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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 /*
159  * Please use this macro to create slab caches. Simply specify the
160  * name of the structure and maybe some flags that are listed above.
161  *
162  * The alignment of the struct determines object alignment. If you
163  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
164  * then the objects will be properly aligned in SMP configurations.
165  */
166 #define KMEM_CACHE(__struct, __flags)                                   \
167                 kmem_cache_create(#__struct, sizeof(struct __struct),   \
168                         __alignof__(struct __struct), (__flags), NULL)
169 
170 /*
171  * To whitelist a single field for copying to/from usercopy, use this
172  * macro instead for KMEM_CACHE() above.
173  */
174 #define KMEM_CACHE_USERCOPY(__struct, __flags, __field)                 \
175                 kmem_cache_create_usercopy(#__struct,                   \
176                         sizeof(struct __struct),                        \
177                         __alignof__(struct __struct), (__flags),        \
178                         offsetof(struct __struct, __field),             \
179                         sizeof_field(struct __struct, __field), NULL)
180 
181 /*
182  * Common kmalloc functions provided by all allocators
183  */
184 void * __must_check krealloc(const void *, size_t, gfp_t);
185 void kfree(const void *);
186 void kfree_sensitive(const void *);
187 size_t __ksize(const void *);
188 size_t ksize(const void *);
189 
190 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
191 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
192                         bool to_user);
193 #else
194 static inline void __check_heap_object(const void *ptr, unsigned long n,
195                                        struct page *page, bool to_user) { }
196 #endif
197 
198 /*
199  * Some archs want to perform DMA into kmalloc caches and need a guaranteed
200  * alignment larger than the alignment of a 64-bit integer.
201  * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
202  */
203 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
204 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
205 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
206 #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
207 #else
208 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
209 #endif
210 
211 /*
212  * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
213  * Intended for arches that get misalignment faults even for 64 bit integer
214  * aligned buffers.
215  */
216 #ifndef ARCH_SLAB_MINALIGN
217 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
218 #endif
219 
220 /*
221  * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
222  * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
223  * aligned pointers.
224  */
225 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
226 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
227 #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
228 
229 /*
230  * Kmalloc array related definitions
231  */
232 
233 #ifdef CONFIG_SLAB
234 /*
235  * The largest kmalloc size supported by the SLAB allocators is
236  * 32 megabyte (2^25) or the maximum allocatable page order if that is
237  * less than 32 MB.
238  *
239  * WARNING: Its not easy to increase this value since the allocators have
240  * to do various tricks to work around compiler limitations in order to
241  * ensure proper constant folding.
242  */
243 #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
244                                 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
245 #define KMALLOC_SHIFT_MAX       KMALLOC_SHIFT_HIGH
246 #ifndef KMALLOC_SHIFT_LOW
247 #define KMALLOC_SHIFT_LOW       5
248 #endif
249 #endif
250 
251 #ifdef CONFIG_SLUB
252 /*
253  * SLUB directly allocates requests fitting in to an order-1 page
254  * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
255  */
256 #define KMALLOC_SHIFT_HIGH      (PAGE_SHIFT + 1)
257 #define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
258 #ifndef KMALLOC_SHIFT_LOW
259 #define KMALLOC_SHIFT_LOW       3
260 #endif
261 #endif
262 
263 #ifdef CONFIG_SLOB
264 /*
265  * SLOB passes all requests larger than one page to the page allocator.
266  * No kmalloc array is necessary since objects of different sizes can
267  * be allocated from the same page.
268  */
269 #define KMALLOC_SHIFT_HIGH      PAGE_SHIFT
270 #define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
271 #ifndef KMALLOC_SHIFT_LOW
272 #define KMALLOC_SHIFT_LOW       3
273 #endif
274 #endif
275 
276 /* Maximum allocatable size */
277 #define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_MAX)
278 /* Maximum size for which we actually use a slab cache */
279 #define KMALLOC_MAX_CACHE_SIZE  (1UL << KMALLOC_SHIFT_HIGH)
280 /* Maximum order allocatable via the slab allocator */
281 #define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
282 
283 /*
284  * Kmalloc subsystem.
