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/cache.h>
16#include <linux/gfp.h>
17#include <linux/overflow.h>
18#include <linux/types.h>
19#include <linux/workqueue.h>
20#include <linux/percpu-refcount.h>
21#include <linux/cleanup.h>
22#include <linux/hash.h>
23
24enum _slab_flag_bits {
25 _SLAB_CONSISTENCY_CHECKS,
26 _SLAB_RED_ZONE,
27 _SLAB_POISON,
28 _SLAB_KMALLOC,
29 _SLAB_HWCACHE_ALIGN,
30 _SLAB_CACHE_DMA,
31 _SLAB_CACHE_DMA32,
32 _SLAB_STORE_USER,
33 _SLAB_PANIC,
34 _SLAB_TYPESAFE_BY_RCU,
35 _SLAB_TRACE,
36#ifdef CONFIG_DEBUG_OBJECTS
37 _SLAB_DEBUG_OBJECTS,
38#endif
39 _SLAB_NOLEAKTRACE,
40 _SLAB_NO_MERGE,
41#ifdef CONFIG_FAILSLAB
42 _SLAB_FAILSLAB,
43#endif
44#ifdef CONFIG_MEMCG_KMEM
45 _SLAB_ACCOUNT,
46#endif
47#ifdef CONFIG_KASAN_GENERIC
48 _SLAB_KASAN,
49#endif
50 _SLAB_NO_USER_FLAGS,
51#ifdef CONFIG_KFENCE
52 _SLAB_SKIP_KFENCE,
53#endif
54#ifndef CONFIG_SLUB_TINY
55 _SLAB_RECLAIM_ACCOUNT,
56#endif
57 _SLAB_OBJECT_POISON,
58 _SLAB_CMPXCHG_DOUBLE,
59 _SLAB_FLAGS_LAST_BIT
60};
61
62#define __SLAB_FLAG_BIT(nr) ((slab_flags_t __force)(1U << (nr)))
63#define __SLAB_FLAG_UNUSED ((slab_flags_t __force)(0U))
64
65/*
66 * Flags to pass to kmem_cache_create().
67 * The ones marked DEBUG need CONFIG_SLUB_DEBUG enabled, otherwise are no-op
68 */
69/* DEBUG: Perform (expensive) checks on alloc/free */
70#define SLAB_CONSISTENCY_CHECKS __SLAB_FLAG_BIT(_SLAB_CONSISTENCY_CHECKS)
71/* DEBUG: Red zone objs in a cache */
72#define SLAB_RED_ZONE __SLAB_FLAG_BIT(_SLAB_RED_ZONE)
73/* DEBUG: Poison objects */
74#define SLAB_POISON __SLAB_FLAG_BIT(_SLAB_POISON)
75/* Indicate a kmalloc slab */
76#define SLAB_KMALLOC __SLAB_FLAG_BIT(_SLAB_KMALLOC)
77/* Align objs on cache lines */
78#define SLAB_HWCACHE_ALIGN __SLAB_FLAG_BIT(_SLAB_HWCACHE_ALIGN)
79/* Use GFP_DMA memory */
80#define SLAB_CACHE_DMA __SLAB_FLAG_BIT(_SLAB_CACHE_DMA)
81/* Use GFP_DMA32 memory */
82#define SLAB_CACHE_DMA32 __SLAB_FLAG_BIT(_SLAB_CACHE_DMA32)
83/* DEBUG: Store the last owner for bug hunting */
84#define SLAB_STORE_USER __SLAB_FLAG_BIT(_SLAB_STORE_USER)
85/* Panic if kmem_cache_create() fails */
86#define SLAB_PANIC __SLAB_FLAG_BIT(_SLAB_PANIC)
87/*
88 * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
89 *
90 * This delays freeing the SLAB page by a grace period, it does _NOT_
91 * delay object freeing. This means that if you do kmem_cache_free()
92 * that memory location is free to be reused at any time. Thus it may
93 * be possible to see another object there in the same RCU grace period.
