1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
4 *
5 * (C) SGI 2006, Christoph Lameter
6 * Cleaned up and restructured to ease the addition of alternative
7 * implementations of SLAB allocators.
8 * (C) Linux Foundation 2008-2013
9 * Unified interface for all slab allocators
10 */
11
12 #ifndef _LINUX_SLAB_H
13 #define _LINUX_SLAB_H
14
15 #include <linux/gfp.h>
16 #include <linux/overflow.h>
17 #include <linux/types.h>
18 #include <linux/workqueue.h>
19 #include <linux/percpu-refcount.h>
20
21
22 /*
23 * Flags to pass to kmem_cache_create().
24 * The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
25 */
26 /* DEBUG: Perform (expensive) checks on alloc/free */
27 #define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100U)
28 /* DEBUG: Red zone objs in a cache */
29 #define SLAB_RED_ZONE ((slab_flags_t __force)0x00000400U)
30 /* DEBUG: Poison objects */
31 #define SLAB_POISON ((slab_flags_t __force)0x00000800U)
32 /* Align objs on cache lines */
33 #define SLAB_HWCACHE_ALIGN ((slab_flags_t __force)0x00002000U)
34 /* Use GFP_DMA memory */
35 #define SLAB_CACHE_DMA ((slab_flags_t __force)0x00004000U)
36 /* Use GFP_DMA32 memory */
37 #define SLAB_CACHE_DMA32 ((slab_flags_t __force)0x00008000U)
38 /* DEBUG: Store the last owner for bug hunting */
39 #define SLAB_STORE_USER ((slab_flags_t __force)0x00010000U)
40 /* Panic if kmem_cache_create() fails */
41 #define SLAB_PANIC ((slab_flags_t __force)0x00040000U)
42 /*
43 * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
44 *
45 * This delays freeing the SLAB page by a grace period, it does _NOT_
46 * delay object freeing. This means that if you do kmem_cache_free()
47 * that memory location is free to be reused at any time. Thus it may
48 * be possible to see another object there in the same RCU grace period.
49 *
50 * This feature only ensures the memory location backing the object
51 * stays valid, the trick to using this is relying on an independent
52 * object validation pass. Something like:
53 *
54 * rcu_read_lock()
55 * again:
56 * obj = lockless_lookup(key);
57 * if (obj) {
58 * if (!try_get_ref(obj)) // might fail for free objects
59 * goto again;
60 *
61 * if (obj->key != key) { // not the object we expected
62 * put_ref(obj);
63 * goto again;
64 * }
65 * }
66 * rcu_read_unlock();
67 *
68 * This is useful if we need to approach a kernel structure obliquely,
69 * from its address obtained without the usual locking. We can lock
70 * the structure to stabilize it and check it's still at the given address,
71 * only if we can be sure that the memory has not been meanwhile reused
72 * for some other kind of object (which our subsystem's lock might corrupt).
73 *
74 * rcu_read_lock before reading the address, then rcu_read_unlock after
75 * taking the spinlock within the structure expected at that address.
76 *
77 * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
78 */
79 /* Defer freeing slabs to RCU */
80 #define SLAB_TYPESAFE_BY_RCU ((slab_flags_t __force)0x00080000U)
81 /* Spread some memory over cpuset */
82 #define SLAB_MEM_SPREAD ((slab_flags_t __force)0x00100000U)
83 /* Trace allocations and frees */
84 #define SLAB_TRACE ((slab_flags_t __force)0x00200000U)
85
86 /* Flag to prevent checks on free */
87 #ifdef CONFIG_DEBUG_OBJECTS
88 # define SLAB_DEBUG_OBJECTS ((slab_flags_t __force)0x00400000U)
89 #else
90 # define SLAB_DEBUG_OBJECTS 0
91 #endif
92
93 /* Avoid kmemleak tracing */
94 #define SLAB_NOLEAKTRACE ((slab_flags_t __force)0x00800000U)
95
96 /* Fault injection mark */
97 #ifdef CONFIG_FAILSLAB
98 # define SLAB_FAILSLAB ((slab_flags_t __force)0x02000000U)
99 #else
100 # define SLAB_FAILSLAB 0
101 #endif
102 /* Account to memcg */
103 #ifdef CONFIG_MEMCG_KMEM
104 # define SLAB_ACCOUNT ((slab_flags_t __force)0x04000000U)
105 #else
106 # define SLAB_ACCOUNT 0
107 #endif
108
109 #ifdef CONFIG_KASAN
110 #define SLAB_KASAN ((slab_flags_t __force)0x08000000U)
111 #else
112 #define SLAB_KASAN 0
113 #endif
114
115 /* The following flags affect the page allocator grouping pages by mobility */
116 /* Objects are reclaimable */
117 #define SLAB_RECLAIM_ACCOUNT ((slab_flags_t __force)0x00020000U)
118 #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
119
120 /* Slab deactivation flag */
121 #define SLAB_DEACTIVATED ((slab_flags_t __force)0x10000000U)
122
123 /*
124 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
125 *
126 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
127 *
128 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
129 * Both make kfree a no-op.
