xref: /openbmc/linux/mm/slab.h (revision 56b5b1c7)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef MM_SLAB_H
3 #define MM_SLAB_H
4 /*
5  * Internal slab definitions
6  */
7 
8 /* Reuses the bits in struct page */
9 struct slab {
10 	unsigned long __page_flags;
11 
12 #if defined(CONFIG_SLAB)
13 
14 	union {
15 		struct list_head slab_list;
16 		struct rcu_head rcu_head;
17 	};
18 	struct kmem_cache *slab_cache;
19 	void *freelist;	/* array of free object indexes */
20 	void *s_mem;	/* first object */
21 	unsigned int active;
22 
23 #elif defined(CONFIG_SLUB)
24 
25 	union {
26 		struct list_head slab_list;
27 		struct rcu_head rcu_head;
28 #ifdef CONFIG_SLUB_CPU_PARTIAL
29 		struct {
30 			struct slab *next;
31 			int slabs;	/* Nr of slabs left */
32 		};
33 #endif
34 	};
35 	struct kmem_cache *slab_cache;
36 	/* Double-word boundary */
37 	void *freelist;		/* first free object */
38 	union {
39 		unsigned long counters;
40 		struct {
41 			unsigned inuse:16;
42 			unsigned objects:15;
43 			unsigned frozen:1;
44 		};
45 	};
46 	unsigned int __unused;
47 
48 #elif defined(CONFIG_SLOB)
49 
50 	struct list_head slab_list;
51 	void *__unused_1;
52 	void *freelist;		/* first free block */
53 	long units;
54 	unsigned int __unused_2;
55 
56 #else
57 #error "Unexpected slab allocator configured"
58 #endif
59 
60 	atomic_t __page_refcount;
61 #ifdef CONFIG_MEMCG
62 	unsigned long memcg_data;
63 #endif
64 };
65 
66 #define SLAB_MATCH(pg, sl)						\
67 	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
68 SLAB_MATCH(flags, __page_flags);
69 SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
70 #ifndef CONFIG_SLOB
71 SLAB_MATCH(rcu_head, rcu_head);
72 #endif
73 SLAB_MATCH(_refcount, __page_refcount);
74 #ifdef CONFIG_MEMCG
75 SLAB_MATCH(memcg_data, memcg_data);
76 #endif
77 #undef SLAB_MATCH
78 static_assert(sizeof(struct slab) <= sizeof(struct page));
79 
80 /**
81  * folio_slab - Converts from folio to slab.
82  * @folio: The folio.
83  *
84  * Currently struct slab is a different representation of a folio where
85  * folio_test_slab() is true.
86  *
87  * Return: The slab which contains this folio.
88  */
89 #define folio_slab(folio)	(_Generic((folio),			\
90 	const struct folio *:	(const struct slab *)(folio),		\
91 	struct folio *:		(struct slab *)(folio)))
92 
93 /**
94  * slab_folio - The folio allocated for a slab
95  * @slab: The slab.
96  *
97  * Slabs are allocated as folios that contain the individual objects and are
98  * using some fields in the first struct page of the folio - those fields are
99  * now accessed by struct slab. It is occasionally necessary to convert back to
100  * a folio in order to communicate with the rest of the mm.  Please use this
101  * helper function instead of casting yourself, as the implementation may change
102  * in the future.
103  */
104 #define slab_folio(s)		(_Generic((s),				\
105 	const struct slab *:	(const struct folio *)s,		\
106 	struct slab *:		(struct folio *)s))
107 
108 /**
109  * page_slab - Converts from first struct page to slab.
110  * @p: The first (either head of compound or single) page of slab.
111  *
112  * A temporary wrapper to convert struct page to struct slab in situations where
113  * we know the page is the compound head, or single order-0 page.
114  *
115  * Long-term ideally everything would work with struct slab directly or go
116  * through folio to struct slab.