94 *
95 * This feature only ensures the memory location backing the object
96 * stays valid, the trick to using this is relying on an independent
97 * object validation pass. Something like:
98 *
99 * begin:
100 * rcu_read_lock();
101 * obj = lockless_lookup(key);
102 * if (obj) {
103 * if (!try_get_ref(obj)) // might fail for free objects
104 * rcu_read_unlock();
105 * goto begin;
106 *
107 * if (obj->key != key) { // not the object we expected
108 * put_ref(obj);
109 * rcu_read_unlock();
110 * goto begin;
111 * }
112 * }
113 * rcu_read_unlock();
114 *
115 * This is useful if we need to approach a kernel structure obliquely,
116 * from its address obtained without the usual locking. We can lock
117 * the structure to stabilize it and check it's still at the given address,
118 * only if we can be sure that the memory has not been meanwhile reused
119 * for some other kind of object (which our subsystem's lock might corrupt).
120 *
121 * rcu_read_lock before reading the address, then rcu_read_unlock after
122 * taking the spinlock within the structure expected at that address.
123 *
124 * Note that it is not possible to acquire a lock within a structure
125 * allocated with SLAB_TYPESAFE_BY_RCU without first acquiring a reference
126 * as described above. The reason is that SLAB_TYPESAFE_BY_RCU pages
127 * are not zeroed before being given to the slab, which means that any
128 * locks must be initialized after each and every kmem_struct_alloc().
129 * Alternatively, make the ctor passed to kmem_cache_create() initialize
130 * the locks at page-allocation time, as is done in __i915_request_ctor(),
131 * sighand_ctor(), and anon_vma_ctor(). Such a ctor permits readers
132 * to safely acquire those ctor-initialized locks under rcu_read_lock()
133 * protection.
134 *
135 * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
136 */
137/* Defer freeing slabs to RCU */
138#define SLAB_TYPESAFE_BY_RCU __SLAB_FLAG_BIT(_SLAB_TYPESAFE_BY_RCU)
139/* Trace allocations and frees */
140#define SLAB_TRACE __SLAB_FLAG_BIT(_SLAB_TRACE)
141
142/* Flag to prevent checks on free */
143#ifdef CONFIG_DEBUG_OBJECTS
144# define SLAB_DEBUG_OBJECTS __SLAB_FLAG_BIT(_SLAB_DEBUG_OBJECTS)
145#else
146# define SLAB_DEBUG_OBJECTS __SLAB_FLAG_UNUSED
147#endif
148
149/* Avoid kmemleak tracing */
150#define SLAB_NOLEAKTRACE __SLAB_FLAG_BIT(_SLAB_NOLEAKTRACE)
151
152/*
153 * Prevent merging with compatible kmem caches. This flag should be used
154 * cautiously. Valid use cases:
155 *
156 * - caches created for self-tests (e.g. kunit)
157 * - general caches created and used by a subsystem, only when a
158 * (subsystem-specific) debug option is enabled
159 * - performance critical caches, should be very rare and consulted with slab
160 * maintainers, and not used together with CONFIG_SLUB_TINY
161 */
162#define SLAB_NO_MERGE __SLAB_FLAG_BIT(_SLAB_NO_MERGE)
163
164/* Fault injection mark */
165#ifdef CONFIG_FAILSLAB
166# define SLAB_FAILSLAB __SLAB_FLAG_BIT(_SLAB_FAILSLAB)
167#else
168# define SLAB_FAILSLAB __SLAB_FLAG_UNUSED
169#endif
170/* Account to memcg */
171#ifdef CONFIG_MEMCG_KMEM
172# define SLAB_ACCOUNT __SLAB_FLAG_BIT(_SLAB_ACCOUNT)
173#else
174# define SLAB_ACCOUNT __SLAB_FLAG_UNUSED
175#endif
176
177#ifdef CONFIG_KASAN_GENERIC
178#define SLAB_KASAN __SLAB_FLAG_BIT(_SLAB_KASAN)
179#else
180#define SLAB_KASAN __SLAB_FLAG_UNUSED
181#endif
182
183/*
184 * Ignore user specified debugging flags.
185 * Intended for caches created for self-tests so they have only flags
186 * specified in the code and other flags are ignored.
187 */
188#define SLAB_NO_USER_FLAGS __SLAB_FLAG_BIT(_SLAB_NO_USER_FLAGS)
189
190#ifdef CONFIG_KFENCE
191#define SLAB_SKIP_KFENCE __SLAB_FLAG_BIT(_SLAB_SKIP_KFENCE)
192#else
193#define SLAB_SKIP_KFENCE __SLAB_FLAG_UNUSED
194#endif
195
196/* The following flags affect the page allocator grouping pages by mobility */
197/* Objects are reclaimable */
198#ifndef CONFIG_SLUB_TINY
199#define SLAB_RECLAIM_ACCOUNT __SLAB_FLAG_BIT(_SLAB_RECLAIM_ACCOUNT)
200#else
201#define SLAB_RECLAIM_ACCOUNT __SLAB_FLAG_UNUSED
202#endif
203#define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
204
205/*
206 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
207 *
208 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
209 *
210 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
211 * Both make kfree a no-op.