130 */
131 #define ZERO_SIZE_PTR ((void *)16)
132
133 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
134 (unsigned long)ZERO_SIZE_PTR)
135
136 #include <linux/kasan.h>
137
138 struct mem_cgroup;
139 /*
140 * struct kmem_cache related prototypes
141 */
142 void __init kmem_cache_init(void);
143 bool slab_is_available(void);
144
145 struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
146 unsigned int align, slab_flags_t flags,
147 void (*ctor)(void *));
148 struct kmem_cache *kmem_cache_create_usercopy(const char *name,
149 unsigned int size, unsigned int align,
150 slab_flags_t flags,
151 unsigned int useroffset, unsigned int usersize,
152 void (*ctor)(void *));
153 void kmem_cache_destroy(struct kmem_cache *s);
154 int kmem_cache_shrink(struct kmem_cache *s);
155
156 /*
157 * Please use this macro to create slab caches. Simply specify the
158 * name of the structure and maybe some flags that are listed above.
159 *
160 * The alignment of the struct determines object alignment. If you
161 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
162 * then the objects will be properly aligned in SMP configurations.
163 */
164 #define KMEM_CACHE(__struct, __flags) \
165 kmem_cache_create(#__struct, sizeof(struct __struct), \
166 __alignof__(struct __struct), (__flags), NULL)
167
168 /*
169 * To whitelist a single field for copying to/from usercopy, use this
170 * macro instead for KMEM_CACHE() above.
171 */
172 #define KMEM_CACHE_USERCOPY(__struct, __flags, __field) \
173 kmem_cache_create_usercopy(#__struct, \
174 sizeof(struct __struct), \
175 __alignof__(struct __struct), (__flags), \
176 offsetof(struct __struct, __field), \
177 sizeof_field(struct __struct, __field), NULL)
178
179 /*
180 * Common kmalloc functions provided by all allocators
181 */
182 void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __alloc_size(2);
183 void kfree(const void *objp);
184 void kfree_sensitive(const void *objp);
185 size_t __ksize(const void *objp);
186 size_t ksize(const void *objp);
187 #ifdef CONFIG_PRINTK
188 bool kmem_valid_obj(void *object);
189 void kmem_dump_obj(void *object);
190 #endif
191
192 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
193 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
194 bool to_user);
195 #else
__check_heap_object(const void * ptr,unsigned long n,struct page * page,bool to_user)196 static inline void __check_heap_object(const void *ptr, unsigned long n,
197 struct page *page, bool to_user) { }
198 #endif
199
200 /*
201 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
202 * alignment larger than the alignment of a 64-bit integer.
203 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
204 */
205 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
206 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
207 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
208 #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
209 #else
210 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
211 #endif
212
213 /*
214 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
215 * Intended for arches that get misalignment faults even for 64 bit integer
216 * aligned buffers.
217 */
218 #ifndef ARCH_SLAB_MINALIGN
219 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
220 #endif
221
222 /*
223 * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
224 * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
225 * aligned pointers.