117  *
118  * Return: The slab which contains this page
119  */
120 #define page_slab(p)		(_Generic((p),				\
121 	const struct page *:	(const struct slab *)(p),		\
122 	struct page *:		(struct slab *)(p)))
123 
124 /**
125  * slab_page - The first struct page allocated for a slab
126  * @slab: The slab.
127  *
128  * A convenience wrapper for converting slab to the first struct page of the
129  * underlying folio, to communicate with code not yet converted to folio or
130  * struct slab.
131  */
132 #define slab_page(s) folio_page(slab_folio(s), 0)
133 
134 /*
135  * If network-based swap is enabled, sl*b must keep track of whether pages
136  * were allocated from pfmemalloc reserves.
137  */
138 static inline bool slab_test_pfmemalloc(const struct slab *slab)
139 {
140 	return folio_test_active((struct folio *)slab_folio(slab));
141 }
142 
143 static inline void slab_set_pfmemalloc(struct slab *slab)
144 {
145 	folio_set_active(slab_folio(slab));
146 }
147 
148 static inline void slab_clear_pfmemalloc(struct slab *slab)
149 {
150 	folio_clear_active(slab_folio(slab));
151 }
152 
153 static inline void __slab_clear_pfmemalloc(struct slab *slab)
154 {
155 	__folio_clear_active(slab_folio(slab));
156 }
157 
158 static inline void *slab_address(const struct slab *slab)
159 {
160 	return folio_address(slab_folio(slab));
161 }
162 
163 static inline int slab_nid(const struct slab *slab)
164 {
165 	return folio_nid(slab_folio(slab));
166 }
167 
168 static inline pg_data_t *slab_pgdat(const struct slab *slab)
169 {
170 	return folio_pgdat(slab_folio(slab));
171 }
172 
173 static inline struct slab *virt_to_slab(const void *addr)
174 {
175 	struct folio *folio = virt_to_folio(addr);
176 
177 	if (!folio_test_slab(folio))
178 		return NULL;
179 
180 	return folio_slab(folio);
181 }
182 
183 static inline int slab_order(const struct slab *slab)
184 {
185 	return folio_order((struct folio *)slab_folio(slab));
186 }
187 
188 static inline size_t slab_size(const struct slab *slab)
189 {
190 	return PAGE_SIZE << slab_order(slab);
191 }
192 
193 #ifdef CONFIG_SLOB
194 /*
195  * Common fields provided in kmem_cache by all slab allocators
196  * This struct is either used directly by the allocator (SLOB)
197  * or the allocator must include definitions for all fields
198  * provided in kmem_cache_common in their definition of kmem_cache.
199  *
200  * Once we can do anonymous structs (C11 standard) we could put a
201  * anonymous struct definition in these allocators so that the
202  * separate allocations in the kmem_cache structure of SLAB and
203  * SLUB is no longer needed.
204  */
205 struct kmem_cache {
206 	unsigned int object_size;/* The original size of the object */
207 	unsigned int size;	/* The aligned/padded/added on size  */
208 	unsigned int align;	/* Alignment as calculated */
209 	slab_flags_t flags;	/* Active flags on the slab */
210 	unsigned int useroffset;/* Usercopy region offset */
211 	unsigned int usersize;	/* Usercopy region size */
212 	const char *name;	/* Slab name for sysfs */
213 	int refcount;		/* Use counter */
214 	void (*ctor)(void *);	/* Called on object slot creation */
215 	struct list_head list;	/* List of all slab caches on the system */
216 };
217 
218 #endif /* CONFIG_SLOB */
219 
220 #ifdef CONFIG_SLAB
221 #include <linux/slab_def.h>
222 #endif
223 
224 #ifdef CONFIG_SLUB
225 #include <linux/slub_def.h>
226 #endif
227 
228 #include <linux/memcontrol.h>
229 #include <linux/fault-inject.h>
230 #include <linux/kasan.h>
231 #include <linux/kmemleak.h>
232 #include <linux/random.h>
233 #include <linux/sched/mm.h>
234 
235 /*
236  * State of the slab allocator.
237  *
238  * This is used to describe the states of the allocator during bootup.
