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 extern bool usercopy_fallback;
146
147 struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
148 unsigned int align, slab_flags_t flags,
149 void (*ctor)(void *));
150 struct kmem_cache *kmem_cache_create_usercopy(const char *name,
151 unsigned int size, unsigned int align,
152 slab_flags_t flags,
153 unsigned int useroffset, unsigned int usersize,
154 void (*ctor)(void *));
155 void kmem_cache_destroy(struct kmem_cache *);
156 int kmem_cache_shrink(struct kmem_cache *);
157
158 /*
159 * Please use this macro to create slab caches. Simply specify the
160 * name of the structure and maybe some flags that are listed above.
161 *
162 * The alignment of the struct determines object alignment. If you
163 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
164 * then the objects will be properly aligned in SMP configurations.
165 */
166 #define KMEM_CACHE(__struct, __flags) \
167 kmem_cache_create(#__struct, sizeof(struct __struct), \
168 __alignof__(struct __struct), (__flags), NULL)
169
170 /*
171 * To whitelist a single field for copying to/from usercopy, use this
172 * macro instead for KMEM_CACHE() above.
173 */
174 #define KMEM_CACHE_USERCOPY(__struct, __flags, __field) \
175 kmem_cache_create_usercopy(#__struct, \
176 sizeof(struct __struct), \
177 __alignof__(struct __struct), (__flags), \
178 offsetof(struct __struct, __field), \
179 sizeof_field(struct __struct, __field), NULL)
180
181 /*
182 * Common kmalloc functions provided by all allocators
183 */
184 void * __must_check krealloc(const void *, size_t, gfp_t);
185 void kfree(const void *);
186 void kfree_sensitive(const void *);
187 size_t __ksize(const void *);
188 size_t ksize(const void *);
189 #ifdef CONFIG_PRINTK
190 bool kmem_valid_obj(void *object);
191 void kmem_dump_obj(void *object);
192 #endif
193
194 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
195 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
196 bool to_user);
197 #else
__check_heap_object(const void * ptr,unsigned long n,struct page * page,bool to_user)198 static inline void __check_heap_object(const void *ptr, unsigned long n,
199 struct page *page, bool to_user) { }
200 #endif
201
202 /*
203 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
204 * alignment larger than the alignment of a 64-bit integer.
205 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
206 */
207 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
208 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
209 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
210 #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
211 #else
212 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
213 #endif
214
215 /*
216 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
217 * Intended for arches that get misalignment faults even for 64 bit integer
218 * aligned buffers.
219 */
220 #ifndef ARCH_SLAB_MINALIGN
221 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
222 #endif
223
224 /*
225 * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
226 * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
227 * aligned pointers.
228 */
229 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
230 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
231 #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
232
233 /*
234 * Kmalloc array related definitions
235 */
236
237 #ifdef CONFIG_SLAB
238 /*
239 * The largest kmalloc size supported by the SLAB allocators is
240 * 32 megabyte (2^25) or the maximum allocatable page order if that is
241 * less than 32 MB.
242 *
243 * WARNING: Its not easy to increase this value since the allocators have
244 * to do various tricks to work around compiler limitations in order to
245 * ensure proper constant folding.
246 */
247 #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
248 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
249 #define KMALLOC_SHIFT_MAX KMALLOC_SHIFT_HIGH
250 #ifndef KMALLOC_SHIFT_LOW
251 #define KMALLOC_SHIFT_LOW 5
252 #endif
253 #endif
254
255 #ifdef CONFIG_SLUB
256 /*
257 * SLUB directly allocates requests fitting in to an order-1 page
258 * (PAGE_SIZE*2). Larger requests are passed to the page allocator.
259 */
260 #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1)
261 #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
262 #ifndef KMALLOC_SHIFT_LOW
263 #define KMALLOC_SHIFT_LOW 3
264 #endif
265 #endif
266
267 #ifdef CONFIG_SLOB
268 /*
269 * SLOB passes all requests larger than one page to the page allocator.
270 * No kmalloc array is necessary since objects of different sizes can
271 * be allocated from the same page.
