xref: /linux/mm/slab.h (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef MM_SLAB_H
3 #define MM_SLAB_H
4 
5 #include <linux/reciprocal_div.h>
6 #include <linux/list_lru.h>
7 #include <linux/local_lock.h>
8 #include <linux/random.h>
9 #include <linux/kobject.h>
10 #include <linux/sched/mm.h>
11 #include <linux/memcontrol.h>
12 #include <linux/kfence.h>
13 #include <linux/kasan.h>
14 
15 /*
16  * Internal slab definitions
17  */
18 
19 #ifdef CONFIG_64BIT
20 # ifdef system_has_cmpxchg128
21 # define system_has_freelist_aba()	system_has_cmpxchg128()
22 # define try_cmpxchg_freelist		try_cmpxchg128
23 # endif
24 #define this_cpu_try_cmpxchg_freelist	this_cpu_try_cmpxchg128
25 typedef u128 freelist_full_t;
26 #else /* CONFIG_64BIT */
27 # ifdef system_has_cmpxchg64
28 # define system_has_freelist_aba()	system_has_cmpxchg64()
29 # define try_cmpxchg_freelist		try_cmpxchg64
30 # endif
31 #define this_cpu_try_cmpxchg_freelist	this_cpu_try_cmpxchg64
32 typedef u64 freelist_full_t;
33 #endif /* CONFIG_64BIT */
34 
35 #if defined(system_has_freelist_aba) && !defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
36 #undef system_has_freelist_aba
37 #endif
38 
39 /*
40  * Freelist pointer and counter to cmpxchg together, avoids the typical ABA
41  * problems with cmpxchg of just a pointer.
42  */
43 typedef union {
44 	struct {
45 		void *freelist;
46 		unsigned long counter;
47 	};
48 	freelist_full_t full;
49 } freelist_aba_t;
50 
51 /* Reuses the bits in struct page */
52 struct slab {
53 	unsigned long __page_flags;
54 
55 	struct kmem_cache *slab_cache;
56 	union {
57 		struct {
58 			union {
59 				struct list_head slab_list;
60 #ifdef CONFIG_SLUB_CPU_PARTIAL
61 				struct {
62 					struct slab *next;
63 					int slabs;	/* Nr of slabs left */
64 				};
65 #endif
66 			};
67 			/* Double-word boundary */
68 			union {
69 				struct {
70 					void *freelist;		/* first free object */
71 					union {
72 						unsigned long counters;
73 						struct {
74 							unsigned inuse:16;
75 							unsigned objects:15;
76 							/*
77 							 * If slab debugging is enabled then the
78 							 * frozen bit can be reused to indicate
79 							 * that the slab was corrupted
80 							 */
81 							unsigned frozen:1;
82 						};
83 					};
84 				};
85 #ifdef system_has_freelist_aba
86 				freelist_aba_t freelist_counter;
87 #endif
88 			};
89 		};
90 		struct rcu_head rcu_head;
91 	};
92 
93 	unsigned int __page_type;
94 	atomic_t __page_refcount;
95 #ifdef CONFIG_SLAB_OBJ_EXT
96 	unsigned long obj_exts;
97 #endif
98 };
99 
100 #define SLAB_MATCH(pg, sl)						\
101 	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
102 SLAB_MATCH(flags, __page_flags);
103 SLAB_MATCH(compound_head, slab_cache);	/* Ensure bit 0 is clear */
104 SLAB_MATCH(_refcount, __page_refcount);
105 #ifdef CONFIG_MEMCG
106 SLAB_MATCH(memcg_data, obj_exts);
107 #elif defined(CONFIG_SLAB_OBJ_EXT)
108 SLAB_MATCH(_unused_slab_obj_exts, obj_exts);
109 #endif
110 #undef SLAB_MATCH
111 static_assert(sizeof(struct slab) <= sizeof(struct page));
112 #if defined(system_has_freelist_aba)
113 static_assert(IS_ALIGNED(offsetof(struct slab, freelist), sizeof(freelist_aba_t)));
114 #endif
115 
116 /**
117  * folio_slab - Converts from folio to slab.
118  * @folio: The folio.
