xref: /openbmc/linux/mm/slub.c (revision ff4a7481c3898ffc3cc271d6aca431d190c37247)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * SLUB: A slab allocator that limits cache line use instead of queuing
4  * objects in per cpu and per node lists.
5  *
6  * The allocator synchronizes using per slab locks or atomic operatios
7  * and only uses a centralized lock to manage a pool of partial slabs.
8  *
9  * (C) 2007 SGI, Christoph Lameter
10  * (C) 2011 Linux Foundation, Christoph Lameter
11  */
12 
13 #include <linux/mm.h>
14 #include <linux/swap.h> /* struct reclaim_state */
15 #include <linux/module.h>
16 #include <linux/bit_spinlock.h>
17 #include <linux/interrupt.h>
18 #include <linux/bitops.h>
19 #include <linux/slab.h>
20 #include "slab.h"
21 #include <linux/proc_fs.h>
22 #include <linux/seq_file.h>
23 #include <linux/kasan.h>
24 #include <linux/cpu.h>
25 #include <linux/cpuset.h>
26 #include <linux/mempolicy.h>
27 #include <linux/ctype.h>
28 #include <linux/debugobjects.h>
29 #include <linux/kallsyms.h>
30 #include <linux/memory.h>
31 #include <linux/math64.h>
32 #include <linux/fault-inject.h>
33 #include <linux/stacktrace.h>
34 #include <linux/prefetch.h>
35 #include <linux/memcontrol.h>
36 #include <linux/random.h>
37 
38 #include <trace/events/kmem.h>
39 
40 #include "internal.h"
41 
42 /*
43  * Lock order:
44  *   1. slab_mutex (Global Mutex)
45  *   2. node->list_lock
46  *   3. slab_lock(page) (Only on some arches and for debugging)
47  *
48  *   slab_mutex
49  *
50  *   The role of the slab_mutex is to protect the list of all the slabs
51  *   and to synchronize major metadata changes to slab cache structures.
52  *
53  *   The slab_lock is only used for debugging and on arches that do not
54  *   have the ability to do a cmpxchg_double. It only protects:
55  *	A. page->freelist	-> List of object free in a page
56  *	B. page->inuse		-> Number of objects in use
57  *	C. page->objects	-> Number of objects in page
58  *	D. page->frozen		-> frozen state
59  *
60  *   If a slab is frozen then it is exempt from list management. It is not
61  *   on any list. The processor that froze the slab is the one who can
62  *   perform list operations on the page. Other processors may put objects
63  *   onto the freelist but the processor that froze the slab is the only
64  *   one that can retrieve the objects from the page's freelist.
65  *
66  *   The list_lock protects the partial and full list on each node and
67  *   the partial slab counter. If taken then no new slabs may be added or
68  *   removed from the lists nor make the number of partial slabs be modified.
69  *   (Note that the total number of slabs is an atomic value that may be
70  *   modified without taking the list lock).
71  *
72  *   The list_lock is a centralized lock and thus we avoid taking it as
73  *   much as possible. As long as SLUB does not have to handle partial
74  *   slabs, operations can continue without any centralized lock. F.e.
75  *   allocating a long series of objects that fill up slabs does not require
76  *   the list lock.
77  *   Interrupts are disabled during allocation and deallocation in order to
78  *   make the slab allocator safe to use in the context of an irq. In addition
79  *   interrupts are disabled to ensure that the processor does not change
80  *   while handling per_cpu slabs, due to kernel preemption.
81  *
82  * SLUB assigns one slab for allocation to each processor.
83  * Allocations only occur from these slabs called cpu slabs.
84  *
85  * Slabs with free elements are kept on a partial list and during regular
86  * operations no list for full slabs is used. If an object in a full slab is
87  * freed then the slab will show up again on the partial lists.
88  * We track full slabs for debugging purposes though because otherwise we
89  * cannot scan all objects.
90  *
91  * Slabs are freed when they become empty. Teardown and setup is
92  * minimal so we rely on the page allocators per cpu caches for
93  * fast frees and allocs.
94  *
95  * Overloading of page flags that are otherwise used for LRU management.
96  *
97  * PageActive 		The slab is frozen and exempt from list processing.
98  * 			This means that the slab is dedicated to a purpose
99  * 			such as satisfying allocations for a specific
100  * 			processor. Objects may be freed in the slab while
101  * 			it is frozen but slab_free will then skip the usual
102  * 			list operations. It is up to the processor holding
103  * 			the slab to integrate the slab into the slab lists
104  * 			when the slab is no longer needed.
105  *
106  * 			One use of this flag is to mark slabs that are
107  * 			used for allocations. Then such a slab becomes a cpu
108  * 			slab. The cpu slab may be equipped with an additional
109  * 			freelist that allows lockless access to
110  * 			free objects in addition to the regular freelist
111  * 			that requires the slab lock.
112  *
113  * PageError		Slab requires special handling due to debug
114  * 			options set. This moves	slab handling out of
115  * 			the fast path and disables lockless freelists.
116  */
117 
118 static inline int kmem_cache_debug(struct kmem_cache *s)
119 {
120 #ifdef CONFIG_SLUB_DEBUG
121 	return unlikely(s->flags & SLAB_DEBUG_FLAGS);
122 #else
123 	return 0;
124 #endif
125 }
126 
127 void *fixup_red_left(struct kmem_cache *s, void *p)
128 {
129 	if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE)
130 		p += s->red_left_pad;
131 
132 	return p;
133 }
134 
135 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
136 {
137 #ifdef CONFIG_SLUB_CPU_PARTIAL
138 	return !kmem_cache_debug(s);
139 #else
140 	return false;
141 #endif
142 }
143 
144 /*
145  * Issues still to be resolved:
146  *
147  * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
148  *
149  * - Variable sizing of the per node arrays
150  */
151 
152 /* Enable to test recovery from slab corruption on boot */
153 #undef SLUB_RESILIENCY_TEST
154 
155 /* Enable to log cmpxchg failures */
156 #undef SLUB_DEBUG_CMPXCHG
157 
158 /*
159  * Mininum number of partial slabs. These will be left on the partial
160  * lists even if they are empty. kmem_cache_shrink may reclaim them.
161  */
162 #define MIN_PARTIAL 5
163 
164 /*
165  * Maximum number of desirable partial slabs.
166  * The existence of more partial slabs makes kmem_cache_shrink
167  * sort the partial list by the number of objects in use.
168  */
169 #define MAX_PARTIAL 10
170 
171 #define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
172 				SLAB_POISON | SLAB_STORE_USER)
173 
174 /*
175  * These debug flags cannot use CMPXCHG because there might be consistency
176  * issues when checking or reading debug information
177  */
178 #define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
179 				SLAB_TRACE)
180 
181 
182 /*
183  * Debugging flags that require metadata to be stored in the slab.  These get
184  * disabled when slub_debug=O is used and a cache's min order increases with
185  * metadata.
186  */
187 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
188 
189 #define OO_SHIFT	16
190 #define OO_MASK		((1 << OO_SHIFT) - 1)
191 #define MAX_OBJS_PER_PAGE	32767 /* since page.objects is u15 */
192 
193 /* Internal SLUB flags */
194 /* Poison object */
195 #define __OBJECT_POISON		((slab_flags_t __force)0x80000000U)
196 /* Use cmpxchg_double */
197 #define __CMPXCHG_DOUBLE	((slab_flags_t __force)0x40000000U)
198 
199 /*
200  * Tracking user of a slab.
201  */
202 #define TRACK_ADDRS_COUNT 16
203 struct track {
204 	unsigned long addr;	/* Called from address */
205 #ifdef CONFIG_STACKTRACE
206 	unsigned long addrs[TRACK_ADDRS_COUNT];	/* Called from address */
207 #endif
208 	int cpu;		/* Was running on cpu */
209 	int pid;		/* Pid context */
210 	unsigned long when;	/* When did the operation occur */
211 };
212 
213 enum track_item { TRACK_ALLOC, TRACK_FREE };
214 
215 #ifdef CONFIG_SYSFS
216 static int sysfs_slab_add(struct kmem_cache *);
217 static int sysfs_slab_alias(struct kmem_cache *, const char *);
218 static void memcg_propagate_slab_attrs(struct kmem_cache *s);
219 static void sysfs_slab_remove(struct kmem_cache *s);
220 #else
221 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
222 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
223 							{ return 0; }
224 static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
225 static inline void sysfs_slab_remove(struct kmem_cache *s) { }
226 #endif
227 
228 static inline void stat(const struct kmem_cache *s, enum stat_item si)
229 {
230 #ifdef CONFIG_SLUB_STATS
231 	/*
232 	 * The rmw is racy on a preemptible kernel but this is acceptable, so
233 	 * avoid this_cpu_add()'s irq-disable overhead.
234 	 */
235 	raw_cpu_inc(s->cpu_slab->stat[si]);
236 #endif
237 }
238 
239 /********************************************************************
240  * 			Core slab cache functions
241  *******************************************************************/
242 
243 /*
244  * Returns freelist pointer (ptr). With hardening, this is obfuscated
245  * with an XOR of the address where the pointer is held and a per-cache
246  * random number.
247  */
248 static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr,
249 				 unsigned long ptr_addr)
250 {
251 #ifdef CONFIG_SLAB_FREELIST_HARDENED
252 	return (void *)((unsigned long)ptr ^ s->random ^ ptr_addr);
253 #else
254 	return ptr;
255 #endif
256 }
257 
258 /* Returns the freelist pointer recorded at location ptr_addr. */
259 static inline void *freelist_dereference(const struct kmem_cache *s,
260 					 void *ptr_addr)
261 {
262 	return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr),
263 			    (unsigned long)ptr_addr);
264 }
265 
266 static inline void *get_freepointer(struct kmem_cache *s, void *object)
267 {
268 	return freelist_dereference(s, object + s->offset);
269 }
270 
271 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
272 {
273 	prefetch(object + s->offset);
274 }
275 
276 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
277 {
278 	unsigned long freepointer_addr;
279 	void *p;
280 
281 	if (!debug_pagealloc_enabled())
282 		return get_freepointer(s, object);
283 
284 	freepointer_addr = (unsigned long)object + s->offset;
285 	probe_kernel_read(&p, (void **)freepointer_addr, sizeof(p));
286 	return freelist_ptr(s, p, freepointer_addr);
287 }
288 
289 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
290 {
291 	unsigned long freeptr_addr = (unsigned long)object + s->offset;
292 
293 #ifdef CONFIG_SLAB_FREELIST_HARDENED
294 	BUG_ON(object == fp); /* naive detection of double free or corruption */
295 #endif
296 
297 	*(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr);
298 }
299 
300 /* Loop over all objects in a slab */
301 #define for_each_object(__p, __s, __addr, __objects) \
302 	for (__p = fixup_red_left(__s, __addr); \
303 		__p < (__addr) + (__objects) * (__s)->size; \
304 		__p += (__s)->size)
305 
306 #define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
307 	for (__p = fixup_red_left(__s, __addr), __idx = 1; \
308 		__idx <= __objects; \
309 		__p += (__s)->size, __idx++)
310 
311 /* Determine object index from a given position */
312 static inline unsigned int slab_index(void *p, struct kmem_cache *s, void *addr)
313 {
314 	return (p - addr) / s->size;
315 }
316 
317 static inline unsigned int order_objects(unsigned int order, unsigned int size)
318 {
319 	return ((unsigned int)PAGE_SIZE << order) / size;
320 }
321 
322 static inline struct kmem_cache_order_objects oo_make(unsigned int order,
323 		unsigned int size)
324 {
325 	struct kmem_cache_order_objects x = {
326 		(order << OO_SHIFT) + order_objects(order, size)
327 	};
328 
329 	return x;
330 }
331 
332 static inline unsigned int oo_order(struct kmem_cache_order_objects x)
333 {
334 	return x.x >> OO_SHIFT;
335 }
336 
337 static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
338 {
339 	return x.x & OO_MASK;
340 }
341 
342 /*
343  * Per slab locking using the pagelock
344  */
345 static __always_inline void slab_lock(struct page *page)
346 {
347 	VM_BUG_ON_PAGE(PageTail(page), page);
348 	bit_spin_lock(PG_locked, &page->flags);
349 }
350 
351 static __always_inline void slab_unlock(struct page *page)
352 {
353 	VM_BUG_ON_PAGE(PageTail(page), page);
354 	__bit_spin_unlock(PG_locked, &page->flags);
355 }
356 
357 /* Interrupts must be disabled (for the fallback code to work right) */
358 static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
359 		void *freelist_old, unsigned long counters_old,
360 		void *freelist_new, unsigned long counters_new,
361 		const char *n)
362 {
363 	VM_BUG_ON(!irqs_disabled());
364 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
365     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
366 	if (s->flags & __CMPXCHG_DOUBLE) {
367 		if (cmpxchg_double(&page->freelist, &page->counters,
368 				   freelist_old, counters_old,
369 				   freelist_new, counters_new))
370 			return true;
371 	} else
372 #endif
373 	{
374 		slab_lock(page);
375 		if (page->freelist == freelist_old &&
376 					page->counters == counters_old) {
377 			page->freelist = freelist_new;
378 			page->counters = counters_new;
379 			slab_unlock(page);
380 			return true;
381 		}
382 		slab_unlock(page);
383 	}
384 
385 	cpu_relax();
386 	stat(s, CMPXCHG_DOUBLE_FAIL);
387 
388 #ifdef SLUB_DEBUG_CMPXCHG
389 	pr_info("%s %s: cmpxchg double redo ", n, s->name);
390 #endif
391 
392 	return false;
393 }
394 
395 static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
396 		void *freelist_old, unsigned long counters_old,
397 		void *freelist_new, unsigned long counters_new,
398 		const char *n)
399 {
400 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
401     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
402 	if (s->flags & __CMPXCHG_DOUBLE) {
403 		if (cmpxchg_double(&page->freelist, &page->counters,
404 				   freelist_old, counters_old,
405 				   freelist_new, counters_new))
406 			return true;
407 	} else
408 #endif
409 	{
410 		unsigned long flags;
411 
412 		local_irq_save(flags);
413 		slab_lock(page);
414 		if (page->freelist == freelist_old &&
415 					page->counters == counters_old) {
416 			page->freelist = freelist_new;
417 			page->counters = counters_new;
418 			slab_unlock(page);
419 			local_irq_restore(flags);
420 			return true;
421 		}
422 		slab_unlock(page);
423 		local_irq_restore(flags);
424 	}
425 
426 	cpu_relax();
427 	stat(s, CMPXCHG_DOUBLE_FAIL);
428 
429 #ifdef SLUB_DEBUG_CMPXCHG
430 	pr_info("%s %s: cmpxchg double redo ", n, s->name);
431 #endif
432 
433 	return false;
434 }
435 
436 #ifdef CONFIG_SLUB_DEBUG
437 /*
438  * Determine a map of object in use on a page.
439  *
440  * Node listlock must be held to guarantee that the page does
441  * not vanish from under us.
442  */
443 static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
444 {
445 	void *p;
446 	void *addr = page_address(page);
447 
448 	for (p = page->freelist; p; p = get_freepointer(s, p))
449 		set_bit(slab_index(p, s, addr), map);
450 }
451 
452 static inline unsigned int size_from_object(struct kmem_cache *s)
453 {
454 	if (s->flags & SLAB_RED_ZONE)
455 		return s->size - s->red_left_pad;
456 
457 	return s->size;
458 }
459 
460 static inline void *restore_red_left(struct kmem_cache *s, void *p)
461 {
462 	if (s->flags & SLAB_RED_ZONE)
463 		p -= s->red_left_pad;
464 
465 	return p;
466 }
467 
468 /*
469  * Debug settings:
470  */
471 #if defined(CONFIG_SLUB_DEBUG_ON)
472 static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
473 #else
474 static slab_flags_t slub_debug;
475 #endif
476 
477 static char *slub_debug_slabs;
478 static int disable_higher_order_debug;
479 
480 /*
481  * slub is about to manipulate internal object metadata.  This memory lies
482  * outside the range of the allocated object, so accessing it would normally
483  * be reported by kasan as a bounds error.  metadata_access_enable() is used
484  * to tell kasan that these accesses are OK.