226 */
227 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
228 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
229 #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
230
231 /*
232 * Kmalloc array related definitions
233 */
234
235 #ifdef CONFIG_SLAB
236 /*
237 * The largest kmalloc size supported by the SLAB allocators is
238 * 32 megabyte (2^25) or the maximum allocatable page order if that is
239 * less than 32 MB.
240 *
241 * WARNING: Its not easy to increase this value since the allocators have
242 * to do various tricks to work around compiler limitations in order to
243 * ensure proper constant folding.
244 */
245 #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
246 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
247 #define KMALLOC_SHIFT_MAX KMALLOC_SHIFT_HIGH
248 #ifndef KMALLOC_SHIFT_LOW
249 #define KMALLOC_SHIFT_LOW 5
250 #endif
251 #endif
252
253 #ifdef CONFIG_SLUB
254 /*
255 * SLUB directly allocates requests fitting in to an order-1 page
256 * (PAGE_SIZE*2). Larger requests are passed to the page allocator.
257 */
258 #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1)
259 #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
260 #ifndef KMALLOC_SHIFT_LOW
261 #define KMALLOC_SHIFT_LOW 3
262 #endif
263 #endif
264
265 #ifdef CONFIG_SLOB
266 /*
267 * SLOB passes all requests larger than one page to the page allocator.
268 * No kmalloc array is necessary since objects of different sizes can
269 * be allocated from the same page.
270 */
271 #define KMALLOC_SHIFT_HIGH PAGE_SHIFT
272 #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
273 #ifndef KMALLOC_SHIFT_LOW
274 #define KMALLOC_SHIFT_LOW 3
275 #endif
276 #endif
277
278 /* Maximum allocatable size */
279 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX)
280 /* Maximum size for which we actually use a slab cache */
281 #define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH)
282 /* Maximum order allocatable via the slab allocator */
283 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
284
285 /*
286 * Kmalloc subsystem.
287 */
288 #ifndef KMALLOC_MIN_SIZE
289 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
290 #endif
291
292 /*
293 * This restriction comes from byte sized index implementation.
294 * Page size is normally 2^12 bytes and, in this case, if we want to use
295 * byte sized index which can represent 2^8 entries, the size of the object
296 * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
297 * If minimum size of kmalloc is less than 16, we use it as minimum object
298 * size and give up to use byte sized index.
299 */
300 #define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \
301 (KMALLOC_MIN_SIZE) : 16)
302
303 /*
304 * Whenever changing this, take care of that kmalloc_type() and
305 * create_kmalloc_caches() still work as intended.
306 *
307 * KMALLOC_NORMAL can contain only unaccounted objects whereas KMALLOC_CGROUP
308 * is for accounted but unreclaimable and non-dma objects. All the other
309 * kmem caches can have both accounted and unaccounted objects.
310 */
311 enum kmalloc_cache_type {
312 KMALLOC_NORMAL = 0,
313 #ifndef CONFIG_ZONE_DMA
314 KMALLOC_DMA = KMALLOC_NORMAL,
315 #endif
316 #ifndef CONFIG_MEMCG_KMEM
317 KMALLOC_CGROUP = KMALLOC_NORMAL,
318 #else
319 KMALLOC_CGROUP,
320 #endif
321 KMALLOC_RECLAIM,
322 #ifdef CONFIG_ZONE_DMA
323 KMALLOC_DMA,
324 #endif
325 NR_KMALLOC_TYPES
326 };
327
328 #ifndef CONFIG_SLOB
329 extern struct kmem_cache *
330 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
331
332 /*
333 * Define gfp bits that should not be set for KMALLOC_NORMAL.
334 */
335 #define KMALLOC_NOT_NORMAL_BITS \
336 (__GFP_RECLAIMABLE | \
337 (IS_ENABLED(CONFIG_ZONE_DMA) ? __GFP_DMA : 0) | \
338 (IS_ENABLED(CONFIG_MEMCG_KMEM) ? __GFP_ACCOUNT : 0))
339
kmalloc_type(gfp_t flags)340 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
341 {
342 /*
343 * The most common case is KMALLOC_NORMAL, so test for it
344 * with a single branch for all the relevant flags.