212 */
213#define ZERO_SIZE_PTR ((void *)16)
214
215#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
216 (unsigned long)ZERO_SIZE_PTR)
217
218#include <linux/kasan.h>
219
220struct list_lru;
221struct mem_cgroup;
222/*
223 * struct kmem_cache related prototypes
224 */
225bool slab_is_available(void);
226
227struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
228 unsigned int align, slab_flags_t flags,
229 void (*ctor)(void *));
230struct kmem_cache *kmem_cache_create_usercopy(const char *name,
231 unsigned int size, unsigned int align,
232 slab_flags_t flags,
233 unsigned int useroffset, unsigned int usersize,
234 void (*ctor)(void *));
235void kmem_cache_destroy(struct kmem_cache *s);
236int kmem_cache_shrink(struct kmem_cache *s);
237
238/*
239 * Please use this macro to create slab caches. Simply specify the
240 * name of the structure and maybe some flags that are listed above.
241 *
242 * The alignment of the struct determines object alignment. If you
243 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
244 * then the objects will be properly aligned in SMP configurations.
245 */
246#define KMEM_CACHE(__struct, __flags) \
247 kmem_cache_create(#__struct, sizeof(struct __struct), \
248 __alignof__(struct __struct), (__flags), NULL)
249
250/*
251 * To whitelist a single field for copying to/from usercopy, use this
252 * macro instead for KMEM_CACHE() above.
253 */
254#define KMEM_CACHE_USERCOPY(__struct, __flags, __field) \
255 kmem_cache_create_usercopy(#__struct, \
256 sizeof(struct __struct), \
257 __alignof__(struct __struct), (__flags), \
258 offsetof(struct __struct, __field), \
259 sizeof_field(struct __struct, __field), NULL)
260
261/*
262 * Common kmalloc functions provided by all allocators
263 */
264void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __realloc_size(2);
265void kfree(const void *objp);
266void kfree_sensitive(const void *objp);
267size_t __ksize(const void *objp);
268
269DEFINE_FREE(kfree, void *, if (_T) kfree(_T))
270
271/**
272 * ksize - Report actual allocation size of associated object
273 *
274 * @objp: Pointer returned from a prior kmalloc()-family allocation.
275 *
276 * This should not be used for writing beyond the originally requested
277 * allocation size. Either use krealloc() or round up the allocation size
278 * with kmalloc_size_roundup() prior to allocation. If this is used to
279 * access beyond the originally requested allocation size, UBSAN_BOUNDS
280 * and/or FORTIFY_SOURCE may trip, since they only know about the
281 * originally allocated size via the __alloc_size attribute.
282 */
283size_t ksize(const void *objp);
284
285#ifdef CONFIG_PRINTK
286bool kmem_dump_obj(void *object);
287#else
288static inline bool kmem_dump_obj(void *object) { return false; }
289#endif
290
291/*
292 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
293 * alignment larger than the alignment of a 64-bit integer.
294 * Setting ARCH_DMA_MINALIGN in arch headers allows that.
295 */
296#ifdef ARCH_HAS_DMA_MINALIGN
297#if ARCH_DMA_MINALIGN > 8 && !defined(ARCH_KMALLOC_MINALIGN)
298#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
299#endif
300#endif
301
302#ifndef ARCH_KMALLOC_MINALIGN
303#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
304#elif ARCH_KMALLOC_MINALIGN > 8
305#define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
306#define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
307#endif
308
309/*
310 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
311 * Intended for arches that get misalignment faults even for 64 bit integer
312 * aligned buffers.
313 */
314#ifndef ARCH_SLAB_MINALIGN
315#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
316#endif
317
318/*
319 * Arches can define this function if they want to decide the minimum slab
320 * alignment at runtime. The value returned by the function must be a power
321 * of two and >= ARCH_SLAB_MINALIGN.
322 */
323#ifndef arch_slab_minalign
324static inline unsigned int arch_slab_minalign(void)
325{
326 return ARCH_SLAB_MINALIGN;
327}
328#endif
329
330/*
331 * kmem_cache_alloc and friends return pointers aligned to ARCH_SLAB_MINALIGN.