485  */
486 static inline void metadata_access_enable(void)
487 {
488 	kasan_disable_current();
489 }
490 
491 static inline void metadata_access_disable(void)
492 {
493 	kasan_enable_current();
494 }
495 
496 /*
497  * Object debugging
498  */
499 
500 /* Verify that a pointer has an address that is valid within a slab page */
501 static inline int check_valid_pointer(struct kmem_cache *s,
502 				struct page *page, void *object)
503 {
504 	void *base;
505 
506 	if (!object)
507 		return 1;
508 
509 	base = page_address(page);
510 	object = restore_red_left(s, object);
511 	if (object < base || object >= base + page->objects * s->size ||
512 		(object - base) % s->size) {
513 		return 0;
514 	}
515 
516 	return 1;
517 }
518 
519 static void print_section(char *level, char *text, u8 *addr,
520 			  unsigned int length)
521 {
522 	metadata_access_enable();
523 	print_hex_dump(level, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
524 			length, 1);
525 	metadata_access_disable();
526 }
527 
528 static struct track *get_track(struct kmem_cache *s, void *object,
529 	enum track_item alloc)
530 {
531 	struct track *p;
532 
533 	if (s->offset)
534 		p = object + s->offset + sizeof(void *);
535 	else
536 		p = object + s->inuse;
537 
538 	return p + alloc;
539 }
540 
541 static void set_track(struct kmem_cache *s, void *object,
542 			enum track_item alloc, unsigned long addr)
543 {
544 	struct track *p = get_track(s, object, alloc);
545 
546 	if (addr) {
547 #ifdef CONFIG_STACKTRACE
548 		struct stack_trace trace;
549 		int i;
550 
551 		trace.nr_entries = 0;
552 		trace.max_entries = TRACK_ADDRS_COUNT;
553 		trace.entries = p->addrs;
554 		trace.skip = 3;
555 		metadata_access_enable();
556 		save_stack_trace(&trace);
557 		metadata_access_disable();
558 
559 		/* See rant in lockdep.c */
560 		if (trace.nr_entries != 0 &&
561 		    trace.entries[trace.nr_entries - 1] == ULONG_MAX)
562 			trace.nr_entries--;
563 
564 		for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
565 			p->addrs[i] = 0;
566 #endif
567 		p->addr = addr;
568 		p->cpu = smp_processor_id();
569 		p->pid = current->pid;
570 		p->when = jiffies;
571 	} else
572 		memset(p, 0, sizeof(struct track));
573 }
574 
575 static void init_tracking(struct kmem_cache *s, void *object)
576 {
577 	if (!(s->flags & SLAB_STORE_USER))
578 		return;
579 
580 	set_track(s, object, TRACK_FREE, 0UL);
581 	set_track(s, object, TRACK_ALLOC, 0UL);
582 }
583 
584 static void print_track(const char *s, struct track *t, unsigned long pr_time)
585 {
586 	if (!t->addr)
587 		return;
588 
589 	pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
590 	       s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
591 #ifdef CONFIG_STACKTRACE
592 	{
593 		int i;
594 		for (i = 0; i < TRACK_ADDRS_COUNT; i++)
595 			if (t->addrs[i])
596 				pr_err("\t%pS\n", (void *)t->addrs[i]);
597 			else
598 				break;
599 	}
600 #endif
601 }
602 
603 static void print_tracking(struct kmem_cache *s, void *object)
604 {
605 	unsigned long pr_time = jiffies;
606 	if (!(s->flags & SLAB_STORE_USER))
607 		return;
608 
609 	print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
610 	print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
611 }
612 
613 static void print_page_info(struct page *page)
614 {
615 	pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
616 	       page, page->objects, page->inuse, page->freelist, page->flags);
617 
618 }
619 
620 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
621 {
622 	struct va_format vaf;
623 	va_list args;
624 
625 	va_start(args, fmt);
626 	vaf.fmt = fmt;
627 	vaf.va = &args;
628 	pr_err("=============================================================================\n");
629 	pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
630 	pr_err("-----------------------------------------------------------------------------\n\n");
631 
632 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
633 	va_end(args);
634 }
635 
636 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
637 {
638 	struct va_format vaf;
639 	va_list args;
640 
641 	va_start(args, fmt);
642 	vaf.fmt = fmt;
643 	vaf.va = &args;
644 	pr_err("FIX %s: %pV\n", s->name, &vaf);
645 	va_end(args);
646 }
647 
648 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
649 {
650 	unsigned int off;	/* Offset of last byte */
651 	u8 *addr = page_address(page);
652 
653 	print_tracking(s, p);
654 
655 	print_page_info(page);
656 
657 	pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
658 	       p, p - addr, get_freepointer(s, p));
659 
660 	if (s->flags & SLAB_RED_ZONE)
661 		print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
662 			      s->red_left_pad);
663 	else if (p > addr + 16)
664 		print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
665 
666 	print_section(KERN_ERR, "Object ", p,
667 		      min_t(unsigned int, s->object_size, PAGE_SIZE));
668 	if (s->flags & SLAB_RED_ZONE)
669 		print_section(KERN_ERR, "Redzone ", p + s->object_size,
670 			s->inuse - s->object_size);
671 
672 	if (s->offset)
673 		off = s->offset + sizeof(void *);
674 	else
675 		off = s->inuse;
676 
677 	if (s->flags & SLAB_STORE_USER)
678 		off += 2 * sizeof(struct track);
679 
680 	off += kasan_metadata_size(s);
681 
682 	if (off != size_from_object(s))
683 		/* Beginning of the filler is the free pointer */
684 		print_section(KERN_ERR, "Padding ", p + off,
685 			      size_from_object(s) - off);
686 
687 	dump_stack();
688 }
689 
690 void object_err(struct kmem_cache *s, struct page *page,
691 			u8 *object, char *reason)
692 {
693 	slab_bug(s, "%s", reason);
694 	print_trailer(s, page, object);
695 }
696 
697 static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page,
698 			const char *fmt, ...)
699 {
700 	va_list args;
701 	char buf[100];
702 
703 	va_start(args, fmt);
704 	vsnprintf(buf, sizeof(buf), fmt, args);
705 	va_end(args);
706 	slab_bug(s, "%s", buf);
707 	print_page_info(page);
708 	dump_stack();
709 }
710 
711 static void init_object(struct kmem_cache *s, void *object, u8 val)
712 {
713 	u8 *p = object;
714 
715 	if (s->flags & SLAB_RED_ZONE)
716 		memset(p - s->red_left_pad, val, s->red_left_pad);
717 
718 	if (s->flags & __OBJECT_POISON) {
719 		memset(p, POISON_FREE, s->object_size - 1);
720 		p[s->object_size - 1] = POISON_END;
721 	}
722 
723 	if (s->flags & SLAB_RED_ZONE)
724 		memset(p + s->object_size, val, s->inuse - s->object_size);
725 }
726 
727 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
728 						void *from, void *to)
729 {
730 	slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
731 	memset(from, data, to - from);
732 }
733 
734 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
735 			u8 *object, char *what,
736 			u8 *start, unsigned int value, unsigned int bytes)
737 {
738 	u8 *fault;
739 	u8 *end;
740 
741 	metadata_access_enable();
742 	fault = memchr_inv(start, value, bytes);
743 	metadata_access_disable();
744 	if (!fault)
745 		return 1;
746 
747 	end = start + bytes;
748 	while (end > fault && end[-1] == value)
749 		end--;
750 
751 	slab_bug(s, "%s overwritten", what);
752 	pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
753 					fault, end - 1, fault[0], value);
754 	print_trailer(s, page, object);
755 
756 	restore_bytes(s, what, value, fault, end);
757 	return 0;
758 }
759 
760 /*
761  * Object layout:
762  *
763  * object address
764  * 	Bytes of the object to be managed.
765  * 	If the freepointer may overlay the object then the free
766  * 	pointer is the first word of the object.
767  *
768  * 	Poisoning uses 0x6b (POISON_FREE) and the last byte is
769  * 	0xa5 (POISON_END)
770  *
771  * object + s->object_size
772  * 	Padding to reach word boundary. This is also used for Redzoning.
773  * 	Padding is extended by another word if Redzoning is enabled and
774  * 	object_size == inuse.
775  *
776  * 	We fill with 0xbb (RED_INACTIVE) for inactive objects and with
777  * 	0xcc (RED_ACTIVE) for objects in use.
778  *
779  * object + s->inuse
780  * 	Meta data starts here.
781  *
782  * 	A. Free pointer (if we cannot overwrite object on free)
783  * 	B. Tracking data for SLAB_STORE_USER
784  * 	C. Padding to reach required alignment boundary or at mininum
785  * 		one word if debugging is on to be able to detect writes
786  * 		before the word boundary.
787  *
788  *	Padding is done using 0x5a (POISON_INUSE)
789  *
790  * object + s->size
791  * 	Nothing is used beyond s->size.
792  *
793  * If slabcaches are merged then the object_size and inuse boundaries are mostly
794  * ignored. And therefore no slab options that rely on these boundaries
795  * may be used with merged slabcaches.
796  */
797 
798 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
799 {
800 	unsigned long off = s->inuse;	/* The end of info */
801 
802 	if (s->offset)
803 		/* Freepointer is placed after the object. */
804 		off += sizeof(void *);
805 
806 	if (s->flags & SLAB_STORE_USER)
807 		/* We also have user information there */
808 		off += 2 * sizeof(struct track);
809 
810 	off += kasan_metadata_size(s);
811 
812 	if (size_from_object(s) == off)
813 		return 1;
814 
815 	return check_bytes_and_report(s, page, p, "Object padding",
816 			p + off, POISON_INUSE, size_from_object(s) - off);
817 }
818 
819 /* Check the pad bytes at the end of a slab page */
820 static int slab_pad_check(struct kmem_cache *s, struct page *page)
821 {
822 	u8 *start;
823 	u8 *fault;
824 	u8 *end;
825 	u8 *pad;
826 	int length;
827 	int remainder;
828 
829 	if (!(s->flags & SLAB_POISON))
830 		return 1;
831 
832 	start = page_address(page);
833 	length = PAGE_SIZE << compound_order(page);
834 	end = start + length;
835 	remainder = length % s->size;
836 	if (!remainder)
837 		return 1;
838 
839 	pad = end - remainder;
840 	metadata_access_enable();
841 	fault = memchr_inv(pad, POISON_INUSE, remainder);
842 	metadata_access_disable();
843 	if (!fault)
844 		return 1;
845 	while (end > fault && end[-1] == POISON_INUSE)
846 		end--;
847 
848 	slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
849 	print_section(KERN_ERR, "Padding ", pad, remainder);
850 
851 	restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
852 	return 0;
853 }
854 
855 static int check_object(struct kmem_cache *s, struct page *page,
856 					void *object, u8 val)
857 {
858 	u8 *p = object;
859 	u8 *endobject = object + s->object_size;
860 
861 	if (s->flags & SLAB_RED_ZONE) {
862 		if (!check_bytes_and_report(s, page, object, "Redzone",
863 			object - s->red_left_pad, val, s->red_left_pad))
864 			return 0;
865 
866 		if (!check_bytes_and_report(s, page, object, "Redzone",
867 			endobject, val, s->inuse - s->object_size))
868 			return 0;
869 	} else {
870 		if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
871 			check_bytes_and_report(s, page, p, "Alignment padding",
872 				endobject, POISON_INUSE,
873 				s->inuse - s->object_size);
874 		}
875 	}
876 
877 	if (s->flags & SLAB_POISON) {
878 		if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
879 			(!check_bytes_and_report(s, page, p, "Poison", p,
880 					POISON_FREE, s->object_size - 1) ||
881 			 !check_bytes_and_report(s, page, p, "Poison",
882 				p + s->object_size - 1, POISON_END, 1)))
883 			return 0;
884 		/*
885 		 * check_pad_bytes cleans up on its own.
886 		 */
887 		check_pad_bytes(s, page, p);
888 	}
889 
890 	if (!s->offset && val == SLUB_RED_ACTIVE)
891 		/*
892 		 * Object and freepointer overlap. Cannot check
893 		 * freepointer while object is allocated.
894 		 */
895 		return 1;
896 
897 	/* Check free pointer validity */
898 	if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
899 		object_err(s, page, p, "Freepointer corrupt");
900 		/*
901 		 * No choice but to zap it and thus lose the remainder
902 		 * of the free objects in this slab. May cause
903 		 * another error because the object count is now wrong.
904 		 */
905 		set_freepointer(s, p, NULL);
906 		return 0;
907 	}
908 	return 1;
909 }
910 
911 static int check_slab(struct kmem_cache *s, struct page *page)
912 {
913 	int maxobj;
914 
915 	VM_BUG_ON(!irqs_disabled());
916 
917 	if (!PageSlab(page)) {
918 		slab_err(s, page, "Not a valid slab page");
919 		return 0;
920 	}
921 
922 	maxobj = order_objects(compound_order(page), s->size);
923 	if (page->objects > maxobj) {
924 		slab_err(s, page, "objects %u > max %u",
925 			page->objects, maxobj);
926 		return 0;
927 	}
928 	if (page->inuse > page->objects) {
929 		slab_err(s, page, "inuse %u > max %u",
930 			page->inuse, page->objects);
931 		return 0;
932 	}
933 	/* Slab_pad_check fixes things up after itself */
934 	slab_pad_check(s, page);
935 	return 1;
936 }
937 
938 /*
939  * Determine if a certain object on a page is on the freelist. Must hold the
940  * slab lock to guarantee that the chains are in a consistent state.
941  */
942 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
943 {
944 	int nr = 0;
945 	void *fp;
946 	void *object = NULL;
947 	int max_objects;
948 
949 	fp = page->freelist;
950 	while (fp && nr <= page->objects) {
951 		if (fp == search)
952 			return 1;
953 		if (!check_valid_pointer(s, page, fp)) {
954 			if (object) {
955 				object_err(s, page, object,
956 					"Freechain corrupt");
957 				set_freepointer(s, object, NULL);
958 			} else {
959 				slab_err(s, page, "Freepointer corrupt");
960 				page->freelist = NULL;
961 				page->inuse = page->objects;
962 				slab_fix(s, "Freelist cleared");
963 				return 0;
964 			}
965 			break;
966 		}
967 		object = fp;
968 		fp = get_freepointer(s, object);
969 		nr++;
970 	}
971 
972 	max_objects = order_objects(compound_order(page), s->size);
973 	if (max_objects > MAX_OBJS_PER_PAGE)
974 		max_objects = MAX_OBJS_PER_PAGE;
975 
976 	if (page->objects != max_objects) {
977 		slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
978 			 page->objects, max_objects);
979 		page->objects = max_objects;
980 		slab_fix(s, "Number of objects adjusted.");
981 	}
982 	if (page->inuse != page->objects - nr) {
983 		slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
984 			 page->inuse, page->objects - nr);
985 		page->inuse = page->objects - nr;
986 		slab_fix(s, "Object count adjusted.");
987 	}
988 	return search == NULL;
989 }
990 
991 static void trace(struct kmem_cache *s, struct page *page, void *object,
992 								int alloc)
993 {
994 	if (s->flags & SLAB_TRACE) {
995 		pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
996 			s->name,
997 			alloc ? "alloc" : "free",
998 			object, page->inuse,
999 			page->freelist);
1000 
1001 		if (!alloc)
1002 			print_section(KERN_INFO, "Object ", (void *)object,
1003 					s->object_size);
1004 
1005 		dump_stack();
1006 	}
1007 }
1008 
1009 /*
1010  * Tracking of fully allocated slabs for debugging purposes.
1011  */
1012 static void add_full(struct kmem_cache *s,
1013 	struct kmem_cache_node *n, struct page *page)
1014 {
1015 	if (!(s->flags & SLAB_STORE_USER))
1016 		return;
1017 
1018 	lockdep_assert_held(&n->list_lock);
1019 	list_add(&page->lru, &n->full);
1020 }
1021 
1022 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
1023 {
1024 	if (!(s->flags & SLAB_STORE_USER))
1025 		return;
1026 
1027 	lockdep_assert_held(&n->list_lock);
1028 	list_del(&page->lru);
1029 }
1030 
1031 /* Tracking of the number of slabs for debugging purposes */
1032 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1033 {
1034 	struct kmem_cache_node *n = get_node(s, node);
1035 
1036 	return atomic_long_read(&n->nr_slabs);
1037 }
1038 
1039 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1040 {
1041 	return atomic_long_read(&n->nr_slabs);
1042 }
1043 
1044 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1045 {
1046 	struct kmem_cache_node *n = get_node(s, node);
1047 
1048 	/*
1049 	 * May be called early in order to allocate a slab for the
1050 	 * kmem_cache_node structure. Solve the chicken-egg
1051 	 * dilemma by deferring the increment of the count during
1052 	 * bootstrap (see early_kmem_cache_node_alloc).
1053 	 */
1054 	if (likely(n)) {
1055 		atomic_long_inc(&n->nr_slabs);
1056 		atomic_long_add(objects, &n->total_objects);
1057 	}
1058 }
1059 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1060 {
1061 	struct kmem_cache_node *n = get_node(s, node);
1062 
1063 	atomic_long_dec(&n->nr_slabs);
1064 	atomic_long_sub(objects, &n->total_objects);
1065 }
1066 
1067 /* Object debug checks for alloc/free paths */
1068 static void setup_object_debug(struct kmem_cache *s, struct page *page,
1069 								void *object)
1070 {
1071 	if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1072 		return;
1073 
1074 	init_object(s, object, SLUB_RED_INACTIVE);
1075 	init_tracking(s, object);
1076 }
1077 
1078 static inline int alloc_consistency_checks(struct kmem_cache *s,
1079 					struct page *page,
1080 					void *object, unsigned long addr)
1081 {
1082 	if (!check_slab(s, page))
1083 		return 0;
1084 
1085 	if (!check_valid_pointer(s, page, object)) {
1086 		object_err(s, page, object, "Freelist Pointer check fails");
1087 		return 0;
1088 	}
1089 
1090 	if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1091 		return 0;
1092 
1093 	return 1;
1094 }
1095 
1096 static noinline int alloc_debug_processing(struct kmem_cache *s,
1097 					struct page *page,
1098 					void *object, unsigned long addr)
1099 {
1100 	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1101 		if (!alloc_consistency_checks(s, page, object, addr))
1102 			goto bad;
1103 	}
1104 
1105 	/* Success perform special debug activities for allocs */
1106 	if (s->flags & SLAB_STORE_USER)
1107 		set_track(s, object, TRACK_ALLOC, addr);
1108 	trace(s, page, object, 1);
1109 	init_object(s, object, SLUB_RED_ACTIVE);
1110 	return 1;
1111 
1112 bad:
1113 	if (PageSlab(page)) {
1114 		/*
1115 		 * If this is a slab page then lets do the best we can
1116 		 * to avoid issues in the future. Marking all objects
1117 		 * as used avoids touching the remaining objects.
