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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
__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  * Arches can define this function if they want to decide the minimum slab
222  * alignment at runtime. The value returned by the function must be a power
223  * of two and >= ARCH_SLAB_MINALIGN.
224  */
225 #ifndef arch_slab_minalign
arch_slab_minalign(void)226 static inline unsigned int arch_slab_minalign(void)
227 {
228 	return ARCH_SLAB_MINALIGN;
229 }
230 #endif
231 
232 /*
233  * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
234  * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
235  * aligned pointers.
236  */
237 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
238 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
239 #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
240 
241 /*
242  * Kmalloc array related definitions
243  */
244 
245 #ifdef CONFIG_SLAB
246 /*
247  * The largest kmalloc size supported by the SLAB allocators is
248  * 32 megabyte (2^25) or the maximum allocatable page order if that is
249  * less than 32 MB.
250  *
251  * WARNING: Its not easy to increase this value since the allocators have
252  * to do various tricks to work around compiler limitations in order to
253  * ensure proper constant folding.
254  */
255 #define KMALLOC_SHIFT_HIGH	((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
256 				(MAX_ORDER + PAGE_SHIFT - 1) : 25)
257 #define KMALLOC_SHIFT_MAX	KMALLOC_SHIFT_HIGH
258 #ifndef KMALLOC_SHIFT_LOW
259 #define KMALLOC_SHIFT_LOW	5
260 #endif
261 #endif
262 
263 #ifdef CONFIG_SLUB
264 /*
265  * SLUB directly allocates requests fitting in to an order-1 page
266  * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
267  */
268 #define KMALLOC_SHIFT_HIGH	(PAGE_SHIFT + 1)
269 #define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
270 #ifndef KMALLOC_SHIFT_LOW
271 #define KMALLOC_SHIFT_LOW	3
272 #endif
273 #endif
274 
275 #ifdef CONFIG_SLOB
276 /*
277  * SLOB passes all requests larger than one page to the page allocator.
278  * No kmalloc array is necessary since objects of different sizes can
279  * be allocated from the same page.
280  */
281 #define KMALLOC_SHIFT_HIGH	PAGE_SHIFT
282 #define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
283 #ifndef KMALLOC_SHIFT_LOW
284 #define KMALLOC_SHIFT_LOW	3
285 #endif
286 #endif
287 
288 /* Maximum allocatable size */
289 #define KMALLOC_MAX_SIZE	(1UL << KMALLOC_SHIFT_MAX)
290 /* Maximum size for which we actually use a slab cache */
291 #define KMALLOC_MAX_CACHE_SIZE	(1UL << KMALLOC_SHIFT_HIGH)
292 /* Maximum order allocatable via the slab allocator */
293 #define KMALLOC_MAX_ORDER	(KMALLOC_SHIFT_MAX - PAGE_SHIFT)
294 
295 /*
296  * Kmalloc subsystem.
297  */
298 #ifndef KMALLOC_MIN_SIZE
299 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
300 #endif
301 
302 /*
303  * This restriction comes from byte sized index implementation.
304  * Page size is normally 2^12 bytes and, in this case, if we want to use
305  * byte sized index which can represent 2^8 entries, the size of the object
306  * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
307  * If minimum size of kmalloc is less than 16, we use it as minimum object
308  * size and give up to use byte sized index.
309  */
310 #define SLAB_OBJ_MIN_SIZE      (KMALLOC_MIN_SIZE < 16 ? \
311                                (KMALLOC_MIN_SIZE) : 16)
312 
313 /*
314  * Whenever changing this, take care of that kmalloc_type() and
315  * create_kmalloc_caches() still work as intended.
316  */
317 enum kmalloc_cache_type {
318 	KMALLOC_NORMAL = 0,
319 	KMALLOC_RECLAIM,
320 #ifdef CONFIG_ZONE_DMA
321 	KMALLOC_DMA,
322 #endif
323 	NR_KMALLOC_TYPES
324 };
325 
326 #ifndef CONFIG_SLOB
327 extern struct kmem_cache *
328 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
329 
kmalloc_type(gfp_t flags)330 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
331 {
332 #ifdef CONFIG_ZONE_DMA
333 	/*
334 	 * The most common case is KMALLOC_NORMAL, so test for it
335 	 * with a single branch for both flags.
