Line data Source code
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 :
23 :
24 : /*
25 : * Flags to pass to kmem_cache_create().
26 : * The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
27 : */
28 : /* DEBUG: Perform (expensive) checks on alloc/free */
29 : #define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100U)
30 : /* DEBUG: Red zone objs in a cache */
31 : #define SLAB_RED_ZONE ((slab_flags_t __force)0x00000400U)
32 : /* DEBUG: Poison objects */
33 : #define SLAB_POISON ((slab_flags_t __force)0x00000800U)
34 : /* Indicate a kmalloc slab */
35 : #define SLAB_KMALLOC ((slab_flags_t __force)0x00001000U)
36 : /* Align objs on cache lines */
37 : #define SLAB_HWCACHE_ALIGN ((slab_flags_t __force)0x00002000U)
38 : /* Use GFP_DMA memory */
39 : #define SLAB_CACHE_DMA ((slab_flags_t __force)0x00004000U)
40 : /* Use GFP_DMA32 memory */
41 : #define SLAB_CACHE_DMA32 ((slab_flags_t __force)0x00008000U)
42 : /* DEBUG: Store the last owner for bug hunting */
43 : #define SLAB_STORE_USER ((slab_flags_t __force)0x00010000U)
44 : /* Panic if kmem_cache_create() fails */
45 : #define SLAB_PANIC ((slab_flags_t __force)0x00040000U)
46 : /*
47 : * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
48 : *
49 : * This delays freeing the SLAB page by a grace period, it does _NOT_
50 : * delay object freeing. This means that if you do kmem_cache_free()
51 : * that memory location is free to be reused at any time. Thus it may
52 : * be possible to see another object there in the same RCU grace period.
53 : *
54 : * This feature only ensures the memory location backing the object
55 : * stays valid, the trick to using this is relying on an independent
56 : * object validation pass. Something like:
57 : *
58 : * begin:
59 : * rcu_read_lock();
60 : * obj = lockless_lookup(key);
61 : * if (obj) {
62 : * if (!try_get_ref(obj)) // might fail for free objects
63 : * rcu_read_unlock();
64 : * goto begin;
65 : *
66 : * if (obj->key != key) { // not the object we expected
67 : * put_ref(obj);
68 : * rcu_read_unlock();
69 : * goto begin;
70 : * }
71 : * }
72 : * rcu_read_unlock();
73 : *
74 : * This is useful if we need to approach a kernel structure obliquely,
75 : * from its address obtained without the usual locking. We can lock
76 : * the structure to stabilize it and check it's still at the given address,
77 : * only if we can be sure that the memory has not been meanwhile reused
78 : * for some other kind of object (which our subsystem's lock might corrupt).
79 : *
80 : * rcu_read_lock before reading the address, then rcu_read_unlock after
81 : * taking the spinlock within the structure expected at that address.
82 : *
83 : * Note that it is not possible to acquire a lock within a structure
84 : * allocated with SLAB_TYPESAFE_BY_RCU without first acquiring a reference
85 : * as described above. The reason is that SLAB_TYPESAFE_BY_RCU pages
86 : * are not zeroed before being given to the slab, which means that any
87 : * locks must be initialized after each and every kmem_struct_alloc().
88 : * Alternatively, make the ctor passed to kmem_cache_create() initialize
89 : * the locks at page-allocation time, as is done in __i915_request_ctor(),
90 : * sighand_ctor(), and anon_vma_ctor(). Such a ctor permits readers
91 : * to safely acquire those ctor-initialized locks under rcu_read_lock()
92 : * protection.