1118 		 */
1119 		slab_fix(s, "Marking all objects used");
1120 		page->inuse = page->objects;
1121 		page->freelist = NULL;
1122 	}
1123 	return 0;
1124 }
1125 
1126 static inline int free_consistency_checks(struct kmem_cache *s,
1127 		struct page *page, void *object, unsigned long addr)
1128 {
1129 	if (!check_valid_pointer(s, page, object)) {
1130 		slab_err(s, page, "Invalid object pointer 0x%p", object);
1131 		return 0;
1132 	}
1133 
1134 	if (on_freelist(s, page, object)) {
1135 		object_err(s, page, object, "Object already free");
1136 		return 0;
1137 	}
1138 
1139 	if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1140 		return 0;
1141 
1142 	if (unlikely(s != page->slab_cache)) {
1143 		if (!PageSlab(page)) {
1144 			slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
1145 				 object);
1146 		} else if (!page->slab_cache) {
1147 			pr_err("SLUB <none>: no slab for object 0x%p.\n",
1148 			       object);
1149 			dump_stack();
1150 		} else
1151 			object_err(s, page, object,
1152 					"page slab pointer corrupt.");
1153 		return 0;
1154 	}
1155 	return 1;
1156 }
1157 
1158 /* Supports checking bulk free of a constructed freelist */
1159 static noinline int free_debug_processing(
1160 	struct kmem_cache *s, struct page *page,
1161 	void *head, void *tail, int bulk_cnt,
1162 	unsigned long addr)
1163 {
1164 	struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1165 	void *object = head;
1166 	int cnt = 0;
1167 	unsigned long uninitialized_var(flags);
1168 	int ret = 0;
1169 
1170 	spin_lock_irqsave(&n->list_lock, flags);
1171 	slab_lock(page);
1172 
1173 	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1174 		if (!check_slab(s, page))
1175 			goto out;
1176 	}
1177 
1178 next_object:
1179 	cnt++;
1180 
1181 	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1182 		if (!free_consistency_checks(s, page, object, addr))
1183 			goto out;
1184 	}
1185 
1186 	if (s->flags & SLAB_STORE_USER)
1187 		set_track(s, object, TRACK_FREE, addr);
1188 	trace(s, page, object, 0);
1189 	/* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1190 	init_object(s, object, SLUB_RED_INACTIVE);
1191 
1192 	/* Reached end of constructed freelist yet? */
1193 	if (object != tail) {
1194 		object = get_freepointer(s, object);
1195 		goto next_object;
1196 	}
1197 	ret = 1;
1198 
1199 out:
1200 	if (cnt != bulk_cnt)
1201 		slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
1202 			 bulk_cnt, cnt);
1203 
1204 	slab_unlock(page);
1205 	spin_unlock_irqrestore(&n->list_lock, flags);
1206 	if (!ret)
1207 		slab_fix(s, "Object at 0x%p not freed", object);
1208 	return ret;
1209 }
1210 
1211 static int __init setup_slub_debug(char *str)
1212 {
1213 	slub_debug = DEBUG_DEFAULT_FLAGS;
1214 	if (*str++ != '=' || !*str)
1215 		/*
1216 		 * No options specified. Switch on full debugging.
1217 		 */
1218 		goto out;
1219 
1220 	if (*str == ',')
1221 		/*
1222 		 * No options but restriction on slabs. This means full
1223 		 * debugging for slabs matching a pattern.
1224 		 */
1225 		goto check_slabs;
1226 
1227 	slub_debug = 0;
1228 	if (*str == '-')
1229 		/*
1230 		 * Switch off all debugging measures.
1231 		 */
1232 		goto out;
1233 
1234 	/*
1235 	 * Determine which debug features should be switched on
1236 	 */
1237 	for (; *str && *str != ','; str++) {
1238 		switch (tolower(*str)) {
1239 		case 'f':
1240 			slub_debug |= SLAB_CONSISTENCY_CHECKS;
1241 			break;
1242 		case 'z':
1243 			slub_debug |= SLAB_RED_ZONE;
1244 			break;
1245 		case 'p':
1246 			slub_debug |= SLAB_POISON;
1247 			break;
1248 		case 'u':
1249 			slub_debug |= SLAB_STORE_USER;
1250 			break;
1251 		case 't':
1252 			slub_debug |= SLAB_TRACE;
1253 			break;
1254 		case 'a':
1255 			slub_debug |= SLAB_FAILSLAB;
1256 			break;
1257 		case 'o':
1258 			/*
1259 			 * Avoid enabling debugging on caches if its minimum
1260 			 * order would increase as a result.
1261 			 */
1262 			disable_higher_order_debug = 1;
1263 			break;
1264 		default:
1265 			pr_err("slub_debug option '%c' unknown. skipped\n",
1266 			       *str);
1267 		}
1268 	}
1269 
1270 check_slabs:
1271 	if (*str == ',')
1272 		slub_debug_slabs = str + 1;
1273 out:
1274 	return 1;
1275 }
1276 
1277 __setup("slub_debug", setup_slub_debug);
1278 
1279 /*
1280  * kmem_cache_flags - apply debugging options to the cache
1281  * @object_size:	the size of an object without meta data
1282  * @flags:		flags to set
1283  * @name:		name of the cache
1284  * @ctor:		constructor function
1285  *
1286  * Debug option(s) are applied to @flags. In addition to the debug
1287  * option(s), if a slab name (or multiple) is specified i.e.
1288  * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
1289  * then only the select slabs will receive the debug option(s).
1290  */
1291 slab_flags_t kmem_cache_flags(unsigned int object_size,
1292 	slab_flags_t flags, const char *name,
1293 	void (*ctor)(void *))
1294 {
1295 	char *iter;
1296 	size_t len;
1297 
1298 	/* If slub_debug = 0, it folds into the if conditional. */
1299 	if (!slub_debug_slabs)
1300 		return flags | slub_debug;
1301 
1302 	len = strlen(name);
1303 	iter = slub_debug_slabs;
1304 	while (*iter) {
1305 		char *end, *glob;
1306 		size_t cmplen;
1307 
1308 		end = strchr(iter, ',');
1309 		if (!end)
1310 			end = iter + strlen(iter);
1311 
1312 		glob = strnchr(iter, end - iter, '*');
1313 		if (glob)
1314 			cmplen = glob - iter;
1315 		else
1316 			cmplen = max_t(size_t, len, (end - iter));
1317 
1318 		if (!strncmp(name, iter, cmplen)) {
1319 			flags |= slub_debug;
1320 			break;
1321 		}
1322 
1323 		if (!*end)
1324 			break;
1325 		iter = end + 1;
1326 	}
1327 
1328 	return flags;
1329 }
1330 #else /* !CONFIG_SLUB_DEBUG */
1331 static inline void setup_object_debug(struct kmem_cache *s,
1332 			struct page *page, void *object) {}
1333 
1334 static inline int alloc_debug_processing(struct kmem_cache *s,
1335 	struct page *page, void *object, unsigned long addr) { return 0; }
1336 
1337 static inline int free_debug_processing(
1338 	struct kmem_cache *s, struct page *page,
1339 	void *head, void *tail, int bulk_cnt,
1340 	unsigned long addr) { return 0; }
1341 
1342 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1343 			{ return 1; }
1344 static inline int check_object(struct kmem_cache *s, struct page *page,
1345 			void *object, u8 val) { return 1; }
1346 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1347 					struct page *page) {}
1348 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1349 					struct page *page) {}
1350 slab_flags_t kmem_cache_flags(unsigned int object_size,
1351 	slab_flags_t flags, const char *name,
1352 	void (*ctor)(void *))
1353 {
1354 	return flags;
1355 }
1356 #define slub_debug 0
1357 
1358 #define disable_higher_order_debug 0
1359 
1360 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1361 							{ return 0; }
1362 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1363 							{ return 0; }
1364 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1365 							int objects) {}
1366 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1367 							int objects) {}
1368 
1369 #endif /* CONFIG_SLUB_DEBUG */
1370 
1371 /*
1372  * Hooks for other subsystems that check memory allocations. In a typical
1373  * production configuration these hooks all should produce no code at all.
1374  */
1375 static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1376 {
1377 	kmemleak_alloc(ptr, size, 1, flags);
1378 	return kasan_kmalloc_large(ptr, size, flags);
1379 }
1380 
1381 static __always_inline void kfree_hook(void *x)
1382 {
1383 	kmemleak_free(x);
1384 	kasan_kfree_large(x, _RET_IP_);
1385 }
1386 
1387 static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x)
1388 {
1389 	kmemleak_free_recursive(x, s->flags);
1390 
1391 	/*
1392 	 * Trouble is that we may no longer disable interrupts in the fast path
1393 	 * So in order to make the debug calls that expect irqs to be
1394 	 * disabled we need to disable interrupts temporarily.
1395 	 */
1396 #ifdef CONFIG_LOCKDEP
1397 	{
1398 		unsigned long flags;
1399 
1400 		local_irq_save(flags);
1401 		debug_check_no_locks_freed(x, s->object_size);
1402 		local_irq_restore(flags);
1403 	}
1404 #endif
1405 	if (!(s->flags & SLAB_DEBUG_OBJECTS))
1406 		debug_check_no_obj_freed(x, s->object_size);
1407 
1408 	/* KASAN might put x into memory quarantine, delaying its reuse */
1409 	return kasan_slab_free(s, x, _RET_IP_);
1410 }
1411 
1412 static inline bool slab_free_freelist_hook(struct kmem_cache *s,
1413 					   void **head, void **tail)
1414 {
1415 /*
1416  * Compiler cannot detect this function can be removed if slab_free_hook()
1417  * evaluates to nothing.  Thus, catch all relevant config debug options here.
1418  */
1419 #if defined(CONFIG_LOCKDEP)	||		\
1420 	defined(CONFIG_DEBUG_KMEMLEAK) ||	\
1421 	defined(CONFIG_DEBUG_OBJECTS_FREE) ||	\
1422 	defined(CONFIG_KASAN)
1423 
1424 	void *object;
1425 	void *next = *head;
1426 	void *old_tail = *tail ? *tail : *head;
1427 
1428 	/* Head and tail of the reconstructed freelist */
1429 	*head = NULL;
1430 	*tail = NULL;
1431 
1432 	do {
1433 		object = next;
1434 		next = get_freepointer(s, object);
1435 		/* If object's reuse doesn't have to be delayed */
1436 		if (!slab_free_hook(s, object)) {
1437 			/* Move object to the new freelist */
1438 			set_freepointer(s, object, *head);
1439 			*head = object;
1440 			if (!*tail)
1441 				*tail = object;
1442 		}
1443 	} while (object != old_tail);
1444 
1445 	if (*head == *tail)
1446 		*tail = NULL;
1447 
1448 	return *head != NULL;
1449 #else
1450 	return true;
1451 #endif
1452 }
1453 
1454 static void *setup_object(struct kmem_cache *s, struct page *page,
1455 				void *object)
1456 {
1457 	setup_object_debug(s, page, object);
1458 	object = kasan_init_slab_obj(s, object);
1459 	if (unlikely(s->ctor)) {
1460 		kasan_unpoison_object_data(s, object);
1461 		s->ctor(object);
1462 		kasan_poison_object_data(s, object);
1463 	}
1464 	return object;
1465 }
1466 
1467 /*
1468  * Slab allocation and freeing
1469  */
1470 static inline struct page *alloc_slab_page(struct kmem_cache *s,
1471 		gfp_t flags, int node, struct kmem_cache_order_objects oo)
1472 {
1473 	struct page *page;
1474 	unsigned int order = oo_order(oo);
1475 
1476 	if (node == NUMA_NO_NODE)
1477 		page = alloc_pages(flags, order);
1478 	else
1479 		page = __alloc_pages_node(node, flags, order);
1480 
1481 	if (page && memcg_charge_slab(page, flags, order, s)) {
1482 		__free_pages(page, order);
1483 		page = NULL;
1484 	}
1485 
1486 	return page;
1487 }
1488 
1489 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1490 /* Pre-initialize the random sequence cache */
1491 static int init_cache_random_seq(struct kmem_cache *s)
1492 {
1493 	unsigned int count = oo_objects(s->oo);
1494 	int err;
1495 
1496 	/* Bailout if already initialised */
1497 	if (s->random_seq)
1498 		return 0;
1499 
1500 	err = cache_random_seq_create(s, count, GFP_KERNEL);
1501 	if (err) {
1502 		pr_err("SLUB: Unable to initialize free list for %s\n",
1503 			s->name);
1504 		return err;
1505 	}
1506 
1507 	/* Transform to an offset on the set of pages */
1508 	if (s->random_seq) {
1509 		unsigned int i;
1510 
1511 		for (i = 0; i < count; i++)
1512 			s->random_seq[i] *= s->size;
1513 	}
1514 	return 0;
1515 }
1516 
1517 /* Initialize each random sequence freelist per cache */
1518 static void __init init_freelist_randomization(void)
1519 {
1520 	struct kmem_cache *s;
1521 
1522 	mutex_lock(&slab_mutex);
1523 
1524 	list_for_each_entry(s, &slab_caches, list)
1525 		init_cache_random_seq(s);
1526 
1527 	mutex_unlock(&slab_mutex);
1528 }
1529 
1530 /* Get the next entry on the pre-computed freelist randomized */
1531 static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
1532 				unsigned long *pos, void *start,
1533 				unsigned long page_limit,
1534 				unsigned long freelist_count)
1535 {
1536 	unsigned int idx;
1537 
1538 	/*
1539 	 * If the target page allocation failed, the number of objects on the
1540 	 * page might be smaller than the usual size defined by the cache.
1541 	 */
1542 	do {
1543 		idx = s->random_seq[*pos];
1544 		*pos += 1;
1545 		if (*pos >= freelist_count)
1546 			*pos = 0;
1547 	} while (unlikely(idx >= page_limit));
1548 
1549 	return (char *)start + idx;
1550 }
1551 
1552 /* Shuffle the single linked freelist based on a random pre-computed sequence */
1553 static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1554 {
1555 	void *start;
1556 	void *cur;
1557 	void *next;
1558 	unsigned long idx, pos, page_limit, freelist_count;
1559 
1560 	if (page->objects < 2 || !s->random_seq)
1561 		return false;
1562 
1563 	freelist_count = oo_objects(s->oo);
1564 	pos = get_random_int() % freelist_count;
1565 
1566 	page_limit = page->objects * s->size;
1567 	start = fixup_red_left(s, page_address(page));
1568 
1569 	/* First entry is used as the base of the freelist */
1570 	cur = next_freelist_entry(s, page, &pos, start, page_limit,
1571 				freelist_count);
1572 	cur = setup_object(s, page, cur);
1573 	page->freelist = cur;
1574 
1575 	for (idx = 1; idx < page->objects; idx++) {
1576 		next = next_freelist_entry(s, page, &pos, start, page_limit,
1577 			freelist_count);
1578 		next = setup_object(s, page, next);
1579 		set_freepointer(s, cur, next);
1580 		cur = next;
1581 	}
1582 	set_freepointer(s, cur, NULL);
1583 
1584 	return true;
1585 }
1586 #else
1587 static inline int init_cache_random_seq(struct kmem_cache *s)
1588 {
1589 	return 0;
1590 }
1591 static inline void init_freelist_randomization(void) { }
1592 static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1593 {
1594 	return false;
1595 }
1596 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1597 
1598 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1599 {
1600 	struct page *page;
1601 	struct kmem_cache_order_objects oo = s->oo;
1602 	gfp_t alloc_gfp;
1603 	void *start, *p, *next;
1604 	int idx, order;
1605 	bool shuffle;
1606 
1607 	flags &= gfp_allowed_mask;
1608 
1609 	if (gfpflags_allow_blocking(flags))
1610 		local_irq_enable();
1611 
1612 	flags |= s->allocflags;
1613 
1614 	/*
1615 	 * Let the initial higher-order allocation fail under memory pressure
1616 	 * so we fall-back to the minimum order allocation.
1617 	 */
1618 	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1619 	if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1620 		alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
1621 
1622 	page = alloc_slab_page(s, alloc_gfp, node, oo);
1623 	if (unlikely(!page)) {
1624 		oo = s->min;
1625 		alloc_gfp = flags;
1626 		/*
1627 		 * Allocation may have failed due to fragmentation.
1628 		 * Try a lower order alloc if possible
1629 		 */
1630 		page = alloc_slab_page(s, alloc_gfp, node, oo);
1631 		if (unlikely(!page))
1632 			goto out;
1633 		stat(s, ORDER_FALLBACK);
1634 	}
1635 
1636 	page->objects = oo_objects(oo);
1637 
1638 	order = compound_order(page);
1639 	page->slab_cache = s;
1640 	__SetPageSlab(page);
1641 	if (page_is_pfmemalloc(page))
1642 		SetPageSlabPfmemalloc(page);
1643 
1644 	start = page_address(page);
1645 
1646 	if (unlikely(s->flags & SLAB_POISON))
1647 		memset(start, POISON_INUSE, PAGE_SIZE << order);
1648 
1649 	kasan_poison_slab(page);
1650 
1651 	shuffle = shuffle_freelist(s, page);
1652 
1653 	if (!shuffle) {
1654 		for_each_object_idx(p, idx, s, start, page->objects) {
1655 			if (likely(idx < page->objects)) {
1656 				next = p + s->size;
1657 				next = setup_object(s, page, next);
1658 				set_freepointer(s, p, next);
1659 			} else
1660 				set_freepointer(s, p, NULL);
1661 		}
1662 		start = fixup_red_left(s, start);
1663 		start = setup_object(s, page, start);
1664 		page->freelist = start;
1665 	}
1666 
1667 	page->inuse = page->objects;
1668 	page->frozen = 1;
1669 
1670 out:
1671 	if (gfpflags_allow_blocking(flags))
1672 		local_irq_disable();
1673 	if (!page)
1674 		return NULL;
1675 
1676 	mod_lruvec_page_state(page,
1677 		(s->flags & SLAB_RECLAIM_ACCOUNT) ?