239  * Allocators use this to gradually bootstrap themselves. Most allocators
240  * have the problem that the structures used for managing slab caches are
241  * allocated from slab caches themselves.
242  */
243 enum slab_state {
244 	DOWN,			/* No slab functionality yet */
245 	PARTIAL,		/* SLUB: kmem_cache_node available */
246 	PARTIAL_NODE,		/* SLAB: kmalloc size for node struct available */
247 	UP,			/* Slab caches usable but not all extras yet */
248 	FULL			/* Everything is working */
249 };
250 
251 extern enum slab_state slab_state;
252 
253 /* The slab cache mutex protects the management structures during changes */
254 extern struct mutex slab_mutex;
255 
256 /* The list of all slab caches on the system */
257 extern struct list_head slab_caches;
258 
259 /* The slab cache that manages slab cache information */
260 extern struct kmem_cache *kmem_cache;
261 
262 /* A table of kmalloc cache names and sizes */
263 extern const struct kmalloc_info_struct {
264 	const char *name[NR_KMALLOC_TYPES];
265 	unsigned int size;
266 } kmalloc_info[];
267 
268 #ifndef CONFIG_SLOB
269 /* Kmalloc array related functions */
270 void setup_kmalloc_cache_index_table(void);
271 void create_kmalloc_caches(slab_flags_t);
272 
273 /* Find the kmalloc slab corresponding for a certain size */
274 struct kmem_cache *kmalloc_slab(size_t, gfp_t);
275 #endif
276 
277 gfp_t kmalloc_fix_flags(gfp_t flags);
278 
279 /* Functions provided by the slab allocators */
280 int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
281 
282 struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size,
283 			slab_flags_t flags, unsigned int useroffset,
284 			unsigned int usersize);
285 extern void create_boot_cache(struct kmem_cache *, const char *name,
286 			unsigned int size, slab_flags_t flags,
287 			unsigned int useroffset, unsigned int usersize);
288 
289 int slab_unmergeable(struct kmem_cache *s);
290 struct kmem_cache *find_mergeable(unsigned size, unsigned align,
291 		slab_flags_t flags, const char *name, void (*ctor)(void *));
292 #ifndef CONFIG_SLOB
293 struct kmem_cache *
294 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
295 		   slab_flags_t flags, void (*ctor)(void *));
296 
297 slab_flags_t kmem_cache_flags(unsigned int object_size,
298 	slab_flags_t flags, const char *name);
299 #else
300 static inline struct kmem_cache *
301 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
302 		   slab_flags_t flags, void (*ctor)(void *))
303 { return NULL; }
304 
305 static inline slab_flags_t kmem_cache_flags(unsigned int object_size,
306 	slab_flags_t flags, const char *name)
307 {
308 	return flags;
309 }
310 #endif
311 
312 
313 /* Legal flag mask for kmem_cache_create(), for various configurations */
314 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
315 			 SLAB_CACHE_DMA32 | SLAB_PANIC | \
316 			 SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
317 
318 #if defined(CONFIG_DEBUG_SLAB)
319 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
320 #elif defined(CONFIG_SLUB_DEBUG)
321 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
322 			  SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
323 #else
324 #define SLAB_DEBUG_FLAGS (0)
325 #endif
326 
327 #if defined(CONFIG_SLAB)
328 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
329 			  SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
330 			  SLAB_ACCOUNT)
331 #elif defined(CONFIG_SLUB)
332 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
333 			  SLAB_TEMPORARY | SLAB_ACCOUNT)
334 #else
335 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE)
336 #endif
337 
338 /* Common flags available with current configuration */
339 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
340 
341 /* Common flags permitted for kmem_cache_create */
342 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
343 			      SLAB_RED_ZONE | \
344 			      SLAB_POISON | \
345 			      SLAB_STORE_USER | \
346 			      SLAB_TRACE | \
347 			      SLAB_CONSISTENCY_CHECKS | \
348 			      SLAB_MEM_SPREAD | \
349 			      SLAB_NOLEAKTRACE | \