285  */
286 #ifndef KMALLOC_MIN_SIZE
287 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
288 #endif
289 
290 /*
291  * This restriction comes from byte sized index implementation.
292  * Page size is normally 2^12 bytes and, in this case, if we want to use
293  * byte sized index which can represent 2^8 entries, the size of the object
294  * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
295  * If minimum size of kmalloc is less than 16, we use it as minimum object
296  * size and give up to use byte sized index.
297  */
298 #define SLAB_OBJ_MIN_SIZE      (KMALLOC_MIN_SIZE < 16 ? \
299                                (KMALLOC_MIN_SIZE) : 16)
300 
301 /*
302  * Whenever changing this, take care of that kmalloc_type() and
303  * create_kmalloc_caches() still work as intended.
304  */
305 enum kmalloc_cache_type {
306         KMALLOC_NORMAL = 0,
307         KMALLOC_RECLAIM,
308 #ifdef CONFIG_ZONE_DMA
309         KMALLOC_DMA,
310 #endif
311         NR_KMALLOC_TYPES
312 };
313 
314 #ifndef CONFIG_SLOB
315 extern struct kmem_cache *
316 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
317 
318 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
319 {
320 #ifdef CONFIG_ZONE_DMA
321         /*
322          * The most common case is KMALLOC_NORMAL, so test for it
323          * with a single branch for both flags.
324          */
325         if (likely((flags & (__GFP_DMA | __GFP_RECLAIMABLE)) == 0))
326                 return KMALLOC_NORMAL;
327 
328         /*
329          * At least one of the flags has to be set. If both are, __GFP_DMA
330          * is more important.
331          */
332         return flags & __GFP_DMA ? KMALLOC_DMA : KMALLOC_RECLAIM;
333 #else
334         return flags & __GFP_RECLAIMABLE ? KMALLOC_RECLAIM : KMALLOC_NORMAL;
335 #endif
336 }
337 
338 /*
339  * Figure out which kmalloc slab an allocation of a certain size
340  * belongs to.
341  * 0 = zero alloc
342  * 1 =  65 .. 96 bytes
343  * 2 = 129 .. 192 bytes
344  * n = 2^(n-1)+1 .. 2^n
345  */
346 static __always_inline unsigned int kmalloc_index(size_t size)
347 {
348         if (!size)
349                 return 0;
350 
351         if (size <= KMALLOC_MIN_SIZE)
352                 return KMALLOC_SHIFT_LOW;
353 
354         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
355                 return 1;
356         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
357                 return 2;
358         if (size <=          8) return 3;
359         if (size <=         16) return 4;
360         if (size <=         32) return 5;
361         if (size <=         64) return 6;
362         if (size <=        128) return 7;
363         if (size <=        256) return 8;
364         if (size <=        512) return 9;
365         if (size <=       1024) return 10;
366         if (size <=   2 * 1024) return 11;
367         if (size <=   4 * 1024) return 12;
368         if (size <=   8 * 1024) return 13;
369         if (size <=  16 * 1024) return 14;
370         if (size <=  32 * 1024) return 15;
371         if (size <=  64 * 1024) return 16;
372         if (size <= 128 * 1024) return 17;
373         if (size <= 256 * 1024) return 18;
374         if (size <= 512 * 1024) return 19;
375         if (size <= 1024 * 1024) return 20;
376         if (size <=  2 * 1024 * 1024) return 21;
377         if (size <=  4 * 1024 * 1024) return 22;
378         if (size <=  8 * 1024 * 1024) return 23;
379         if (size <=  16 * 1024 * 1024) return 24;
380         if (size <=  32 * 1024 * 1024) return 25;
381         if (size <=  64 * 1024 * 1024) return 26;
382         BUG();
383 
384         /* Will never be reached. Needed because the compiler may complain */
385         return -1;
386 }
387 #endif /* !CONFIG_SLOB */
388 
389 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
390 void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __assume_slab_alignment __malloc;
391 void kmem_cache_free(struct kmem_cache *, void *);
392 
393 /*
394  * Bulk allocation and freeing operations. These are accelerated in an
395  * allocator specific way to avoid taking locks repeatedly or building
396  * metadata structures unnecessarily.