1678 		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1679 		1 << oo_order(oo));
1680 
1681 	inc_slabs_node(s, page_to_nid(page), page->objects);
1682 
1683 	return page;
1684 }
1685 
1686 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1687 {
1688 	if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
1689 		gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
1690 		flags &= ~GFP_SLAB_BUG_MASK;
1691 		pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
1692 				invalid_mask, &invalid_mask, flags, &flags);
1693 		dump_stack();
1694 	}
1695 
1696 	return allocate_slab(s,
1697 		flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1698 }
1699 
1700 static void __free_slab(struct kmem_cache *s, struct page *page)
1701 {
1702 	int order = compound_order(page);
1703 	int pages = 1 << order;
1704 
1705 	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1706 		void *p;
1707 
1708 		slab_pad_check(s, page);
1709 		for_each_object(p, s, page_address(page),
1710 						page->objects)
1711 			check_object(s, page, p, SLUB_RED_INACTIVE);
1712 	}
1713 
1714 	mod_lruvec_page_state(page,
1715 		(s->flags & SLAB_RECLAIM_ACCOUNT) ?
1716 		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1717 		-pages);
1718 
1719 	__ClearPageSlabPfmemalloc(page);
1720 	__ClearPageSlab(page);
1721 
1722 	page->mapping = NULL;
1723 	if (current->reclaim_state)
1724 		current->reclaim_state->reclaimed_slab += pages;
1725 	memcg_uncharge_slab(page, order, s);
1726 	__free_pages(page, order);
1727 }
1728 
1729 static void rcu_free_slab(struct rcu_head *h)
1730 {
1731 	struct page *page = container_of(h, struct page, rcu_head);
1732 
1733 	__free_slab(page->slab_cache, page);
1734 }
1735 
1736 static void free_slab(struct kmem_cache *s, struct page *page)
1737 {
1738 	if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
1739 		call_rcu(&page->rcu_head, rcu_free_slab);
1740 	} else
1741 		__free_slab(s, page);
1742 }
1743 
1744 static void discard_slab(struct kmem_cache *s, struct page *page)
1745 {
1746 	dec_slabs_node(s, page_to_nid(page), page->objects);
1747 	free_slab(s, page);
1748 }
1749 
1750 /*
1751  * Management of partially allocated slabs.
1752  */
1753 static inline void
1754 __add_partial(struct kmem_cache_node *n, struct page *page, int tail)
1755 {
1756 	n->nr_partial++;
1757 	if (tail == DEACTIVATE_TO_TAIL)
1758 		list_add_tail(&page->lru, &n->partial);
1759 	else
1760 		list_add(&page->lru, &n->partial);
1761 }
1762 
1763 static inline void add_partial(struct kmem_cache_node *n,
1764 				struct page *page, int tail)
1765 {
1766 	lockdep_assert_held(&n->list_lock);
1767 	__add_partial(n, page, tail);
1768 }
1769 
1770 static inline void remove_partial(struct kmem_cache_node *n,
1771 					struct page *page)
1772 {
1773 	lockdep_assert_held(&n->list_lock);
1774 	list_del(&page->lru);
1775 	n->nr_partial--;
1776 }
1777 
1778 /*
1779  * Remove slab from the partial list, freeze it and
1780  * return the pointer to the freelist.
1781  *
1782  * Returns a list of objects or NULL if it fails.
1783  */
1784 static inline void *acquire_slab(struct kmem_cache *s,
1785 		struct kmem_cache_node *n, struct page *page,
1786 		int mode, int *objects)
1787 {
1788 	void *freelist;
1789 	unsigned long counters;
1790 	struct page new;
1791 
1792 	lockdep_assert_held(&n->list_lock);
1793 
1794 	/*
1795 	 * Zap the freelist and set the frozen bit.
1796 	 * The old freelist is the list of objects for the
1797 	 * per cpu allocation list.
1798 	 */
1799 	freelist = page->freelist;
1800 	counters = page->counters;
1801 	new.counters = counters;
1802 	*objects = new.objects - new.inuse;
1803 	if (mode) {
1804 		new.inuse = page->objects;
1805 		new.freelist = NULL;
1806 	} else {
1807 		new.freelist = freelist;
1808 	}
1809 
1810 	VM_BUG_ON(new.frozen);
1811 	new.frozen = 1;
1812 
1813 	if (!__cmpxchg_double_slab(s, page,
1814 			freelist, counters,
1815 			new.freelist, new.counters,
1816 			"acquire_slab"))
1817 		return NULL;
1818 
1819 	remove_partial(n, page);
1820 	WARN_ON(!freelist);
1821 	return freelist;
1822 }
1823 
1824 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1825 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1826 
1827 /*
1828  * Try to allocate a partial slab from a specific node.
1829  */
1830 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1831 				struct kmem_cache_cpu *c, gfp_t flags)
1832 {
1833 	struct page *page, *page2;
1834 	void *object = NULL;
1835 	unsigned int available = 0;
1836 	int objects;
1837 
1838 	/*
1839 	 * Racy check. If we mistakenly see no partial slabs then we
1840 	 * just allocate an empty slab. If we mistakenly try to get a
1841 	 * partial slab and there is none available then get_partials()
1842 	 * will return NULL.
1843 	 */
1844 	if (!n || !n->nr_partial)
1845 		return NULL;
1846 
1847 	spin_lock(&n->list_lock);
1848 	list_for_each_entry_safe(page, page2, &n->partial, lru) {
1849 		void *t;
1850 
1851 		if (!pfmemalloc_match(page, flags))
1852 			continue;
1853 
1854 		t = acquire_slab(s, n, page, object == NULL, &objects);
1855 		if (!t)
1856 			break;
1857 
1858 		available += objects;
1859 		if (!object) {
1860 			c->page = page;
1861 			stat(s, ALLOC_FROM_PARTIAL);
1862 			object = t;
1863 		} else {
1864 			put_cpu_partial(s, page, 0);
1865 			stat(s, CPU_PARTIAL_NODE);
1866 		}
1867 		if (!kmem_cache_has_cpu_partial(s)
1868 			|| available > slub_cpu_partial(s) / 2)
1869 			break;
1870 
1871 	}
1872 	spin_unlock(&n->list_lock);
1873 	return object;
1874 }
1875 
1876 /*
1877  * Get a page from somewhere. Search in increasing NUMA distances.
1878  */
1879 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1880 		struct kmem_cache_cpu *c)
1881 {
1882 #ifdef CONFIG_NUMA
1883 	struct zonelist *zonelist;
1884 	struct zoneref *z;
1885 	struct zone *zone;
1886 	enum zone_type high_zoneidx = gfp_zone(flags);
1887 	void *object;
1888 	unsigned int cpuset_mems_cookie;
1889 
1890 	/*
1891 	 * The defrag ratio allows a configuration of the tradeoffs between
1892 	 * inter node defragmentation and node local allocations. A lower
1893 	 * defrag_ratio increases the tendency to do local allocations
1894 	 * instead of attempting to obtain partial slabs from other nodes.
1895 	 *
1896 	 * If the defrag_ratio is set to 0 then kmalloc() always
1897 	 * returns node local objects. If the ratio is higher then kmalloc()
1898 	 * may return off node objects because partial slabs are obtained
1899 	 * from other nodes and filled up.
1900 	 *
1901 	 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
1902 	 * (which makes defrag_ratio = 1000) then every (well almost)
1903 	 * allocation will first attempt to defrag slab caches on other nodes.
1904 	 * This means scanning over all nodes to look for partial slabs which
1905 	 * may be expensive if we do it every time we are trying to find a slab
1906 	 * with available objects.
1907 	 */
1908 	if (!s->remote_node_defrag_ratio ||
1909 			get_cycles() % 1024 > s->remote_node_defrag_ratio)
1910 		return NULL;
1911 
1912 	do {
1913 		cpuset_mems_cookie = read_mems_allowed_begin();
1914 		zonelist = node_zonelist(mempolicy_slab_node(), flags);
1915 		for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1916 			struct kmem_cache_node *n;
1917 
1918 			n = get_node(s, zone_to_nid(zone));
1919 
1920 			if (n && cpuset_zone_allowed(zone, flags) &&
1921 					n->nr_partial > s->min_partial) {
1922 				object = get_partial_node(s, n, c, flags);
1923 				if (object) {
1924 					/*
1925 					 * Don't check read_mems_allowed_retry()
1926 					 * here - if mems_allowed was updated in
1927 					 * parallel, that was a harmless race
1928 					 * between allocation and the cpuset
1929 					 * update
1930 					 */
1931 					return object;
1932 				}
1933 			}
1934 		}
1935 	} while (read_mems_allowed_retry(cpuset_mems_cookie));
1936 #endif
1937 	return NULL;
1938 }
1939 
1940 /*
1941  * Get a partial page, lock it and return it.
1942  */
1943 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1944 		struct kmem_cache_cpu *c)
1945 {
1946 	void *object;
1947 	int searchnode = node;
1948 
1949 	if (node == NUMA_NO_NODE)
1950 		searchnode = numa_mem_id();
1951 	else if (!node_present_pages(node))
1952 		searchnode = node_to_mem_node(node);
1953 
1954 	object = get_partial_node(s, get_node(s, searchnode), c, flags);
1955 	if (object || node != NUMA_NO_NODE)
1956 		return object;
1957 
1958 	return get_any_partial(s, flags, c);
1959 }
1960 
1961 #ifdef CONFIG_PREEMPT
1962 /*
1963  * Calculate the next globally unique transaction for disambiguiation
1964  * during cmpxchg. The transactions start with the cpu number and are then
1965  * incremented by CONFIG_NR_CPUS.
1966  */
1967 #define TID_STEP  roundup_pow_of_two(CONFIG_NR_CPUS)
1968 #else
1969 /*
1970  * No preemption supported therefore also no need to check for
1971  * different cpus.
1972  */
1973 #define TID_STEP 1
1974 #endif
1975 
1976 static inline unsigned long next_tid(unsigned long tid)
1977 {
1978 	return tid + TID_STEP;
1979 }
1980 
1981 static inline unsigned int tid_to_cpu(unsigned long tid)
1982 {
1983 	return tid % TID_STEP;
1984 }
1985 
1986 static inline unsigned long tid_to_event(unsigned long tid)
1987 {
1988 	return tid / TID_STEP;
1989 }
1990 
1991 static inline unsigned int init_tid(int cpu)
1992 {
1993 	return cpu;
1994 }
1995 
1996 static inline void note_cmpxchg_failure(const char *n,
1997 		const struct kmem_cache *s, unsigned long tid)
1998 {
1999 #ifdef SLUB_DEBUG_CMPXCHG
2000 	unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
2001 
2002 	pr_info("%s %s: cmpxchg redo ", n, s->name);
2003 
2004 #ifdef CONFIG_PREEMPT
2005 	if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
2006 		pr_warn("due to cpu change %d -> %d\n",
2007 			tid_to_cpu(tid), tid_to_cpu(actual_tid));
2008 	else
2009 #endif
2010 	if (tid_to_event(tid) != tid_to_event(actual_tid))
2011 		pr_warn("due to cpu running other code. Event %ld->%ld\n",
2012 			tid_to_event(tid), tid_to_event(actual_tid));
2013 	else
2014 		pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2015 			actual_tid, tid, next_tid(tid));
2016 #endif
2017 	stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2018 }
2019 
2020 static void init_kmem_cache_cpus(struct kmem_cache *s)
2021 {
2022 	int cpu;
2023 
2024 	for_each_possible_cpu(cpu)
2025 		per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
2026 }
2027 
2028 /*
2029  * Remove the cpu slab
2030  */
2031 static void deactivate_slab(struct kmem_cache *s, struct page *page,
2032 				void *freelist, struct kmem_cache_cpu *c)
2033 {
2034 	enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
2035 	struct kmem_cache_node *n = get_node(s, page_to_nid(page));
2036 	int lock = 0;
2037 	enum slab_modes l = M_NONE, m = M_NONE;
2038 	void *nextfree;
2039 	int tail = DEACTIVATE_TO_HEAD;
2040 	struct page new;
2041 	struct page old;
2042 
2043 	if (page->freelist) {
2044 		stat(s, DEACTIVATE_REMOTE_FREES);
2045 		tail = DEACTIVATE_TO_TAIL;
2046 	}
2047 
2048 	/*
2049 	 * Stage one: Free all available per cpu objects back
2050 	 * to the page freelist while it is still frozen. Leave the
2051 	 * last one.
2052 	 *
2053 	 * There is no need to take the list->lock because the page
2054 	 * is still frozen.
2055 	 */
2056 	while (freelist && (nextfree = get_freepointer(s, freelist))) {
2057 		void *prior;
2058 		unsigned long counters;
2059 
2060 		do {
2061 			prior = page->freelist;
2062 			counters = page->counters;
2063 			set_freepointer(s, freelist, prior);
2064 			new.counters = counters;
2065 			new.inuse--;
2066 			VM_BUG_ON(!new.frozen);
2067 
2068 		} while (!__cmpxchg_double_slab(s, page,
2069 			prior, counters,
2070 			freelist, new.counters,
2071 			"drain percpu freelist"));
2072 
2073 		freelist = nextfree;
2074 	}
2075 
2076 	/*
2077 	 * Stage two: Ensure that the page is unfrozen while the
2078 	 * list presence reflects the actual number of objects
2079 	 * during unfreeze.
2080 	 *
2081 	 * We setup the list membership and then perform a cmpxchg
2082 	 * with the count. If there is a mismatch then the page
2083 	 * is not unfrozen but the page is on the wrong list.
2084 	 *
2085 	 * Then we restart the process which may have to remove
2086 	 * the page from the list that we just put it on again
2087 	 * because the number of objects in the slab may have
2088 	 * changed.
2089 	 */
2090 redo:
2091 
2092 	old.freelist = page->freelist;
2093 	old.counters = page->counters;
2094 	VM_BUG_ON(!old.frozen);
2095 
2096 	/* Determine target state of the slab */
2097 	new.counters = old.counters;
2098 	if (freelist) {
2099 		new.inuse--;
2100 		set_freepointer(s, freelist, old.freelist);
2101 		new.freelist = freelist;
2102 	} else
2103 		new.freelist = old.freelist;
2104 
2105 	new.frozen = 0;
2106 
2107 	if (!new.inuse && n->nr_partial >= s->min_partial)
2108 		m = M_FREE;
2109 	else if (new.freelist) {
2110 		m = M_PARTIAL;
2111 		if (!lock) {
2112 			lock = 1;
2113 			/*
2114 			 * Taking the spinlock removes the possiblity
2115 			 * that acquire_slab() will see a slab page that
2116 			 * is frozen
2117 			 */
2118 			spin_lock(&n->list_lock);
2119 		}
2120 	} else {
2121 		m = M_FULL;
2122 		if (kmem_cache_debug(s) && !lock) {
2123 			lock = 1;
2124 			/*
2125 			 * This also ensures that the scanning of full
2126 			 * slabs from diagnostic functions will not see
2127 			 * any frozen slabs.
2128 			 */
2129 			spin_lock(&n->list_lock);
2130 		}
2131 	}
2132 
2133 	if (l != m) {
2134 
2135 		if (l == M_PARTIAL)
2136 
2137 			remove_partial(n, page);
2138 
2139 		else if (l == M_FULL)
2140 
2141 			remove_full(s, n, page);
2142 
2143 		if (m == M_PARTIAL) {
2144 
2145 			add_partial(n, page, tail);
2146 			stat(s, tail);
2147 
2148 		} else if (m == M_FULL) {
2149 
2150 			stat(s, DEACTIVATE_FULL);
2151 			add_full(s, n, page);
2152 
2153 		}
2154 	}
2155 
2156 	l = m;
2157 	if (!__cmpxchg_double_slab(s, page,
2158 				old.freelist, old.counters,
2159 				new.freelist, new.counters,
2160 				"unfreezing slab"))
2161 		goto redo;
2162 
2163 	if (lock)
2164 		spin_unlock(&n->list_lock);
2165 
2166 	if (m == M_FREE) {
2167 		stat(s, DEACTIVATE_EMPTY);
2168 		discard_slab(s, page);
2169 		stat(s, FREE_SLAB);
2170 	}
2171 
2172 	c->page = NULL;
2173 	c->freelist = NULL;
2174 }
2175 
2176 /*
2177  * Unfreeze all the cpu partial slabs.
2178  *
2179  * This function must be called with interrupts disabled
2180  * for the cpu using c (or some other guarantee must be there
2181  * to guarantee no concurrent accesses).
2182  */
2183 static void unfreeze_partials(struct kmem_cache *s,
2184 		struct kmem_cache_cpu *c)
2185 {
2186 #ifdef CONFIG_SLUB_CPU_PARTIAL
2187 	struct kmem_cache_node *n = NULL, *n2 = NULL;
2188 	struct page *page, *discard_page = NULL;
2189 
2190 	while ((page = c->partial)) {
2191 		struct page new;
2192 		struct page old;
2193 
2194 		c->partial = page->next;
2195 
2196 		n2 = get_node(s, page_to_nid(page));
2197 		if (n != n2) {
2198 			if (n)
2199 				spin_unlock(&n->list_lock);
2200 
2201 			n = n2;
2202 			spin_lock(&n->list_lock);
2203 		}
2204 
2205 		do {
2206 
2207 			old.freelist = page->freelist;
2208 			old.counters = page->counters;
2209 			VM_BUG_ON(!old.frozen);
2210 
2211 			new.counters = old.counters;
2212 			new.freelist = old.freelist;
2213 
2214 			new.frozen = 0;
2215 
2216 		} while (!__cmpxchg_double_slab(s, page,
2217 				old.freelist, old.counters,
2218 				new.freelist, new.counters,
2219 				"unfreezing slab"));
2220 
2221 		if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2222 			page->next = discard_page;
2223 			discard_page = page;
2224 		} else {
2225 			add_partial(n, page, DEACTIVATE_TO_TAIL);
2226 			stat(s, FREE_ADD_PARTIAL);
2227 		}
2228 	}
2229 
2230 	if (n)
2231 		spin_unlock(&n->list_lock);
2232 
2233 	while (discard_page) {
2234 		page = discard_page;
2235 		discard_page = discard_page->next;
2236 
2237 		stat(s, DEACTIVATE_EMPTY);
2238 		discard_slab(s, page);
2239 		stat(s, FREE_SLAB);
2240 	}
2241 #endif
2242 }
2243 
2244 /*
2245  * Put a page that was just frozen (in __slab_free) into a partial page
2246  * slot if available.