332 * kmalloc and friends return pointers aligned to both ARCH_KMALLOC_MINALIGN
333 * and ARCH_SLAB_MINALIGN, but here we only assume the former alignment.
334 */
335#define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
336#define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
337#define __assume_page_alignment __assume_aligned(PAGE_SIZE)
338
339/*
340 * Kmalloc array related definitions
341 */
342
343/*
344 * SLUB directly allocates requests fitting in to an order-1 page
345 * (PAGE_SIZE*2). Larger requests are passed to the page allocator.
346 */
347#define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1)
348#define KMALLOC_SHIFT_MAX (MAX_PAGE_ORDER + PAGE_SHIFT)
349#ifndef KMALLOC_SHIFT_LOW
350#define KMALLOC_SHIFT_LOW 3
351#endif
352
353/* Maximum allocatable size */
354#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX)
355/* Maximum size for which we actually use a slab cache */
356#define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH)
357/* Maximum order allocatable via the slab allocator */
358#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
359
360/*
361 * Kmalloc subsystem.
362 */
363#ifndef KMALLOC_MIN_SIZE
364#define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
365#endif
366
367/*
368 * This restriction comes from byte sized index implementation.
369 * Page size is normally 2^12 bytes and, in this case, if we want to use
370 * byte sized index which can represent 2^8 entries, the size of the object
371 * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
372 * If minimum size of kmalloc is less than 16, we use it as minimum object
373 * size and give up to use byte sized index.
374 */
375#define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \
376 (KMALLOC_MIN_SIZE) : 16)
377
378#ifdef CONFIG_RANDOM_KMALLOC_CACHES
379#define RANDOM_KMALLOC_CACHES_NR 15 // # of cache copies
380#else
381#define RANDOM_KMALLOC_CACHES_NR 0
382#endif
383
384/*
385 * Whenever changing this, take care of that kmalloc_type() and
386 * create_kmalloc_caches() still work as intended.
387 *
388 * KMALLOC_NORMAL can contain only unaccounted objects whereas KMALLOC_CGROUP
389 * is for accounted but unreclaimable and non-dma objects. All the other
390 * kmem caches can have both accounted and unaccounted objects.
391 */
392enum kmalloc_cache_type {
393 KMALLOC_NORMAL = 0,
394#ifndef CONFIG_ZONE_DMA
395 KMALLOC_DMA = KMALLOC_NORMAL,
396#endif
397#ifndef CONFIG_MEMCG_KMEM
398 KMALLOC_CGROUP = KMALLOC_NORMAL,
399#endif
400 KMALLOC_RANDOM_START = KMALLOC_NORMAL,
401 KMALLOC_RANDOM_END = KMALLOC_RANDOM_START + RANDOM_KMALLOC_CACHES_NR,
402#ifdef CONFIG_SLUB_TINY
403 KMALLOC_RECLAIM = KMALLOC_NORMAL,
404#else
405 KMALLOC_RECLAIM,
406#endif
407#ifdef CONFIG_ZONE_DMA
408 KMALLOC_DMA,
409#endif
410#ifdef CONFIG_MEMCG_KMEM
411 KMALLOC_CGROUP,
412#endif
413 NR_KMALLOC_TYPES
414};
415
416extern struct kmem_cache *
417kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
418
419/*
420 * Define gfp bits that should not be set for KMALLOC_NORMAL.
421 */
422#define KMALLOC_NOT_NORMAL_BITS \
423 (__GFP_RECLAIMABLE | \
424 (IS_ENABLED(CONFIG_ZONE_DMA) ? __GFP_DMA : 0) | \
425 (IS_ENABLED(CONFIG_MEMCG_KMEM) ? __GFP_ACCOUNT : 0))
426
427extern unsigned long random_kmalloc_seed;
428
429static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags, unsigned long caller)
430{
431 /*
432 * The most common case is KMALLOC_NORMAL, so test for it
433 * with a single branch for all the relevant flags.
