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/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 it is not possible to acquire a lock within a structure
80 : * allocated with SLAB_TYPESAFE_BY_RCU without first acquiring a reference
81 : * as described above. The reason is that SLAB_TYPESAFE_BY_RCU pages
82 : * are not zeroed before being given to the slab, which means that any
83 : * locks must be initialized after each and every kmem_struct_alloc().
84 : * Alternatively, make the ctor passed to kmem_cache_create() initialize
85 : * the locks at page-allocation time, as is done in __i915_request_ctor(),
86 : * sighand_ctor(), and anon_vma_ctor(). Such a ctor permits readers
87 : * to safely acquire those ctor-initialized locks under rcu_read_lock()
88 : * protection.
89 : *
90 : * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
91 : */
92 : /* Defer freeing slabs to RCU */
93 : #define SLAB_TYPESAFE_BY_RCU ((slab_flags_t __force)0x00080000U)
94 : /* Spread some memory over cpuset */
95 : #define SLAB_MEM_SPREAD ((slab_flags_t __force)0x00100000U)
96 : /* Trace allocations and frees */
97 : #define SLAB_TRACE ((slab_flags_t __force)0x00200000U)
98 :
99 : /* Flag to prevent checks on free */
100 : #ifdef CONFIG_DEBUG_OBJECTS
101 : # define SLAB_DEBUG_OBJECTS ((slab_flags_t __force)0x00400000U)
102 : #else
103 : # define SLAB_DEBUG_OBJECTS 0
104 : #endif
105 :
106 : /* Avoid kmemleak tracing */
107 : #define SLAB_NOLEAKTRACE ((slab_flags_t __force)0x00800000U)
108 :
109 : /* Fault injection mark */
110 : #ifdef CONFIG_FAILSLAB
111 : # define SLAB_FAILSLAB ((slab_flags_t __force)0x02000000U)
112 : #else
113 : # define SLAB_FAILSLAB 0
114 : #endif
115 : /* Account to memcg */
116 : #ifdef CONFIG_MEMCG_KMEM
117 : # define SLAB_ACCOUNT ((slab_flags_t __force)0x04000000U)
118 : #else
119 : # define SLAB_ACCOUNT 0
120 : #endif
121 :
122 : #ifdef CONFIG_KASAN_GENERIC
123 : #define SLAB_KASAN ((slab_flags_t __force)0x08000000U)
124 : #else
125 : #define SLAB_KASAN 0
126 : #endif
127 :
128 : /*
129 : * Ignore user specified debugging flags.
130 : * Intended for caches created for self-tests so they have only flags
131 : * specified in the code and other flags are ignored.
132 : */
133 : #define SLAB_NO_USER_FLAGS ((slab_flags_t __force)0x10000000U)
134 :
135 : #ifdef CONFIG_KFENCE
136 : #define SLAB_SKIP_KFENCE ((slab_flags_t __force)0x20000000U)
137 : #else
138 : #define SLAB_SKIP_KFENCE 0
139 : #endif
140 :
141 : /* The following flags affect the page allocator grouping pages by mobility */
142 : /* Objects are reclaimable */
143 : #ifndef CONFIG_SLUB_TINY
144 : #define SLAB_RECLAIM_ACCOUNT ((slab_flags_t __force)0x00020000U)
145 : #else
146 : #define SLAB_RECLAIM_ACCOUNT ((slab_flags_t __force)0)
147 : #endif
148 : #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
149 :
150 : /*
151 : * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
152 : *
153 : * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
154 : *
155 : * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
156 : * Both make kfree a no-op.