93 : *
94 : * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
95 : */
96 : /* Defer freeing slabs to RCU */
97 : #define SLAB_TYPESAFE_BY_RCU ((slab_flags_t __force)0x00080000U)
98 : /* Spread some memory over cpuset */
99 : #define SLAB_MEM_SPREAD ((slab_flags_t __force)0x00100000U)
100 : /* Trace allocations and frees */
101 : #define SLAB_TRACE ((slab_flags_t __force)0x00200000U)
102 :
103 : /* Flag to prevent checks on free */
104 : #ifdef CONFIG_DEBUG_OBJECTS
105 : # define SLAB_DEBUG_OBJECTS ((slab_flags_t __force)0x00400000U)
106 : #else
107 : # define SLAB_DEBUG_OBJECTS 0
108 : #endif
109 :
110 : /* Avoid kmemleak tracing */
111 : #define SLAB_NOLEAKTRACE ((slab_flags_t __force)0x00800000U)
112 :
113 : /*
114 : * Prevent merging with compatible kmem caches. This flag should be used
115 : * cautiously. Valid use cases:
116 : *
117 : * - caches created for self-tests (e.g. kunit)
118 : * - general caches created and used by a subsystem, only when a
119 : * (subsystem-specific) debug option is enabled
120 : * - performance critical caches, should be very rare and consulted with slab
121 : * maintainers, and not used together with CONFIG_SLUB_TINY
122 : */
123 : #define SLAB_NO_MERGE ((slab_flags_t __force)0x01000000U)
124 :
125 : /* Fault injection mark */
126 : #ifdef CONFIG_FAILSLAB
127 : # define SLAB_FAILSLAB ((slab_flags_t __force)0x02000000U)
128 : #else
129 : # define SLAB_FAILSLAB 0
130 : #endif
131 : /* Account to memcg */
132 : #ifdef CONFIG_MEMCG_KMEM
133 : # define SLAB_ACCOUNT ((slab_flags_t __force)0x04000000U)
134 : #else
135 : # define SLAB_ACCOUNT 0
136 : #endif
137 :
138 : #ifdef CONFIG_KASAN_GENERIC
139 : #define SLAB_KASAN ((slab_flags_t __force)0x08000000U)
140 : #else
141 : #define SLAB_KASAN 0
142 : #endif
143 :
144 : /*
145 : * Ignore user specified debugging flags.
146 : * Intended for caches created for self-tests so they have only flags
147 : * specified in the code and other flags are ignored.
148 : */
149 : #define SLAB_NO_USER_FLAGS ((slab_flags_t __force)0x10000000U)
150 :
151 : #ifdef CONFIG_KFENCE
152 : #define SLAB_SKIP_KFENCE ((slab_flags_t __force)0x20000000U)
153 : #else
154 : #define SLAB_SKIP_KFENCE 0
155 : #endif
156 :
157 : /* The following flags affect the page allocator grouping pages by mobility */
158 : /* Objects are reclaimable */
159 : #ifndef CONFIG_SLUB_TINY
160 : #define SLAB_RECLAIM_ACCOUNT ((slab_flags_t __force)0x00020000U)
161 : #else
162 : #define SLAB_RECLAIM_ACCOUNT ((slab_flags_t __force)0)
163 : #endif
164 : #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
165 :
166 : /*
167 : * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
168 : *
169 : * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
170 : *
171 : * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
172 : * Both make kfree a no-op.
173 : */
174 : #define ZERO_SIZE_PTR ((void *)16)
175 :
176 : #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
177 : (unsigned long)ZERO_SIZE_PTR)
178 :
179 : #include <linux/kasan.h>
180 :
181 : struct list_lru;
182 : struct mem_cgroup;
183 : /*
184 : * struct kmem_cache related prototypes
185 : */
186 : bool slab_is_available(void);
187 :
188 : struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
189 : unsigned int align, slab_flags_t flags,
190 : void (*ctor)(void *));
191 : struct kmem_cache *kmem_cache_create_usercopy(const char *name,
192 : unsigned int size, unsigned int align,
193 : slab_flags_t flags,
194 : unsigned int useroffset, unsigned int usersize,
195 : void (*ctor)(void *));
196 : void kmem_cache_destroy(struct kmem_cache *s);
197 : int kmem_cache_shrink(struct kmem_cache *s);
198 :
199 : /*
200 : * Please use this macro to create slab caches. Simply specify the
201 : * name of the structure and maybe some flags that are listed above.
202 : *
203 : * The alignment of the struct determines object alignment. If you
204 : * f.e. add ____cacheline_aligned_in_smp to the struct declaration
205 : * then the objects will be properly aligned in SMP configurations.
206 : */
207 : #define KMEM_CACHE(__struct, __flags) \
208 : kmem_cache_create(#__struct, sizeof(struct __struct), \
209 : __alignof__(struct __struct), (__flags), NULL)
210 :
211 : /*
212 : * To whitelist a single field for copying to/from usercopy, use this
213 : * macro instead for KMEM_CACHE() above.
