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 /* Indicate a kmalloc slab */
33 #define SLAB_KMALLOC		((slab_flags_t __force)0x00001000U)
34 /* Align objs on cache lines */
35 #define SLAB_HWCACHE_ALIGN	((slab_flags_t __force)0x00002000U)
36 /* Use GFP_DMA memory */
37 #define SLAB_CACHE_DMA		((slab_flags_t __force)0x00004000U)
38 /* Use GFP_DMA32 memory */
39 #define SLAB_CACHE_DMA32	((slab_flags_t __force)0x00008000U)
40 /* DEBUG: Store the last owner for bug hunting */
41 #define SLAB_STORE_USER		((slab_flags_t __force)0x00010000U)
42 /* Panic if kmem_cache_create() fails */
43 #define SLAB_PANIC		((slab_flags_t __force)0x00040000U)
44 /*
45  * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
46  *
47  * This delays freeing the SLAB page by a grace period, it does _NOT_
48  * delay object freeing. This means that if you do kmem_cache_free()
49  * that memory location is free to be reused at any time. Thus it may
50  * be possible to see another object there in the same RCU grace period.
51  *
52  * This feature only ensures the memory location backing the object
53  * stays valid, the trick to using this is relying on an independent
54  * object validation pass. Something like:
55  *
56  *  rcu_read_lock()
57  * again:
58  *  obj = lockless_lookup(key);
59  *  if (obj) {
60  *    if (!try_get_ref(obj)) // might fail for free objects
61  *      goto again;
62  *
63  *    if (obj->key != key) { // not the object we expected
64  *      put_ref(obj);
65  *      goto again;
66  *    }
67  *  }
68  *  rcu_read_unlock();
69  *
70  * This is useful if we need to approach a kernel structure obliquely,
71  * from its address obtained without the usual locking. We can lock
72  * the structure to stabilize it and check it's still at the given address,
73  * only if we can be sure that the memory has not been meanwhile reused
74  * for some other kind of object (which our subsystem's lock might corrupt).
75  *
76  * rcu_read_lock before reading the address, then rcu_read_unlock after
77  * taking the spinlock within the structure expected at that address.
78  *
79  * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
80  */
81 /* Defer freeing slabs to RCU */
82 #define SLAB_TYPESAFE_BY_RCU	((slab_flags_t __force)0x00080000U)
83 /* Spread some memory over cpuset */
84 #define SLAB_MEM_SPREAD		((slab_flags_t __force)0x00100000U)
85 /* Trace allocations and frees */
86 #define SLAB_TRACE		((slab_flags_t __force)0x00200000U)
87 
88 /* Flag to prevent checks on free */
89 #ifdef CONFIG_DEBUG_OBJECTS
90 # define SLAB_DEBUG_OBJECTS	((slab_flags_t __force)0x00400000U)
91 #else
92 # define SLAB_DEBUG_OBJECTS	0
93 #endif
94 
95 /* Avoid kmemleak tracing */
96 #define SLAB_NOLEAKTRACE	((slab_flags_t __force)0x00800000U)
97 
98 /* Fault injection mark */
99 #ifdef CONFIG_FAILSLAB
100 # define SLAB_FAILSLAB		((slab_flags_t __force)0x02000000U)
101 #else
102 # define SLAB_FAILSLAB		0
103 #endif
104 /* Account to memcg */
105 #ifdef CONFIG_MEMCG_KMEM
106 # define SLAB_ACCOUNT		((slab_flags_t __force)0x04000000U)
107 #else
108 # define SLAB_ACCOUNT		0
109 #endif
110 
111 #ifdef CONFIG_KASAN_GENERIC
112 #define SLAB_KASAN		((slab_flags_t __force)0x08000000U)
113 #else
114 #define SLAB_KASAN		0
115 #endif
116 
117 /*
118  * Ignore user specified debugging flags.
119  * Intended for caches created for self-tests so they have only flags
120  * specified in the code and other flags are ignored.
