of memory to allocate (see kmalloc).
667  */
668 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
669 {
670         size_t bytes;
671 
672         if (unlikely(check_mul_overflow(n, size, &bytes)))
673                 return NULL;
674         if (__builtin_constant_p(n) && __builtin_constant_p(size))
675                 return kmalloc(bytes, flags);
676         return __kmalloc(bytes, flags);
677 }
678 
679 /**
680  * kcalloc - allocate memory for an array. The memory is set to zero.
681  * @n: number of elements.
682  * @size: element size.
683  * @flags: the type of memory to allocate (see kmalloc).
684  */
685 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
686 {
687         return kmalloc_array(n, size, flags | __GFP_ZERO);
688 }
689 
690 /*
691  * kmalloc_track_caller is a special version of kmalloc that records the
692  * calling function of the routine calling it for slab leak tracking instead
693  * of just the calling function (confusing, eh?).
694  * It's useful when the call to kmalloc comes from a widely-used standard
695  * allocator where we care about the real place the memory allocation
696  * request comes from.
697  */
698 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
699 #define kmalloc_track_caller(size, flags) \
700         __kmalloc_track_caller(size, flags, _RET_IP_)
701 
702 static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
703                                        int node)
704 {
705         size_t bytes;
706 
707         if (unlikely(check_mul_overflow(n, size, &bytes)))
708                 return NULL;
709         if (__builtin_constant_p(n) && __builtin_constant_p(size))
710                 return kmalloc_node(bytes, flags, node);
711         return __kmalloc_node(bytes, flags, node);
712 }
713 
714 static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
715 {
716         return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
717 }
718 
719 
720 #ifdef CONFIG_NUMA
721 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
722 #define kmalloc_node_track_caller(size, flags, node) \
723         __kmalloc_node_track_caller(size, flags, node, \
724                         _RET_IP_)
725 
726 #else /* CONFIG_NUMA */
727 
728 #define kmalloc_node_track_caller(size, flags, node) \
729         kmalloc_track_caller(size, flags)
730 
731 #endif /* CONFIG_NUMA */
732 
733 /*
734  * Shortcuts
735  */
736 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
737 {
738         return kmem_cache_alloc(k, flags | __GFP_ZERO);
739 }
740 
741 /**
742  * kzalloc - allocate memory. The memory is set to zero.
743  * @size: how many bytes of memory are required.
744  * @flags: the type of memory to allocate (see kmalloc).
745  */
746 static inline void *kzalloc(size_t size, gfp_t flags)
747 {
748         return kmalloc(size, flags | __GFP_ZERO);
749 }
750 
751 /**
752  * kzalloc_node - allocate zeroed memory from a particular memory node.
753  * @size: how many bytes of memory are required.
754  * @flags: the type of memory to allocate (see kmalloc).
755  * @node: memory node from which to allocate
756  */
757 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
758 {
759         return kmalloc_node(size, flags | __GFP_ZERO, node);
760 }
761 
762 unsigned int kmem_cache_size(struct kmem_cache *s);
763 void __init kmem_cache_init_late(void);
764 
765 #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
766 int slab_prepare_cpu(unsigned int cpu);
767 int slab_dead_cpu(unsigned int cpu);
768 #else
769 #define slab_prepare_cpu        NULL
770 #define slab_dead_cpu           NULL
771 #endif
772 
773 #endif  /* _LINUX_SLAB_H */
774 

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