350 			      SLAB_RECLAIM_ACCOUNT | \
351 			      SLAB_TEMPORARY | \
352 			      SLAB_ACCOUNT)
353 
354 bool __kmem_cache_empty(struct kmem_cache *);
355 int __kmem_cache_shutdown(struct kmem_cache *);
356 void __kmem_cache_release(struct kmem_cache *);
357 int __kmem_cache_shrink(struct kmem_cache *);
358 void slab_kmem_cache_release(struct kmem_cache *);
359 
360 struct seq_file;
361 struct file;
362 
363 struct slabinfo {
364 	unsigned long active_objs;
365 	unsigned long num_objs;
366 	unsigned long active_slabs;
367 	unsigned long num_slabs;
368 	unsigned long shared_avail;
369 	unsigned int limit;
370 	unsigned int batchcount;
371 	unsigned int shared;
372 	unsigned int objects_per_slab;
373 	unsigned int cache_order;
374 };
375 
376 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
377 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
378 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
379 		       size_t count, loff_t *ppos);
380 
381 /*
382  * Generic implementation of bulk operations
383  * These are useful for situations in which the allocator cannot
384  * perform optimizations. In that case segments of the object listed
385  * may be allocated or freed using these operations.
386  */
387 void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
388 int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
389 
390 static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s)
391 {
392 	return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
393 		NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
394 }
395 
396 #ifdef CONFIG_SLUB_DEBUG
397 #ifdef CONFIG_SLUB_DEBUG_ON
398 DECLARE_STATIC_KEY_TRUE(slub_debug_enabled);
399 #else
400 DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
401 #endif
402 extern void print_tracking(struct kmem_cache *s, void *object);
403 long validate_slab_cache(struct kmem_cache *s);
404 static inline bool __slub_debug_enabled(void)
405 {
406 	return static_branch_unlikely(&slub_debug_enabled);
407 }
408 #else
409 static inline void print_tracking(struct kmem_cache *s, void *object)
410 {
411 }
412 static inline bool __slub_debug_enabled(void)
413 {
414 	return false;
415 }
416 #endif
417 
418 /*
419  * Returns true if any of the specified slub_debug flags is enabled for the
420  * cache. Use only for flags parsed by setup_slub_debug() as it also enables
421  * the static key.
422  */
423 static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)
424 {
425 	if (IS_ENABLED(CONFIG_SLUB_DEBUG))
426 		VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
427 	if (__slub_debug_enabled())
428 		return s->flags & flags;
429 	return false;
430 }
431 
432 #ifdef CONFIG_MEMCG_KMEM
433 /*
434  * slab_objcgs - get the object cgroups vector associated with a slab
435  * @slab: a pointer to the slab struct
436  *
437  * Returns a pointer to the object cgroups vector associated with the slab,
438  * or NULL if no such vector has been associated yet.
439  */
440 static inline struct obj_cgroup **slab_objcgs(struct slab *slab)
441 {
442 	unsigned long memcg_data = READ_ONCE(slab->memcg_data);
443 
444 	VM_BUG_ON_PAGE(memcg_data && !(memcg_data & MEMCG_DATA_OBJCGS),
445 							slab_page(slab));
446 	VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_KMEM, slab_page(slab));
447 
448 	return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
449 }
450 
451 int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
452 				 gfp_t gfp, bool new_slab);
453 void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
454 		     enum node_stat_item idx, int nr);
455 
456 static inline void memcg_free_slab_cgroups(struct slab *slab)
457 {
458 	kfree(slab_objcgs(slab));
459 	slab->memcg_data = 0;
460 }
461 
462 static inline size_t obj_full_size(struct kmem_cache *s)
463 {
464 	/*
465 	 * For each accounted object there is an extra space which is used
466 	 * to store obj_cgroup membership. Charge it too.
467 	 */
468 	return s->size + sizeof(struct obj_cgroup *);
469 }
470 
471 /*
472  * Returns false if the allocation should fail.