2247  *
2248  * If we did not find a slot then simply move all the partials to the
2249  * per node partial list.
2250  */
2251 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
2252 {
2253 #ifdef CONFIG_SLUB_CPU_PARTIAL
2254 	struct page *oldpage;
2255 	int pages;
2256 	int pobjects;
2257 
2258 	preempt_disable();
2259 	do {
2260 		pages = 0;
2261 		pobjects = 0;
2262 		oldpage = this_cpu_read(s->cpu_slab->partial);
2263 
2264 		if (oldpage) {
2265 			pobjects = oldpage->pobjects;
2266 			pages = oldpage->pages;
2267 			if (drain && pobjects > s->cpu_partial) {
2268 				unsigned long flags;
2269 				/*
2270 				 * partial array is full. Move the existing
2271 				 * set to the per node partial list.
2272 				 */
2273 				local_irq_save(flags);
2274 				unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2275 				local_irq_restore(flags);
2276 				oldpage = NULL;
2277 				pobjects = 0;
2278 				pages = 0;
2279 				stat(s, CPU_PARTIAL_DRAIN);
2280 			}
2281 		}
2282 
2283 		pages++;
2284 		pobjects += page->objects - page->inuse;
2285 
2286 		page->pages = pages;
2287 		page->pobjects = pobjects;
2288 		page->next = oldpage;
2289 
2290 	} while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2291 								!= oldpage);
2292 	if (unlikely(!s->cpu_partial)) {
2293 		unsigned long flags;
2294 
2295 		local_irq_save(flags);
2296 		unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2297 		local_irq_restore(flags);
2298 	}
2299 	preempt_enable();
2300 #endif
2301 }
2302 
2303 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2304 {
2305 	stat(s, CPUSLAB_FLUSH);
2306 	deactivate_slab(s, c->page, c->freelist, c);
2307 
2308 	c->tid = next_tid(c->tid);
2309 }
2310 
2311 /*
2312  * Flush cpu slab.
2313  *
2314  * Called from IPI handler with interrupts disabled.
2315  */
2316 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2317 {
2318 	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2319 
2320 	if (likely(c)) {
2321 		if (c->page)
2322 			flush_slab(s, c);
2323 
2324 		unfreeze_partials(s, c);
2325 	}
2326 }
2327 
2328 static void flush_cpu_slab(void *d)
2329 {
2330 	struct kmem_cache *s = d;
2331 
2332 	__flush_cpu_slab(s, smp_processor_id());
2333 }
2334 
2335 static bool has_cpu_slab(int cpu, void *info)
2336 {
2337 	struct kmem_cache *s = info;
2338 	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2339 
2340 	return c->page || slub_percpu_partial(c);
2341 }
2342 
2343 static void flush_all(struct kmem_cache *s)
2344 {
2345 	on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2346 }
2347 
2348 /*
2349  * Use the cpu notifier to insure that the cpu slabs are flushed when
2350  * necessary.
2351  */
2352 static int slub_cpu_dead(unsigned int cpu)
2353 {
2354 	struct kmem_cache *s;
2355 	unsigned long flags;
2356 
2357 	mutex_lock(&slab_mutex);
2358 	list_for_each_entry(s, &slab_caches, list) {
2359 		local_irq_save(flags);
2360 		__flush_cpu_slab(s, cpu);
2361 		local_irq_restore(flags);
2362 	}
2363 	mutex_unlock(&slab_mutex);
2364 	return 0;
2365 }
2366 
2367 /*
2368  * Check if the objects in a per cpu structure fit numa
2369  * locality expectations.
2370  */
2371 static inline int node_match(struct page *page, int node)
2372 {
2373 #ifdef CONFIG_NUMA
2374 	if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
2375 		return 0;
2376 #endif
2377 	return 1;
2378 }
2379 
2380 #ifdef CONFIG_SLUB_DEBUG
2381 static int count_free(struct page *page)
2382 {
2383 	return page->objects - page->inuse;
2384 }
2385 
2386 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2387 {
2388 	return atomic_long_read(&n->total_objects);
2389 }
2390 #endif /* CONFIG_SLUB_DEBUG */
2391 
2392 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2393 static unsigned long count_partial(struct kmem_cache_node *n,
2394 					int (*get_count)(struct page *))
2395 {
2396 	unsigned long flags;
2397 	unsigned long x = 0;
2398 	struct page *page;
2399 
2400 	spin_lock_irqsave(&n->list_lock, flags);
2401 	list_for_each_entry(page, &n->partial, lru)
2402 		x += get_count(page);
2403 	spin_unlock_irqrestore(&n->list_lock, flags);
2404 	return x;
2405 }
2406 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2407 
2408 static noinline void
2409 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2410 {
2411 #ifdef CONFIG_SLUB_DEBUG
2412 	static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2413 				      DEFAULT_RATELIMIT_BURST);
2414 	int node;
2415 	struct kmem_cache_node *n;
2416 
2417 	if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2418 		return;
2419 
2420 	pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2421 		nid, gfpflags, &gfpflags);
2422 	pr_warn("  cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
2423 		s->name, s->object_size, s->size, oo_order(s->oo),
2424 		oo_order(s->min));
2425 
2426 	if (oo_order(s->min) > get_order(s->object_size))
2427 		pr_warn("  %s debugging increased min order, use slub_debug=O to disable.\n",
2428 			s->name);
2429 
2430 	for_each_kmem_cache_node(s, node, n) {
2431 		unsigned long nr_slabs;
2432 		unsigned long nr_objs;
2433 		unsigned long nr_free;
2434 
2435 		nr_free  = count_partial(n, count_free);
2436 		nr_slabs = node_nr_slabs(n);
2437 		nr_objs  = node_nr_objs(n);
2438 
2439 		pr_warn("  node %d: slabs: %ld, objs: %ld, free: %ld\n",
2440 			node, nr_slabs, nr_objs, nr_free);
2441 	}
2442 #endif
2443 }
2444 
2445 static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2446 			int node, struct kmem_cache_cpu **pc)
2447 {
2448 	void *freelist;
2449 	struct kmem_cache_cpu *c = *pc;
2450 	struct page *page;
2451 
2452 	WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
2453 
2454 	freelist = get_partial(s, flags, node, c);
2455 
2456 	if (freelist)
2457 		return freelist;
2458 
2459 	page = new_slab(s, flags, node);
2460 	if (page) {
2461 		c = raw_cpu_ptr(s->cpu_slab);
2462 		if (c->page)
2463 			flush_slab(s, c);
2464 
2465 		/*
2466 		 * No other reference to the page yet so we can
2467 		 * muck around with it freely without cmpxchg
2468 		 */
2469 		freelist = page->freelist;
2470 		page->freelist = NULL;
2471 
2472 		stat(s, ALLOC_SLAB);
2473 		c->page = page;
2474 		*pc = c;
2475 	} else
2476 		freelist = NULL;
2477 
2478 	return freelist;
2479 }
2480 
2481 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2482 {
2483 	if (unlikely(PageSlabPfmemalloc(page)))
2484 		return gfp_pfmemalloc_allowed(gfpflags);
2485 
2486 	return true;
2487 }
2488 
2489 /*
2490  * Check the page->freelist of a page and either transfer the freelist to the
2491  * per cpu freelist or deactivate the page.
2492  *
2493  * The page is still frozen if the return value is not NULL.
2494  *
2495  * If this function returns NULL then the page has been unfrozen.
2496  *
2497  * This function must be called with interrupt disabled.
2498  */
2499 static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2500 {
2501 	struct page new;
2502 	unsigned long counters;
2503 	void *freelist;
2504 
2505 	do {
2506 		freelist = page->freelist;
2507 		counters = page->counters;
2508 
2509 		new.counters = counters;
2510 		VM_BUG_ON(!new.frozen);
2511 
2512 		new.inuse = page->objects;
2513 		new.frozen = freelist != NULL;
2514 
2515 	} while (!__cmpxchg_double_slab(s, page,
2516 		freelist, counters,
2517 		NULL, new.counters,
2518 		"get_freelist"));
2519 
2520 	return freelist;
2521 }
2522 
2523 /*
2524  * Slow path. The lockless freelist is empty or we need to perform
2525  * debugging duties.
2526  *
2527  * Processing is still very fast if new objects have been freed to the
2528  * regular freelist. In that case we simply take over the regular freelist
2529  * as the lockless freelist and zap the regular freelist.
2530  *
2531  * If that is not working then we fall back to the partial lists. We take the
2532  * first element of the freelist as the object to allocate now and move the
2533  * rest of the freelist to the lockless freelist.
2534  *
2535  * And if we were unable to get a new slab from the partial slab lists then
2536  * we need to allocate a new slab. This is the slowest path since it involves
2537  * a call to the page allocator and the setup of a new slab.
2538  *
2539  * Version of __slab_alloc to use when we know that interrupts are
2540  * already disabled (which is the case for bulk allocation).
2541  */
2542 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2543 			  unsigned long addr, struct kmem_cache_cpu *c)
2544 {
2545 	void *freelist;
2546 	struct page *page;
2547 
2548 	page = c->page;
2549 	if (!page)
2550 		goto new_slab;
2551 redo:
2552 
2553 	if (unlikely(!node_match(page, node))) {
2554 		int searchnode = node;
2555 
2556 		if (node != NUMA_NO_NODE && !node_present_pages(node))
2557 			searchnode = node_to_mem_node(node);
2558 
2559 		if (unlikely(!node_match(page, searchnode))) {
2560 			stat(s, ALLOC_NODE_MISMATCH);
2561 			deactivate_slab(s, page, c->freelist, c);
2562 			goto new_slab;
2563 		}
2564 	}
2565 
2566 	/*
2567 	 * By rights, we should be searching for a slab page that was
2568 	 * PFMEMALLOC but right now, we are losing the pfmemalloc
2569 	 * information when the page leaves the per-cpu allocator
2570 	 */
2571 	if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2572 		deactivate_slab(s, page, c->freelist, c);
2573 		goto new_slab;
2574 	}
2575 
2576 	/* must check again c->freelist in case of cpu migration or IRQ */
2577 	freelist = c->freelist;
2578 	if (freelist)
2579 		goto load_freelist;
2580 
2581 	freelist = get_freelist(s, page);
2582 
2583 	if (!freelist) {
2584 		c->page = NULL;
2585 		stat(s, DEACTIVATE_BYPASS);
2586 		goto new_slab;
2587 	}
2588 
2589 	stat(s, ALLOC_REFILL);
2590 
2591 load_freelist:
2592 	/*
2593 	 * freelist is pointing to the list of objects to be used.
2594 	 * page is pointing to the page from which the objects are obtained.
2595 	 * That page must be frozen for per cpu allocations to work.
2596 	 */
2597 	VM_BUG_ON(!c->page->frozen);
2598 	c->freelist = get_freepointer(s, freelist);
2599 	c->tid = next_tid(c->tid);
2600 	return freelist;
2601 
2602 new_slab:
2603 
2604 	if (slub_percpu_partial(c)) {
2605 		page = c->page = slub_percpu_partial(c);
2606 		slub_set_percpu_partial(c, page);
2607 		stat(s, CPU_PARTIAL_ALLOC);
2608 		goto redo;
2609 	}
2610 
2611 	freelist = new_slab_objects(s, gfpflags, node, &c);
2612 
2613 	if (unlikely(!freelist)) {
2614 		slab_out_of_memory(s, gfpflags, node);
2615 		return NULL;
2616 	}
2617 
2618 	page = c->page;
2619 	if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2620 		goto load_freelist;
2621 
2622 	/* Only entered in the debug case */
2623 	if (kmem_cache_debug(s) &&
2624 			!alloc_debug_processing(s, page, freelist, addr))
2625 		goto new_slab;	/* Slab failed checks. Next slab needed */
2626 
2627 	deactivate_slab(s, page, get_freepointer(s, freelist), c);
2628 	return freelist;
2629 }
2630 
2631 /*
2632  * Another one that disabled interrupt and compensates for possible
2633  * cpu changes by refetching the per cpu area pointer.
2634  */
2635 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2636 			  unsigned long addr, struct kmem_cache_cpu *c)
2637 {
2638 	void *p;
2639 	unsigned long flags;
2640 
2641 	local_irq_save(flags);
2642 #ifdef CONFIG_PREEMPT
2643 	/*
2644 	 * We may have been preempted and rescheduled on a different
2645 	 * cpu before disabling interrupts. Need to reload cpu area
2646 	 * pointer.
2647 	 */
2648 	c = this_cpu_ptr(s->cpu_slab);
2649 #endif
2650 
2651 	p = ___slab_alloc(s, gfpflags, node, addr, c);
2652 	local_irq_restore(flags);
2653 	return p;
2654 }
2655 
2656 /*
2657  * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2658  * have the fastpath folded into their functions. So no function call
2659  * overhead for requests that can be satisfied on the fastpath.
2660  *
2661  * The fastpath works by first checking if the lockless freelist can be used.
2662  * If not then __slab_alloc is called for slow processing.
2663  *
2664  * Otherwise we can simply pick the next object from the lockless free list.
2665  */
2666 static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2667 		gfp_t gfpflags, int node, unsigned long addr)
2668 {
2669 	void *object;
2670 	struct kmem_cache_cpu *c;
2671 	struct page *page;
2672 	unsigned long tid;
2673 
2674 	s = slab_pre_alloc_hook(s, gfpflags);
2675 	if (!s)
2676 		return NULL;
2677 redo:
2678 	/*
2679 	 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2680 	 * enabled. We may switch back and forth between cpus while
2681 	 * reading from one cpu area. That does not matter as long
2682 	 * as we end up on the original cpu again when doing the cmpxchg.
2683 	 *
2684 	 * We should guarantee that tid and kmem_cache are retrieved on
2685 	 * the same cpu. It could be different if CONFIG_PREEMPT so we need
2686 	 * to check if it is matched or not.
2687 	 */
2688 	do {
2689 		tid = this_cpu_read(s->cpu_slab->tid);
2690 		c = raw_cpu_ptr(s->cpu_slab);
2691 	} while (IS_ENABLED(CONFIG_PREEMPT) &&
2692 		 unlikely(tid != READ_ONCE(c->tid)));
2693 
2694 	/*
2695 	 * Irqless object alloc/free algorithm used here depends on sequence
2696 	 * of fetching cpu_slab's data. tid should be fetched before anything
2697 	 * on c to guarantee that object and page associated with previous tid
2698 	 * won't be used with current tid. If we fetch tid first, object and
2699 	 * page could be one associated with next tid and our alloc/free
2700 	 * request will be failed. In this case, we will retry. So, no problem.
2701 	 */
2702 	barrier();
2703 
2704 	/*
2705 	 * The transaction ids are globally unique per cpu and per operation on
2706 	 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2707 	 * occurs on the right processor and that there was no operation on the
2708 	 * linked list in between.
2709 	 */
2710 
2711 	object = c->freelist;
2712 	page = c->page;
2713 	if (unlikely(!object || !node_match(page, node))) {
2714 		object = __slab_alloc(s, gfpflags, node, addr, c);
2715 		stat(s, ALLOC_SLOWPATH);
2716 	} else {
2717 		void *next_object = get_freepointer_safe(s, object);
2718 
2719 		/*
2720 		 * The cmpxchg will only match if there was no additional
2721 		 * operation and if we are on the right processor.
2722 		 *
2723 		 * The cmpxchg does the following atomically (without lock
2724 		 * semantics!)
2725 		 * 1. Relocate first pointer to the current per cpu area.
2726 		 * 2. Verify that tid and freelist have not been changed
2727 		 * 3. If they were not changed replace tid and freelist
2728 		 *
2729 		 * Since this is without lock semantics the protection is only
2730 		 * against code executing on this cpu *not* from access by
2731 		 * other cpus.
2732 		 */
2733 		if (unlikely(!this_cpu_cmpxchg_double(
2734 				s->cpu_slab->freelist, s->cpu_slab->tid,
2735 				object, tid,
2736 				next_object, next_tid(tid)))) {
2737 
2738 			note_cmpxchg_failure("slab_alloc", s, tid);
2739 			goto redo;
2740 		}
2741 		prefetch_freepointer(s, next_object);
2742 		stat(s, ALLOC_FASTPATH);
2743 	}
2744 
2745 	if (unlikely(gfpflags & __GFP_ZERO) && object)
2746 		memset(object, 0, s->object_size);
2747 
2748 	slab_post_alloc_hook(s, gfpflags, 1, &object);
2749 
2750 	return object;
2751 }
2752 
2753 static __always_inline void *slab_alloc(struct kmem_cache *s,
2754 		gfp_t gfpflags, unsigned long addr)
2755 {
2756 	return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2757 }
2758 
2759 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2760 {
2761 	void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2762 
2763 	trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2764 				s->size, gfpflags);
2765 
2766 	return ret;
2767 }
2768 EXPORT_SYMBOL(kmem_cache_alloc);
2769 
2770 #ifdef CONFIG_TRACING
2771 void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2772 {
2773 	void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2774 	trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2775 	ret = kasan_kmalloc(s, ret, size, gfpflags);
2776 	return ret;
2777 }
2778 EXPORT_SYMBOL(kmem_cache_alloc_trace);
2779 #endif
2780 
2781 #ifdef CONFIG_NUMA
2782 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2783 {
2784 	void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2785 
2786 	trace_kmem_cache_alloc_node(_RET_IP_, ret,
2787 				    s->object_size, s->size, gfpflags, node);
2788 
2789 	return ret;
2790 }
2791 EXPORT_SYMBOL(kmem_cache_alloc_node);
2792 
2793 #ifdef CONFIG_TRACING
2794 void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2795 				    gfp_t gfpflags,
2796 				    int node, size_t size)
2797 {
2798 	void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2799 
2800 	trace_kmalloc_node(_RET_IP_, ret,
2801 			   size, s->size, gfpflags, node);
2802 
2803 	ret = kasan_kmalloc(s, ret, size, gfpflags);
2804 	return ret;
2805 }
2806 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2807 #endif
2808 #endif
2809 
2810 /*
2811  * Slow path handling. This may still be called frequently since objects
2812  * have a longer lifetime than the cpu slabs in most processing loads.