121  */
122 #define SLAB_NO_USER_FLAGS	((slab_flags_t __force)0x10000000U)
123 
124 #ifdef CONFIG_KFENCE
125 #define SLAB_SKIP_KFENCE	((slab_flags_t __force)0x20000000U)
126 #else
127 #define SLAB_SKIP_KFENCE	0
128 #endif
129 
130 /* The following flags affect the page allocator grouping pages by mobility */
131 /* Objects are reclaimable */
132 #define SLAB_RECLAIM_ACCOUNT	((slab_flags_t __force)0x00020000U)
133 #define SLAB_TEMPORARY		SLAB_RECLAIM_ACCOUNT	/* Objects are short-lived */
134 
135 /*
136  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
137  *
138  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
139  *
140  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
141  * Both make kfree a no-op.
142  */
143 #define ZERO_SIZE_PTR ((void *)16)
144 
145 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
146 				(unsigned long)ZERO_SIZE_PTR)
147 
148 #include <linux/kasan.h>
149 
150 struct list_lru;
151 struct mem_cgroup;
152 /*
153  * struct kmem_cache related prototypes
154  */
155 void __init kmem_cache_init(void);
156 bool slab_is_available(void);
157 
158 struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
159 			unsigned int align, slab_flags_t flags,
160 			void (*ctor)(void *));
161 struct kmem_cache *kmem_cache_create_usercopy(const char *name,
162 			unsigned int size, unsigned int align,
163 			slab_flags_t flags,
164 			unsigned int useroffset, unsigned int usersize,
165 			void (*ctor)(void *));
166 void kmem_cache_destroy(struct kmem_cache *s);
167 int kmem_cache_shrink(struct kmem_cache *s);
168 
169 /*
170  * Please use this macro to create slab caches. Simply specify the
171  * name of the structure and maybe some flags that are listed above.
172  *
173  * The alignment of the struct determines object alignment. If you
174  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
175  * then the objects will be properly aligned in SMP configurations.
176  */
177 #define KMEM_CACHE(__struct, __flags)					\
178 		kmem_cache_create(#__struct, sizeof(struct __struct),	\
179 			__alignof__(struct __struct), (__flags), NULL)
180 
181 /*
182  * To whitelist a single field for copying to/from usercopy, use this
183  * macro instead for KMEM_CACHE() above.
184  */
185 #define KMEM_CACHE_USERCOPY(__struct, __flags, __field)			\
186 		kmem_cache_create_usercopy(#__struct,			\
187 			sizeof(struct __struct),			\
188 			__alignof__(struct __struct), (__flags),	\
189 			offsetof(struct __struct, __field),		\
190 			sizeof_field(struct __struct, __field), NULL)
191 
192 /*
193  * Common kmalloc functions provided by all allocators
194  */
195 void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __realloc_size(2);
196 void kfree(const void *objp);
197 void kfree_sensitive(const void *objp);
198 size_t __ksize(const void *objp);
199 
200 /**
201  * ksize - Report actual allocation size of associated object
202  *
203  * @objp: Pointer returned from a prior kmalloc()-family allocation.
204  *
205  * This should not be used for writing beyond the originally requested
206  * allocation size. Either use krealloc() or round up the allocation size
207  * with kmalloc_size_roundup() prior to allocation. If this is used to
208  * access beyond the originally requested allocation size, UBSAN_BOUNDS
209  * and/or FORTIFY_SOURCE may trip, since they only know about the
210  * originally allocated size via the __alloc_size attribute.
211  */
212 size_t ksize(const void *objp);
213 
214 #ifdef CONFIG_PRINTK
215 bool kmem_valid_obj(void *object);
216 void kmem_dump_obj(void *object);
217 #endif
218 
219 /*
220  * Some archs want to perform DMA into kmalloc caches and need a guaranteed
221  * alignment larger than the alignment of a 64-bit integer.
222  * Setting ARCH_DMA_MINALIGN in arch headers allows that.
223  */
224 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
225 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
226 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
227 #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
228 #else
229 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
230 #endif
231 
232 /*
233  * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
234  * Intended for arches that get misalignment faults even for 64 bit integer
235  * aligned buffers.