119  *
120  * Currently struct slab is a different representation of a folio where
121  * folio_test_slab() is true.
122  *
123  * Return: The slab which contains this folio.
124  */
125 #define folio_slab(folio)	(_Generic((folio),			\
126 	const struct folio *:	(const struct slab *)(folio),		\
127 	struct folio *:		(struct slab *)(folio)))
128 
129 /**
130  * slab_folio - The folio allocated for a slab
131  * @slab: The slab.
132  *
133  * Slabs are allocated as folios that contain the individual objects and are
134  * using some fields in the first struct page of the folio - those fields are
135  * now accessed by struct slab. It is occasionally necessary to convert back to
136  * a folio in order to communicate with the rest of the mm.  Please use this
137  * helper function instead of casting yourself, as the implementation may change
138  * in the future.
139  */
140 #define slab_folio(s)		(_Generic((s),				\
141 	const struct slab *:	(const struct folio *)s,		\
142 	struct slab *:		(struct folio *)s))
143 
144 /**
145  * page_slab - Converts from first struct page to slab.
146  * @p: The first (either head of compound or single) page of slab.
147  *
148  * A temporary wrapper to convert struct page to struct slab in situations where
149  * we know the page is the compound head, or single order-0 page.
150  *
151  * Long-term ideally everything would work with struct slab directly or go
152  * through folio to struct slab.
153  *
154  * Return: The slab which contains this page
155  */
156 #define page_slab(p)		(_Generic((p),				\
157 	const struct page *:	(const struct slab *)(p),		\
158 	struct page *:		(struct slab *)(p)))
159 
160 /**
161  * slab_page - The first struct page allocated for a slab
162  * @slab: The slab.
163  *
164  * A convenience wrapper for converting slab to the first struct page of the
165  * underlying folio, to communicate with code not yet converted to folio or
166  * struct slab.
167  */
168 #define slab_page(s) folio_page(slab_folio(s), 0)
169 
170 /*
171  * If network-based swap is enabled, sl*b must keep track of whether pages
172  * were allocated from pfmemalloc reserves.
173  */
174 static inline bool slab_test_pfmemalloc(const struct slab *slab)
175 {
176 	return folio_test_active(slab_folio(slab));
177 }
178 
179 static inline void slab_set_pfmemalloc(struct slab *slab)
180 {
181 	folio_set_active(slab_folio(slab));
182 }
183 
184 static inline void slab_clear_pfmemalloc(struct slab *slab)
185 {
186 	folio_clear_active(slab_folio(slab));
187 }
188 
189 static inline void __slab_clear_pfmemalloc(struct slab *slab)
190 {
191 	__folio_clear_active(slab_folio(slab));
192 }
193 
194 static inline void *slab_address(const struct slab *slab)
195 {
196 	return folio_address(slab_folio(slab));
197 }
198 
199 static inline int slab_nid(const struct slab *slab)
200 {
201 	return folio_nid(slab_folio(slab));
202 }
203 
204 static inline pg_data_t *slab_pgdat(const struct slab *slab)
205 {
206 	return folio_pgdat(slab_folio(slab));
207 }
208 
209 static inline struct slab *virt_to_slab(const void *addr)
210 {
211 	struct folio *folio = virt_to_folio(addr);
212 
213 	if (!folio_test_slab(folio))
214 		return NULL;
215 
216 	return folio_slab(folio);
217 }
218 
219 static inline int slab_order(const struct slab *slab)
220 {
221 	return folio_order(slab_folio(slab));
222 }
223 
224 static inline size_t slab_size(const struct slab *slab)
225 {
226 	return PAGE_SIZE << slab_order(slab);
227 }
228 
229 #ifdef CONFIG_SLUB_CPU_PARTIAL
230 #define slub_percpu_partial(c)			((c)->partial)
231 
232 #define slub_set_percpu_partial(c, p)		\
233 ({						\
234 	slub_percpu_partial(c) = (p)->next;	\
235 })
236 
237 #define slub_percpu_partial_read_once(c)	READ_ONCE(slub_percpu_partial(c))
238 #else
239 #define slub_percpu_partial(c)			NULL
240 
241 #define slub_set_percpu_partial(c, p)
242 
243 #define slub_percpu_partial_read_once(c)	NULL
244 #endif // CONFIG_SLUB_CPU_PARTIAL
245 
246 /*
247  * Word size structure that can be atomically updated or read and that
248  * contains both the order and the number of objects that a slab of the
249  * given order would contain.