2813  *
2814  * So we still attempt to reduce cache line usage. Just take the slab
2815  * lock and free the item. If there is no additional partial page
2816  * handling required then we can return immediately.
2817  */
2818 static void __slab_free(struct kmem_cache *s, struct page *page,
2819 			void *head, void *tail, int cnt,
2820 			unsigned long addr)
2821 
2822 {
2823 	void *prior;
2824 	int was_frozen;
2825 	struct page new;
2826 	unsigned long counters;
2827 	struct kmem_cache_node *n = NULL;
2828 	unsigned long uninitialized_var(flags);
2829 
2830 	stat(s, FREE_SLOWPATH);
2831 
2832 	if (kmem_cache_debug(s) &&
2833 	    !free_debug_processing(s, page, head, tail, cnt, addr))
2834 		return;
2835 
2836 	do {
2837 		if (unlikely(n)) {
2838 			spin_unlock_irqrestore(&n->list_lock, flags);
2839 			n = NULL;
2840 		}
2841 		prior = page->freelist;
2842 		counters = page->counters;
2843 		set_freepointer(s, tail, prior);
2844 		new.counters = counters;
2845 		was_frozen = new.frozen;
2846 		new.inuse -= cnt;
2847 		if ((!new.inuse || !prior) && !was_frozen) {
2848 
2849 			if (kmem_cache_has_cpu_partial(s) && !prior) {
2850 
2851 				/*
2852 				 * Slab was on no list before and will be
2853 				 * partially empty
2854 				 * We can defer the list move and instead
2855 				 * freeze it.
2856 				 */
2857 				new.frozen = 1;
2858 
2859 			} else { /* Needs to be taken off a list */
2860 
2861 				n = get_node(s, page_to_nid(page));
2862 				/*
2863 				 * Speculatively acquire the list_lock.
2864 				 * If the cmpxchg does not succeed then we may
2865 				 * drop the list_lock without any processing.
2866 				 *
2867 				 * Otherwise the list_lock will synchronize with
2868 				 * other processors updating the list of slabs.
2869 				 */
2870 				spin_lock_irqsave(&n->list_lock, flags);
2871 
2872 			}
2873 		}
2874 
2875 	} while (!cmpxchg_double_slab(s, page,
2876 		prior, counters,
2877 		head, new.counters,
2878 		"__slab_free"));
2879 
2880 	if (likely(!n)) {
2881 
2882 		/*
2883 		 * If we just froze the page then put it onto the
2884 		 * per cpu partial list.
2885 		 */
2886 		if (new.frozen && !was_frozen) {
2887 			put_cpu_partial(s, page, 1);
2888 			stat(s, CPU_PARTIAL_FREE);
2889 		}
2890 		/*
2891 		 * The list lock was not taken therefore no list
2892 		 * activity can be necessary.
2893 		 */
2894 		if (was_frozen)
2895 			stat(s, FREE_FROZEN);
2896 		return;
2897 	}
2898 
2899 	if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
2900 		goto slab_empty;
2901 
2902 	/*
2903 	 * Objects left in the slab. If it was not on the partial list before
2904 	 * then add it.
2905 	 */
2906 	if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
2907 		if (kmem_cache_debug(s))
2908 			remove_full(s, n, page);
2909 		add_partial(n, page, DEACTIVATE_TO_TAIL);
2910 		stat(s, FREE_ADD_PARTIAL);
2911 	}
2912 	spin_unlock_irqrestore(&n->list_lock, flags);
2913 	return;
2914 
2915 slab_empty:
2916 	if (prior) {
2917 		/*
2918 		 * Slab on the partial list.
2919 		 */
2920 		remove_partial(n, page);
2921 		stat(s, FREE_REMOVE_PARTIAL);
2922 	} else {
2923 		/* Slab must be on the full list */
2924 		remove_full(s, n, page);
2925 	}
2926 
2927 	spin_unlock_irqrestore(&n->list_lock, flags);
2928 	stat(s, FREE_SLAB);
2929 	discard_slab(s, page);
2930 }
2931 
2932 /*
2933  * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2934  * can perform fastpath freeing without additional function calls.
2935  *
2936  * The fastpath is only possible if we are freeing to the current cpu slab
2937  * of this processor. This typically the case if we have just allocated
2938  * the item before.
2939  *
2940  * If fastpath is not possible then fall back to __slab_free where we deal
2941  * with all sorts of special processing.
2942  *
2943  * Bulk free of a freelist with several objects (all pointing to the
2944  * same page) possible by specifying head and tail ptr, plus objects
2945  * count (cnt). Bulk free indicated by tail pointer being set.
2946  */
2947 static __always_inline void do_slab_free(struct kmem_cache *s,
2948 				struct page *page, void *head, void *tail,
2949 				int cnt, unsigned long addr)
2950 {
2951 	void *tail_obj = tail ? : head;
2952 	struct kmem_cache_cpu *c;
2953 	unsigned long tid;
2954 redo:
2955 	/*
2956 	 * Determine the currently cpus per cpu slab.
2957 	 * The cpu may change afterward. However that does not matter since
2958 	 * data is retrieved via this pointer. If we are on the same cpu
2959 	 * during the cmpxchg then the free will succeed.
2960 	 */
2961 	do {
2962 		tid = this_cpu_read(s->cpu_slab->tid);
2963 		c = raw_cpu_ptr(s->cpu_slab);
2964 	} while (IS_ENABLED(CONFIG_PREEMPT) &&
2965 		 unlikely(tid != READ_ONCE(c->tid)));
2966 
2967 	/* Same with comment on barrier() in slab_alloc_node() */
2968 	barrier();
2969 
2970 	if (likely(page == c->page)) {
2971 		set_freepointer(s, tail_obj, c->freelist);
2972 
2973 		if (unlikely(!this_cpu_cmpxchg_double(
2974 				s->cpu_slab->freelist, s->cpu_slab->tid,
2975 				c->freelist, tid,
2976 				head, next_tid(tid)))) {
2977 
2978 			note_cmpxchg_failure("slab_free", s, tid);
2979 			goto redo;
2980 		}
2981 		stat(s, FREE_FASTPATH);
2982 	} else
2983 		__slab_free(s, page, head, tail_obj, cnt, addr);
2984 
2985 }
2986 
2987 static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
2988 				      void *head, void *tail, int cnt,
2989 				      unsigned long addr)
2990 {
2991 	/*
2992 	 * With KASAN enabled slab_free_freelist_hook modifies the freelist
2993 	 * to remove objects, whose reuse must be delayed.
2994 	 */
2995 	if (slab_free_freelist_hook(s, &head, &tail))
2996 		do_slab_free(s, page, head, tail, cnt, addr);
2997 }
2998 
2999 #ifdef CONFIG_KASAN_GENERIC
3000 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
3001 {
3002 	do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
3003 }
3004 #endif
3005 
3006 void kmem_cache_free(struct kmem_cache *s, void *x)
3007 {
3008 	s = cache_from_obj(s, x);
3009 	if (!s)
3010 		return;
3011 	slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
3012 	trace_kmem_cache_free(_RET_IP_, x);
3013 }
3014 EXPORT_SYMBOL(kmem_cache_free);
3015 
3016 struct detached_freelist {
3017 	struct page *page;
3018 	void *tail;
3019 	void *freelist;
3020 	int cnt;
3021 	struct kmem_cache *s;
3022 };
3023 
3024 /*
3025  * This function progressively scans the array with free objects (with
3026  * a limited look ahead) and extract objects belonging to the same
3027  * page.  It builds a detached freelist directly within the given
3028  * page/objects.  This can happen without any need for
3029  * synchronization, because the objects are owned by running process.
3030  * The freelist is build up as a single linked list in the objects.
3031  * The idea is, that this detached freelist can then be bulk
3032  * transferred to the real freelist(s), but only requiring a single
3033  * synchronization primitive.  Look ahead in the array is limited due
3034  * to performance reasons.
3035  */
3036 static inline
3037 int build_detached_freelist(struct kmem_cache *s, size_t size,
3038 			    void **p, struct detached_freelist *df)
3039 {
3040 	size_t first_skipped_index = 0;
3041 	int lookahead = 3;
3042 	void *object;
3043 	struct page *page;
3044 
3045 	/* Always re-init detached_freelist */
3046 	df->page = NULL;
3047 
3048 	do {
3049 		object = p[--size];
3050 		/* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
3051 	} while (!object && size);
3052 
3053 	if (!object)
3054 		return 0;
3055 
3056 	page = virt_to_head_page(object);
3057 	if (!s) {
3058 		/* Handle kalloc'ed objects */
3059 		if (unlikely(!PageSlab(page))) {
3060 			BUG_ON(!PageCompound(page));
3061 			kfree_hook(object);
3062 			__free_pages(page, compound_order(page));
3063 			p[size] = NULL; /* mark object processed */
3064 			return size;
3065 		}
3066 		/* Derive kmem_cache from object */
3067 		df->s = page->slab_cache;
3068 	} else {
3069 		df->s = cache_from_obj(s, object); /* Support for memcg */
3070 	}
3071 
3072 	/* Start new detached freelist */
3073 	df->page = page;
3074 	set_freepointer(df->s, object, NULL);
3075 	df->tail = object;
3076 	df->freelist = object;
3077 	p[size] = NULL; /* mark object processed */
3078 	df->cnt = 1;
3079 
3080 	while (size) {
3081 		object = p[--size];
3082 		if (!object)
3083 			continue; /* Skip processed objects */
3084 
3085 		/* df->page is always set at this point */
3086 		if (df->page == virt_to_head_page(object)) {
3087 			/* Opportunity build freelist */
3088 			set_freepointer(df->s, object, df->freelist);
3089 			df->freelist = object;
3090 			df->cnt++;
3091 			p[size] = NULL; /* mark object processed */
3092 
3093 			continue;
3094 		}
3095 
3096 		/* Limit look ahead search */
3097 		if (!--lookahead)
3098 			break;
3099 
3100 		if (!first_skipped_index)
3101 			first_skipped_index = size + 1;
3102 	}
3103 
3104 	return first_skipped_index;
3105 }
3106 
3107 /* Note that interrupts must be enabled when calling this function. */
3108 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3109 {
3110 	if (WARN_ON(!size))
3111 		return;
3112 
3113 	do {
3114 		struct detached_freelist df;
3115 
3116 		size = build_detached_freelist(s, size, p, &df);
3117 		if (!df.page)
3118 			continue;
3119 
3120 		slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);
3121 	} while (likely(size));
3122 }
3123 EXPORT_SYMBOL(kmem_cache_free_bulk);
3124 
3125 /* Note that interrupts must be enabled when calling this function. */
3126 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3127 			  void **p)
3128 {
3129 	struct kmem_cache_cpu *c;
3130 	int i;
3131 
3132 	/* memcg and kmem_cache debug support */
3133 	s = slab_pre_alloc_hook(s, flags);
3134 	if (unlikely(!s))
3135 		return false;
3136 	/*
3137 	 * Drain objects in the per cpu slab, while disabling local
3138 	 * IRQs, which protects against PREEMPT and interrupts
3139 	 * handlers invoking normal fastpath.
3140 	 */
3141 	local_irq_disable();
3142 	c = this_cpu_ptr(s->cpu_slab);
3143 
3144 	for (i = 0; i < size; i++) {
3145 		void *object = c->freelist;
3146 
3147 		if (unlikely(!object)) {
3148 			/*
3149 			 * Invoking slow path likely have side-effect
3150 			 * of re-populating per CPU c->freelist
3151 			 */
3152 			p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3153 					    _RET_IP_, c);
3154 			if (unlikely(!p[i]))
3155 				goto error;
3156 
3157 			c = this_cpu_ptr(s->cpu_slab);
3158 			continue; /* goto for-loop */
3159 		}
3160 		c->freelist = get_freepointer(s, object);
3161 		p[i] = object;
3162 	}
3163 	c->tid = next_tid(c->tid);
3164 	local_irq_enable();
3165 
3166 	/* Clear memory outside IRQ disabled fastpath loop */
3167 	if (unlikely(flags & __GFP_ZERO)) {
3168 		int j;
3169 
3170 		for (j = 0; j < i; j++)
3171 			memset(p[j], 0, s->object_size);
3172 	}
3173 
3174 	/* memcg and kmem_cache debug support */
3175 	slab_post_alloc_hook(s, flags, size, p);
3176 	return i;
3177 error:
3178 	local_irq_enable();
3179 	slab_post_alloc_hook(s, flags, i, p);
3180 	__kmem_cache_free_bulk(s, i, p);
3181 	return 0;
3182 }
3183 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3184 
3185 
3186 /*
3187  * Object placement in a slab is made very easy because we always start at
3188  * offset 0. If we tune the size of the object to the alignment then we can
3189  * get the required alignment by putting one properly sized object after
3190  * another.
3191  *
3192  * Notice that the allocation order determines the sizes of the per cpu
3193  * caches. Each processor has always one slab available for allocations.
3194  * Increasing the allocation order reduces the number of times that slabs
3195  * must be moved on and off the partial lists and is therefore a factor in
3196  * locking overhead.
3197  */
3198 
3199 /*
3200  * Mininum / Maximum order of slab pages. This influences locking overhead
3201  * and slab fragmentation. A higher order reduces the number of partial slabs
3202  * and increases the number of allocations possible without having to
3203  * take the list_lock.
3204  */
3205 static unsigned int slub_min_order;
3206 static unsigned int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3207 static unsigned int slub_min_objects;
3208 
3209 /*
3210  * Calculate the order of allocation given an slab object size.
3211  *
3212  * The order of allocation has significant impact on performance and other
3213  * system components. Generally order 0 allocations should be preferred since
3214  * order 0 does not cause fragmentation in the page allocator. Larger objects
3215  * be problematic to put into order 0 slabs because there may be too much
3216  * unused space left. We go to a higher order if more than 1/16th of the slab
3217  * would be wasted.
3218  *
3219  * In order to reach satisfactory performance we must ensure that a minimum
3220  * number of objects is in one slab. Otherwise we may generate too much
3221  * activity on the partial lists which requires taking the list_lock. This is
3222  * less a concern for large slabs though which are rarely used.
3223  *
3224  * slub_max_order specifies the order where we begin to stop considering the
3225  * number of objects in a slab as critical. If we reach slub_max_order then
3226  * we try to keep the page order as low as possible. So we accept more waste
3227  * of space in favor of a small page order.
3228  *
3229  * Higher order allocations also allow the placement of more objects in a
3230  * slab and thereby reduce object handling overhead. If the user has
3231  * requested a higher mininum order then we start with that one instead of
3232  * the smallest order which will fit the object.
3233  */
3234 static inline unsigned int slab_order(unsigned int size,
3235 		unsigned int min_objects, unsigned int max_order,
3236 		unsigned int fract_leftover)
3237 {
3238 	unsigned int min_order = slub_min_order;
3239 	unsigned int order;
3240 
3241 	if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
3242 		return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3243 
3244 	for (order = max(min_order, (unsigned int)get_order(min_objects * size));
3245 			order <= max_order; order++) {
3246 
3247 		unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
3248 		unsigned int rem;
3249 
3250 		rem = slab_size % size;
3251 
3252 		if (rem <= slab_size / fract_leftover)
3253 			break;
3254 	}
3255 
3256 	return order;
3257 }
3258 
3259 static inline int calculate_order(unsigned int size)
3260 {
3261 	unsigned int order;
3262 	unsigned int min_objects;
3263 	unsigned int max_objects;
3264 
3265 	/*
3266 	 * Attempt to find best configuration for a slab. This
3267 	 * works by first attempting to generate a layout with
3268 	 * the best configuration and backing off gradually.
3269 	 *
3270 	 * First we increase the acceptable waste in a slab. Then
3271 	 * we reduce the minimum objects required in a slab.
3272 	 */
3273 	min_objects = slub_min_objects;
3274 	if (!min_objects)
3275 		min_objects = 4 * (fls(nr_cpu_ids) + 1);
3276 	max_objects = order_objects(slub_max_order, size);
3277 	min_objects = min(min_objects, max_objects);
3278 
3279 	while (min_objects > 1) {
3280 		unsigned int fraction;
3281 
3282 		fraction = 16;
3283 		while (fraction >= 4) {
3284 			order = slab_order(size, min_objects,
3285 					slub_max_order, fraction);
3286 			if (order <= slub_max_order)
3287 				return order;
3288 			fraction /= 2;
3289 		}
3290 		min_objects--;
3291 	}
3292 
3293 	/*
3294 	 * We were unable to place multiple objects in a slab. Now
3295 	 * lets see if we can place a single object there.
3296 	 */
3297 	order = slab_order(size, 1, slub_max_order, 1);
3298 	if (order <= slub_max_order)
3299 		return order;
3300 
3301 	/*
3302 	 * Doh this slab cannot be placed using slub_max_order.