236  */
237 #ifndef ARCH_SLAB_MINALIGN
238 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
239 #endif
240 
241 /*
242  * Arches can define this function if they want to decide the minimum slab
243  * alignment at runtime. The value returned by the function must be a power
244  * of two and >= ARCH_SLAB_MINALIGN.
245  */
246 #ifndef arch_slab_minalign
arch_slab_minalign(void)247 static inline unsigned int arch_slab_minalign(void)
248 {
249 	return ARCH_SLAB_MINALIGN;
250 }
251 #endif
252 
253 /*
254  * kmem_cache_alloc and friends return pointers aligned to ARCH_SLAB_MINALIGN.
255  * kmalloc and friends return pointers aligned to both ARCH_KMALLOC_MINALIGN
256  * and ARCH_SLAB_MINALIGN, but here we only assume the former alignment.
257  */
258 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
259 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
260 #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
261 
262 /*
263  * Kmalloc array related definitions
264  */
265 
266 #ifdef CONFIG_SLAB
267 /*
268  * SLAB and SLUB directly allocates requests fitting in to an order-1 page
269  * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
270  */
271 #define KMALLOC_SHIFT_HIGH	(PAGE_SHIFT + 1)
272 #define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
273 #ifndef KMALLOC_SHIFT_LOW
274 #define KMALLOC_SHIFT_LOW	5
275 #endif
276 #endif
277 
278 #ifdef CONFIG_SLUB
279 #define KMALLOC_SHIFT_HIGH	(PAGE_SHIFT + 1)
280 #define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
281 #ifndef KMALLOC_SHIFT_LOW
282 #define KMALLOC_SHIFT_LOW	3
283 #endif
284 #endif
285 
286 #ifdef CONFIG_SLOB
287 /*
288  * SLOB passes all requests larger than one page to the page allocator.
289  * No kmalloc array is necessary since objects of different sizes can
290  * be allocated from the same page.
291  */
292 #define KMALLOC_SHIFT_HIGH	PAGE_SHIFT
293 #define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
294 #ifndef KMALLOC_SHIFT_LOW
295 #define KMALLOC_SHIFT_LOW	3
296 #endif
297 #endif
298 
299 /* Maximum allocatable size */
300 #define KMALLOC_MAX_SIZE	(1UL << KMALLOC_SHIFT_MAX)
301 /* Maximum size for which we actually use a slab cache */
302 #define KMALLOC_MAX_CACHE_SIZE	(1UL << KMALLOC_SHIFT_HIGH)
303 /* Maximum order allocatable via the slab allocator */
304 #define KMALLOC_MAX_ORDER	(KMALLOC_SHIFT_MAX - PAGE_SHIFT)
305 
306 /*
307  * Kmalloc subsystem.
308  */
309 #ifndef KMALLOC_MIN_SIZE
310 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
311 #endif
312 
313 /*
314  * This restriction comes from byte sized index implementation.
315  * Page size is normally 2^12 bytes and, in this case, if we want to use
316  * byte sized index which can represent 2^8 entries, the size of the object
317  * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
318  * If minimum size of kmalloc is less than 16, we use it as minimum object
319  * size and give up to use byte sized index.
320  */
321 #define SLAB_OBJ_MIN_SIZE      (KMALLOC_MIN_SIZE < 16 ? \
322                                (KMALLOC_MIN_SIZE) : 16)
323 
324 /*
325  * Whenever changing this, take care of that kmalloc_type() and
326  * create_kmalloc_caches() still work as intended.
327  *
328  * KMALLOC_NORMAL can contain only unaccounted objects whereas KMALLOC_CGROUP
329  * is for accounted but unreclaimable and non-dma objects. All the other
330  * kmem caches can have both accounted and unaccounted objects.