345 */
346 if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0))
347 return KMALLOC_NORMAL;
348
349 /*
350 * At least one of the flags has to be set. Their priorities in
351 * decreasing order are:
352 * 1) __GFP_DMA
353 * 2) __GFP_RECLAIMABLE
354 * 3) __GFP_ACCOUNT
355 */
356 if (IS_ENABLED(CONFIG_ZONE_DMA) && (flags & __GFP_DMA))
357 return KMALLOC_DMA;
358 if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || (flags & __GFP_RECLAIMABLE))
359 return KMALLOC_RECLAIM;
360 else
361 return KMALLOC_CGROUP;
362 }
363
364 /*
365 * Figure out which kmalloc slab an allocation of a certain size
366 * belongs to.
367 * 0 = zero alloc
368 * 1 = 65 .. 96 bytes
369 * 2 = 129 .. 192 bytes
370 * n = 2^(n-1)+1 .. 2^n
371 *
372 * Note: __kmalloc_index() is compile-time optimized, and not runtime optimized;
373 * typical usage is via kmalloc_index() and therefore evaluated at compile-time.
374 * Callers where !size_is_constant should only be test modules, where runtime
375 * overheads of __kmalloc_index() can be tolerated. Also see kmalloc_slab().
376 */
__kmalloc_index(size_t size,bool size_is_constant)377 static __always_inline unsigned int __kmalloc_index(size_t size,
378 bool size_is_constant)
379 {
380 if (!size)
381 return 0;
382
383 if (size <= KMALLOC_MIN_SIZE)
384 return KMALLOC_SHIFT_LOW;
385
386 if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
387 return 1;
388 if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
389 return 2;
390 if (size <= 8) return 3;
391 if (size <= 16) return 4;
392 if (size <= 32) return 5;
393 if (size <= 64) return 6;
394 if (size <= 128) return 7;
395 if (size <= 256) return 8;
396 if (size <= 512) return 9;
397 if (size <= 1024) return 10;
398 if (size <= 2 * 1024) return 11;
399 if (size <= 4 * 1024) return 12;
400 if (size <= 8 * 1024) return 13;
401 if (size <= 16 * 1024) return 14;
402 if (size <= 32 * 1024) return 15;
403 if (size <= 64 * 1024) return 16;
404 if (size <= 128 * 1024) return 17;
405 if (size <= 256 * 1024) return 18;
406 if (size <= 512 * 1024) return 19;
407 if (size <= 1024 * 1024) return 20;
408 if (size <= 2 * 1024 * 1024) return 21;
409 if (size <= 4 * 1024 * 1024) return 22;
410 if (size <= 8 * 1024 * 1024) return 23;
411 if (size <= 16 * 1024 * 1024) return 24;
412 if (size <= 32 * 1024 * 1024) return 25;
413
414 if ((IS_ENABLED(CONFIG_CC_IS_GCC) || CONFIG_CLANG_VERSION >= 110000)
415 && !IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && size_is_constant)
416 BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()");
417 else
418 BUG();
419
420 /* Will never be reached. Needed because the compiler may complain */
421 return -1;
422 }
423 #define kmalloc_index(s) __kmalloc_index(s, true)
424 #endif /* !CONFIG_SLOB */
425
426 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
427 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc;
428 void kmem_cache_free(struct kmem_cache *s, void *objp);
429
430 /*
431 * Bulk allocation and freeing operations. These are accelerated in an
432 * allocator specific way to avoid taking locks repeatedly or building
433 * metadata structures unnecessarily.
434 *
435 * Note that interrupts must be enabled when calling these functions.
436 */
437 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p);
438 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, void **p);
439
440 /*
441 * Caller must not use kfree_bulk() on memory not originally allocated
442 * by kmalloc(), because the SLOB allocator cannot handle this.