434 */
435 if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0))
436#ifdef CONFIG_RANDOM_KMALLOC_CACHES
437 /* RANDOM_KMALLOC_CACHES_NR (=15) copies + the KMALLOC_NORMAL */
438 return KMALLOC_RANDOM_START + hash_64(caller ^ random_kmalloc_seed,
439 ilog2(RANDOM_KMALLOC_CACHES_NR + 1));
440#else
441 return KMALLOC_NORMAL;
442#endif
443
444 /*
445 * At least one of the flags has to be set. Their priorities in
446 * decreasing order are:
447 * 1) __GFP_DMA
448 * 2) __GFP_RECLAIMABLE
449 * 3) __GFP_ACCOUNT
450 */
451 if (IS_ENABLED(CONFIG_ZONE_DMA) && (flags & __GFP_DMA))
452 return KMALLOC_DMA;
453 if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || (flags & __GFP_RECLAIMABLE))
454 return KMALLOC_RECLAIM;
455 else
456 return KMALLOC_CGROUP;
457}
458
459/*
460 * Figure out which kmalloc slab an allocation of a certain size
461 * belongs to.
462 * 0 = zero alloc
463 * 1 = 65 .. 96 bytes
464 * 2 = 129 .. 192 bytes
465 * n = 2^(n-1)+1 .. 2^n
466 *
467 * Note: __kmalloc_index() is compile-time optimized, and not runtime optimized;
468 * typical usage is via kmalloc_index() and therefore evaluated at compile-time.
469 * Callers where !size_is_constant should only be test modules, where runtime
470 * overheads of __kmalloc_index() can be tolerated. Also see kmalloc_slab().
471 */
472static __always_inline unsigned int __kmalloc_index(size_t size,
473 bool size_is_constant)
474{
475 if (!size)
476 return 0;
477
478 if (size <= KMALLOC_MIN_SIZE)
479 return KMALLOC_SHIFT_LOW;
480
481 if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
482 return 1;
483 if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
484 return 2;
485 if (size <= 8) return 3;
486 if (size <= 16) return 4;
487 if (size <= 32) return 5;
488 if (size <= 64) return 6;
489 if (size <= 128) return 7;
490 if (size <= 256) return 8;
491 if (size <= 512) return 9;
492 if (size <= 1024) return 10;
493 if (size <= 2 * 1024) return 11;
494 if (size <= 4 * 1024) return 12;
495 if (size <= 8 * 1024) return 13;
496 if (size <= 16 * 1024) return 14;
497 if (size <= 32 * 1024) return 15;
498 if (size <= 64 * 1024) return 16;
499 if (size <= 128 * 1024) return 17;
500 if (size <= 256 * 1024) return 18;
501 if (size <= 512 * 1024) return 19;
502 if (size <= 1024 * 1024) return 20;
503 if (size <= 2 * 1024 * 1024) return 21;
504
505 if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && size_is_constant)
506 BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()");
507 else
508 BUG();
509
510 /* Will never be reached. Needed because the compiler may complain */
511 return -1;
512}
513static_assert(PAGE_SHIFT <= 20);
514#define kmalloc_index(s) __kmalloc_index(s, true)
515
516void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
517
518/**
519 * kmem_cache_alloc - Allocate an object
520 * @cachep: The cache to allocate from.
521 * @flags: See kmalloc().
522 *
523 * Allocate an object from this cache.
524 * See kmem_cache_zalloc() for a shortcut of adding __GFP_ZERO to flags.
525 *
526 * Return: pointer to the new object or %NULL in case of error
527 */
528void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) __assume_slab_alignment __malloc;
529void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
530 gfp_t gfpflags) __assume_slab_alignment __malloc;
531void kmem_cache_free(struct kmem_cache *s, void *objp);
532
533/*
534 * Bulk allocation and freeing operations. These are accelerated in an
535 * allocator specific way to avoid taking locks repeatedly or building
536 * metadata structures unnecessarily.
537 *
538 * Note that interrupts must be enabled when calling these functions.
539 */
540void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p);
541int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, void **p);
542
543static __always_inline void kfree_bulk(size_t size, void **p)
544{
545 kmem_cache_free_bulk(NULL, size, p);
546}
547
548void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment
549 __alloc_size(1);
550void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
551 __malloc;
552
553void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
554 __assume_kmalloc_alignment __alloc_size(3);
555
556void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
557 int node, size_t size) __assume_kmalloc_alignment
558 __alloc_size(4);
559void *kmalloc_large(size_t size, gfp_t flags) __assume_page_alignment
560 __alloc_size(1);
561
562void *kmalloc_large_node(size_t size, gfp_t flags, int node) __assume_page_alignment
563 __alloc_size(1);
564
565/**
566 * kmalloc - allocate kernel memory
567 * @size: how many bytes of memory are required.