214 : */
215 : #define KMEM_CACHE_USERCOPY(__struct, __flags, __field) \
216 : kmem_cache_create_usercopy(#__struct, \
217 : sizeof(struct __struct), \
218 : __alignof__(struct __struct), (__flags), \
219 : offsetof(struct __struct, __field), \
220 : sizeof_field(struct __struct, __field), NULL)
221 :
222 : /*
223 : * Common kmalloc functions provided by all allocators
224 : */
225 : void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __realloc_size(2);
226 : void kfree(const void *objp);
227 : void kfree_sensitive(const void *objp);
228 : size_t __ksize(const void *objp);
229 :
230 : DEFINE_FREE(kfree, void *, if (_T) kfree(_T))
231 :
232 : /**
233 : * ksize - Report actual allocation size of associated object
234 : *
235 : * @objp: Pointer returned from a prior kmalloc()-family allocation.
236 : *
237 : * This should not be used for writing beyond the originally requested
238 : * allocation size. Either use krealloc() or round up the allocation size
239 : * with kmalloc_size_roundup() prior to allocation. If this is used to
240 : * access beyond the originally requested allocation size, UBSAN_BOUNDS
241 : * and/or FORTIFY_SOURCE may trip, since they only know about the
242 : * originally allocated size via the __alloc_size attribute.
243 : */
244 : size_t ksize(const void *objp);
245 :
246 : #ifdef CONFIG_PRINTK
247 : bool kmem_valid_obj(void *object);
248 : void kmem_dump_obj(void *object);
249 : #endif
250 :
251 : /*
252 : * Some archs want to perform DMA into kmalloc caches and need a guaranteed
253 : * alignment larger than the alignment of a 64-bit integer.
254 : * Setting ARCH_DMA_MINALIGN in arch headers allows that.
255 : */
256 : #ifdef ARCH_HAS_DMA_MINALIGN
257 : #if ARCH_DMA_MINALIGN > 8 && !defined(ARCH_KMALLOC_MINALIGN)
258 : #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
259 : #endif
260 : #endif
261 :
262 : #ifndef ARCH_KMALLOC_MINALIGN
263 : #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
264 : #elif ARCH_KMALLOC_MINALIGN > 8
265 : #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
266 : #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
267 : #endif
268 :
269 : /*
270 : * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
271 : * Intended for arches that get misalignment faults even for 64 bit integer
272 : * aligned buffers.
273 : */
274 : #ifndef ARCH_SLAB_MINALIGN
275 : #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
276 : #endif
277 :
278 : /*
279 : * Arches can define this function if they want to decide the minimum slab
280 : * alignment at runtime. The value returned by the function must be a power
281 : * of two and >= ARCH_SLAB_MINALIGN.
282 : */
283 : #ifndef arch_slab_minalign
284 : static inline unsigned int arch_slab_minalign(void)
285 : {
286 : return ARCH_SLAB_MINALIGN;
287 : }
288 : #endif
289 :
290 : /*
291 : * kmem_cache_alloc and friends return pointers aligned to ARCH_SLAB_MINALIGN.
292 : * kmalloc and friends return pointers aligned to both ARCH_KMALLOC_MINALIGN
293 : * and ARCH_SLAB_MINALIGN, but here we only assume the former alignment.
294 : */
295 : #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
296 : #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
297 : #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
298 :
299 : /*
300 : * Kmalloc array related definitions
301 : */
302 :
303 : #ifdef CONFIG_SLAB
304 : /*
305 : * SLAB and SLUB directly allocates requests fitting in to an order-1 page
306 : * (PAGE_SIZE*2). Larger requests are passed to the page allocator.
307 : */
308 : #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1)
309 : #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT)
310 : #ifndef KMALLOC_SHIFT_LOW
311 : #define KMALLOC_SHIFT_LOW 5
312 : #endif
313 : #endif
314 :
315 : #ifdef CONFIG_SLUB
316 : #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1)
317 : #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT)
318 : #ifndef KMALLOC_SHIFT_LOW
319 : #define KMALLOC_SHIFT_LOW 3
320 : #endif
321 : #endif
322 :
323 : /* Maximum allocatable size */
324 : #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX)
325 : /* Maximum size for which we actually use a slab cache */
326 : #define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH)
327 : /* Maximum order allocatable via the slab allocator */
328 : #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
329 :
330 : /*
331 : * Kmalloc subsystem.