331  */
332 enum kmalloc_cache_type {
333 	KMALLOC_NORMAL = 0,
334 #ifndef CONFIG_ZONE_DMA
335 	KMALLOC_DMA = KMALLOC_NORMAL,
336 #endif
337 #ifndef CONFIG_MEMCG_KMEM
338 	KMALLOC_CGROUP = KMALLOC_NORMAL,
339 #else
340 	KMALLOC_CGROUP,
341 #endif
342 	KMALLOC_RECLAIM,
343 #ifdef CONFIG_ZONE_DMA
344 	KMALLOC_DMA,
345 #endif
346 	NR_KMALLOC_TYPES
347 };
348 
349 #ifndef CONFIG_SLOB
350 extern struct kmem_cache *
351 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
352 
353 /*
354  * Define gfp bits that should not be set for KMALLOC_NORMAL.
355  */
356 #define KMALLOC_NOT_NORMAL_BITS					\
357 	(__GFP_RECLAIMABLE |					\
358 	(IS_ENABLED(CONFIG_ZONE_DMA)   ? __GFP_DMA : 0) |	\
359 	(IS_ENABLED(CONFIG_MEMCG_KMEM) ? __GFP_ACCOUNT : 0))
360 
kmalloc_type(gfp_t flags)361 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
362 {
363 	/*
364 	 * The most common case is KMALLOC_NORMAL, so test for it
365 	 * with a single branch for all the relevant flags.
366 	 */
367 	if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0))
368 		return KMALLOC_NORMAL;
369 
370 	/*
371 	 * At least one of the flags has to be set. Their priorities in
372 	 * decreasing order are:
373 	 *  1) __GFP_DMA
374 	 *  2) __GFP_RECLAIMABLE
375 	 *  3) __GFP_ACCOUNT
376 	 */
377 	if (IS_ENABLED(CONFIG_ZONE_DMA) && (flags & __GFP_DMA))
378 		return KMALLOC_DMA;
379 	if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || (flags & __GFP_RECLAIMABLE))
380 		return KMALLOC_RECLAIM;
381 	else
382 		return KMALLOC_CGROUP;
383 }
384 
385 /*
386  * Figure out which kmalloc slab an allocation of a certain size
387  * belongs to.
388  * 0 = zero alloc
389  * 1 =  65 .. 96 bytes
390  * 2 = 129 .. 192 bytes
391  * n = 2^(n-1)+1 .. 2^n
392  *
393  * Note: __kmalloc_index() is compile-time optimized, and not runtime optimized;
394  * typical usage is via kmalloc_index() and therefore evaluated at compile-time.
395  * Callers where !size_is_constant should only be test modules, where runtime
396  * overheads of __kmalloc_index() can be tolerated.  Also see kmalloc_slab().
397  */
__kmalloc_index(size_t size,bool size_is_constant)398 static __always_inline unsigned int __kmalloc_index(size_t size,
399 						    bool size_is_constant)
400 {
401 	if (!size)
402 		return 0;
403 
404 	if (size <= KMALLOC_MIN_SIZE)
405 		return KMALLOC_SHIFT_LOW;
406 
407 	if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
408 		return 1;
409 	if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
410 		return 2;
411 	if (size <=          8) return 3;
412 	if (size <=         16) return 4;
413 	if (size <=         32) return 5;
414 	if (size <=         64) return 6;
415 	if (size <=        128) return 7;
416 	if (size <=        256) return 8;
417 	if (size <=        512) return 9;
418 	if (size <=       1024) return 10;
419 	if (size <=   2 * 1024) return 11;
420 	if (size <=   4 * 1024) return 12;
421 	if (size <=   8 * 1024) return 13;
422 	if (size <=  16 * 1024) return 14;
423 	if (size <=  32 * 1024) return 15;
424 	if (size <=  64 * 1024) return 16;
425 	if (size <= 128 * 1024) return 17;
426 	if (size <= 256 * 1024) return 18;
427 	if (size <= 512 * 1024) return 19;
428 	if (size <= 1024 * 1024) return 20;
429 	if (size <=  2 * 1024 * 1024) return 21;
430 
431 	if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && size_is_constant)
432 		BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()");
433 	else
434 		BUG();
435 
436 	/* Will never be reached. Needed because the compiler may complain */
437 	return -1;
438 }
439 static_assert(PAGE_SHIFT <= 20);
440 #define kmalloc_index(s) __kmalloc_index(s, true)
441 #endif /* !CONFIG_SLOB */
442 
443 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
444 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc;
445 void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
446 			   gfp_t gfpflags) __assume_slab_alignment __malloc;
447 void kmem_cache_free(struct kmem_cache *s, void *objp);
448 
449 /*
450  * Bulk allocation and freeing operations. These are accelerated in an
451  * allocator specific way to avoid taking locks repeatedly or building
452  * metadata structures unnecessarily.