250  */
251 struct kmem_cache_order_objects {
252 	unsigned int x;
253 };
254 
255 /*
256  * Slab cache management.
257  */
258 struct kmem_cache {
259 #ifndef CONFIG_SLUB_TINY
260 	struct kmem_cache_cpu __percpu *cpu_slab;
261 #endif
262 	/* Used for retrieving partial slabs, etc. */
263 	slab_flags_t flags;
264 	unsigned long min_partial;
265 	unsigned int size;		/* Object size including metadata */
266 	unsigned int object_size;	/* Object size without metadata */
267 	struct reciprocal_value reciprocal_size;
268 	unsigned int offset;		/* Free pointer offset */
269 #ifdef CONFIG_SLUB_CPU_PARTIAL
270 	/* Number of per cpu partial objects to keep around */
271 	unsigned int cpu_partial;
272 	/* Number of per cpu partial slabs to keep around */
273 	unsigned int cpu_partial_slabs;
274 #endif
275 	struct kmem_cache_order_objects oo;
276 
277 	/* Allocation and freeing of slabs */
278 	struct kmem_cache_order_objects min;
279 	gfp_t allocflags;		/* gfp flags to use on each alloc */
280 	int refcount;			/* Refcount for slab cache destroy */
281 	void (*ctor)(void *object);	/* Object constructor */
282 	unsigned int inuse;		/* Offset to metadata */
283 	unsigned int align;		/* Alignment */
284 	unsigned int red_left_pad;	/* Left redzone padding size */
285 	const char *name;		/* Name (only for display!) */
286 	struct list_head list;		/* List of slab caches */
287 #ifdef CONFIG_SYSFS
288 	struct kobject kobj;		/* For sysfs */
289 #endif
290 #ifdef CONFIG_SLAB_FREELIST_HARDENED
291 	unsigned long random;
292 #endif
293 
294 #ifdef CONFIG_NUMA
295 	/*
296 	 * Defragmentation by allocating from a remote node.
297 	 */
298 	unsigned int remote_node_defrag_ratio;
299 #endif
300 
301 #ifdef CONFIG_SLAB_FREELIST_RANDOM
302 	unsigned int *random_seq;
303 #endif
304 
305 #ifdef CONFIG_KASAN_GENERIC
306 	struct kasan_cache kasan_info;
307 #endif
308 
309 #ifdef CONFIG_HARDENED_USERCOPY
310 	unsigned int useroffset;	/* Usercopy region offset */
311 	unsigned int usersize;		/* Usercopy region size */
312 #endif
313 
314 	struct kmem_cache_node *node[MAX_NUMNODES];
315 };
316 
317 #if defined(CONFIG_SYSFS) && !defined(CONFIG_SLUB_TINY)
318 #define SLAB_SUPPORTS_SYSFS 1
319 void sysfs_slab_unlink(struct kmem_cache *s);
320 void sysfs_slab_release(struct kmem_cache *s);
321 #else
322 static inline void sysfs_slab_unlink(struct kmem_cache *s) { }
323 static inline void sysfs_slab_release(struct kmem_cache *s) { }
324 #endif
325 
326 void *fixup_red_left(struct kmem_cache *s, void *p);
327 
328 static inline void *nearest_obj(struct kmem_cache *cache,
329 				const struct slab *slab, void *x)
330 {
331 	void *object = x - (x - slab_address(slab)) % cache->size;
332 	void *last_object = slab_address(slab) +
333 		(slab->objects - 1) * cache->size;
334 	void *result = (unlikely(object > last_object)) ? last_object : object;
335 
336 	result = fixup_red_left(cache, result);
337 	return result;
338 }
339 
340 /* Determine object index from a given position */
341 static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
342 					  void *addr, void *obj)
343 {
344 	return reciprocal_divide(kasan_reset_tag(obj) - addr,
345 				 cache->reciprocal_size);
346 }
347 
348 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
349 					const struct slab *slab, void *obj)
350 {
351 	if (is_kfence_address(obj))
352 		return 0;
353 	return __obj_to_index(cache, slab_address(slab), obj);
354 }
355 
356 static inline int objs_per_slab(const struct kmem_cache *cache,
357 				const struct slab *slab)
358 {
359 	return slab->objects;
360 }
361 
362 /*
363  * State of the slab allocator.