332 : */
333 : #ifndef KMALLOC_MIN_SIZE
334 : #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
335 : #endif
336 :
337 : /*
338 : * This restriction comes from byte sized index implementation.
339 : * Page size is normally 2^12 bytes and, in this case, if we want to use
340 : * byte sized index which can represent 2^8 entries, the size of the object
341 : * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
342 : * If minimum size of kmalloc is less than 16, we use it as minimum object
343 : * size and give up to use byte sized index.
344 : */
345 : #define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \
346 : (KMALLOC_MIN_SIZE) : 16)
347 :
348 : /*
349 : * Whenever changing this, take care of that kmalloc_type() and
350 : * create_kmalloc_caches() still work as intended.
351 : *
352 : * KMALLOC_NORMAL can contain only unaccounted objects whereas KMALLOC_CGROUP
353 : * is for accounted but unreclaimable and non-dma objects. All the other
354 : * kmem caches can have both accounted and unaccounted objects.
355 : */
356 : enum kmalloc_cache_type {
357 : KMALLOC_NORMAL = 0,
358 : #ifndef CONFIG_ZONE_DMA
359 : KMALLOC_DMA = KMALLOC_NORMAL,
360 : #endif
361 : #ifndef CONFIG_MEMCG_KMEM
362 : KMALLOC_CGROUP = KMALLOC_NORMAL,
363 : #endif
364 : #ifdef CONFIG_SLUB_TINY
365 : KMALLOC_RECLAIM = KMALLOC_NORMAL,
366 : #else
367 : KMALLOC_RECLAIM,
368 : #endif
369 : #ifdef CONFIG_ZONE_DMA
370 : KMALLOC_DMA,
371 : #endif
372 : #ifdef CONFIG_MEMCG_KMEM
373 : KMALLOC_CGROUP,
374 : #endif
375 : NR_KMALLOC_TYPES
376 : };
377 :
378 : extern struct kmem_cache *
379 : kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
380 :
381 : /*
382 : * Define gfp bits that should not be set for KMALLOC_NORMAL.
383 : */
384 : #define KMALLOC_NOT_NORMAL_BITS \
385 : (__GFP_RECLAIMABLE | \
386 : (IS_ENABLED(CONFIG_ZONE_DMA) ? __GFP_DMA : 0) | \
387 : (IS_ENABLED(CONFIG_MEMCG_KMEM) ? __GFP_ACCOUNT : 0))
388 :
389 : static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
390 : {
391 : /*
392 : * The most common case is KMALLOC_NORMAL, so test for it
393 : * with a single branch for all the relevant flags.
394 : */
395 5135 : if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0))
396 : return KMALLOC_NORMAL;
397 :
398 : /*
399 : * At least one of the flags has to be set. Their priorities in
400 : * decreasing order are:
401 : * 1) __GFP_DMA
402 : * 2) __GFP_RECLAIMABLE
403 : * 3) __GFP_ACCOUNT
404 : */
405 : if (IS_ENABLED(CONFIG_ZONE_DMA) && (flags & __GFP_DMA))
406 : return KMALLOC_DMA;
407 : if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || (flags & __GFP_RECLAIMABLE))
408 : return KMALLOC_RECLAIM;
409 : else
410 : return KMALLOC_CGROUP;
411 : }
412 :
413 : /*
414 : * Figure out which kmalloc slab an allocation of a certain size
415 : * belongs to.
416 : * 0 = zero alloc
417 : * 1 = 65 .. 96 bytes
418 : * 2 = 129 .. 192 bytes
419 : * n = 2^(n-1)+1 .. 2^n
420 : *
421 : * Note: __kmalloc_index() is compile-time optimized, and not runtime optimized;
422 : * typical usage is via kmalloc_index() and therefore evaluated at compile-time.
423 : * Callers where !size_is_constant should only be test modules, where runtime
424 : * overheads of __kmalloc_index() can be tolerated. Also see kmalloc_slab().