453  *
454  * Note that interrupts must be enabled when calling these functions.
455  */
456 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p);
457 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, void **p);
458 
459 /*
460  * Caller must not use kfree_bulk() on memory not originally allocated
461  * by kmalloc(), because the SLOB allocator cannot handle this.
462  */
kfree_bulk(size_t size,void ** p)463 static __always_inline void kfree_bulk(size_t size, void **p)
464 {
465 	kmem_cache_free_bulk(NULL, size, p);
466 }
467 
468 void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment
469 							 __alloc_size(1);
470 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
471 									 __malloc;
472 
473 void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
474 		    __assume_kmalloc_alignment __alloc_size(3);
475 
476 void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
477 			 int node, size_t size) __assume_kmalloc_alignment
478 						__alloc_size(4);
479 void *kmalloc_large(size_t size, gfp_t flags) __assume_page_alignment
480 					      __alloc_size(1);
481 
482 void *kmalloc_large_node(size_t size, gfp_t flags, int node) __assume_page_alignment
483 							     __alloc_size(1);
484 
485 /**
486  * kmalloc - allocate memory
487  * @size: how many bytes of memory are required.
488  * @flags: the type of memory to allocate.
489  *
490  * kmalloc is the normal method of allocating memory
491  * for objects smaller than page size in the kernel.
492  *
493  * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
494  * bytes. For @size of power of two bytes, the alignment is also guaranteed
495  * to be at least to the size.
496  *
497  * The @flags argument may be one of the GFP flags defined at
498  * include/linux/gfp.h and described at
499  * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
500  *
501  * The recommended usage of the @flags is described at
502  * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>`
503  *
504  * Below is a brief outline of the most useful GFP flags
505  *
506  * %GFP_KERNEL
507  *	Allocate normal kernel ram. May sleep.
508  *
509  * %GFP_NOWAIT
510  *	Allocation will not sleep.
511  *
512  * %GFP_ATOMIC
513  *	Allocation will not sleep.  May use emergency pools.
514  *
515  * %GFP_HIGHUSER
516  *	Allocate memory from high memory on behalf of user.
517  *
518  * Also it is possible to set different flags by OR'ing
519  * in one or more of the following additional @flags:
520  *
521  * %__GFP_HIGH
522  *	This allocation has high priority and may use emergency pools.
523  *
524  * %__GFP_NOFAIL
525  *	Indicate that this allocation is in no way allowed to fail
526  *	(think twice before using).
527  *
528  * %__GFP_NORETRY
529  *	If memory is not immediately available,
530  *	then give up at once.
531  *
532  * %__GFP_NOWARN
533  *	If allocation fails, don't issue any warnings.
534  *
535  * %__GFP_RETRY_MAYFAIL
536  *	Try really hard to succeed the allocation but fail
537  *	eventually.