364  *
365  * This is used to describe the states of the allocator during bootup.
366  * Allocators use this to gradually bootstrap themselves. Most allocators
367  * have the problem that the structures used for managing slab caches are
368  * allocated from slab caches themselves.
369  */
370 enum slab_state {
371 	DOWN,			/* No slab functionality yet */
372 	PARTIAL,		/* SLUB: kmem_cache_node available */
373 	UP,			/* Slab caches usable but not all extras yet */
374 	FULL			/* Everything is working */
375 };
376 
377 extern enum slab_state slab_state;
378 
379 /* The slab cache mutex protects the management structures during changes */
380 extern struct mutex slab_mutex;
381 
382 /* The list of all slab caches on the system */
383 extern struct list_head slab_caches;
384 
385 /* The slab cache that manages slab cache information */
386 extern struct kmem_cache *kmem_cache;
387 
388 /* A table of kmalloc cache names and sizes */
389 extern const struct kmalloc_info_struct {
390 	const char *name[NR_KMALLOC_TYPES];
391 	unsigned int size;
392 } kmalloc_info[];
393 
394 /* Kmalloc array related functions */
395 void setup_kmalloc_cache_index_table(void);
396 void create_kmalloc_caches(void);
397 
398 extern u8 kmalloc_size_index[24];
399 
400 static inline unsigned int size_index_elem(unsigned int bytes)
401 {
402 	return (bytes - 1) / 8;
403 }
404 
405 /*
406  * Find the kmem_cache structure that serves a given size of
407  * allocation
408  *
409  * This assumes size is larger than zero and not larger than
410  * KMALLOC_MAX_CACHE_SIZE and the caller must check that.
411  */
412 static inline struct kmem_cache *
413 kmalloc_slab(size_t size, kmem_buckets *b, gfp_t flags, unsigned long caller)
414 {
415 	unsigned int index;
416 
417 	if (!b)
418 		b = &kmalloc_caches[kmalloc_type(flags, caller)];
419 	if (size <= 192)
420 		index = kmalloc_size_index[size_index_elem(size)];
421 	else
422 		index = fls(size - 1);
423 
424 	return (*b)[index];
425 }
426 
427 gfp_t kmalloc_fix_flags(gfp_t flags);
428 
429 /* Functions provided by the slab allocators */
430 int do_kmem_cache_create(struct kmem_cache *s, const char *name,
431 			 unsigned int size, struct kmem_cache_args *args,
432 			 slab_flags_t flags);
433 
434 void __init kmem_cache_init(void);
435 extern void create_boot_cache(struct kmem_cache *, const char *name,
436 			unsigned int size, slab_flags_t flags,
437 			unsigned int useroffset, unsigned int usersize);
438 
439 int slab_unmergeable(struct kmem_cache *s);
440 struct kmem_cache *find_mergeable(unsigned size, unsigned align,
441 		slab_flags_t flags, const char *name, void (*ctor)(void *));
442 struct kmem_cache *
443 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
444 		   slab_flags_t flags, void (*ctor)(void *));
445 
446 slab_flags_t kmem_cache_flags(slab_flags_t flags, const char *name);
447 
448 static inline bool is_kmalloc_cache(struct kmem_cache *s)
449 {
450 	return (s->flags & SLAB_KMALLOC);
451 }
452 
453 static inline bool is_kmalloc_normal(struct kmem_cache *s)
454 {
455 	if (!is_kmalloc_cache(s))
456 		return false;
457 	return !(s->flags & (SLAB_CACHE_DMA|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT));
458 }
459 
460 /* Legal flag mask for kmem_cache_create(), for various configurations */
461 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
462 			 SLAB_CACHE_DMA32 | SLAB_PANIC | \