425 : */
426 : static __always_inline unsigned int __kmalloc_index(size_t size,
427 : bool size_is_constant)
428 : {
429 : if (!size)
430 : return 0;
431 :
432 1291 : if (size <= KMALLOC_MIN_SIZE)
433 : return KMALLOC_SHIFT_LOW;
434 :
435 1275 : if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
436 : return 1;
437 1275 : if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
438 : return 2;
439 : if (size <= 8) return 3;
440 1274 : if (size <= 16) return 4;
441 1273 : if (size <= 32) return 5;
442 1242 : if (size <= 64) return 6;
443 1226 : if (size <= 128) return 7;
444 1226 : if (size <= 256) return 8;
445 1226 : if (size <= 512) return 9;
446 1202 : if (size <= 1024) return 10;
447 665 : if (size <= 2 * 1024) return 11;
448 650 : if (size <= 4 * 1024) return 12;
449 : if (size <= 8 * 1024) return 13;
450 : if (size <= 16 * 1024) return 14;
451 : if (size <= 32 * 1024) return 15;
452 : if (size <= 64 * 1024) return 16;
453 : if (size <= 128 * 1024) return 17;
454 : if (size <= 256 * 1024) return 18;
455 : if (size <= 512 * 1024) return 19;
456 : if (size <= 1024 * 1024) return 20;
457 : if (size <= 2 * 1024 * 1024) return 21;
458 :
459 : if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && size_is_constant)
460 : BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()");
461 : else
462 : BUG();
463 :
464 : /* Will never be reached. Needed because the compiler may complain */
465 : return -1;
466 : }
467 : static_assert(PAGE_SHIFT <= 20);
468 : #define kmalloc_index(s) __kmalloc_index(s, true)
469 :
470 : void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
471 :
472 : /**
473 : * kmem_cache_alloc - Allocate an object
474 : * @cachep: The cache to allocate from.
475 : * @flags: See kmalloc().
476 : *
477 : * Allocate an object from this cache.
478 : * See kmem_cache_zalloc() for a shortcut of adding __GFP_ZERO to flags.
479 : *
480 : * Return: pointer to the new object or %NULL in case of error
481 : */
482 : void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) __assume_slab_alignment __malloc;
483 : void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
484 : gfp_t gfpflags) __assume_slab_alignment __malloc;
485 : void kmem_cache_free(struct kmem_cache *s, void *objp);
486 :
487 : /*
488 : * Bulk allocation and freeing operations. These are accelerated in an
489 : * allocator specific way to avoid taking locks repeatedly or building
490 : * metadata structures unnecessarily.
491 : *
492 : * Note that interrupts must be enabled when calling these functions.
493 : */
494 : void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p);
495 : int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, void **p);
496 :
497 : static __always_inline void kfree_bulk(size_t size, void **p)
498 : {
499 : kmem_cache_free_bulk(NULL, size, p);
500 : }
501 :
502 : void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment
503 : __alloc_size(1);
504 : void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
505 : __malloc;
506 :
507 : void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
508 : __assume_kmalloc_alignment __alloc_size(3);
509 :
510 : void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
511 : int node, size_t size) __assume_kmalloc_alignment
512 : __alloc_size(4);
513 : void *kmalloc_large(size_t size, gfp_t flags) __assume_page_alignment
514 : __alloc_size(1);
515 :
516 : void *kmalloc_large_node(size_t size, gfp_t flags, int node) __assume_page_alignment
517 : __alloc_size(1);
518 :
519 : /**
520 : * kmalloc - allocate kernel memory
521 : * @size: how many bytes of memory are required.
522 : * @flags: describe the allocation context
523 : *
524 : * kmalloc is the normal method of allocating memory
525 : * for objects smaller than page size in the kernel.
526 : *
527 : * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
528 : * bytes. For @size of power of two bytes, the alignment is also guaranteed
529 : * to be at least to the size.
530 : *
531 : * The @flags argument may be one of the GFP flags defined at
532 : * include/linux/gfp_types.h and described at
533 : * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
534 : *
535 : * The recommended usage of the @flags is described at
536 : * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>`
537 : *
538 : * Below is a brief outline of the most useful GFP flags
539 : *
540 : * %GFP_KERNEL
541 : * Allocate normal kernel ram. May sleep.
542 : *
543 : * %GFP_NOWAIT
544 : * Allocation will not sleep.
545 : *
546 : * %GFP_ATOMIC
547 : * Allocation will not sleep. May use emergency pools.
548 : *
549 : * Also it is possible to set different flags by OR'ing
550 : * in one or more of the following additional @flags:
551 : *
552 : * %__GFP_ZERO
553 : * Zero the allocated memory before returning. Also see kzalloc().