336 	 */
337 	if (likely((flags & (__GFP_DMA | __GFP_RECLAIMABLE)) == 0))
338 		return KMALLOC_NORMAL;
339 
340 	/*
341 	 * At least one of the flags has to be set. If both are, __GFP_DMA
342 	 * is more important.
343 	 */
344 	return flags & __GFP_DMA ? KMALLOC_DMA : KMALLOC_RECLAIM;
345 #else
346 	return flags & __GFP_RECLAIMABLE ? KMALLOC_RECLAIM : KMALLOC_NORMAL;
347 #endif
348 }
349 
350 /*
351  * Figure out which kmalloc slab an allocation of a certain size
352  * belongs to.
353  * 0 = zero alloc
354  * 1 =  65 .. 96 bytes
355  * 2 = 129 .. 192 bytes
356  * n = 2^(n-1)+1 .. 2^n
357  */
kmalloc_index(size_t size)358 static __always_inline unsigned int kmalloc_index(size_t size)
359 {
360 	if (!size)
361 		return 0;
362 
363 	if (size <= KMALLOC_MIN_SIZE)
364 		return KMALLOC_SHIFT_LOW;
365 
366 	if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
367 		return 1;
368 	if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
369 		return 2;
370 	if (size <=          8) return 3;
371 	if (size <=         16) return 4;
372 	if (size <=         32) return 5;
373 	if (size <=         64) return 6;
374 	if (size <=        128) return 7;
375 	if (size <=        256) return 8;
376 	if (size <=        512) return 9;
377 	if (size <=       1024) return 10;
378 	if (size <=   2 * 1024) return 11;
379 	if (size <=   4 * 1024) return 12;
380 	if (size <=   8 * 1024) return 13;
381 	if (size <=  16 * 1024) return 14;
382 	if (size <=  32 * 1024) return 15;
383 	if (size <=  64 * 1024) return 16;
384 	if (size <= 128 * 1024) return 17;
385 	if (size <= 256 * 1024) return 18;
386 	if (size <= 512 * 1024) return 19;
387 	if (size <= 1024 * 1024) return 20;
388 	if (size <=  2 * 1024 * 1024) return 21;
389 	if (size <=  4 * 1024 * 1024) return 22;
390 	if (size <=  8 * 1024 * 1024) return 23;
391 	if (size <=  16 * 1024 * 1024) return 24;
392 	if (size <=  32 * 1024 * 1024) return 25;
393 	if (size <=  64 * 1024 * 1024) return 26;
394 	BUG();
395 
396 	/* Will never be reached. Needed because the compiler may complain */
397 	return -1;
398 }
399 #endif /* !CONFIG_SLOB */
400 
401 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
402 void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __assume_slab_alignment __malloc;
403 void kmem_cache_free(struct kmem_cache *, void *);
404 
405 /*
406  * Bulk allocation and freeing operations. These are accelerated in an
407  * allocator specific way to avoid taking locks repeatedly or building
408  * metadata structures unnecessarily.
409  *
410  * Note that interrupts must be enabled when calling these functions.
411  */
412 void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
413 int kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
414 
415 /*
416  * Caller must not use kfree_bulk() on memory not originally allocated
417  * by kmalloc(), because the SLOB allocator cannot handle this.