272 */
273 #define KMALLOC_SHIFT_HIGH PAGE_SHIFT
274 #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
275 #ifndef KMALLOC_SHIFT_LOW
276 #define KMALLOC_SHIFT_LOW 3
277 #endif
278 #endif
279
280 /* Maximum allocatable size */
281 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX)
282 /* Maximum size for which we actually use a slab cache */
283 #define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH)
284 /* Maximum order allocatable via the slab allocator */
285 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
286
287 /*
288 * Kmalloc subsystem.
289 */
290 #ifndef KMALLOC_MIN_SIZE
291 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
292 #endif
293
294 /*
295 * This restriction comes from byte sized index implementation.
296 * Page size is normally 2^12 bytes and, in this case, if we want to use
297 * byte sized index which can represent 2^8 entries, the size of the object
298 * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
299 * If minimum size of kmalloc is less than 16, we use it as minimum object
300 * size and give up to use byte sized index.
301 */
302 #define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \
303 (KMALLOC_MIN_SIZE) : 16)
304
305 /*
306 * Whenever changing this, take care of that kmalloc_type() and
307 * create_kmalloc_caches() still work as intended.
308 *
309 * KMALLOC_NORMAL can contain only unaccounted objects whereas KMALLOC_CGROUP
310 * is for accounted but unreclaimable and non-dma objects. All the other
311 * kmem caches can have both accounted and unaccounted objects.
312 */
313 enum kmalloc_cache_type {
314 KMALLOC_NORMAL = 0,
315 #ifndef CONFIG_ZONE_DMA
316 KMALLOC_DMA = KMALLOC_NORMAL,
317 #endif
318 #ifndef CONFIG_MEMCG_KMEM
319 KMALLOC_CGROUP = KMALLOC_NORMAL,
320 #else
321 KMALLOC_CGROUP,
322 #endif
323 KMALLOC_RECLAIM,
324 #ifdef CONFIG_ZONE_DMA
325 KMALLOC_DMA,
326 #endif
327 NR_KMALLOC_TYPES
328 };
329
330 #ifndef CONFIG_SLOB
331 extern struct kmem_cache *
332 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
333
334 /*
335 * Define gfp bits that should not be set for KMALLOC_NORMAL.
336 */
337 #define KMALLOC_NOT_NORMAL_BITS \
338 (__GFP_RECLAIMABLE | \
339 (IS_ENABLED(CONFIG_ZONE_DMA) ? __GFP_DMA : 0) | \
340 (IS_ENABLED(CONFIG_MEMCG_KMEM) ? __GFP_ACCOUNT : 0))
341
kmalloc_type(gfp_t flags)342 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
343 {
344 /*
345 * The most common case is KMALLOC_NORMAL, so test for it
346 * with a single branch for all the relevant flags.
347 */
348 if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0))
349 return KMALLOC_NORMAL;
350
351 /*
352 * At least one of the flags has to be set. Their priorities in
353 * decreasing order are:
354 * 1) __GFP_DMA
355 * 2) __GFP_RECLAIMABLE
356 * 3) __GFP_ACCOUNT
357 */
358 if (IS_ENABLED(CONFIG_ZONE_DMA) && (flags & __GFP_DMA))
359 return KMALLOC_DMA;
360 if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || (flags & __GFP_RECLAIMABLE))
361 return KMALLOC_RECLAIM;
362 else
363 return KMALLOC_CGROUP;
364 }
365
366 /*
367 * Figure out which kmalloc slab an allocation of a certain size
368 * belongs to.
369 * 0 = zero alloc
370 * 1 = 65 .. 96 bytes
371 * 2 = 129 .. 192 bytes
372 * n = 2^(n-1)+1 .. 2^n
373 *
374 * Note: __kmalloc_index() is compile-time optimized, and not runtime optimized;
375 * typical usage is via kmalloc_index() and therefore evaluated at compile-time.
376 * Callers where !size_is_constant should only be test modules, where runtime
377 * overheads of __kmalloc_index() can be tolerated. Also see kmalloc_slab().