568 * @flags: describe the allocation context
569 *
570 * kmalloc is the normal method of allocating memory
571 * for objects smaller than page size in the kernel.
572 *
573 * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
574 * bytes. For @size of power of two bytes, the alignment is also guaranteed
575 * to be at least to the size.
576 *
577 * The @flags argument may be one of the GFP flags defined at
578 * include/linux/gfp_types.h and described at
579 * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
580 *
581 * The recommended usage of the @flags is described at
582 * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>`
583 *
584 * Below is a brief outline of the most useful GFP flags
585 *
586 * %GFP_KERNEL
587 * Allocate normal kernel ram. May sleep.
588 *
589 * %GFP_NOWAIT
590 * Allocation will not sleep.
591 *
592 * %GFP_ATOMIC
593 * Allocation will not sleep. May use emergency pools.
594 *
595 * Also it is possible to set different flags by OR'ing
596 * in one or more of the following additional @flags:
597 *
598 * %__GFP_ZERO
599 * Zero the allocated memory before returning. Also see kzalloc().
600 *
601 * %__GFP_HIGH
602 * This allocation has high priority and may use emergency pools.
603 *
604 * %__GFP_NOFAIL
605 * Indicate that this allocation is in no way allowed to fail
606 * (think twice before using).
607 *
608 * %__GFP_NORETRY
609 * If memory is not immediately available,
610 * then give up at once.
611 *
612 * %__GFP_NOWARN
613 * If allocation fails, don't issue any warnings.
614 *
615 * %__GFP_RETRY_MAYFAIL
616 * Try really hard to succeed the allocation but fail
617 * eventually.
618 */
619static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
620{
621 if (__builtin_constant_p(size) && size) {
622 unsigned int index;
623
624 if (size > KMALLOC_MAX_CACHE_SIZE)
625 return kmalloc_large(size, flags);
626
627 index = kmalloc_index(size);
628 return kmalloc_trace(
629 s: kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index],
630 flags, size);
631 }
632 return __kmalloc(size, flags);
633}
634
635static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
636{
637 if (__builtin_constant_p(size) && size) {
638 unsigned int index;
639
640 if (size > KMALLOC_MAX_CACHE_SIZE)
641 return kmalloc_large_node(size, flags, node);
642
643 index = kmalloc_index(size);
644 return kmalloc_node_trace(
645 s: kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index],
646 gfpflags: flags, node, size);
647 }
648 return __kmalloc_node(size, flags, node);
649}
650
651/**
652 * kmalloc_array - allocate memory for an array.
653 * @n: number of elements.
654 * @size: element size.
655 * @flags: the type of memory to allocate (see kmalloc).
656 */
657static inline __alloc_size(1, 2) void *kmalloc_array(size_t n, size_t size, gfp_t flags)
658{
659 size_t bytes;
660
661 if (unlikely(check_mul_overflow(n, size, &bytes)))
662 return NULL;
663 if (__builtin_constant_p(n) && __builtin_constant_p(size))
664 return kmalloc(size: bytes, flags);
665 return __kmalloc(size: bytes, flags);
666}
667
668/**
669 * krealloc_array - reallocate memory for an array.
670 * @p: pointer to the memory chunk to reallocate
671 * @new_n: new number of elements to alloc
672 * @new_size: new size of a single member of the array
673 * @flags: the type of memory to allocate (see kmalloc)
674 */
675static inline __realloc_size(2, 3) void * __must_check krealloc_array(void *p,
676 size_t new_n,
677 size_t new_size,
678 gfp_t flags)
679{
680 size_t bytes;
681
682 if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
683 return NULL;
684
685 return krealloc(objp: p, new_size: bytes, flags);
686}
687
688/**
689 * kcalloc - allocate memory for an array. The memory is set to zero.
690 * @n: number of elements.
691 * @size: element size.
692 * @flags: the type of memory to allocate (see kmalloc).
693 */
694static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flags)
695{
696 return kmalloc_array(n, size, flags: flags | __GFP_ZERO);
697}
698
699void *__kmalloc_node_track_caller(size_t size, gfp_t flags, int node,
700 unsigned long caller) __alloc_size(1);
701#define kmalloc_node_track_caller(size, flags, node) \
702 __kmalloc_node_track_caller(size, flags, node, \
703 _RET_IP_)
704
705/*
706 * kmalloc_track_caller is a special version of kmalloc that records the
707 * calling function of the routine calling it for slab leak tracking instead
708 * of just the calling function (confusing, eh?).