554 : *
555 : * %__GFP_HIGH
556 : * This allocation has high priority and may use emergency pools.
557 : *
558 : * %__GFP_NOFAIL
559 : * Indicate that this allocation is in no way allowed to fail
560 : * (think twice before using).
561 : *
562 : * %__GFP_NORETRY
563 : * If memory is not immediately available,
564 : * then give up at once.
565 : *
566 : * %__GFP_NOWARN
567 : * If allocation fails, don't issue any warnings.
568 : *
569 : * %__GFP_RETRY_MAYFAIL
570 : * Try really hard to succeed the allocation but fail
571 : * eventually.
572 : */
573 : static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
574 : {
575 2112 : if (__builtin_constant_p(size) && size) {
576 : unsigned int index;
577 :
578 1274 : if (size > KMALLOC_MAX_CACHE_SIZE)
579 0 : return kmalloc_large(size, flags);
580 :
581 2972 : index = kmalloc_index(size);
582 2972 : return kmalloc_trace(
583 2972 : kmalloc_caches[kmalloc_type(flags)][index],
584 : flags, size);
585 : }
586 838 : return __kmalloc(size, flags);
587 : }
588 :
589 : static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
590 : {
591 33 : if (__builtin_constant_p(size) && size) {
592 : unsigned int index;
593 :
594 17 : if (size > KMALLOC_MAX_CACHE_SIZE)
595 0 : return kmalloc_large_node(size, flags, node);
596 :
597 27 : index = kmalloc_index(size);
598 27 : return kmalloc_node_trace(
599 27 : kmalloc_caches[kmalloc_type(flags)][index],
600 : flags, node, size);
601 : }
602 16 : return __kmalloc_node(size, flags, node);
603 : }
604 :
605 : /**
606 : * kmalloc_array - allocate memory for an array.
607 : * @n: number of elements.
608 : * @size: element size.
609 : * @flags: the type of memory to allocate (see kmalloc).
610 : */
611 451 : static inline __alloc_size(1, 2) void *kmalloc_array(size_t n, size_t size, gfp_t flags)
612 : {
613 : size_t bytes;
614 :
615 902 : if (unlikely(check_mul_overflow(n, size, &bytes)))
616 : return NULL;
617 451 : if (__builtin_constant_p(n) && __builtin_constant_p(size))
618 32 : return kmalloc(bytes, flags);
619 419 : return __kmalloc(bytes, flags);
620 : }
621 :
622 : /**
623 : * krealloc_array - reallocate memory for an array.
624 : * @p: pointer to the memory chunk to reallocate
625 : * @new_n: new number of elements to alloc
626 : * @new_size: new size of a single member of the array
627 : * @flags: the type of memory to allocate (see kmalloc)
628 : */
629 : static inline __realloc_size(2, 3) void * __must_check krealloc_array(void *p,
630 : size_t new_n,
631 : size_t new_size,
632 : gfp_t flags)
633 : {
634 : size_t bytes;
635 :
636 0 : if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
637 : return NULL;
638 :
639 0 : return krealloc(p, bytes, flags);
640 : }
641 :
642 : /**
643 : * kcalloc - allocate memory for an array. The memory is set to zero.
644 : * @n: number of elements.
645 : * @size: element size.
646 : * @flags: the type of memory to allocate (see kmalloc).
647 : */
648 : static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flags)
649 : {
650 144 : return kmalloc_array(n, size, flags | __GFP_ZERO);
651 : }
652 :
653 : void *__kmalloc_node_track_caller(size_t size, gfp_t flags, int node,
654 : unsigned long caller) __alloc_size(1);
655 : #define kmalloc_node_track_caller(size, flags, node) \
656 : __kmalloc_node_track_caller(size, flags, node, \
657 : _RET_IP_)
658 :
659 : /*
660 : * kmalloc_track_caller is a special version of kmalloc that records the
661 : * calling function of the routine calling it for slab leak tracking instead
662 : * of just the calling function (confusing, eh?).
663 : * It's useful when the call to kmalloc comes from a widely-used standard
664 : * allocator where we care about the real place the memory allocation
665 : * request comes from.