378 */
__kmalloc_index(size_t size,bool size_is_constant)379 static __always_inline unsigned int __kmalloc_index(size_t size,
380 bool size_is_constant)
381 {
382 if (!size)
383 return 0;
384
385 if (size <= KMALLOC_MIN_SIZE)
386 return KMALLOC_SHIFT_LOW;
387
388 if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
389 return 1;
390 if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
391 return 2;
392 if (size <= 8) return 3;
393 if (size <= 16) return 4;
394 if (size <= 32) return 5;
395 if (size <= 64) return 6;
396 if (size <= 128) return 7;
397 if (size <= 256) return 8;
398 if (size <= 512) return 9;
399 if (size <= 1024) return 10;
400 if (size <= 2 * 1024) return 11;
401 if (size <= 4 * 1024) return 12;
402 if (size <= 8 * 1024) return 13;
403 if (size <= 16 * 1024) return 14;
404 if (size <= 32 * 1024) return 15;
405 if (size <= 64 * 1024) return 16;
406 if (size <= 128 * 1024) return 17;
407 if (size <= 256 * 1024) return 18;
408 if (size <= 512 * 1024) return 19;
409 if (size <= 1024 * 1024) return 20;
410 if (size <= 2 * 1024 * 1024) return 21;
411 if (size <= 4 * 1024 * 1024) return 22;
412 if (size <= 8 * 1024 * 1024) return 23;
413 if (size <= 16 * 1024 * 1024) return 24;
414 if (size <= 32 * 1024 * 1024) return 25;
415
416 if ((IS_ENABLED(CONFIG_CC_IS_GCC) || CONFIG_CLANG_VERSION >= 110000)
417 && !IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && size_is_constant)
418 BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()");
419 else
420 BUG();
421
422 /* Will never be reached. Needed because the compiler may complain */
423 return -1;
424 }
425 #define kmalloc_index(s) __kmalloc_index(s, true)
426 #endif /* !CONFIG_SLOB */
427
428 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
429 void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __assume_slab_alignment __malloc;
430 void kmem_cache_free(struct kmem_cache *, void *);
431
432 /*
433 * Bulk allocation and freeing operations. These are accelerated in an
434 * allocator specific way to avoid taking locks repeatedly or building
435 * metadata structures unnecessarily.
436 *
437 * Note that interrupts must be enabled when calling these functions.
438 */
439 void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
440 int kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
441
442 /*
443 * Caller must not use kfree_bulk() on memory not originally allocated
444 * by kmalloc(), because the SLOB allocator cannot handle this.
445 */
kfree_bulk(size_t size,void ** p)446 static __always_inline void kfree_bulk(size_t size, void **p)
447 {
448 kmem_cache_free_bulk(NULL, size, p);
449 }
450
451 #ifdef CONFIG_NUMA
452 void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
453 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node) __assume_slab_alignment __malloc;
454 #else
__kmalloc_node(size_t size,gfp_t flags,int node)455 static __always_inline 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 *, gfp_t, size_t) __assume_slab_alignment __malloc;
468
469 #ifdef CONFIG_NUMA
470 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
471 gfp_t gfpflags,
472 int node, size_t size) __assume_slab_alignment __malloc;
473 #else
474 static __always_inline void *
kmem_cache_alloc_node_trace(struct kmem_cache * s,gfp_t gfpflags,int node,size_t size)475 kmem_cache_alloc_node_trace(struct kmem_cache *s,
476 gfp_t gfpflags,
477 int node, size_t size)
478 {
479 return kmem_cache_alloc_trace(s, gfpflags, size);
480 }
481 #endif /* CONFIG_NUMA */
482
483 #else /* CONFIG_TRACING */
kmem_cache_alloc_trace(struct kmem_cache * s,gfp_t flags,size_t size)484 static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
485 gfp_t flags, size_t size)
486 {
487 void *ret = kmem_cache_alloc(s, flags);
488
489 ret = kasan_kmalloc(s, ret, size, flags);
490 return ret;
491 }
492
493 static __always_inline void *
kmem_cache_alloc_node_trace(struct kmem_cache * s,gfp_t gfpflags,int node,size_t size)494 kmem_cache_alloc_node_trace(struct kmem_cache *s,
495 gfp_t gfpflags,
496 int node, size_t size)
497 {
498 void *ret = kmem_cache_alloc_node(s, gfpflags, node);
499
500 ret = kasan_kmalloc(s, ret, size, gfpflags);
501 return ret;
502 }
503 #endif /* CONFIG_TRACING */
504
505 extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
506
507 #ifdef CONFIG_TRACING
508 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
509 #else
510 static __always_inline void *
kmalloc_order_trace(size_t size,gfp_t flags,unsigned int order)511 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
512 {
513 return kmalloc_order(size, flags, order);
514 }
515 #endif
516
kmalloc_large(size_t size,gfp_t flags)517 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
518 {
519 unsigned int order = get_order(size);
520 return kmalloc_order_trace(size, flags, order);
521 }
522
523 /**
524 * kmalloc - allocate memory
525 * @size: how many bytes of memory are required.