443 */
kfree_bulk(size_t size,void ** p)444 static __always_inline void kfree_bulk(size_t size, void **p)
445 {
446 kmem_cache_free_bulk(NULL, size, p);
447 }
448
449 #ifdef CONFIG_NUMA
450 void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment
451 __alloc_size(1);
452 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
453 __malloc;
454 #else
__kmalloc_node(size_t size,gfp_t flags,int node)455 static __always_inline __alloc_size(1) void *__kmalloc_node(size_t size, gfp_t flags, int node)
456 {
457 return __kmalloc(size, flags);
458 }
459
kmem_cache_alloc_node(struct kmem_cache * s,gfp_t flags,int node)460 static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
461 {
462 return kmem_cache_alloc(s, flags);
463 }
464 #endif
465
466 #ifdef CONFIG_TRACING
467 extern void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
468 __assume_slab_alignment __alloc_size(3);
469
470 #ifdef CONFIG_NUMA
471 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
472 int node, size_t size) __assume_slab_alignment
473 __alloc_size(4);
474 #else
kmem_cache_alloc_node_trace(struct kmem_cache * s,gfp_t gfpflags,int node,size_t size)475 static __always_inline __alloc_size(4) void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
476 gfp_t gfpflags, int node, size_t size)
477 {
478 return kmem_cache_alloc_trace(s, gfpflags, size);
479 }
480 #endif /* CONFIG_NUMA */
481
482 #else /* CONFIG_TRACING */
kmem_cache_alloc_trace(struct kmem_cache * s,gfp_t flags,size_t size)483 static __always_inline __alloc_size(3) void *kmem_cache_alloc_trace(struct kmem_cache *s,
484 gfp_t flags, size_t size)
485 {
486 void *ret = kmem_cache_alloc(s, flags);
487
488 ret = kasan_kmalloc(s, ret, size, flags);
489 return ret;
490 }
491
kmem_cache_alloc_node_trace(struct kmem_cache * s,gfp_t gfpflags,int node,size_t size)492 static __always_inline void *kmem_cache_alloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
493 int node, size_t size)
494 {
495 void *ret = kmem_cache_alloc_node(s, gfpflags, node);
496
497 ret = kasan_kmalloc(s, ret, size, gfpflags);
498 return ret;
499 }
500 #endif /* CONFIG_TRACING */
501
502 extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment
503 __alloc_size(1);
504
505 #ifdef CONFIG_TRACING
506 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
507 __assume_page_alignment __alloc_size(1);
508 #else
kmalloc_order_trace(size_t size,gfp_t flags,unsigned int order)509 static __always_inline __alloc_size(1) void *kmalloc_order_trace(size_t size, gfp_t flags,
510 unsigned int order)
511 {
512 return kmalloc_order(size, flags, order);
513 }
514 #endif
515
kmalloc_large(size_t size,gfp_t flags)516 static __always_inline __alloc_size(1) void *kmalloc_large(size_t size, gfp_t flags)
517 {
518 unsigned int order = get_order(size);
519 return kmalloc_order_trace(size, flags, order);
520 }
521
522 /**
523 * kmalloc - allocate memory
524 * @size: how many bytes of memory are required.
525 * @flags: the type of memory to allocate.
526 *
527 * kmalloc is the normal method of allocating memory
528 * for objects smaller than page size in the kernel.
529 *
530 * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
531 * bytes. For @size of power of two bytes, the alignment is also guaranteed
532 * to be at least to the size.
533 *
534 * The @flags argument may be one of the GFP flags defined at
535 * include/linux/gfp.h and described at
536 * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
537 *
538 * The recommended usage of the @flags is described at
539 * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>`
540 *
541 * Below is a brief outline of the most useful GFP flags
542 *
543 * %GFP_KERNEL
544 * Allocate normal kernel ram. May sleep.
545 *
546 * %GFP_NOWAIT
547 * Allocation will not sleep.
548 *
549 * %GFP_ATOMIC
550 * Allocation will not sleep. May use emergency pools.
551 *
552 * %GFP_HIGHUSER
553 * Allocate memory from high memory on behalf of user.
554 *
555 * Also it is possible to set different flags by OR'ing
556 * in one or more of the following additional @flags:
557 *
558 * %__GFP_HIGH
559 * This allocation has high priority and may use emergency pools.
560 *
561 * %__GFP_NOFAIL
562 * Indicate that this allocation is in no way allowed to fail
563 * (think twice before using).
564 *
565 * %__GFP_NORETRY
566 * If memory is not immediately available,
567 * then give up at once.