473  */
474 static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
475 					     struct obj_cgroup **objcgp,
476 					     size_t objects, gfp_t flags)
477 {
478 	struct obj_cgroup *objcg;
479 
480 	if (!memcg_kmem_enabled())
481 		return true;
482 
483 	if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT))
484 		return true;
485 
486 	objcg = get_obj_cgroup_from_current();
487 	if (!objcg)
488 		return true;
489 
490 	if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) {
491 		obj_cgroup_put(objcg);
492 		return false;
493 	}
494 
495 	*objcgp = objcg;
496 	return true;
497 }
498 
499 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
500 					      struct obj_cgroup *objcg,
501 					      gfp_t flags, size_t size,
502 					      void **p)
503 {
504 	struct slab *slab;
505 	unsigned long off;
506 	size_t i;
507 
508 	if (!memcg_kmem_enabled() || !objcg)
509 		return;
510 
511 	for (i = 0; i < size; i++) {
512 		if (likely(p[i])) {
513 			slab = virt_to_slab(p[i]);
514 
515 			if (!slab_objcgs(slab) &&
516 			    memcg_alloc_slab_cgroups(slab, s, flags,
517 							 false)) {
518 				obj_cgroup_uncharge(objcg, obj_full_size(s));
519 				continue;
520 			}
521 
522 			off = obj_to_index(s, slab, p[i]);
523 			obj_cgroup_get(objcg);
524 			slab_objcgs(slab)[off] = objcg;
525 			mod_objcg_state(objcg, slab_pgdat(slab),
526 					cache_vmstat_idx(s), obj_full_size(s));
527 		} else {
528 			obj_cgroup_uncharge(objcg, obj_full_size(s));
529 		}
530 	}
531 	obj_cgroup_put(objcg);
532 }
533 
534 static inline void memcg_slab_free_hook(struct kmem_cache *s_orig,
535 					void **p, int objects)
536 {
537 	struct kmem_cache *s;
538 	struct obj_cgroup **objcgs;
539 	struct obj_cgroup *objcg;
540 	struct slab *slab;
541 	unsigned int off;
542 	int i;
543 
544 	if (!memcg_kmem_enabled())
545 		return;
546 
547 	for (i = 0; i < objects; i++) {
548 		if (unlikely(!p[i]))
549 			continue;
550 
551 		slab = virt_to_slab(p[i]);
552 		/* we could be given a kmalloc_large() object, skip those */
553 		if (!slab)
554 			continue;
555 
556 		objcgs = slab_objcgs(slab);
557 		if (!objcgs)
558 			continue;
559 
560 		if (!s_orig)
561 			s = slab->slab_cache;
562 		else
563 			s = s_orig;
564 
565 		off = obj_to_index(s, slab, p[i]);
566 		objcg = objcgs[off];
567 		if (!objcg)
568 			continue;
569 
570 		objcgs[off] = NULL;
571 		obj_cgroup_uncharge(objcg, obj_full_size(s));
572 		mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s),
573 				-obj_full_size(s));
574 		obj_cgroup_put(objcg);
575 	}
576 }
577 
578 #else /* CONFIG_MEMCG_KMEM */
579 static inline struct obj_cgroup **slab_objcgs(struct slab *slab)
580 {
581 	return NULL;
582 }
583 
584 static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr)
585 {
586 	return NULL;
587 }
588 
589 static inline int memcg_alloc_slab_cgroups(struct slab *slab,
590 					       struct kmem_cache *s, gfp_t gfp,
591 					       bool new_slab)
592 {
593 	return 0;
594 }
595 
596 static inline void memcg_free_slab_cgroups(struct slab *slab)
597 {
598 }
599 
600 static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
601 					     struct obj_cgroup **objcgp,
602 					     size_t objects, gfp_t flags)
603 {
604 	return true;
605 }
606 
607 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
608 					      struct obj_cgroup *objcg,
609 					      gfp_t flags, size_t size,
610 					      void **p)
611 {
612 }
613 
614 static inline void memcg_slab_free_hook(struct kmem_cache *s,
615 					void **p, int objects)
616 {
617 }
618 #endif /* CONFIG_MEMCG_KMEM */
619 
620 #ifndef CONFIG_SLOB