157 : */
158 : #define ZERO_SIZE_PTR ((void *)16)
159 :
160 : #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
161 : (unsigned long)ZERO_SIZE_PTR)
162 :
163 : #include <linux/kasan.h>
164 :
165 : struct list_lru;
166 : struct mem_cgroup;
167 : /*
168 : * struct kmem_cache related prototypes
169 : */
170 : void __init kmem_cache_init(void);
171 : bool slab_is_available(void);
172 :
173 : struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
174 : unsigned int align, slab_flags_t flags,
175 : void (*ctor)(void *));
176 : struct kmem_cache *kmem_cache_create_usercopy(const char *name,
177 : unsigned int size, unsigned int align,
178 : slab_flags_t flags,
179 : unsigned int useroffset, unsigned int usersize,
180 : void (*ctor)(void *));
181 : void kmem_cache_destroy(struct kmem_cache *s);
182 : int kmem_cache_shrink(struct kmem_cache *s);
183 :
184 : /*
185 : * Please use this macro to create slab caches. Simply specify the
186 : * name of the structure and maybe some flags that are listed above.
187 : *
188 : * The alignment of the struct determines object alignment. If you
189 : * f.e. add ____cacheline_aligned_in_smp to the struct declaration
190 : * then the objects will be properly aligned in SMP configurations.
191 : */
192 : #define KMEM_CACHE(__struct, __flags) \
193 : kmem_cache_create(#__struct, sizeof(struct __struct), \
194 : __alignof__(struct __struct), (__flags), NULL)
195 :
196 : /*
197 : * To whitelist a single field for copying to/from usercopy, use this
198 : * macro instead for KMEM_CACHE() above.
199 : */
200 : #define KMEM_CACHE_USERCOPY(__struct, __flags, __field) \
201 : kmem_cache_create_usercopy(#__struct, \
202 : sizeof(struct __struct), \
203 : __alignof__(struct __struct), (__flags), \
204 : offsetof(struct __struct, __field), \
205 : sizeof_field(struct __struct, __field), NULL)
206 :
207 : /*
208 : * Common kmalloc functions provided by all allocators
209 : */
210 : void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __realloc_size(2);
211 : void kfree(const void *objp);
212 : void kfree_sensitive(const void *objp);
213 : size_t __ksize(const void *objp);
214 :
215 : /**
216 : * ksize - Report actual allocation size of associated object
217 : *
218 : * @objp: Pointer returned from a prior kmalloc()-family allocation.
219 : *
220 : * This should not be used for writing beyond the originally requested
221 : * allocation size. Either use krealloc() or round up the allocation size
222 : * with kmalloc_size_roundup() prior to allocation. If this is used to
223 : * access beyond the originally requested allocation size, UBSAN_BOUNDS
224 : * and/or FORTIFY_SOURCE may trip, since they only know about the
225 : * originally allocated size via the __alloc_size attribute.
226 : */
227 : size_t ksize(const void *objp);
228 :
229 : #ifdef CONFIG_PRINTK
230 : bool kmem_valid_obj(void *object);
231 : void kmem_dump_obj(void *object);
232 : #endif
233 :
234 : /*
235 : * Some archs want to perform DMA into kmalloc caches and need a guaranteed
236 : * alignment larger than the alignment of a 64-bit integer.
237 : * Setting ARCH_DMA_MINALIGN in arch headers allows that.
238 : */
239 : #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
240 : #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
241 : #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
242 : #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
243 : #else
244 : #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
245 : #endif
246 :
247 : /*
248 : * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
249 : * Intended for arches that get misalignment faults even for 64 bit integer
250 : * aligned buffers.
251 : */
252 : #ifndef ARCH_SLAB_MINALIGN
253 : #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
254 : #endif
255 :
256 : /*
257 : * Arches can define this function if they want to decide the minimum slab
258 : * alignment at runtime. The value returned by the function must be a power
259 : * of two and >= ARCH_SLAB_MINALIGN.
260 : */
261 : #ifndef arch_slab_minalign
262 : static inline unsigned int arch_slab_minalign(void)
263 : {
264 : return ARCH_SLAB_MINALIGN;
265 : }
266 : #endif
267 :
268 : /*
269 : * kmem_cache_alloc and friends return pointers aligned to ARCH_SLAB_MINALIGN.
270 : * kmalloc and friends return pointers aligned to both ARCH_KMALLOC_MINALIGN
271 : * and ARCH_SLAB_MINALIGN, but here we only assume the former alignment.