3303 	 */
3304 	order = slab_order(size, 1, MAX_ORDER, 1);
3305 	if (order < MAX_ORDER)
3306 		return order;
3307 	return -ENOSYS;
3308 }
3309 
3310 static void
3311 init_kmem_cache_node(struct kmem_cache_node *n)
3312 {
3313 	n->nr_partial = 0;
3314 	spin_lock_init(&n->list_lock);
3315 	INIT_LIST_HEAD(&n->partial);
3316 #ifdef CONFIG_SLUB_DEBUG
3317 	atomic_long_set(&n->nr_slabs, 0);
3318 	atomic_long_set(&n->total_objects, 0);
3319 	INIT_LIST_HEAD(&n->full);
3320 #endif
3321 }
3322 
3323 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3324 {
3325 	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3326 			KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3327 
3328 	/*
3329 	 * Must align to double word boundary for the double cmpxchg
3330 	 * instructions to work; see __pcpu_double_call_return_bool().
3331 	 */
3332 	s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3333 				     2 * sizeof(void *));
3334 
3335 	if (!s->cpu_slab)
3336 		return 0;
3337 
3338 	init_kmem_cache_cpus(s);
3339 
3340 	return 1;
3341 }
3342 
3343 static struct kmem_cache *kmem_cache_node;
3344 
3345 /*
3346  * No kmalloc_node yet so do it by hand. We know that this is the first
3347  * slab on the node for this slabcache. There are no concurrent accesses
3348  * possible.
3349  *
3350  * Note that this function only works on the kmem_cache_node
3351  * when allocating for the kmem_cache_node. This is used for bootstrapping
3352  * memory on a fresh node that has no slab structures yet.
3353  */
3354 static void early_kmem_cache_node_alloc(int node)
3355 {
3356 	struct page *page;
3357 	struct kmem_cache_node *n;
3358 
3359 	BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3360 
3361 	page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3362 
3363 	BUG_ON(!page);
3364 	if (page_to_nid(page) != node) {
3365 		pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3366 		pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3367 	}
3368 
3369 	n = page->freelist;
3370 	BUG_ON(!n);
3371 #ifdef CONFIG_SLUB_DEBUG
3372 	init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3373 	init_tracking(kmem_cache_node, n);
3374 #endif
3375 	n = kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node),
3376 		      GFP_KERNEL);
3377 	page->freelist = get_freepointer(kmem_cache_node, n);
3378 	page->inuse = 1;
3379 	page->frozen = 0;
3380 	kmem_cache_node->node[node] = n;
3381 	init_kmem_cache_node(n);
3382 	inc_slabs_node(kmem_cache_node, node, page->objects);
3383 
3384 	/*
3385 	 * No locks need to be taken here as it has just been
3386 	 * initialized and there is no concurrent access.
3387 	 */
3388 	__add_partial(n, page, DEACTIVATE_TO_HEAD);
3389 }
3390 
3391 static void free_kmem_cache_nodes(struct kmem_cache *s)
3392 {
3393 	int node;
3394 	struct kmem_cache_node *n;
3395 
3396 	for_each_kmem_cache_node(s, node, n) {
3397 		s->node[node] = NULL;
3398 		kmem_cache_free(kmem_cache_node, n);
3399 	}
3400 }
3401 
3402 void __kmem_cache_release(struct kmem_cache *s)
3403 {
3404 	cache_random_seq_destroy(s);
3405 	free_percpu(s->cpu_slab);
3406 	free_kmem_cache_nodes(s);
3407 }
3408 
3409 static int init_kmem_cache_nodes(struct kmem_cache *s)
3410 {
3411 	int node;
3412 
3413 	for_each_node_state(node, N_NORMAL_MEMORY) {
3414 		struct kmem_cache_node *n;
3415 
3416 		if (slab_state == DOWN) {
3417 			early_kmem_cache_node_alloc(node);
3418 			continue;
3419 		}
3420 		n = kmem_cache_alloc_node(kmem_cache_node,
3421 						GFP_KERNEL, node);
3422 
3423 		if (!n) {
3424 			free_kmem_cache_nodes(s);
3425 			return 0;
3426 		}
3427 
3428 		init_kmem_cache_node(n);
3429 		s->node[node] = n;
3430 	}
3431 	return 1;
3432 }
3433 
3434 static void set_min_partial(struct kmem_cache *s, unsigned long min)
3435 {
3436 	if (min < MIN_PARTIAL)
3437 		min = MIN_PARTIAL;
3438 	else if (min > MAX_PARTIAL)
3439 		min = MAX_PARTIAL;
3440 	s->min_partial = min;
3441 }
3442 
3443 static void set_cpu_partial(struct kmem_cache *s)
3444 {
3445 #ifdef CONFIG_SLUB_CPU_PARTIAL
3446 	/*
3447 	 * cpu_partial determined the maximum number of objects kept in the
3448 	 * per cpu partial lists of a processor.
3449 	 *
3450 	 * Per cpu partial lists mainly contain slabs that just have one
3451 	 * object freed. If they are used for allocation then they can be
3452 	 * filled up again with minimal effort. The slab will never hit the
3453 	 * per node partial lists and therefore no locking will be required.
3454 	 *
3455 	 * This setting also determines
3456 	 *
3457 	 * A) The number of objects from per cpu partial slabs dumped to the
3458 	 *    per node list when we reach the limit.
3459 	 * B) The number of objects in cpu partial slabs to extract from the
3460 	 *    per node list when we run out of per cpu objects. We only fetch
3461 	 *    50% to keep some capacity around for frees.
3462 	 */
3463 	if (!kmem_cache_has_cpu_partial(s))
3464 		s->cpu_partial = 0;
3465 	else if (s->size >= PAGE_SIZE)
3466 		s->cpu_partial = 2;
3467 	else if (s->size >= 1024)
3468 		s->cpu_partial = 6;
3469 	else if (s->size >= 256)
3470 		s->cpu_partial = 13;
3471 	else
3472 		s->cpu_partial = 30;
3473 #endif
3474 }
3475 
3476 /*
3477  * calculate_sizes() determines the order and the distribution of data within
3478  * a slab object.
3479  */
3480 static int calculate_sizes(struct kmem_cache *s, int forced_order)
3481 {
3482 	slab_flags_t flags = s->flags;
3483 	unsigned int size = s->object_size;
3484 	unsigned int order;
3485 
3486 	/*
3487 	 * Round up object size to the next word boundary. We can only
3488 	 * place the free pointer at word boundaries and this determines
3489 	 * the possible location of the free pointer.
3490 	 */
3491 	size = ALIGN(size, sizeof(void *));
3492 
3493 #ifdef CONFIG_SLUB_DEBUG
3494 	/*
3495 	 * Determine if we can poison the object itself. If the user of
3496 	 * the slab may touch the object after free or before allocation
3497 	 * then we should never poison the object itself.
3498 	 */
3499 	if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
3500 			!s->ctor)
3501 		s->flags |= __OBJECT_POISON;
3502 	else
3503 		s->flags &= ~__OBJECT_POISON;
3504 
3505 
3506 	/*
3507 	 * If we are Redzoning then check if there is some space between the
3508 	 * end of the object and the free pointer. If not then add an
3509 	 * additional word to have some bytes to store Redzone information.
3510 	 */
3511 	if ((flags & SLAB_RED_ZONE) && size == s->object_size)
3512 		size += sizeof(void *);
3513 #endif
3514 
3515 	/*
3516 	 * With that we have determined the number of bytes in actual use
3517 	 * by the object. This is the potential offset to the free pointer.
3518 	 */
3519 	s->inuse = size;
3520 
3521 	if (((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
3522 		s->ctor)) {
3523 		/*
3524 		 * Relocate free pointer after the object if it is not
3525 		 * permitted to overwrite the first word of the object on
3526 		 * kmem_cache_free.
3527 		 *
3528 		 * This is the case if we do RCU, have a constructor or
3529 		 * destructor or are poisoning the objects.
3530 		 */
3531 		s->offset = size;
3532 		size += sizeof(void *);
3533 	}
3534 
3535 #ifdef CONFIG_SLUB_DEBUG
3536 	if (flags & SLAB_STORE_USER)
3537 		/*
3538 		 * Need to store information about allocs and frees after
3539 		 * the object.
3540 		 */
3541 		size += 2 * sizeof(struct track);
3542 #endif
3543 
3544 	kasan_cache_create(s, &size, &s->flags);
3545 #ifdef CONFIG_SLUB_DEBUG
3546 	if (flags & SLAB_RED_ZONE) {
3547 		/*
3548 		 * Add some empty padding so that we can catch
3549 		 * overwrites from earlier objects rather than let
3550 		 * tracking information or the free pointer be
3551 		 * corrupted if a user writes before the start
3552 		 * of the object.
3553 		 */
3554 		size += sizeof(void *);
3555 
3556 		s->red_left_pad = sizeof(void *);
3557 		s->red_left_pad = ALIGN(s->red_left_pad, s->align);
3558 		size += s->red_left_pad;
3559 	}
3560 #endif
3561 
3562 	/*
3563 	 * SLUB stores one object immediately after another beginning from
3564 	 * offset 0. In order to align the objects we have to simply size
3565 	 * each object to conform to the alignment.
3566 	 */
3567 	size = ALIGN(size, s->align);
3568 	s->size = size;
3569 	if (forced_order >= 0)
3570 		order = forced_order;
3571 	else
3572 		order = calculate_order(size);
3573 
3574 	if ((int)order < 0)
3575 		return 0;
3576 
3577 	s->allocflags = 0;
3578 	if (order)
3579 		s->allocflags |= __GFP_COMP;
3580 
3581 	if (s->flags & SLAB_CACHE_DMA)
3582 		s->allocflags |= GFP_DMA;
3583 
3584 	if (s->flags & SLAB_RECLAIM_ACCOUNT)
3585 		s->allocflags |= __GFP_RECLAIMABLE;
3586 
3587 	/*
3588 	 * Determine the number of objects per slab
3589 	 */
3590 	s->oo = oo_make(order, size);
3591 	s->min = oo_make(get_order(size), size);
3592 	if (oo_objects(s->oo) > oo_objects(s->max))
3593 		s->max = s->oo;
3594 
3595 	return !!oo_objects(s->oo);
3596 }
3597 
3598 static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
3599 {
3600 	s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3601 #ifdef CONFIG_SLAB_FREELIST_HARDENED
3602 	s->random = get_random_long();
3603 #endif
3604 
3605 	if (!calculate_sizes(s, -1))
3606 		goto error;
3607 	if (disable_higher_order_debug) {
3608 		/*
3609 		 * Disable debugging flags that store metadata if the min slab
3610 		 * order increased.
3611 		 */
3612 		if (get_order(s->size) > get_order(s->object_size)) {
3613 			s->flags &= ~DEBUG_METADATA_FLAGS;
3614 			s->offset = 0;
3615 			if (!calculate_sizes(s, -1))
3616 				goto error;
3617 		}
3618 	}
3619 
3620 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3621     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3622 	if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
3623 		/* Enable fast mode */
3624 		s->flags |= __CMPXCHG_DOUBLE;
3625 #endif
3626 
3627 	/*
3628 	 * The larger the object size is, the more pages we want on the partial
3629 	 * list to avoid pounding the page allocator excessively.
3630 	 */
3631 	set_min_partial(s, ilog2(s->size) / 2);
3632 
3633 	set_cpu_partial(s);
3634 
3635 #ifdef CONFIG_NUMA
3636 	s->remote_node_defrag_ratio = 1000;
3637 #endif
3638 
3639 	/* Initialize the pre-computed randomized freelist if slab is up */
3640 	if (slab_state >= UP) {
3641 		if (init_cache_random_seq(s))
3642 			goto error;
3643 	}
3644 
3645 	if (!init_kmem_cache_nodes(s))
3646 		goto error;
3647 
3648 	if (alloc_kmem_cache_cpus(s))
3649 		return 0;
3650 
3651 	free_kmem_cache_nodes(s);
3652 error:
3653 	if (flags & SLAB_PANIC)
3654 		panic("Cannot create slab %s size=%u realsize=%u order=%u offset=%u flags=%lx\n",
3655 		      s->name, s->size, s->size,
3656 		      oo_order(s->oo), s->offset, (unsigned long)flags);
3657 	return -EINVAL;
3658 }
3659 
3660 static void list_slab_objects(struct kmem_cache *s, struct page *page,
3661 							const char *text)
3662 {
3663 #ifdef CONFIG_SLUB_DEBUG
3664 	void *addr = page_address(page);
3665 	void *p;
3666 	unsigned long *map = bitmap_zalloc(page->objects, GFP_ATOMIC);
3667 	if (!map)
3668 		return;
3669 	slab_err(s, page, text, s->name);
3670 	slab_lock(page);
3671 
3672 	get_map(s, page, map);
3673 	for_each_object(p, s, addr, page->objects) {
3674 
3675 		if (!test_bit(slab_index(p, s, addr), map)) {
3676 			pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
3677 			print_tracking(s, p);
3678 		}
3679 	}
3680 	slab_unlock(page);
3681 	bitmap_free(map);
3682 #endif
3683 }
3684 
3685 /*
3686  * Attempt to free all partial slabs on a node.
3687  * This is called from __kmem_cache_shutdown(). We must take list_lock
3688  * because sysfs file might still access partial list after the shutdowning.
3689  */
3690 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3691 {
3692 	LIST_HEAD(discard);
3693 	struct page *page, *h;
3694 
3695 	BUG_ON(irqs_disabled());
3696 	spin_lock_irq(&n->list_lock);
3697 	list_for_each_entry_safe(page, h, &n->partial, lru) {
3698 		if (!page->inuse) {
3699 			remove_partial(n, page);
3700 			list_add(&page->lru, &discard);
3701 		} else {
3702 			list_slab_objects(s, page,
3703 			"Objects remaining in %s on __kmem_cache_shutdown()");
3704 		}
3705 	}
3706 	spin_unlock_irq(&n->list_lock);
3707 
3708 	list_for_each_entry_safe(page, h, &discard, lru)
3709 		discard_slab(s, page);
3710 }
3711 
3712 bool __kmem_cache_empty(struct kmem_cache *s)
3713 {
3714 	int node;
3715 	struct kmem_cache_node *n;
3716 
3717 	for_each_kmem_cache_node(s, node, n)
3718 		if (n->nr_partial || slabs_node(s, node))
3719 			return false;
3720 	return true;
3721 }
3722 
3723 /*
3724  * Release all resources used by a slab cache.
3725  */
3726 int __kmem_cache_shutdown(struct kmem_cache *s)
3727 {
3728 	int node;
3729 	struct kmem_cache_node *n;
3730 
3731 	flush_all(s);
3732 	/* Attempt to free all objects */
3733 	for_each_kmem_cache_node(s, node, n) {
3734 		free_partial(s, n);
3735 		if (n->nr_partial || slabs_node(s, node))
3736 			return 1;
3737 	}
3738 	sysfs_slab_remove(s);
3739 	return 0;
3740 }
3741 
3742 /********************************************************************
3743  *		Kmalloc subsystem
3744  *******************************************************************/
3745 
3746 static int __init setup_slub_min_order(char *str)
3747 {
3748 	get_option(&str, (int *)&slub_min_order);
3749 
3750 	return 1;
3751 }
3752 
3753 __setup("slub_min_order=", setup_slub_min_order);
3754 
3755 static int __init setup_slub_max_order(char *str)
3756 {
3757 	get_option(&str, (int *)&slub_max_order);
3758 	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
3759 
3760 	return 1;
3761 }
3762 
3763 __setup("slub_max_order=", setup_slub_max_order);
3764 
3765 static int __init setup_slub_min_objects(char *str)
3766 {
3767 	get_option(&str, (int *)&slub_min_objects);
3768 
3769 	return 1;
3770 }
3771 
3772 __setup("slub_min_objects=", setup_slub_min_objects);
3773 
3774 void *__kmalloc(size_t size, gfp_t flags)
3775 {
3776 	struct kmem_cache *s;
3777 	void *ret;
3778 
3779 	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3780 		return kmalloc_large(size, flags);
3781 
3782 	s = kmalloc_slab(size, flags);
3783 
3784 	if (unlikely(ZERO_OR_NULL_PTR(s)))
3785 		return s;
3786 
3787 	ret = slab_alloc(s, flags, _RET_IP_);
3788 
3789 	trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3790 
3791 	ret = kasan_kmalloc(s, ret, size, flags);
3792 
3793 	return ret;
3794 }
3795 EXPORT_SYMBOL(__kmalloc);
3796 
3797 #ifdef CONFIG_NUMA
3798 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3799 {
3800 	struct page *page;
3801 	void *ptr = NULL;
3802 
3803 	flags |= __GFP_COMP;
3804 	page = alloc_pages_node(node, flags, get_order(size));
3805 	if (page)
3806 		ptr = page_address(page);
3807 
3808 	return kmalloc_large_node_hook(ptr, size, flags);
3809 }
3810 
3811 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3812 {
3813 	struct kmem_cache *s;
3814 	void *ret;
3815 
3816 	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3817 		ret = kmalloc_large_node(size, flags, node);
3818 
3819 		trace_kmalloc_node(_RET_IP_, ret,
3820 				   size, PAGE_SIZE << get_order(size),
3821 				   flags, node);
3822 
3823 		return ret;
3824 	}
3825 
3826 	s = kmalloc_slab(size, flags);
3827 
3828 	if (unlikely(ZERO_OR_NULL_PTR(s)))
3829 		return s;
3830 
3831 	ret = slab_alloc_node(s, flags, node, _RET_IP_);
3832 
3833 	trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3834 
3835 	ret = kasan_kmalloc(s, ret, size, flags);
3836 
3837 	return ret;
3838 }
3839 EXPORT_SYMBOL(__kmalloc_node);
3840 #endif
3841 
3842 #ifdef CONFIG_HARDENED_USERCOPY
3843 /*
3844  * Rejects incorrectly sized objects and objects that are to be copied
3845  * to/from userspace but do not fall entirely within the containing slab
3846  * cache's usercopy region.