621 static inline struct kmem_cache *virt_to_cache(const void *obj)
622 {
623 	struct slab *slab;
624 
625 	slab = virt_to_slab(obj);
626 	if (WARN_ONCE(!slab, "%s: Object is not a Slab page!\n",
627 					__func__))
628 		return NULL;
629 	return slab->slab_cache;
630 }
631 
632 static __always_inline void account_slab(struct slab *slab, int order,
633 					 struct kmem_cache *s, gfp_t gfp)
634 {
635 	if (memcg_kmem_enabled() && (s->flags & SLAB_ACCOUNT))
636 		memcg_alloc_slab_cgroups(slab, s, gfp, true);
637 
638 	mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
639 			    PAGE_SIZE << order);
640 }
641 
642 static __always_inline void unaccount_slab(struct slab *slab, int order,
643 					   struct kmem_cache *s)
644 {
645 	if (memcg_kmem_enabled())
646 		memcg_free_slab_cgroups(slab);
647 
648 	mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
649 			    -(PAGE_SIZE << order));
650 }
651 
652 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
653 {
654 	struct kmem_cache *cachep;
655 
656 	if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
657 	    !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
658 		return s;
659 
660 	cachep = virt_to_cache(x);
661 	if (WARN(cachep && cachep != s,
662 		  "%s: Wrong slab cache. %s but object is from %s\n",
663 		  __func__, s->name, cachep->name))
664 		print_tracking(cachep, x);
665 	return cachep;
666 }
667 #endif /* CONFIG_SLOB */
668 
669 static inline size_t slab_ksize(const struct kmem_cache *s)
670 {
671 #ifndef CONFIG_SLUB
672 	return s->object_size;
673 
674 #else /* CONFIG_SLUB */
675 # ifdef CONFIG_SLUB_DEBUG
676 	/*
677 	 * Debugging requires use of the padding between object
678 	 * and whatever may come after it.
679 	 */
680 	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
681 		return s->object_size;
682 # endif
683 	if (s->flags & SLAB_KASAN)
684 		return s->object_size;
685 	/*
686 	 * If we have the need to store the freelist pointer
687 	 * back there or track user information then we can
688 	 * only use the space before that information.
689 	 */
690 	if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER))
691 		return s->inuse;
692 	/*
693 	 * Else we can use all the padding etc for the allocation
694 	 */
695 	return s->size;
696 #endif
697 }
698 
699 static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
700 						     struct obj_cgroup **objcgp,
701 						     size_t size, gfp_t flags)
702 {
703 	flags &= gfp_allowed_mask;
704 
705 	might_alloc(flags);
706 
707 	if (should_failslab(s, flags))
708 		return NULL;
709 
710 	if (!memcg_slab_pre_alloc_hook(s, objcgp, size, flags))
711 		return NULL;
712 
713 	return s;
714 }
715 
716 static inline void slab_post_alloc_hook(struct kmem_cache *s,
717 					struct obj_cgroup *objcg, gfp_t flags,
718 					size_t size, void **p, bool init)
719 {
720 	size_t i;
721 
722 	flags &= gfp_allowed_mask;
723 
724 	/*
725 	 * As memory initialization might be integrated into KASAN,
726 	 * kasan_slab_alloc and initialization memset must be
727 	 * kept together to avoid discrepancies in behavior.
728 	 *
729 	 * As p[i] might get tagged, memset and kmemleak hook come after KASAN.
730 	 */
731 	for (i = 0; i < size; i++) {
732 		p[i] = kasan_slab_alloc(s, p[i], flags, init);
733 		if (p[i] && init && !kasan_has_integrated_init())
734 			memset(p[i], 0, s->object_size);
735 		kmemleak_alloc_recursive(p[i], s->object_size, 1,
736 					 s->flags, flags);
737 	}
738 
739 	memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
740 }
741 
742 #ifndef CONFIG_SLOB
743 /*
744  * The slab lists for all objects.