272 : */
273 : #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
274 : #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
275 : #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
276 :
277 : /*
278 : * Kmalloc array related definitions
279 : */
280 :
281 : #ifdef CONFIG_SLAB
282 : /*
283 : * SLAB and SLUB directly allocates requests fitting in to an order-1 page
284 : * (PAGE_SIZE*2). Larger requests are passed to the page allocator.
285 : */
286 : #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1)
287 : #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
288 : #ifndef KMALLOC_SHIFT_LOW
289 : #define KMALLOC_SHIFT_LOW 5
290 : #endif
291 : #endif
292 :
293 : #ifdef CONFIG_SLUB
294 : #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1)
295 : #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
296 : #ifndef KMALLOC_SHIFT_LOW
297 : #define KMALLOC_SHIFT_LOW 3
298 : #endif
299 : #endif
300 :
301 : #ifdef CONFIG_SLOB
302 : /*
303 : * SLOB passes all requests larger than one page to the page allocator.
304 : * No kmalloc array is necessary since objects of different sizes can
305 : * be allocated from the same page.
306 : */
307 : #define KMALLOC_SHIFT_HIGH PAGE_SHIFT
308 : #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
309 : #ifndef KMALLOC_SHIFT_LOW
310 : #define KMALLOC_SHIFT_LOW 3
311 : #endif
312 : #endif
313 :
314 : /* Maximum allocatable size */
315 : #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX)
316 : /* Maximum size for which we actually use a slab cache */
317 : #define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH)
318 : /* Maximum order allocatable via the slab allocator */
319 : #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
320 :
321 : /*
322 : * Kmalloc subsystem.
323 : */
324 : #ifndef KMALLOC_MIN_SIZE
325 : #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
326 : #endif
327 :
328 : /*
329 : * This restriction comes from byte sized index implementation.
330 : * Page size is normally 2^12 bytes and, in this case, if we want to use
331 : * byte sized index which can represent 2^8 entries, the size of the object
332 : * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
333 : * If minimum size of kmalloc is less than 16, we use it as minimum object
334 : * size and give up to use byte sized index.
335 : */
336 : #define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \
337 : (KMALLOC_MIN_SIZE) : 16)
338 :
339 : /*
340 : * Whenever changing this, take care of that kmalloc_type() and
341 : * create_kmalloc_caches() still work as intended.
342 : *
343 : * KMALLOC_NORMAL can contain only unaccounted objects whereas KMALLOC_CGROUP
344 : * is for accounted but unreclaimable and non-dma objects. All the other
345 : * kmem caches can have both accounted and unaccounted objects.
346 : */
347 : enum kmalloc_cache_type {
348 : KMALLOC_NORMAL = 0,
349 : #ifndef CONFIG_ZONE_DMA
350 : KMALLOC_DMA = KMALLOC_NORMAL,
351 : #endif
352 : #ifndef CONFIG_MEMCG_KMEM
353 : KMALLOC_CGROUP = KMALLOC_NORMAL,
354 : #endif
355 : #ifdef CONFIG_SLUB_TINY
356 : KMALLOC_RECLAIM = KMALLOC_NORMAL,
357 : #else
358 : KMALLOC_RECLAIM,
359 : #endif
360 : #ifdef CONFIG_ZONE_DMA
361 : KMALLOC_DMA,
362 : #endif
363 : #ifdef CONFIG_MEMCG_KMEM
364 : KMALLOC_CGROUP,
365 : #endif
366 : NR_KMALLOC_TYPES
367 : };
368 :
369 : #ifndef CONFIG_SLOB
370 : extern struct kmem_cache *
371 : kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
372 :
373 : /*
374 : * Define gfp bits that should not be set for KMALLOC_NORMAL.
