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
__check_heap_object(const void * ptr,unsigned long n,struct page * page,bool to_user)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
kmalloc_type(gfp_t flags)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 */
kmalloc_index(size_t size)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 */
kfree_bulk(size_t size,void ** p)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
__kmalloc_node(size_t size,gfp_t flags,int node)416 static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
417 {
418 return __kmalloc(size, flags);
419 }
420
kmem_cache_alloc_node(struct kmem_cache * s,gfp_t flags,int node)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 *
kmem_cache_alloc_node_trace(struct kmem_cache * s,gfp_t gfpflags,int node,size_t size)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 */
kmem_cache_alloc_trace(struct kmem_cache * s,gfp_t flags,size_t size)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 *
kmem_cache_alloc_node_trace(struct kmem_cache * s,gfp_t gfpflags,int node,size_t size)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 *
kmalloc_order_trace(size_t size,gfp_t flags,unsigned int order)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
kmalloc_large(size_t size,gfp_t flags)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 */
kmalloc(size_t size,gfp_t flags)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
kmalloc_node(size_t size,gfp_t flags,int node)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 */
kmalloc_array(size_t n,size_t size,gfp_t flags)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 * kcalloc - allocate memory for an array. The memory is set to zero.
597 * @n: number of elements.
598 * @size: element size.
599 * @flags: the type of memory to allocate (see kmalloc).
600 */
kcalloc(size_t n,size_t size,gfp_t flags)601 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
602 {
603 return kmalloc_array(n, size, flags | __GFP_ZERO);
604 }
605
606 /*
607 * kmalloc_track_caller is a special version of kmalloc that records the
608 * calling function of the routine calling it for slab leak tracking instead
609 * of just the calling function (confusing, eh?).
610 * It's useful when the call to kmalloc comes from a widely-used standard
611 * allocator where we care about the real place the memory allocation
612 * request comes from.
613 */
614 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
615 #define kmalloc_track_caller(size, flags) \
616 __kmalloc_track_caller(size, flags, _RET_IP_)
617
kmalloc_array_node(size_t n,size_t size,gfp_t flags,int node)618 static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
619 int node)
620 {
621 size_t bytes;
622
623 if (unlikely(check_mul_overflow(n, size, &bytes)))
624 return NULL;
625 if (__builtin_constant_p(n) && __builtin_constant_p(size))
626 return kmalloc_node(bytes, flags, node);
627 return __kmalloc_node(bytes, flags, node);
628 }
629
kcalloc_node(size_t n,size_t size,gfp_t flags,int node)630 static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
631 {
632 return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
633 }
634
635
636 #ifdef CONFIG_NUMA
637 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
638 #define kmalloc_node_track_caller(size, flags, node) \
639 __kmalloc_node_track_caller(size, flags, node, \
640 _RET_IP_)
641
642 #else /* CONFIG_NUMA */
643
644 #define kmalloc_node_track_caller(size, flags, node) \
645 kmalloc_track_caller(size, flags)
646
647 #endif /* CONFIG_NUMA */
648
649 /*
650 * Shortcuts
651 */
kmem_cache_zalloc(struct kmem_cache * k,gfp_t flags)652 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
653 {
654 return kmem_cache_alloc(k, flags | __GFP_ZERO);
655 }
656
657 /**
658 * kzalloc - allocate memory. The memory is set to zero.
659 * @size: how many bytes of memory are required.
660 * @flags: the type of memory to allocate (see kmalloc).
661 */
kzalloc(size_t size,gfp_t flags)662 static inline void *kzalloc(size_t size, gfp_t flags)
663 {
664 return kmalloc(size, flags | __GFP_ZERO);
665 }
666
667 /**
668 * kzalloc_node - allocate zeroed memory from a particular memory node.
669 * @size: how many bytes of memory are required.
670 * @flags: the type of memory to allocate (see kmalloc).
671 * @node: memory node from which to allocate
672 */
kzalloc_node(size_t size,gfp_t flags,int node)673 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
674 {
675 return kmalloc_node(size, flags | __GFP_ZERO, node);
676 }
677
678 unsigned int kmem_cache_size(struct kmem_cache *s);
679 void __init kmem_cache_init_late(void);
680
681 #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
682 int slab_prepare_cpu(unsigned int cpu);
683 int slab_dead_cpu(unsigned int cpu);
684 #else
685 #define slab_prepare_cpu NULL
686 #define slab_dead_cpu NULL
687 #endif
688
689 #endif /* _LINUX_SLAB_H */
690