666 : */
667 : #define kmalloc_track_caller(size, flags) \
668 : __kmalloc_node_track_caller(size, flags, \
669 : NUMA_NO_NODE, _RET_IP_)
670 :
671 4 : static inline __alloc_size(1, 2) void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
672 : int node)
673 : {
674 : size_t bytes;
675 :
676 8 : if (unlikely(check_mul_overflow(n, size, &bytes)))
677 : return NULL;
678 4 : if (__builtin_constant_p(n) && __builtin_constant_p(size))
679 0 : return kmalloc_node(bytes, flags, node);
680 4 : return __kmalloc_node(bytes, flags, node);
681 : }
682 :
683 : static inline __alloc_size(1, 2) void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
684 : {
685 0 : return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
686 : }
687 :
688 : /*
689 : * Shortcuts
690 : */
691 : static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
692 : {
693 8864 : return kmem_cache_alloc(k, flags | __GFP_ZERO);
694 : }
695 :
696 : /**
697 : * kzalloc - allocate memory. The memory is set to zero.
698 : * @size: how many bytes of memory are required.
699 : * @flags: the type of memory to allocate (see kmalloc).
700 : */
701 1970 : static inline __alloc_size(1) void *kzalloc(size_t size, gfp_t flags)
702 : {
703 6822 : return kmalloc(size, flags | __GFP_ZERO);
704 : }
705 :
706 : /**
707 : * kzalloc_node - allocate zeroed memory from a particular memory node.
708 : * @size: how many bytes of memory are required.
709 : * @flags: the type of memory to allocate (see kmalloc).
710 : * @node: memory node from which to allocate
711 : */
712 17 : static inline __alloc_size(1) void *kzalloc_node(size_t size, gfp_t flags, int node)
713 : {
714 54 : return kmalloc_node(size, flags | __GFP_ZERO, node);
715 : }
716 :
717 : extern void *kvmalloc_node(size_t size, gfp_t flags, int node) __alloc_size(1);
718 : static inline __alloc_size(1) void *kvmalloc(size_t size, gfp_t flags)
719 : {
720 0 : return kvmalloc_node(size, flags, NUMA_NO_NODE);
721 : }
722 : static inline __alloc_size(1) void *kvzalloc_node(size_t size, gfp_t flags, int node)
723 : {
724 0 : return kvmalloc_node(size, flags | __GFP_ZERO, node);
725 : }
726 : static inline __alloc_size(1) void *kvzalloc(size_t size, gfp_t flags)
727 : {
728 0 : return kvmalloc(size, flags | __GFP_ZERO);
729 : }
730 :
731 : static inline __alloc_size(1, 2) void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
732 : {
733 : size_t bytes;
734 :
735 0 : if (unlikely(check_mul_overflow(n, size, &bytes)))
736 : return NULL;
737 :
738 0 : return kvmalloc(bytes, flags);
739 : }
740 :
741 : static inline __alloc_size(1, 2) void *kvcalloc(size_t n, size_t size, gfp_t flags)
742 : {
743 0 : return kvmalloc_array(n, size, flags | __GFP_ZERO);
744 : }
745 :
746 : extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
747 : __realloc_size(3);
748 : extern void kvfree(const void *addr);
749 : extern void kvfree_sensitive(const void *addr, size_t len);
750 :
751 : unsigned int kmem_cache_size(struct kmem_cache *s);
752 :
753 : /**
754 : * kmalloc_size_roundup - Report allocation bucket size for the given size
755 : *
756 : * @size: Number of bytes to round up from.
757 : *
758 : * This returns the number of bytes that would be available in a kmalloc()
759 : * allocation of @size bytes. For example, a 126 byte request would be
760 : * rounded up to the next sized kmalloc bucket, 128 bytes. (This is strictly
761 : * for the general-purpose kmalloc()-based allocations, and is not for the
762 : * pre-sized kmem_cache_alloc()-based allocations.)
763 : *
764 : * Use this to kmalloc() the full bucket size ahead of time instead of using
765 : * ksize() to query the size after an allocation.
766 : */
767 : size_t kmalloc_size_roundup(size_t size);
768 :
769 : void __init kmem_cache_init_late(void);
770 :
771 : #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
772 : int slab_prepare_cpu(unsigned int cpu);
773 : int slab_dead_cpu(unsigned int cpu);
774 : #else
775 : #define slab_prepare_cpu NULL
776 : #define slab_dead_cpu NULL
777 : #endif
778 :
779 : #endif /* _LINUX_SLAB_H */
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