709 * It's useful when the call to kmalloc comes from a widely-used standard
710 * allocator where we care about the real place the memory allocation
711 * request comes from.
712 */
713#define kmalloc_track_caller(size, flags) \
714 __kmalloc_node_track_caller(size, flags, \
715 NUMA_NO_NODE, _RET_IP_)
716
717static inline __alloc_size(1, 2) void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
718 int node)
719{
720 size_t bytes;
721
722 if (unlikely(check_mul_overflow(n, size, &bytes)))
723 return NULL;
724 if (__builtin_constant_p(n) && __builtin_constant_p(size))
725 return kmalloc_node(size: bytes, flags, node);
726 return __kmalloc_node(size: bytes, flags, node);
727}
728
729static inline __alloc_size(1, 2) void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
730{
731 return kmalloc_array_node(n, size, flags: flags | __GFP_ZERO, node);
732}
733
734/*
735 * Shortcuts
736 */
737static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
738{
739 return kmem_cache_alloc(cachep: k, flags: flags | __GFP_ZERO);
740}
741
742/**
743 * kzalloc - allocate memory. The memory is set to zero.
744 * @size: how many bytes of memory are required.
745 * @flags: the type of memory to allocate (see kmalloc).
746 */
747static inline __alloc_size(1) void *kzalloc(size_t size, gfp_t flags)
748{
749 return kmalloc(size, flags: flags | __GFP_ZERO);
750}
751
752/**
753 * kzalloc_node - allocate zeroed memory from a particular memory node.
754 * @size: how many bytes of memory are required.
755 * @flags: the type of memory to allocate (see kmalloc).
756 * @node: memory node from which to allocate
757 */
758static inline __alloc_size(1) void *kzalloc_node(size_t size, gfp_t flags, int node)
759{
760 return kmalloc_node(size, flags: flags | __GFP_ZERO, node);
761}
762
763extern void *kvmalloc_node(size_t size, gfp_t flags, int node) __alloc_size(1);
764static inline __alloc_size(1) void *kvmalloc(size_t size, gfp_t flags)
765{
766 return kvmalloc_node(size, flags, NUMA_NO_NODE);
767}
768static inline __alloc_size(1) void *kvzalloc_node(size_t size, gfp_t flags, int node)
769{
770 return kvmalloc_node(size, flags: flags | __GFP_ZERO, node);
771}
772static inline __alloc_size(1) void *kvzalloc(size_t size, gfp_t flags)
773{
774 return kvmalloc(size, flags: flags | __GFP_ZERO);
775}
776
777static inline __alloc_size(1, 2) void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
778{
779 size_t bytes;
780
781 if (unlikely(check_mul_overflow(n, size, &bytes)))
782 return NULL;
783
784 return kvmalloc(size: bytes, flags);
785}
786
787static inline __alloc_size(1, 2) void *kvcalloc(size_t n, size_t size, gfp_t flags)
788{
789 return kvmalloc_array(n, size, flags: flags | __GFP_ZERO);
790}
791
792extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
793 __realloc_size(3);
794extern void kvfree(const void *addr);
795DEFINE_FREE(kvfree, void *, if (_T) kvfree(_T))
796
797extern void kvfree_sensitive(const void *addr, size_t len);
798
799unsigned int kmem_cache_size(struct kmem_cache *s);
800
801/**
802 * kmalloc_size_roundup - Report allocation bucket size for the given size
803 *
804 * @size: Number of bytes to round up from.
805 *
806 * This returns the number of bytes that would be available in a kmalloc()
807 * allocation of @size bytes. For example, a 126 byte request would be
808 * rounded up to the next sized kmalloc bucket, 128 bytes. (This is strictly
809 * for the general-purpose kmalloc()-based allocations, and is not for the
810 * pre-sized kmem_cache_alloc()-based allocations.)
811 *
812 * Use this to kmalloc() the full bucket size ahead of time instead of using
813 * ksize() to query the size after an allocation.
814 */
815size_t kmalloc_size_roundup(size_t size);
816
817void __init kmem_cache_init_late(void);
818
819#endif /* _LINUX_SLAB_H */
820

source code of linux/include/linux/slab.h