745  */
746 struct kmem_cache_node {
747 	spinlock_t list_lock;
748 
749 #ifdef CONFIG_SLAB
750 	struct list_head slabs_partial;	/* partial list first, better asm code */
751 	struct list_head slabs_full;
752 	struct list_head slabs_free;
753 	unsigned long total_slabs;	/* length of all slab lists */
754 	unsigned long free_slabs;	/* length of free slab list only */
755 	unsigned long free_objects;
756 	unsigned int free_limit;
757 	unsigned int colour_next;	/* Per-node cache coloring */
758 	struct array_cache *shared;	/* shared per node */
759 	struct alien_cache **alien;	/* on other nodes */
760 	unsigned long next_reap;	/* updated without locking */
761 	int free_touched;		/* updated without locking */
762 #endif
763 
764 #ifdef CONFIG_SLUB
765 	unsigned long nr_partial;
766 	struct list_head partial;
767 #ifdef CONFIG_SLUB_DEBUG
768 	atomic_long_t nr_slabs;
769 	atomic_long_t total_objects;
770 	struct list_head full;
771 #endif
772 #endif
773 
774 };
775 
776 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
777 {
778 	return s->node[node];
779 }
780 
781 /*
782  * Iterator over all nodes. The body will be executed for each node that has
783  * a kmem_cache_node structure allocated (which is true for all online nodes)
784  */
785 #define for_each_kmem_cache_node(__s, __node, __n) \
786 	for (__node = 0; __node < nr_node_ids; __node++) \
787 		 if ((__n = get_node(__s, __node)))
788 
789 #endif
790 
791 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
792 void dump_unreclaimable_slab(void);
793 #else
794 static inline void dump_unreclaimable_slab(void)
795 {
796 }
797 #endif
798 
799 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
800 
801 #ifdef CONFIG_SLAB_FREELIST_RANDOM
802 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
803 			gfp_t gfp);
804 void cache_random_seq_destroy(struct kmem_cache *cachep);
805 #else
806 static inline int cache_random_seq_create(struct kmem_cache *cachep,
807 					unsigned int count, gfp_t gfp)
808 {
809 	return 0;
810 }
811 static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
812 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
813 
814 static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
815 {
816 	if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON,
817 				&init_on_alloc)) {
818 		if (c->ctor)
819 			return false;
820 		if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
821 			return flags & __GFP_ZERO;
822 		return true;
823 	}
824 	return flags & __GFP_ZERO;
825 }
826 
827 static inline bool slab_want_init_on_free(struct kmem_cache *c)
828 {
829 	if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON,
830 				&init_on_free))
831 		return !(c->ctor ||
832 			 (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
833 	return false;
834 }
835 
836 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
837 void debugfs_slab_release(struct kmem_cache *);
838 #else
839 static inline void debugfs_slab_release(struct kmem_cache *s) { }
840 #endif
841 
842 #ifdef CONFIG_PRINTK
843 #define KS_ADDRS_COUNT 16
844 struct kmem_obj_info {
845 	void *kp_ptr;
846 	struct slab *kp_slab;
847 	void *kp_objp;
848 	unsigned long kp_data_offset;
849 	struct kmem_cache *kp_slab_cache;
850 	void *kp_ret;
851 	void *kp_stack[KS_ADDRS_COUNT];
852 	void *kp_free_stack[KS_ADDRS_COUNT];
853 };
854 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab);
855 #endif
856 
857 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
858 void __check_heap_object(const void *ptr, unsigned long n,
859 			 const struct slab *slab, bool to_user);
860 #else
861 static inline
862 void __check_heap_object(const void *ptr, unsigned long n,
863 			 const struct slab *slab, bool to_user)
864 {
865 }
866 #endif
867 
868 #endif /* MM_SLAB_H */
869