397  *
398  * Note that interrupts must be enabled when calling these functions.
399  */
400 void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
401 int kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
402 
403 /*
404  * Caller must not use kfree_bulk() on memory not originally allocated
405  * by kmalloc(), because the SLOB allocator cannot handle this.
406  */
407 static __always_inline void kfree_bulk(size_t size, void **p)
408 {
409         kmem_cache_free_bulk(NULL, size, p);
410 }
411 
412 #ifdef CONFIG_NUMA
413 void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
414 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node) __assume_slab_alignment __malloc;
415 #else
416 static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
417 {
418         return __kmalloc(size, flags);
419 }
420 
421 static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
422 {
423         return kmem_cache_alloc(s, flags);
424 }
425 #endif
426 
427 #ifdef CONFIG_TRACING
428 extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t) __assume_slab_alignment __malloc;
429 
430 #ifdef CONFIG_NUMA
431 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
432                                            gfp_t gfpflags,
433                                            int node, size_t size) __assume_slab_alignment __malloc;
434 #else
435 static __always_inline void *
436 kmem_cache_alloc_node_trace(struct kmem_cache *s,
437                               gfp_t gfpflags,
438                               int node, size_t size)
439 {
440         return kmem_cache_alloc_trace(s, gfpflags, size);
441 }
442 #endif /* CONFIG_NUMA */
443 
444 #else /* CONFIG_TRACING */
445 static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
446                 gfp_t flags, size_t size)
447 {
448         void *ret = kmem_cache_alloc(s, flags);
449 
450         ret = kasan_kmalloc(s, ret, size, flags);
451         return ret;
452 }
453 
454 static __always_inline void *
455 kmem_cache_alloc_node_trace(struct kmem_cache *s,
456                               gfp_t gfpflags,
457                               int node, size_t size)
458 {
459         void *ret = kmem_cache_alloc_node(s, gfpflags, node);
460 
461         ret = kasan_kmalloc(s, ret, size, gfpflags);
462         return ret;
463 }
464 #endif /* CONFIG_TRACING */
465 
466 extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
467 
468 #ifdef CONFIG_TRACING
469 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
470 #else
471 static __always_inline void *
472 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
473 {
474         return kmalloc_order(size, flags, order);
475 }
476 #endif
477 
478 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
479 {
480         unsigned int order = get_order(size);
481         return kmalloc_order_trace(size, flags, order);
482 }
483 
484 /**
485  * kmalloc - allocate memory
486  * @size: how many bytes of memory are required.
487  * @flags: the type of memory to allocate.
488  *
489  * kmalloc is the normal method of allocating memory
490  * for objects smaller than page size in the kernel.
491  *
492  * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
493  * bytes. For @size of power of two bytes, the alignment is also guaranteed
494  * to be at least to the size.
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 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
561 {
562 #ifndef CONFIG_SLOB
563         if (__builtin_constant_p(size) &&
564                 size <= KMALLOC_MAX_CACHE_SIZE) {
565                 unsigned int i = kmalloc_index(size);
566 
567                 if (!i)
568                         return ZERO_SIZE_PTR;
569 
570                 return kmem_cache_alloc_node_trace(
571                                 kmalloc_caches[kmalloc_type(flags)][i],
572                                                 flags, node, size);
573         }
574 #endif
575         return __kmalloc_node(size, flags, node);
576 }
577 
578 /**
579  * kmalloc_array - allocate memory for an array.
580  * @n: number of elements.
581  * @size: element size.
582  * @flags: the type of memory to allocate (see kmalloc).