375 : */
376 : #define KMALLOC_NOT_NORMAL_BITS \
377 : (__GFP_RECLAIMABLE | \
378 : (IS_ENABLED(CONFIG_ZONE_DMA) ? __GFP_DMA : 0) | \
379 : (IS_ENABLED(CONFIG_MEMCG_KMEM) ? __GFP_ACCOUNT : 0))
380 :
381 : static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
382 : {
383 : /*
384 : * The most common case is KMALLOC_NORMAL, so test for it
385 : * with a single branch for all the relevant flags.
386 : */
387 7011 : if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0))
388 : return KMALLOC_NORMAL;
389 :
390 : /*
391 : * At least one of the flags has to be set. Their priorities in
392 : * decreasing order are:
393 : * 1) __GFP_DMA
394 : * 2) __GFP_RECLAIMABLE
395 : * 3) __GFP_ACCOUNT
396 : */
397 : if (IS_ENABLED(CONFIG_ZONE_DMA) && (flags & __GFP_DMA))
398 : return KMALLOC_DMA;
399 : if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || (flags & __GFP_RECLAIMABLE))
400 : return KMALLOC_RECLAIM;
401 : else
402 : return KMALLOC_CGROUP;
403 : }
404 :
405 : /*
406 : * Figure out which kmalloc slab an allocation of a certain size
407 : * belongs to.
408 : * 0 = zero alloc
409 : * 1 = 65 .. 96 bytes
410 : * 2 = 129 .. 192 bytes
411 : * n = 2^(n-1)+1 .. 2^n
412 : *
413 : * Note: __kmalloc_index() is compile-time optimized, and not runtime optimized;
414 : * typical usage is via kmalloc_index() and therefore evaluated at compile-time.
415 : * Callers where !size_is_constant should only be test modules, where runtime
416 : * overheads of __kmalloc_index() can be tolerated. Also see kmalloc_slab().
417 : */
418 : static __always_inline unsigned int __kmalloc_index(size_t size,
419 : bool size_is_constant)
420 : {
421 : if (!size)
422 : return 0;
423 :
424 1992 : if (size <= KMALLOC_MIN_SIZE)
425 : return KMALLOC_SHIFT_LOW;
426 :
427 1964 : if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
428 : return 1;
429 1964 : if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
430 : return 2;
431 : if (size <= 8) return 3;
432 1963 : if (size <= 16) return 4;
433 1962 : if (size <= 32) return 5;
434 1907 : if (size <= 64) return 6;
435 1321 : if (size <= 128) return 7;
436 1321 : if (size <= 256) return 8;
437 1321 : if (size <= 512) return 9;
438 1298 : if (size <= 1024) return 10;
439 748 : if (size <= 2 * 1024) return 11;
440 721 : if (size <= 4 * 1024) return 12;
441 : if (size <= 8 * 1024) return 13;
442 : if (size <= 16 * 1024) return 14;
443 : if (size <= 32 * 1024) return 15;
444 : if (size <= 64 * 1024) return 16;
445 : if (size <= 128 * 1024) return 17;
446 : if (size <= 256 * 1024) return 18;
447 : if (size <= 512 * 1024) return 19;
448 : if (size <= 1024 * 1024) return 20;
449 : if (size <= 2 * 1024 * 1024) return 21;
450 :
451 : if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && size_is_constant)
452 : BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()");
453 : else
454 : BUG();
455 :
456 : /* Will never be reached. Needed because the compiler may complain */
457 : return -1;
458 : }
459 : static_assert(PAGE_SHIFT <= 20);
460 : #define kmalloc_index(s) __kmalloc_index(s, true)
461 : #endif /* !CONFIG_SLOB */
462 :
463 : void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
464 :
465 : /**
466 : * kmem_cache_alloc - Allocate an object
467 : * @cachep: The cache to allocate from.
468 : * @flags: See kmalloc().
469 : *
470 : * Allocate an object from this cache.
471 : * See kmem_cache_zalloc() for a shortcut of adding __GFP_ZERO to flags.