418  */
kfree_bulk(size_t size,void ** p)419 static __always_inline void kfree_bulk(size_t size, void **p)
420 {
421 	kmem_cache_free_bulk(NULL, size, p);
422 }
423 
424 #ifdef CONFIG_NUMA
425 void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
426 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node) __assume_slab_alignment __malloc;
427 #else
__kmalloc_node(size_t size,gfp_t flags,int node)428 static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
429 {
430 	return __kmalloc(size, flags);
431 }
432 
kmem_cache_alloc_node(struct kmem_cache * s,gfp_t flags,int node)433 static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
434 {
435 	return kmem_cache_alloc(s, flags);
436 }
437 #endif
438 
439 #ifdef CONFIG_TRACING
440 extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t) __assume_slab_alignment __malloc;
441 
442 #ifdef CONFIG_NUMA
443 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
444 					   gfp_t gfpflags,
445 					   int node, size_t size) __assume_slab_alignment __malloc;
446 #else
447 static __always_inline void *
kmem_cache_alloc_node_trace(struct kmem_cache * s,gfp_t gfpflags,int node,size_t size)448 kmem_cache_alloc_node_trace(struct kmem_cache *s,
449 			      gfp_t gfpflags,
450 			      int node, size_t size)
451 {
452 	return kmem_cache_alloc_trace(s, gfpflags, size);
453 }
454 #endif /* CONFIG_NUMA */
455 
456 #else /* CONFIG_TRACING */
kmem_cache_alloc_trace(struct kmem_cache * s,gfp_t flags,size_t size)457 static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
458 		gfp_t flags, size_t size)
459 {
460 	void *ret = kmem_cache_alloc(s, flags);
461 
462 	ret = kasan_kmalloc(s, ret, size, flags);
463 	return ret;
464 }
465 
466 static __always_inline void *
kmem_cache_alloc_node_trace(struct kmem_cache * s,gfp_t gfpflags,int node,size_t size)467 kmem_cache_alloc_node_trace(struct kmem_cache *s,
468 			      gfp_t gfpflags,
469 			      int node, size_t size)
470 {
471 	void *ret = kmem_cache_alloc_node(s, gfpflags, node);
472 
473 	ret = kasan_kmalloc(s, ret, size, gfpflags);
474 	return ret;
475 }
476 #endif /* CONFIG_TRACING */
477 
478 extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
479 
480 #ifdef CONFIG_TRACING
481 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
482 #else
483 static __always_inline void *
kmalloc_order_trace(size_t size,gfp_t flags,unsigned int order)484 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
485 {
486 	return kmalloc_order(size, flags, order);
487 }
488 #endif
489 
kmalloc_large(size_t size,gfp_t flags)490 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
491 {
492 	unsigned int order = get_order(size);
493 	return kmalloc_order_trace(size, flags, order);
494 }
495 
496 /**
497  * kmalloc - allocate memory
498  * @size: how many bytes of memory are required.
499  * @flags: the type of memory to allocate.
500  *
501  * kmalloc is the normal method of allocating memory
502  * for objects smaller than page size in the kernel.
503  *
504  * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
505  * bytes. For @size of power of two bytes, the alignment is also guaranteed
506  * to be at least to the size.
507  *
508  * The @flags argument may be one of the GFP flags defined at
509  * include/linux/gfp.h and described at
510  * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
511  *
512  * The recommended usage of the @flags is described at
513  * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>`
514  *
515  * Below is a brief outline of the most useful GFP flags
516  *
517  * %GFP_KERNEL
518  *	Allocate normal kernel ram. May sleep.
519  *
520  * %GFP_NOWAIT
521  *	Allocation will not sleep.
522  *
523  * %GFP_ATOMIC
524  *	Allocation will not sleep.  May use emergency pools.
525  *
526  * %GFP_HIGHUSER
527  *	Allocate memory from high memory on behalf of user.
528  *
529  * Also it is possible to set different flags by OR'ing
530  * in one or more of the following additional @flags:
531  *
532  * %__GFP_HIGH
533  *	This allocation has high priority and may use emergency pools.
534  *
535  * %__GFP_NOFAIL
536  *	Indicate that this allocation is in no way allowed to fail
537  *	(think twice before using).
538  *
539  * %__GFP_NORETRY
540  *	If memory is not immediately available,
541  *	then give up at once.
542  *
543  * %__GFP_NOWARN
544  *	If allocation fails, don't issue any warnings.
545  *
546  * %__GFP_RETRY_MAYFAIL
547  *	Try really hard to succeed the allocation but fail
548  *	eventually.
549  */
kmalloc(size_t size,gfp_t flags)550 static __always_inline void *kmalloc(size_t size, gfp_t flags)
551 {
552 	if (__builtin_constant_p(size)) {
553 #ifndef CONFIG_SLOB
554 		unsigned int index;
555 #endif
556 		if (size > KMALLOC_MAX_CACHE_SIZE)
557 			return kmalloc_large(size, flags);
558 #ifndef CONFIG_SLOB
559 		index = kmalloc_index(size);
560 
561 		if (!index)
562 			return ZERO_SIZE_PTR;
563 
564 		return kmem_cache_alloc_trace(
565 				kmalloc_caches[kmalloc_type(flags)][index],
566 				flags, size);
567 #endif
568 	}
569 	return __kmalloc(size, flags);
570 }
571 
kmalloc_node(size_t size,gfp_t flags,int node)572 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
573 {
574 #ifndef CONFIG_SLOB
575 	if (__builtin_constant_p(size) &&
576 		size <= KMALLOC_MAX_CACHE_SIZE) {
577 		unsigned int i = kmalloc_index(size);
578 
579 		if (!i)
580 			return ZERO_SIZE_PTR;
581 
582 		return kmem_cache_alloc_node_trace(
583 				kmalloc_caches[kmalloc_type(flags)][i],
584 						flags, node, size);
585 	}
586 #endif
587 	return __kmalloc_node(size, flags, node);
588 }
589 
590 /**
591  * kmalloc_array - allocate memory for an array.