583  */
584 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
585 {
586         size_t bytes;
587 
588         if (unlikely(check_mul_overflow(n, size, &bytes)))
589                 return NULL;
590         if (__builtin_constant_p(n) && __builtin_constant_p(size))
591                 return kmalloc(bytes, flags);
592         return __kmalloc(bytes, flags);
593 }
594 
595 /**
596  * krealloc_array - reallocate memory for an array.
597  * @p: pointer to the memory chunk to reallocate
598  * @new_n: new number of elements to alloc
599  * @new_size: new size of a single member of the array
600  * @flags: the type of memory to allocate (see kmalloc)
601  */
602 static __must_check inline void *
603 krealloc_array(void *p, size_t new_n, size_t new_size, gfp_t flags)
604 {
605         size_t bytes;
606 
607         if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
608                 return NULL;
609 
610         return krealloc(p, bytes, flags);
611 }
612 
613 /**
614  * kcalloc - allocate memory for an array. The memory is set to zero.
615  * @n: number of elements.
616  * @size: element size.
617  * @flags: the type of memory to allocate (see kmalloc).
618  */
619 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
620 {
621         return kmalloc_array(n, size, flags | __GFP_ZERO);
622 }
623 
624 /*
625  * kmalloc_track_caller is a special version of kmalloc that records the
626  * calling function of the routine calling it for slab leak tracking instead
627  * of just the calling function (confusing, eh?).
628  * It's useful when the call to kmalloc comes from a widely-used standard
629  * allocator where we care about the real place the memory allocation
630  * request comes from.
631  */
632 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
633 #define kmalloc_track_caller(size, flags) \
634         __kmalloc_track_caller(size, flags, _RET_IP_)
635 
636 static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
637                                        int node)
638 {
639         size_t bytes;
640 
641         if (unlikely(check_mul_overflow(n, size, &bytes)))
642                 return NULL;
643         if (__builtin_constant_p(n) && __builtin_constant_p(size))
644                 return kmalloc_node(bytes, flags, node);
645         return __kmalloc_node(bytes, flags, node);
646 }
647 
648 static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
649 {
650         return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
651 }
652 
653 
654 #ifdef CONFIG_NUMA
655 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
656 #define kmalloc_node_track_caller(size, flags, node) \
657         __kmalloc_node_track_caller(size, flags, node, \
658                         _RET_IP_)
659 
660 #else /* CONFIG_NUMA */
661 
662 #define kmalloc_node_track_caller(size, flags, node) \
663         kmalloc_track_caller(size, flags)
664 
665 #endif /* CONFIG_NUMA */
666 
667 /*
668  * Shortcuts
669  */
670 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
671 {
672         return kmem_cache_alloc(k, flags | __GFP_ZERO);
673 }
674 
675 /**
676  * kzalloc - allocate memory. The memory is set to zero.
677  * @size: how many bytes of memory are required.
678  * @flags: the type of memory to allocate (see kmalloc).
679  */
680 static inline void *kzalloc(size_t size, gfp_t flags)
681 {
682         return kmalloc(size, flags | __GFP_ZERO);
683 }
684 
685 /**
686  * kzalloc_node - allocate zeroed memory from a particular memory node.
687  * @size: how many bytes of memory are required.
688  * @flags: the type of memory to allocate (see kmalloc).
689  * @node: memory node from which to allocate
690  */
691 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
692 {
693         return kmalloc_node(size, flags | __GFP_ZERO, node);
694 }
695 
696 unsigned int kmem_cache_size(struct kmem_cache *s);
697 void __init kmem_cache_init_late(void);
698 
699 #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
700 int slab_prepare_cpu(unsigned int cpu);
701 int slab_dead_cpu(unsigned int cpu);
702 #else
703 #define slab_prepare_cpu        NULL
704 #define slab_dead_cpu           NULL
705 #endif
706 
707 #endif  /* _LINUX_SLAB_H */
708 

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