568 *
569 * %__GFP_NOWARN
570 * If allocation fails, don't issue any warnings.
571 *
572 * %__GFP_RETRY_MAYFAIL
573 * Try really hard to succeed the allocation but fail
574 * eventually.
575 */
kmalloc(size_t size,gfp_t flags)576 static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
577 {
578 if (__builtin_constant_p(size)) {
579 #ifndef CONFIG_SLOB
580 unsigned int index;
581 #endif
582 if (size > KMALLOC_MAX_CACHE_SIZE)
583 return kmalloc_large(size, flags);
584 #ifndef CONFIG_SLOB
585 index = kmalloc_index(size);
586
587 if (!index)
588 return ZERO_SIZE_PTR;
589
590 return kmem_cache_alloc_trace(
591 kmalloc_caches[kmalloc_type(flags)][index],
592 flags, size);
593 #endif
594 }
595 return __kmalloc(size, flags);
596 }
597
kmalloc_node(size_t size,gfp_t flags,int node)598 static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
599 {
600 #ifndef CONFIG_SLOB
601 if (__builtin_constant_p(size) &&
602 size <= KMALLOC_MAX_CACHE_SIZE) {
603 unsigned int i = kmalloc_index(size);
604
605 if (!i)
606 return ZERO_SIZE_PTR;
607
608 return kmem_cache_alloc_node_trace(
609 kmalloc_caches[kmalloc_type(flags)][i],
610 flags, node, size);
611 }
612 #endif
613 return __kmalloc_node(size, flags, node);
614 }
615
616 /**
617 * kmalloc_array - allocate memory for an array.
618 * @n: number of elements.
619 * @size: element size.
620 * @flags: the type of memory to allocate (see kmalloc).
621 */
kmalloc_array(size_t n,size_t size,gfp_t flags)622 static inline __alloc_size(1, 2) void *kmalloc_array(size_t n, size_t size, gfp_t flags)
623 {
624 size_t bytes;
625
626 if (unlikely(check_mul_overflow(n, size, &bytes)))
627 return NULL;
628 if (__builtin_constant_p(n) && __builtin_constant_p(size))
629 return kmalloc(bytes, flags);
630 return __kmalloc(bytes, flags);
631 }
632
633 /**
634 * krealloc_array - reallocate memory for an array.
635 * @p: pointer to the memory chunk to reallocate
636 * @new_n: new number of elements to alloc
637 * @new_size: new size of a single member of the array
638 * @flags: the type of memory to allocate (see kmalloc)
639 */
krealloc_array(void * p,size_t new_n,size_t new_size,gfp_t flags)640 static inline __alloc_size(2, 3) void * __must_check krealloc_array(void *p,
641 size_t new_n,
642 size_t new_size,
643 gfp_t flags)
644 {
645 size_t bytes;
646
647 if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
648 return NULL;
649
650 return krealloc(p, bytes, flags);
651 }
652
653 /**
654 * kcalloc - allocate memory for an array. The memory is set to zero.
655 * @n: number of elements.
656 * @size: element size.
657 * @flags: the type of memory to allocate (see kmalloc).
658 */
kcalloc(size_t n,size_t size,gfp_t flags)659 static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flags)
660 {
661 return kmalloc_array(n, size, flags | __GFP_ZERO);
662 }
663
664 /*
665 * kmalloc_track_caller is a special version of kmalloc that records the
666 * calling function of the routine calling it for slab leak tracking instead
667 * of just the calling function (confusing, eh?).
668 * It's useful when the call to kmalloc comes from a widely-used standard
669 * allocator where we care about the real place the memory allocation
670 * request comes from.