538  */
kmalloc(size_t size,gfp_t flags)539 static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
540 {
541 	if (__builtin_constant_p(size)) {
542 #ifndef CONFIG_SLOB
543 		unsigned int index;
544 #endif
545 		if (size > KMALLOC_MAX_CACHE_SIZE)
546 			return kmalloc_large(size, flags);
547 #ifndef CONFIG_SLOB
548 		index = kmalloc_index(size);
549 
550 		if (!index)
551 			return ZERO_SIZE_PTR;
552 
553 		return kmalloc_trace(
554 				kmalloc_caches[kmalloc_type(flags)][index],
555 				flags, size);
556 #endif
557 	}
558 	return __kmalloc(size, flags);
559 }
560 
561 #ifndef CONFIG_SLOB
kmalloc_node(size_t size,gfp_t flags,int node)562 static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
563 {
564 	if (__builtin_constant_p(size)) {
565 		unsigned int index;
566 
567 		if (size > KMALLOC_MAX_CACHE_SIZE)
568 			return kmalloc_large_node(size, flags, node);
569 
570 		index = kmalloc_index(size);
571 
572 		if (!index)
573 			return ZERO_SIZE_PTR;
574 
575 		return kmalloc_node_trace(
576 				kmalloc_caches[kmalloc_type(flags)][index],
577 				flags, node, size);
578 	}
579 	return __kmalloc_node(size, flags, node);
580 }
581 #else
kmalloc_node(size_t size,gfp_t flags,int node)582 static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
583 {
584 	if (__builtin_constant_p(size) && size > KMALLOC_MAX_CACHE_SIZE)
585 		return kmalloc_large_node(size, flags, node);
586 
587 	return __kmalloc_node(size, flags, node);
588 }
589 #endif
590 
591 /**
592  * kmalloc_array - allocate memory for an array.
593  * @n: number of elements.
594  * @size: element size.
595  * @flags: the type of memory to allocate (see kmalloc).
596  */
kmalloc_array(size_t n,size_t size,gfp_t flags)597 static inline __alloc_size(1, 2) void *kmalloc_array(size_t n, size_t size, gfp_t flags)
598 {
599 	size_t bytes;
600 
601 	if (unlikely(check_mul_overflow(n, size, &bytes)))
602 		return NULL;
603 	if (__builtin_constant_p(n) && __builtin_constant_p(size))
604 		return kmalloc(bytes, flags);
605 	return __kmalloc(bytes, flags);
606 }
607 
608 /**
609  * krealloc_array - reallocate memory for an array.
610  * @p: pointer to the memory chunk to reallocate
611  * @new_n: new number of elements to alloc
612  * @new_size: new size of a single member of the array
613  * @flags: the type of memory to allocate (see kmalloc)
614  */
krealloc_array(void * p,size_t new_n,size_t new_size,gfp_t flags)615 static inline __realloc_size(2, 3) void * __must_check krealloc_array(void *p,
616 								      size_t new_n,
617 								      size_t new_size,
618 								      gfp_t flags)
619 {
620 	size_t bytes;
621 
622 	if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
623 		return NULL;
624 
625 	return krealloc(p, bytes, flags);
626 }
627 
628 /**
629  * kcalloc - allocate memory for an array. The memory is set to zero.
630  * @n: number of elements.
631  * @size: element size.
632  * @flags: the type of memory to allocate (see kmalloc).
633  */
kcalloc(size_t n,size_t size,gfp_t flags)634 static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flags)
635 {
636 	return kmalloc_array(n, size, flags | __GFP_ZERO);
637 }
638 
639 void *__kmalloc_node_track_caller(size_t size, gfp_t flags, int node,
640 				  unsigned long caller) __alloc_size(1);
641 #define kmalloc_node_track_caller(size, flags, node) \
642 	__kmalloc_node_track_caller(size, flags, node, \
643 				    _RET_IP_)
644 
645 /*
646  * kmalloc_track_caller is a special version of kmalloc that records the
647  * calling function of the routine calling it for slab leak tracking instead
648  * of just the calling function (confusing, eh?).
649  * It's useful when the call to kmalloc comes from a widely-used standard
650  * allocator where we care about the real place the memory allocation
651  * request comes from.
652  */
653 #define kmalloc_track_caller(size, flags) \
654 	__kmalloc_node_track_caller(size, flags, \
655 				    NUMA_NO_NODE, _RET_IP_)
656 
kmalloc_array_node(size_t n,size_t size,gfp_t flags,int node)657 static inline __alloc_size(1, 2) void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
658 							  int node)
659 {
660 	size_t bytes;
661 
662 	if (unlikely(check_mul_overflow(n, size, &bytes)))
663 		return NULL;
664 	if (__builtin_constant_p(n) && __builtin_constant_p(size))
665 		return kmalloc_node(bytes, flags, node);
666 	return __kmalloc_node(bytes, flags, node);
667 }
668 
kcalloc_node(size_t n,size_t size,gfp_t flags,int node)669 static inline __alloc_size(1, 2) void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
670 {
671 	return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
672 }
673 
674 /*
675  * Shortcuts
676  */
kmem_cache_zalloc(struct kmem_cache * k,gfp_t flags)677 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
678 {
679 	return kmem_cache_alloc(k, flags | __GFP_ZERO);
680 }
681 
682 /**
683  * kzalloc - allocate memory. The memory is set to zero.