472 : *
473 : * Return: pointer to the new object or %NULL in case of error
474 : */
475 : void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) __assume_slab_alignment __malloc;
476 : void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
477 : gfp_t gfpflags) __assume_slab_alignment __malloc;
478 : void kmem_cache_free(struct kmem_cache *s, void *objp);
479 :
480 : /*
481 : * Bulk allocation and freeing operations. These are accelerated in an
482 : * allocator specific way to avoid taking locks repeatedly or building
483 : * metadata structures unnecessarily.
484 : *
485 : * Note that interrupts must be enabled when calling these functions.
486 : */
487 : void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p);
488 : int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, void **p);
489 :
490 : /*
491 : * Caller must not use kfree_bulk() on memory not originally allocated
492 : * by kmalloc(), because the SLOB allocator cannot handle this.
493 : */
494 : static __always_inline void kfree_bulk(size_t size, void **p)
495 : {
496 : kmem_cache_free_bulk(NULL, size, p);
497 : }
498 :
499 : void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment
500 : __alloc_size(1);
501 : void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
502 : __malloc;
503 :
504 : void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
505 : __assume_kmalloc_alignment __alloc_size(3);
506 :
507 : void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
508 : int node, size_t size) __assume_kmalloc_alignment
509 : __alloc_size(4);
510 : void *kmalloc_large(size_t size, gfp_t flags) __assume_page_alignment
511 : __alloc_size(1);
512 :
513 : void *kmalloc_large_node(size_t size, gfp_t flags, int node) __assume_page_alignment
514 : __alloc_size(1);
515 :
516 : /**
517 : * kmalloc - allocate kernel memory
518 : * @size: how many bytes of memory are required.
519 : * @flags: describe the allocation context
520 : *
521 : * kmalloc is the normal method of allocating memory
522 : * for objects smaller than page size in the kernel.
523 : *
524 : * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
525 : * bytes. For @size of power of two bytes, the alignment is also guaranteed
526 : * to be at least to the size.
527 : *
528 : * The @flags argument may be one of the GFP flags defined at
529 : * include/linux/gfp.h and described at
530 : * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
531 : *
532 : * The recommended usage of the @flags is described at
533 : * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>`
534 : *
535 : * Below is a brief outline of the most useful GFP flags
536 : *
537 : * %GFP_KERNEL
538 : * Allocate normal kernel ram. May sleep.
539 : *
540 : * %GFP_NOWAIT
541 : * Allocation will not sleep.
542 : *
543 : * %GFP_ATOMIC
544 : * Allocation will not sleep. May use emergency pools.
545 : *
546 : * Also it is possible to set different flags by OR'ing
547 : * in one or more of the following additional @flags:
548 : *
549 : * %__GFP_ZERO
550 : * Zero the allocated memory before returning. Also see kzalloc().
551 : *
552 : * %__GFP_HIGH
553 : * This allocation has high priority and may use emergency pools.
554 : *
555 : * %__GFP_NOFAIL
556 : * Indicate that this allocation is in no way allowed to fail
557 : * (think twice before using).
558 : *
559 : * %__GFP_NORETRY
560 : * If memory is not immediately available,
561 : * then give up at once.
562 : *
563 : * %__GFP_NOWARN
564 : * If allocation fails, don't issue any warnings.
565 : *
566 : * %__GFP_RETRY_MAYFAIL
567 : * Try really hard to succeed the allocation but fail
568 : * eventually.