671 */
672 extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
673 __alloc_size(1);
674 #define kmalloc_track_caller(size, flags) \
675 __kmalloc_track_caller(size, flags, _RET_IP_)
676
kmalloc_array_node(size_t n,size_t size,gfp_t flags,int node)677 static inline __alloc_size(1, 2) void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
678 int node)
679 {
680 size_t bytes;
681
682 if (unlikely(check_mul_overflow(n, size, &bytes)))
683 return NULL;
684 if (__builtin_constant_p(n) && __builtin_constant_p(size))
685 return kmalloc_node(bytes, flags, node);
686 return __kmalloc_node(bytes, flags, node);
687 }
688
kcalloc_node(size_t n,size_t size,gfp_t flags,int node)689 static inline __alloc_size(1, 2) void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
690 {
691 return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
692 }
693
694
695 #ifdef CONFIG_NUMA
696 extern void *__kmalloc_node_track_caller(size_t size, gfp_t flags, int node,
697 unsigned long caller) __alloc_size(1);
698 #define kmalloc_node_track_caller(size, flags, node) \
699 __kmalloc_node_track_caller(size, flags, node, \
700 _RET_IP_)
701
702 #else /* CONFIG_NUMA */
703
704 #define kmalloc_node_track_caller(size, flags, node) \
705 kmalloc_track_caller(size, flags)
706
707 #endif /* CONFIG_NUMA */
708
709 /*
710 * Shortcuts
711 */
kmem_cache_zalloc(struct kmem_cache * k,gfp_t flags)712 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
713 {
714 return kmem_cache_alloc(k, flags | __GFP_ZERO);
715 }
716
717 /**
718 * kzalloc - allocate memory. The memory is set to zero.
719 * @size: how many bytes of memory are required.
720 * @flags: the type of memory to allocate (see kmalloc).
721 */
kzalloc(size_t size,gfp_t flags)722 static inline __alloc_size(1) void *kzalloc(size_t size, gfp_t flags)
723 {
724 return kmalloc(size, flags | __GFP_ZERO);
725 }
726
727 /**
728 * kzalloc_node - allocate zeroed memory from a particular memory node.
729 * @size: how many bytes of memory are required.
730 * @flags: the type of memory to allocate (see kmalloc).
731 * @node: memory node from which to allocate
732 */
kzalloc_node(size_t size,gfp_t flags,int node)733 static inline __alloc_size(1) void *kzalloc_node(size_t size, gfp_t flags, int node)
734 {
735 return kmalloc_node(size, flags | __GFP_ZERO, node);
736 }
737
738 extern void *kvmalloc_node(size_t size, gfp_t flags, int node) __alloc_size(1);
kvmalloc(size_t size,gfp_t flags)739 static inline __alloc_size(1) void *kvmalloc(size_t size, gfp_t flags)
740 {
741 return kvmalloc_node(size, flags, NUMA_NO_NODE);
742 }
kvzalloc_node(size_t size,gfp_t flags,int node)743 static inline __alloc_size(1) void *kvzalloc_node(size_t size, gfp_t flags, int node)
744 {
745 return kvmalloc_node(size, flags | __GFP_ZERO, node);
746 }
kvzalloc(size_t size,gfp_t flags)747 static inline __alloc_size(1) void *kvzalloc(size_t size, gfp_t flags)
748 {
749 return kvmalloc(size, flags | __GFP_ZERO);
750 }
751
kvmalloc_array(size_t n,size_t size,gfp_t flags)752 static inline __alloc_size(1, 2) void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
753 {
754 size_t bytes;
755
756 if (unlikely(check_mul_overflow(n, size, &bytes)))
757 return NULL;
758
759 return kvmalloc(bytes, flags);
760 }
761
kvcalloc(size_t n,size_t size,gfp_t flags)762 static inline __alloc_size(1, 2) void *kvcalloc(size_t n, size_t size, gfp_t flags)
763 {
764 return kvmalloc_array(n, size, flags | __GFP_ZERO);
765 }
766
767 extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
768 __alloc_size(3);
769 extern void kvfree(const void *addr);
770 extern void kvfree_sensitive(const void *addr, size_t len);
771
772 unsigned int kmem_cache_size(struct kmem_cache *s);
773 void __init kmem_cache_init_late(void);
774
775 #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
776 int slab_prepare_cpu(unsigned int cpu);
777 int slab_dead_cpu(unsigned int cpu);
778 #else
779 #define slab_prepare_cpu NULL
780 #define slab_dead_cpu NULL
781 #endif
782
783 #endif /* _LINUX_SLAB_H */
784