684  * @size: how many bytes of memory are required.
685  * @flags: the type of memory to allocate (see kmalloc).
686  */
kzalloc(size_t size,gfp_t flags)687 static inline __alloc_size(1) void *kzalloc(size_t size, gfp_t flags)
688 {
689 	return kmalloc(size, flags | __GFP_ZERO);
690 }
691 
692 /**
693  * kzalloc_node - allocate zeroed memory from a particular memory node.
694  * @size: how many bytes of memory are required.
695  * @flags: the type of memory to allocate (see kmalloc).
696  * @node: memory node from which to allocate
697  */
kzalloc_node(size_t size,gfp_t flags,int node)698 static inline __alloc_size(1) void *kzalloc_node(size_t size, gfp_t flags, int node)
699 {
700 	return kmalloc_node(size, flags | __GFP_ZERO, node);
701 }
702 
703 extern void *kvmalloc_node(size_t size, gfp_t flags, int node) __alloc_size(1);
kvmalloc(size_t size,gfp_t flags)704 static inline __alloc_size(1) void *kvmalloc(size_t size, gfp_t flags)
705 {
706 	return kvmalloc_node(size, flags, NUMA_NO_NODE);
707 }
kvzalloc_node(size_t size,gfp_t flags,int node)708 static inline __alloc_size(1) void *kvzalloc_node(size_t size, gfp_t flags, int node)
709 {
710 	return kvmalloc_node(size, flags | __GFP_ZERO, node);
711 }
kvzalloc(size_t size,gfp_t flags)712 static inline __alloc_size(1) void *kvzalloc(size_t size, gfp_t flags)
713 {
714 	return kvmalloc(size, flags | __GFP_ZERO);
715 }
716 
kvmalloc_array(size_t n,size_t size,gfp_t flags)717 static inline __alloc_size(1, 2) void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
718 {
719 	size_t bytes;
720 
721 	if (unlikely(check_mul_overflow(n, size, &bytes)))
722 		return NULL;
723 
724 	return kvmalloc(bytes, flags);
725 }
726 
kvcalloc(size_t n,size_t size,gfp_t flags)727 static inline __alloc_size(1, 2) void *kvcalloc(size_t n, size_t size, gfp_t flags)
728 {
729 	return kvmalloc_array(n, size, flags | __GFP_ZERO);
730 }
731 
732 extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
733 		      __realloc_size(3);
734 extern void kvfree(const void *addr);
735 extern void kvfree_sensitive(const void *addr, size_t len);
736 
737 unsigned int kmem_cache_size(struct kmem_cache *s);
738 
739 /**
740  * kmalloc_size_roundup - Report allocation bucket size for the given size
741  *
742  * @size: Number of bytes to round up from.
743  *
744  * This returns the number of bytes that would be available in a kmalloc()
745  * allocation of @size bytes. For example, a 126 byte request would be
746  * rounded up to the next sized kmalloc bucket, 128 bytes. (This is strictly
747  * for the general-purpose kmalloc()-based allocations, and is not for the
748  * pre-sized kmem_cache_alloc()-based allocations.)
749  *
750  * Use this to kmalloc() the full bucket size ahead of time instead of using
751  * ksize() to query the size after an allocation.
752  */
753 size_t kmalloc_size_roundup(size_t size);
754 
755 void __init kmem_cache_init_late(void);
756 
757 #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
758 int slab_prepare_cpu(unsigned int cpu);
759 int slab_dead_cpu(unsigned int cpu);
760 #else
761 #define slab_prepare_cpu	NULL
762 #define slab_dead_cpu		NULL
763 #endif
764 
765 #endif	/* _LINUX_SLAB_H */
766