569 : */
570 : #ifndef CONFIG_SLOB
571 : static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
572 : {
573 2597 : if (__builtin_constant_p(size) && size) {
574 : unsigned int index;
575 :
576 1717 : if (size > KMALLOC_MAX_CACHE_SIZE)
577 0 : return kmalloc_large(size, flags);
578 :
579 41293 : index = kmalloc_index(size);
580 41293 : return kmalloc_trace(
581 41293 : kmalloc_caches[kmalloc_type(flags)][index],
582 : flags, size);
583 : }
584 880 : return __kmalloc(size, flags);
585 : }
586 : #else
587 : static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
588 : {
589 : if (__builtin_constant_p(size) && size > KMALLOC_MAX_CACHE_SIZE)
590 : return kmalloc_large(size, flags);
591 :
592 : return __kmalloc(size, flags);
593 : }
594 : #endif
595 :
596 : #ifndef CONFIG_SLOB
597 : static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
598 : {
599 548 : if (__builtin_constant_p(size) && size) {
600 : unsigned int index;
601 :
602 275 : if (size > KMALLOC_MAX_CACHE_SIZE)
603 0 : return kmalloc_large_node(size, flags, node);
604 :
605 285 : index = kmalloc_index(size);
606 285 : return kmalloc_node_trace(
607 285 : kmalloc_caches[kmalloc_type(flags)][index],
608 : flags, node, size);
609 : }
610 273 : return __kmalloc_node(size, flags, node);
611 : }
612 : #else
613 : static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
614 : {
615 : if (__builtin_constant_p(size) && size > KMALLOC_MAX_CACHE_SIZE)
616 : return kmalloc_large_node(size, flags, node);
617 :
618 : return __kmalloc_node(size, flags, node);
619 : }
620 : #endif
621 :
622 : /**
623 : * kmalloc_array - allocate memory for an array.
624 : * @n: number of elements.
625 : * @size: element size.
626 : * @flags: the type of memory to allocate (see kmalloc).
627 : */
628 996 : static inline __alloc_size(1, 2) void *kmalloc_array(size_t n, size_t size, gfp_t flags)
629 : {
630 : size_t bytes;
631 :
632 1992 : if (unlikely(check_mul_overflow(n, size, &bytes)))
633 : return NULL;
634 996 : if (__builtin_constant_p(n) && __builtin_constant_p(size))
635 56 : return kmalloc(bytes, flags);
636 940 : return __kmalloc(bytes, flags);
637 : }
638 :
639 : /**
640 : * krealloc_array - reallocate memory for an array.
641 : * @p: pointer to the memory chunk to reallocate
642 : * @new_n: new number of elements to alloc
643 : * @new_size: new size of a single member of the array
644 : * @flags: the type of memory to allocate (see kmalloc)
645 : */
646 : static inline __realloc_size(2, 3) void * __must_check krealloc_array(void *p,
647 : size_t new_n,
648 : size_t new_size,
649 : gfp_t flags)
650 : {
651 : size_t bytes;
652 :
653 0 : if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
654 : return NULL;
655 :
656 0 : return krealloc(p, bytes, flags);
657 : }
658 :
659 : /**
660 : * kcalloc - allocate memory for an array. The memory is set to zero.
661 : * @n: number of elements.
662 : * @size: element size.
663 : * @flags: the type of memory to allocate (see kmalloc).
664 : */
665 : static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flags)
666 : {
667 498 : return kmalloc_array(n, size, flags | __GFP_ZERO);
668 : }
669 :
670 : void *__kmalloc_node_track_caller(size_t size, gfp_t flags, int node,
671 : unsigned long caller) __alloc_size(1);
672 : #define kmalloc_node_track_caller(size, flags, node) \
673 : __kmalloc_node_track_caller(size, flags, node, \
674 : _RET_IP_)
675 :
676 : /*
677 : * kmalloc_track_caller is a special version of kmalloc that records the
678 : * calling function of the routine calling it for slab leak tracking instead
679 : * of just the calling function (confusing, eh?).
680 : * It's useful when the call to kmalloc comes from a widely-used standard
681 : * allocator where we care about the real place the memory allocation
682 : * request comes from.
683 : */
684 : #define kmalloc_track_caller(size, flags) \
685 : __kmalloc_node_track_caller(size, flags, \
686 : NUMA_NO_NODE, _RET_IP_)
687 :
688 4 : static inline __alloc_size(1, 2) void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
689 : int node)
690 : {
691 : size_t bytes;
692 :
693 8 : if (unlikely(check_mul_overflow(n, size, &bytes)))
694 : return NULL;
695 4 : if (__builtin_constant_p(n) && __builtin_constant_p(size))
696 0 : return kmalloc_node(bytes, flags, node);
697 4 : return __kmalloc_node(bytes, flags, node);
698 : }
699 :
700 : static inline __alloc_size(1, 2) void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
701 : {
702 0 : return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
703 : }
704 :
705 : /*
706 : * Shortcuts
707 : */
708 : static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
709 : {
710 371690 : return kmem_cache_alloc(k, flags | __GFP_ZERO);
711 : }
712 :
713 : /**
714 : * kzalloc - allocate memory. The memory is set to zero.