526 * @flags: the type of memory to allocate.
527 *
528 * kmalloc is the normal method of allocating memory
529 * for objects smaller than page size in the kernel.
530 *
531 * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
532 * bytes. For @size of power of two bytes, the alignment is also guaranteed
533 * to be at least to the size.
534 *
535 * The @flags argument may be one of the GFP flags defined at
536 * include/linux/gfp.h and described at
537 * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
538 *
539 * The recommended usage of the @flags is described at
540 * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>`
541 *
542 * Below is a brief outline of the most useful GFP flags
543 *
544 * %GFP_KERNEL
545 * Allocate normal kernel ram. May sleep.
546 *
547 * %GFP_NOWAIT
548 * Allocation will not sleep.
549 *
550 * %GFP_ATOMIC
551 * Allocation will not sleep. May use emergency pools.
552 *
553 * %GFP_HIGHUSER
554 * Allocate memory from high memory on behalf of user.
555 *
556 * Also it is possible to set different flags by OR'ing
557 * in one or more of the following additional @flags:
558 *
559 * %__GFP_HIGH
560 * This allocation has high priority and may use emergency pools.
561 *
562 * %__GFP_NOFAIL
563 * Indicate that this allocation is in no way allowed to fail
564 * (think twice before using).
565 *
566 * %__GFP_NORETRY
567 * If memory is not immediately available,
568 * then give up at once.
569 *
570 * %__GFP_NOWARN
571 * If allocation fails, don't issue any warnings.
572 *
573 * %__GFP_RETRY_MAYFAIL
574 * Try really hard to succeed the allocation but fail
575 * eventually.
576 */
kmalloc(size_t size,gfp_t flags)577 static __always_inline void *kmalloc(size_t size, gfp_t flags)
578 {
579 if (__builtin_constant_p(size)) {
580 #ifndef CONFIG_SLOB
581 unsigned int index;
582 #endif
583 if (size > KMALLOC_MAX_CACHE_SIZE)
584 return kmalloc_large(size, flags);
585 #ifndef CONFIG_SLOB
586 index = kmalloc_index(size);
587
588 if (!index)
589 return ZERO_SIZE_PTR;
590
591 return kmem_cache_alloc_trace(
592 kmalloc_caches[kmalloc_type(flags)][index],
593 flags, size);
594 #endif
595 }
596 return __kmalloc(size, flags);
597 }
598
kmalloc_node(size_t size,gfp_t flags,int node)599 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
600 {
601 #ifndef CONFIG_SLOB
602 if (__builtin_constant_p(size) &&
603 size <= KMALLOC_MAX_CACHE_SIZE) {
604 unsigned int i = kmalloc_index(size);
605
606 if (!i)
607 return ZERO_SIZE_PTR;
608
609 return kmem_cache_alloc_node_trace(
610 kmalloc_caches[kmalloc_type(flags)][i],
611 flags, node, size);
612 }
613 #endif
614 return __kmalloc_node(size, flags, node);
615 }
616
617 /**
618 * kmalloc_array - allocate memory for an array.
619 * @n: number of elements.
620 * @size: element size.
621 * @flags: the type of memory to allocate (see kmalloc).