463 			 SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
464 
465 #ifdef CONFIG_SLUB_DEBUG
466 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
467 			  SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
468 #else
469 #define SLAB_DEBUG_FLAGS (0)
470 #endif
471 
472 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
473 			  SLAB_TEMPORARY | SLAB_ACCOUNT | \
474 			  SLAB_NO_USER_FLAGS | SLAB_KMALLOC | SLAB_NO_MERGE)
475 
476 /* Common flags available with current configuration */
477 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
478 
479 /* Common flags permitted for kmem_cache_create */
480 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
481 			      SLAB_RED_ZONE | \
482 			      SLAB_POISON | \
483 			      SLAB_STORE_USER | \
484 			      SLAB_TRACE | \
485 			      SLAB_CONSISTENCY_CHECKS | \
486 			      SLAB_NOLEAKTRACE | \
487 			      SLAB_RECLAIM_ACCOUNT | \
488 			      SLAB_TEMPORARY | \
489 			      SLAB_ACCOUNT | \
490 			      SLAB_KMALLOC | \
491 			      SLAB_NO_MERGE | \
492 			      SLAB_NO_USER_FLAGS)
493 
494 bool __kmem_cache_empty(struct kmem_cache *);
495 int __kmem_cache_shutdown(struct kmem_cache *);
496 void __kmem_cache_release(struct kmem_cache *);
497 int __kmem_cache_shrink(struct kmem_cache *);
498 void slab_kmem_cache_release(struct kmem_cache *);
499 
500 struct seq_file;
501 struct file;
502 
503 struct slabinfo {
504 	unsigned long active_objs;
505 	unsigned long num_objs;
506 	unsigned long active_slabs;
507 	unsigned long num_slabs;
508 	unsigned long shared_avail;
509 	unsigned int limit;
510 	unsigned int batchcount;
511 	unsigned int shared;
512 	unsigned int objects_per_slab;
513 	unsigned int cache_order;
514 };
515 
516 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
517 
518 #ifdef CONFIG_SLUB_DEBUG
519 #ifdef CONFIG_SLUB_DEBUG_ON
520 DECLARE_STATIC_KEY_TRUE(slub_debug_enabled);
521 #else
522 DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
523 #endif
524 extern void print_tracking(struct kmem_cache *s, void *object);
525 long validate_slab_cache(struct kmem_cache *s);
526 static inline bool __slub_debug_enabled(void)
527 {
528 	return static_branch_unlikely(&slub_debug_enabled);
529 }
530 #else
531 static inline void print_tracking(struct kmem_cache *s, void *object)
532 {
533 }
534 static inline bool __slub_debug_enabled(void)
535 {
536 	return false;
537 }
538 #endif
539 
540 /*
541  * Returns true if any of the specified slab_debug flags is enabled for the
542  * cache. Use only for flags parsed by setup_slub_debug() as it also enables
543  * the static key.
544  */
545 static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)
546 {
547 	if (IS_ENABLED(CONFIG_SLUB_DEBUG))
548 		VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
549 	if (__slub_debug_enabled())
550 		return s->flags & flags;
551 	return false;
552 }
553 
554 #if IS_ENABLED(CONFIG_SLUB_DEBUG) && IS_ENABLED(CONFIG_KUNIT)
555 bool slab_in_kunit_test(void);
556 #else
557 static inline bool slab_in_kunit_test(void) { return false; }
558 #endif
559 
560 #ifdef CONFIG_SLAB_OBJ_EXT
561 
562 /*
563  * slab_obj_exts - get the pointer to the slab object extension vector
564  * associated with a slab.
565  * @slab: a pointer to the slab struct
566  *
567  * Returns a pointer to the object extension vector associated with the slab,
568  * or NULL if no such vector has been associated yet.