715 : * @size: how many bytes of memory are required.
716 : * @flags: the type of memory to allocate (see kmalloc).
717 : */
718 2482 : static inline __alloc_size(1) void *kzalloc(size_t size, gfp_t flags)
719 : {
720 83238 : return kmalloc(size, flags | __GFP_ZERO);
721 : }
722 :
723 : /**
724 : * kzalloc_node - allocate zeroed memory from a particular memory node.
725 : * @size: how many bytes of memory are required.
726 : * @flags: the type of memory to allocate (see kmalloc).
727 : * @node: memory node from which to allocate
728 : */
729 275 : static inline __alloc_size(1) void *kzalloc_node(size_t size, gfp_t flags, int node)
730 : {
731 570 : return kmalloc_node(size, flags | __GFP_ZERO, node);
732 : }
733 :
734 : extern void *kvmalloc_node(size_t size, gfp_t flags, int node) __alloc_size(1);
735 : static inline __alloc_size(1) void *kvmalloc(size_t size, gfp_t flags)
736 : {
737 0 : return kvmalloc_node(size, flags, NUMA_NO_NODE);
738 : }
739 : static inline __alloc_size(1) void *kvzalloc_node(size_t size, gfp_t flags, int node)
740 : {
741 0 : return kvmalloc_node(size, flags | __GFP_ZERO, node);
742 : }
743 : static inline __alloc_size(1) void *kvzalloc(size_t size, gfp_t flags)
744 : {
745 0 : return kvmalloc(size, flags | __GFP_ZERO);
746 : }
747 :
748 : static inline __alloc_size(1, 2) void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
749 : {
750 : size_t bytes;
751 :
752 0 : if (unlikely(check_mul_overflow(n, size, &bytes)))
753 : return NULL;
754 :
755 0 : return kvmalloc(bytes, flags);
756 : }
757 :
758 : static inline __alloc_size(1, 2) void *kvcalloc(size_t n, size_t size, gfp_t flags)
759 : {
760 0 : return kvmalloc_array(n, size, flags | __GFP_ZERO);
761 : }
762 :
763 : extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
764 : __realloc_size(3);
765 : extern void kvfree(const void *addr);
766 : extern void kvfree_sensitive(const void *addr, size_t len);
767 :
768 : unsigned int kmem_cache_size(struct kmem_cache *s);
769 :
770 : /**
771 : * kmalloc_size_roundup - Report allocation bucket size for the given size
772 : *
773 : * @size: Number of bytes to round up from.
774 : *
775 : * This returns the number of bytes that would be available in a kmalloc()
776 : * allocation of @size bytes. For example, a 126 byte request would be
777 : * rounded up to the next sized kmalloc bucket, 128 bytes. (This is strictly
778 : * for the general-purpose kmalloc()-based allocations, and is not for the
779 : * pre-sized kmem_cache_alloc()-based allocations.)
780 : *
781 : * Use this to kmalloc() the full bucket size ahead of time instead of using
782 : * ksize() to query the size after an allocation.
783 : */
784 : size_t kmalloc_size_roundup(size_t size);
785 :
786 : void __init kmem_cache_init_late(void);
787 :
788 : #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
789 : int slab_prepare_cpu(unsigned int cpu);
790 : int slab_dead_cpu(unsigned int cpu);
791 : #else
792 : #define slab_prepare_cpu NULL
793 : #define slab_dead_cpu NULL
794 : #endif
795 :
796 : #endif /* _LINUX_SLAB_H */
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