622 */
kmalloc_array(size_t n,size_t size,gfp_t flags)623 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
624 {
625 size_t bytes;
626
627 if (unlikely(check_mul_overflow(n, size, &bytes)))
628 return NULL;
629 if (__builtin_constant_p(n) && __builtin_constant_p(size))
630 return kmalloc(bytes, flags);
631 return __kmalloc(bytes, flags);
632 }
633
634 /**
635 * krealloc_array - reallocate memory for an array.
636 * @p: pointer to the memory chunk to reallocate
637 * @new_n: new number of elements to alloc
638 * @new_size: new size of a single member of the array
639 * @flags: the type of memory to allocate (see kmalloc)
640 */
641 static __must_check inline void *
krealloc_array(void * p,size_t new_n,size_t new_size,gfp_t flags)642 krealloc_array(void *p, size_t new_n, size_t new_size, gfp_t flags)
643 {
644 size_t bytes;
645
646 if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
647 return NULL;
648
649 return krealloc(p, bytes, flags);
650 }
651
652 /**
653 * kcalloc - allocate memory for an array. The memory is set to zero.
654 * @n: number of elements.
655 * @size: element size.
656 * @flags: the type of memory to allocate (see kmalloc).
657 */
kcalloc(size_t n,size_t size,gfp_t flags)658 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
659 {
660 return kmalloc_array(n, size, flags | __GFP_ZERO);
661 }
662
663 /*
664 * kmalloc_track_caller is a special version of kmalloc that records the
665 * calling function of the routine calling it for slab leak tracking instead
666 * of just the calling function (confusing, eh?).
667 * It's useful when the call to kmalloc comes from a widely-used standard
668 * allocator where we care about the real place the memory allocation
669 * request comes from.
670 */
671 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
672 #define kmalloc_track_caller(size, flags) \
673 __kmalloc_track_caller(size, flags, _RET_IP_)
674
kmalloc_array_node(size_t n,size_t size,gfp_t flags,int node)675 static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
676 int node)
677 {
678 size_t bytes;
679
680 if (unlikely(check_mul_overflow(n, size, &bytes)))
681 return NULL;
682 if (__builtin_constant_p(n) && __builtin_constant_p(size))
683 return kmalloc_node(bytes, flags, node);
684 return __kmalloc_node(bytes, flags, node);
685 }
686
kcalloc_node(size_t n,size_t size,gfp_t flags,int node)687 static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
688 {
689 return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
690 }
691
692
693 #ifdef CONFIG_NUMA
694 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
695 #define kmalloc_node_track_caller(size, flags, node) \
696 __kmalloc_node_track_caller(size, flags, node, \
697 _RET_IP_)
698
699 #else /* CONFIG_NUMA */
700
701 #define kmalloc_node_track_caller(size, flags, node) \
702 kmalloc_track_caller(size, flags)
703
704 #endif /* CONFIG_NUMA */
705
706 /*
707 * Shortcuts
708 */
kmem_cache_zalloc(struct kmem_cache * k,gfp_t flags)709 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
710 {
711 return kmem_cache_alloc(k, flags | __GFP_ZERO);
712 }
713
714 /**
715 * kzalloc - allocate memory. The memory is set to zero.
716 * @size: how many bytes of memory are required.
717 * @flags: the type of memory to allocate (see kmalloc).
718 */
kzalloc(size_t size,gfp_t flags)719 static inline void *kzalloc(size_t size, gfp_t flags)
720 {
721 return kmalloc(size, flags | __GFP_ZERO);
722 }
723
724 /**
725 * kzalloc_node - allocate zeroed memory from a particular memory node.
726 * @size: how many bytes of memory are required.
727 * @flags: the type of memory to allocate (see kmalloc).
728 * @node: memory node from which to allocate
729 */
kzalloc_node(size_t size,gfp_t flags,int node)730 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
731 {
732 return kmalloc_node(size, flags | __GFP_ZERO, node);
733 }
734
735 unsigned int kmem_cache_size(struct kmem_cache *s);
736 void __init kmem_cache_init_late(void);
737
738 #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
739 int slab_prepare_cpu(unsigned int cpu);
740 int slab_dead_cpu(unsigned int cpu);
741 #else
742 #define slab_prepare_cpu NULL
743 #define slab_dead_cpu NULL
744 #endif
745
746 #endif /* _LINUX_SLAB_H */
747