592  * @n: number of elements.
593  * @size: element size.
594  * @flags: the type of memory to allocate (see kmalloc).
595  */
kmalloc_array(size_t n,size_t size,gfp_t flags)596 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
597 {
598 	size_t bytes;
599 
600 	if (unlikely(check_mul_overflow(n, size, &bytes)))
601 		return NULL;
602 	if (__builtin_constant_p(n) && __builtin_constant_p(size))
603 		return kmalloc(bytes, flags);
604 	return __kmalloc(bytes, flags);
605 }
606 
607 /**
608  * kcalloc - allocate memory for an array. The memory is set to zero.
609  * @n: number of elements.
610  * @size: element size.
611  * @flags: the type of memory to allocate (see kmalloc).
612  */
kcalloc(size_t n,size_t size,gfp_t flags)613 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
614 {
615 	return kmalloc_array(n, size, flags | __GFP_ZERO);
616 }
617 
618 /*
619  * kmalloc_track_caller is a special version of kmalloc that records the
620  * calling function of the routine calling it for slab leak tracking instead
621  * of just the calling function (confusing, eh?).
622  * It's useful when the call to kmalloc comes from a widely-used standard
623  * allocator where we care about the real place the memory allocation
624  * request comes from.
625  */
626 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
627 #define kmalloc_track_caller(size, flags) \
628 	__kmalloc_track_caller(size, flags, _RET_IP_)
629 
kmalloc_array_node(size_t n,size_t size,gfp_t flags,int node)630 static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
631 				       int node)
632 {
633 	size_t bytes;
634 
635 	if (unlikely(check_mul_overflow(n, size, &bytes)))
636 		return NULL;
637 	if (__builtin_constant_p(n) && __builtin_constant_p(size))
638 		return kmalloc_node(bytes, flags, node);
639 	return __kmalloc_node(bytes, flags, node);
640 }
641 
kcalloc_node(size_t n,size_t size,gfp_t flags,int node)642 static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
643 {
644 	return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
645 }
646 
647 
648 #ifdef CONFIG_NUMA
649 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
650 #define kmalloc_node_track_caller(size, flags, node) \
651 	__kmalloc_node_track_caller(size, flags, node, \
652 			_RET_IP_)
653 
654 #else /* CONFIG_NUMA */
655 
656 #define kmalloc_node_track_caller(size, flags, node) \
657 	kmalloc_track_caller(size, flags)
658 
659 #endif /* CONFIG_NUMA */
660 
661 /*
662  * Shortcuts
663  */
kmem_cache_zalloc(struct kmem_cache * k,gfp_t flags)664 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
665 {
666 	return kmem_cache_alloc(k, flags | __GFP_ZERO);
667 }
668 
669 /**
670  * kzalloc - allocate memory. The memory is set to zero.
671  * @size: how many bytes of memory are required.
672  * @flags: the type of memory to allocate (see kmalloc).
673  */
kzalloc(size_t size,gfp_t flags)674 static inline void *kzalloc(size_t size, gfp_t flags)
675 {
676 	return kmalloc(size, flags | __GFP_ZERO);
677 }
678 
679 /**
680  * kzalloc_node - allocate zeroed memory from a particular memory node.
681  * @size: how many bytes of memory are required.
682  * @flags: the type of memory to allocate (see kmalloc).
683  * @node: memory node from which to allocate
684  */
kzalloc_node(size_t size,gfp_t flags,int node)685 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
686 {
687 	return kmalloc_node(size, flags | __GFP_ZERO, node);
688 }
689 
690 unsigned int kmem_cache_size(struct kmem_cache *s);
691 void __init kmem_cache_init_late(void);
692 
693 #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
694 int slab_prepare_cpu(unsigned int cpu);
695 int slab_dead_cpu(unsigned int cpu);
696 #else
697 #define slab_prepare_cpu	NULL
698 #define slab_dead_cpu		NULL
699 #endif
700 
701 #endif	/* _LINUX_SLAB_H */
702