569  */
570 static inline struct slabobj_ext *slab_obj_exts(struct slab *slab)
571 {
572 	unsigned long obj_exts = READ_ONCE(slab->obj_exts);
573 
574 #ifdef CONFIG_MEMCG
575 	VM_BUG_ON_PAGE(obj_exts && !(obj_exts & MEMCG_DATA_OBJEXTS),
576 							slab_page(slab));
577 	VM_BUG_ON_PAGE(obj_exts & MEMCG_DATA_KMEM, slab_page(slab));
578 #endif
579 	return (struct slabobj_ext *)(obj_exts & ~OBJEXTS_FLAGS_MASK);
580 }
581 
582 int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
583                         gfp_t gfp, bool new_slab);
584 
585 #else /* CONFIG_SLAB_OBJ_EXT */
586 
587 static inline struct slabobj_ext *slab_obj_exts(struct slab *slab)
588 {
589 	return NULL;
590 }
591 
592 #endif /* CONFIG_SLAB_OBJ_EXT */
593 
594 static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s)
595 {
596 	return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
597 		NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
598 }
599 
600 #ifdef CONFIG_MEMCG
601 bool __memcg_slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru,
602 				  gfp_t flags, size_t size, void **p);
603 void __memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
604 			    void **p, int objects, struct slabobj_ext *obj_exts);
605 #endif
606 
607 size_t __ksize(const void *objp);
608 
609 static inline size_t slab_ksize(const struct kmem_cache *s)
610 {
611 #ifdef CONFIG_SLUB_DEBUG
612 	/*
613 	 * Debugging requires use of the padding between object
614 	 * and whatever may come after it.
615 	 */
616 	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
617 		return s->object_size;
618 #endif
619 	if (s->flags & SLAB_KASAN)
620 		return s->object_size;
621 	/*
622 	 * If we have the need to store the freelist pointer
623 	 * back there or track user information then we can
624 	 * only use the space before that information.
625 	 */
626 	if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER))
627 		return s->inuse;
628 	/*
629 	 * Else we can use all the padding etc for the allocation
630 	 */
631 	return s->size;
632 }
633 
634 #ifdef CONFIG_SLUB_DEBUG
635 void dump_unreclaimable_slab(void);
636 #else
637 static inline void dump_unreclaimable_slab(void)
638 {
639 }
640 #endif
641 
642 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
643 
644 #ifdef CONFIG_SLAB_FREELIST_RANDOM
645 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
646 			gfp_t gfp);
647 void cache_random_seq_destroy(struct kmem_cache *cachep);
648 #else
649 static inline int cache_random_seq_create(struct kmem_cache *cachep,
650 					unsigned int count, gfp_t gfp)
651 {
652 	return 0;
653 }
654 static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
655 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
656 
657 static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
658 {
659 	if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON,
660 				&init_on_alloc)) {
661 		if (c->ctor)
662 			return false;
663 		if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
664 			return flags & __GFP_ZERO;
665 		return true;
666 	}
667 	return flags & __GFP_ZERO;
668 }
669 
670 static inline bool slab_want_init_on_free(struct kmem_cache *c)
671 {
672 	if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON,
673 				&init_on_free))
674 		return !(c->ctor ||
675 			 (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
676 	return false;
677 }
678 
679 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
680 void debugfs_slab_release(struct kmem_cache *);
681 #else
682 static inline void debugfs_slab_release(struct kmem_cache *s) { }
683 #endif
684 
685 #ifdef CONFIG_PRINTK
686 #define KS_ADDRS_COUNT 16
687 struct kmem_obj_info {
688 	void *kp_ptr;
689 	struct slab *kp_slab;
690 	void *kp_objp;
691 	unsigned long kp_data_offset;
692 	struct kmem_cache *kp_slab_cache;
693 	void *kp_ret;
694 	void *kp_stack[KS_ADDRS_COUNT];
695 	void *kp_free_stack[KS_ADDRS_COUNT];
696 };
697 void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab);
698 #endif
699 
700 void __check_heap_object(const void *ptr, unsigned long n,
701 			 const struct slab *slab, bool to_user);
702 
703 static inline bool slub_debug_orig_size(struct kmem_cache *s)
704 {
705 	return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
706 			(s->flags & SLAB_KMALLOC));
707 }
708 
709 #ifdef CONFIG_SLUB_DEBUG
710 void skip_orig_size_check(struct kmem_cache *s, const void *object);
711 #endif
712 
713 #endif /* MM_SLAB_H */
714