3847  *
3848  * Returns NULL if check passes, otherwise const char * to name of cache
3849  * to indicate an error.
3850  */
3851 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
3852 			 bool to_user)
3853 {
3854 	struct kmem_cache *s;
3855 	unsigned int offset;
3856 	size_t object_size;
3857 
3858 	/* Find object and usable object size. */
3859 	s = page->slab_cache;
3860 
3861 	/* Reject impossible pointers. */
3862 	if (ptr < page_address(page))
3863 		usercopy_abort("SLUB object not in SLUB page?!", NULL,
3864 			       to_user, 0, n);
3865 
3866 	/* Find offset within object. */
3867 	offset = (ptr - page_address(page)) % s->size;
3868 
3869 	/* Adjust for redzone and reject if within the redzone. */
3870 	if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) {
3871 		if (offset < s->red_left_pad)
3872 			usercopy_abort("SLUB object in left red zone",
3873 				       s->name, to_user, offset, n);
3874 		offset -= s->red_left_pad;
3875 	}
3876 
3877 	/* Allow address range falling entirely within usercopy region. */
3878 	if (offset >= s->useroffset &&
3879 	    offset - s->useroffset <= s->usersize &&
3880 	    n <= s->useroffset - offset + s->usersize)
3881 		return;
3882 
3883 	/*
3884 	 * If the copy is still within the allocated object, produce
3885 	 * a warning instead of rejecting the copy. This is intended
3886 	 * to be a temporary method to find any missing usercopy
3887 	 * whitelists.
3888 	 */
3889 	object_size = slab_ksize(s);
3890 	if (usercopy_fallback &&
3891 	    offset <= object_size && n <= object_size - offset) {
3892 		usercopy_warn("SLUB object", s->name, to_user, offset, n);
3893 		return;
3894 	}
3895 
3896 	usercopy_abort("SLUB object", s->name, to_user, offset, n);
3897 }
3898 #endif /* CONFIG_HARDENED_USERCOPY */
3899 
3900 static size_t __ksize(const void *object)
3901 {
3902 	struct page *page;
3903 
3904 	if (unlikely(object == ZERO_SIZE_PTR))
3905 		return 0;
3906 
3907 	page = virt_to_head_page(object);
3908 
3909 	if (unlikely(!PageSlab(page))) {
3910 		WARN_ON(!PageCompound(page));
3911 		return PAGE_SIZE << compound_order(page);
3912 	}
3913 
3914 	return slab_ksize(page->slab_cache);
3915 }
3916 
3917 size_t ksize(const void *object)
3918 {
3919 	size_t size = __ksize(object);
3920 	/* We assume that ksize callers could use whole allocated area,
3921 	 * so we need to unpoison this area.
3922 	 */
3923 	kasan_unpoison_shadow(object, size);
3924 	return size;
3925 }
3926 EXPORT_SYMBOL(ksize);
3927 
3928 void kfree(const void *x)
3929 {
3930 	struct page *page;
3931 	void *object = (void *)x;
3932 
3933 	trace_kfree(_RET_IP_, x);
3934 
3935 	if (unlikely(ZERO_OR_NULL_PTR(x)))
3936 		return;
3937 
3938 	page = virt_to_head_page(x);
3939 	if (unlikely(!PageSlab(page))) {
3940 		BUG_ON(!PageCompound(page));
3941 		kfree_hook(object);
3942 		__free_pages(page, compound_order(page));
3943 		return;
3944 	}
3945 	slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
3946 }
3947 EXPORT_SYMBOL(kfree);
3948 
3949 #define SHRINK_PROMOTE_MAX 32
3950 
3951 /*
3952  * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3953  * up most to the head of the partial lists. New allocations will then
3954  * fill those up and thus they can be removed from the partial lists.
3955  *
3956  * The slabs with the least items are placed last. This results in them
3957  * being allocated from last increasing the chance that the last objects
3958  * are freed in them.
3959  */
3960 int __kmem_cache_shrink(struct kmem_cache *s)
3961 {
3962 	int node;
3963 	int i;
3964 	struct kmem_cache_node *n;
3965 	struct page *page;
3966 	struct page *t;
3967 	struct list_head discard;
3968 	struct list_head promote[SHRINK_PROMOTE_MAX];
3969 	unsigned long flags;
3970 	int ret = 0;
3971 
3972 	flush_all(s);
3973 	for_each_kmem_cache_node(s, node, n) {
3974 		INIT_LIST_HEAD(&discard);
3975 		for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
3976 			INIT_LIST_HEAD(promote + i);
3977 
3978 		spin_lock_irqsave(&n->list_lock, flags);
3979 
3980 		/*
3981 		 * Build lists of slabs to discard or promote.
3982 		 *
3983 		 * Note that concurrent frees may occur while we hold the
3984 		 * list_lock. page->inuse here is the upper limit.
3985 		 */
3986 		list_for_each_entry_safe(page, t, &n->partial, lru) {
3987 			int free = page->objects - page->inuse;
3988 
3989 			/* Do not reread page->inuse */
3990 			barrier();
3991 
3992 			/* We do not keep full slabs on the list */
3993 			BUG_ON(free <= 0);
3994 
3995 			if (free == page->objects) {
3996 				list_move(&page->lru, &discard);
3997 				n->nr_partial--;
3998 			} else if (free <= SHRINK_PROMOTE_MAX)
3999 				list_move(&page->lru, promote + free - 1);
4000 		}
4001 
4002 		/*
4003 		 * Promote the slabs filled up most to the head of the
4004 		 * partial list.
4005 		 */
4006 		for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
4007 			list_splice(promote + i, &n->partial);
4008 
4009 		spin_unlock_irqrestore(&n->list_lock, flags);
4010 
4011 		/* Release empty slabs */
4012 		list_for_each_entry_safe(page, t, &discard, lru)
4013 			discard_slab(s, page);
4014 
4015 		if (slabs_node(s, node))
4016 			ret = 1;
4017 	}
4018 
4019 	return ret;
4020 }
4021 
4022 #ifdef CONFIG_MEMCG
4023 static void kmemcg_cache_deact_after_rcu(struct kmem_cache *s)
4024 {
4025 	/*
4026 	 * Called with all the locks held after a sched RCU grace period.
4027 	 * Even if @s becomes empty after shrinking, we can't know that @s
4028 	 * doesn't have allocations already in-flight and thus can't
4029 	 * destroy @s until the associated memcg is released.
4030 	 *
4031 	 * However, let's remove the sysfs files for empty caches here.
4032 	 * Each cache has a lot of interface files which aren't
4033 	 * particularly useful for empty draining caches; otherwise, we can
4034 	 * easily end up with millions of unnecessary sysfs files on
4035 	 * systems which have a lot of memory and transient cgroups.
4036 	 */
4037 	if (!__kmem_cache_shrink(s))
4038 		sysfs_slab_remove(s);
4039 }
4040 
4041 void __kmemcg_cache_deactivate(struct kmem_cache *s)
4042 {
4043 	/*
4044 	 * Disable empty slabs caching. Used to avoid pinning offline
4045 	 * memory cgroups by kmem pages that can be freed.
4046 	 */
4047 	slub_set_cpu_partial(s, 0);
4048 	s->min_partial = 0;
4049 
4050 	/*
4051 	 * s->cpu_partial is checked locklessly (see put_cpu_partial), so
4052 	 * we have to make sure the change is visible before shrinking.
4053 	 */
4054 	slab_deactivate_memcg_cache_rcu_sched(s, kmemcg_cache_deact_after_rcu);
4055 }
4056 #endif
4057 
4058 static int slab_mem_going_offline_callback(void *arg)
4059 {
4060 	struct kmem_cache *s;
4061 
4062 	mutex_lock(&slab_mutex);
4063 	list_for_each_entry(s, &slab_caches, list)
4064 		__kmem_cache_shrink(s);
4065 	mutex_unlock(&slab_mutex);
4066 
4067 	return 0;
4068 }
4069 
4070 static void slab_mem_offline_callback(void *arg)
4071 {
4072 	struct kmem_cache_node *n;
4073 	struct kmem_cache *s;
4074 	struct memory_notify *marg = arg;
4075 	int offline_node;
4076 
4077 	offline_node = marg->status_change_nid_normal;
4078 
4079 	/*
4080 	 * If the node still has available memory. we need kmem_cache_node
4081 	 * for it yet.
4082 	 */
4083 	if (offline_node < 0)
4084 		return;
4085 
4086 	mutex_lock(&slab_mutex);
4087 	list_for_each_entry(s, &slab_caches, list) {
4088 		n = get_node(s, offline_node);
4089 		if (n) {
4090 			/*
4091 			 * if n->nr_slabs > 0, slabs still exist on the node
4092 			 * that is going down. We were unable to free them,
4093 			 * and offline_pages() function shouldn't call this
4094 			 * callback. So, we must fail.
4095 			 */
4096 			BUG_ON(slabs_node(s, offline_node));
4097 
4098 			s->node[offline_node] = NULL;
4099 			kmem_cache_free(kmem_cache_node, n);
4100 		}
4101 	}
4102 	mutex_unlock(&slab_mutex);
4103 }
4104 
4105 static int slab_mem_going_online_callback(void *arg)
4106 {
4107 	struct kmem_cache_node *n;
4108 	struct kmem_cache *s;
4109 	struct memory_notify *marg = arg;
4110 	int nid = marg->status_change_nid_normal;
4111 	int ret = 0;
4112 
4113 	/*
4114 	 * If the node's memory is already available, then kmem_cache_node is
4115 	 * already created. Nothing to do.
4116 	 */
4117 	if (nid < 0)
4118 		return 0;
4119 
4120 	/*
4121 	 * We are bringing a node online. No memory is available yet. We must
4122 	 * allocate a kmem_cache_node structure in order to bring the node
4123 	 * online.
4124 	 */
4125 	mutex_lock(&slab_mutex);
4126 	list_for_each_entry(s, &slab_caches, list) {
4127 		/*
4128 		 * XXX: kmem_cache_alloc_node will fallback to other nodes
4129 		 *      since memory is not yet available from the node that
4130 		 *      is brought up.
4131 		 */
4132 		n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
4133 		if (!n) {
4134 			ret = -ENOMEM;
4135 			goto out;
4136 		}
4137 		init_kmem_cache_node(n);
4138 		s->node[nid] = n;
4139 	}
4140 out:
4141 	mutex_unlock(&slab_mutex);
4142 	return ret;
4143 }
4144 
4145 static int slab_memory_callback(struct notifier_block *self,
4146 				unsigned long action, void *arg)
4147 {
4148 	int ret = 0;
4149 
4150 	switch (action) {
4151 	case MEM_GOING_ONLINE:
4152 		ret = slab_mem_going_online_callback(arg);
4153 		break;
4154 	case MEM_GOING_OFFLINE:
4155 		ret = slab_mem_going_offline_callback(arg);
4156 		break;
4157 	case MEM_OFFLINE:
4158 	case MEM_CANCEL_ONLINE:
4159 		slab_mem_offline_callback(arg);
4160 		break;
4161 	case MEM_ONLINE:
4162 	case MEM_CANCEL_OFFLINE:
4163 		break;
4164 	}
4165 	if (ret)
4166 		ret = notifier_from_errno(ret);
4167 	else
4168 		ret = NOTIFY_OK;
4169 	return ret;
4170 }
4171 
4172 static struct notifier_block slab_memory_callback_nb = {
4173 	.notifier_call = slab_memory_callback,
4174 	.priority = SLAB_CALLBACK_PRI,
4175 };
4176 
4177 /********************************************************************
4178  *			Basic setup of slabs
4179  *******************************************************************/
4180 
4181 /*
4182  * Used for early kmem_cache structures that were allocated using
4183  * the page allocator. Allocate them properly then fix up the pointers
4184  * that may be pointing to the wrong kmem_cache structure.
4185  */
4186 
4187 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4188 {
4189 	int node;
4190 	struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4191 	struct kmem_cache_node *n;
4192 
4193 	memcpy(s, static_cache, kmem_cache->object_size);
4194 
4195 	/*
4196 	 * This runs very early, and only the boot processor is supposed to be
4197 	 * up.  Even if it weren't true, IRQs are not up so we couldn't fire
4198 	 * IPIs around.
4199 	 */
4200 	__flush_cpu_slab(s, smp_processor_id());
4201 	for_each_kmem_cache_node(s, node, n) {
4202 		struct page *p;
4203 
4204 		list_for_each_entry(p, &n->partial, lru)
4205 			p->slab_cache = s;
4206 
4207 #ifdef CONFIG_SLUB_DEBUG
4208 		list_for_each_entry(p, &n->full, lru)
4209 			p->slab_cache = s;
4210 #endif
4211 	}
4212 	slab_init_memcg_params(s);
4213 	list_add(&s->list, &slab_caches);
4214 	memcg_link_cache(s);
4215 	return s;
4216 }
4217 
4218 void __init kmem_cache_init(void)
4219 {
4220 	static __initdata struct kmem_cache boot_kmem_cache,
4221 		boot_kmem_cache_node;
4222 
4223 	if (debug_guardpage_minorder())
4224 		slub_max_order = 0;
4225 
4226 	kmem_cache_node = &boot_kmem_cache_node;
4227 	kmem_cache = &boot_kmem_cache;
4228 
4229 	create_boot_cache(kmem_cache_node, "kmem_cache_node",
4230 		sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
4231 
4232 	register_hotmemory_notifier(&slab_memory_callback_nb);
4233 
4234 	/* Able to allocate the per node structures */
4235 	slab_state = PARTIAL;
4236 
4237 	create_boot_cache(kmem_cache, "kmem_cache",
4238 			offsetof(struct kmem_cache, node) +
4239 				nr_node_ids * sizeof(struct kmem_cache_node *),
4240 		       SLAB_HWCACHE_ALIGN, 0, 0);
4241 
4242 	kmem_cache = bootstrap(&boot_kmem_cache);
4243 	kmem_cache_node = bootstrap(&boot_kmem_cache_node);
4244 
4245 	/* Now we can use the kmem_cache to allocate kmalloc slabs */
4246 	setup_kmalloc_cache_index_table();
4247 	create_kmalloc_caches(0);
4248 
4249 	/* Setup random freelists for each cache */
4250 	init_freelist_randomization();
4251 
4252 	cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
4253 				  slub_cpu_dead);
4254 
4255 	pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%d\n",
4256 		cache_line_size(),
4257 		slub_min_order, slub_max_order, slub_min_objects,
4258 		nr_cpu_ids, nr_node_ids);
4259 }
4260 
4261 void __init kmem_cache_init_late(void)
4262 {
4263 }
4264 
4265 struct kmem_cache *
4266 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
4267 		   slab_flags_t flags, void (*ctor)(void *))
4268 {
4269 	struct kmem_cache *s, *c;
4270 
4271 	s = find_mergeable(size, align, flags, name, ctor);
4272 	if (s) {
4273 		s->refcount++;
4274 
4275 		/*
4276 		 * Adjust the object sizes so that we clear
4277 		 * the complete object on kzalloc.
4278 		 */
4279 		s->object_size = max(s->object_size, size);
4280 		s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
4281 
4282 		for_each_memcg_cache(c, s) {
4283 			c->object_size = s->object_size;
4284 			c->inuse = max(c->inuse, ALIGN(size, sizeof(void *)));
4285 		}
4286 
4287 		if (sysfs_slab_alias(s, name)) {
4288 			s->refcount--;
4289 			s = NULL;
4290 		}
4291 	}
4292 
4293 	return s;
4294 }
4295 
4296 int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
4297 {
4298 	int err;
4299 
4300 	err = kmem_cache_open(s, flags);
4301 	if (err)
4302 		return err;
4303 
4304 	/* Mutex is not taken during early boot */
4305 	if (slab_state <= UP)
4306 		return 0;
4307 
4308 	memcg_propagate_slab_attrs(s);
4309 	err = sysfs_slab_add(s);
4310 	if (err)
4311 		__kmem_cache_release(s);
4312 
4313 	return err;
4314 }
4315 
4316 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4317 {
4318 	struct kmem_cache *s;
4319 	void *ret;
4320 
4321 	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4322 		return kmalloc_large(size, gfpflags);
4323 
4324 	s = kmalloc_slab(size, gfpflags);
4325 
4326 	if (unlikely(ZERO_OR_NULL_PTR(s)))
4327 		return s;
4328 
4329 	ret = slab_alloc(s, gfpflags, caller);
4330 
4331 	/* Honor the call site pointer we received. */
4332 	trace_kmalloc(caller, ret, size, s->size, gfpflags);
4333 
4334 	return ret;
4335 }
4336 
4337 #ifdef CONFIG_NUMA
4338 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4339 					int node, unsigned long caller)
4340 {
4341 	struct kmem_cache *s;
4342 	void *ret;
4343 
4344 	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4345 		ret = kmalloc_large_node(size, gfpflags, node);
4346 
4347 		trace_kmalloc_node(caller, ret,
4348 				   size, PAGE_SIZE << get_order(size),
4349 				   gfpflags, node);
4350 
4351 		return ret;
4352 	}
4353 
4354 	s = kmalloc_slab(size, gfpflags);
4355 
4356 	if (unlikely(ZERO_OR_NULL_PTR(s)))
4357 		return s;
4358 
4359 	ret = slab_alloc_node(s, gfpflags, node, caller);
4360 
4361 	/* Honor the call site pointer we received. */
4362 	trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4363 
4364 	return ret;
4365 }
4366 #endif
4367 
4368 #ifdef CONFIG_SYSFS
4369 static int count_inuse(struct page *page)
4370 {
4371 	return page->inuse;
4372 }
4373 
4374 static int count_total(struct page *page)
4375 {
4376 	return page->objects;
4377 }
4378 #endif
4379 
4380 #ifdef CONFIG_SLUB_DEBUG
4381 static int validate_slab(struct kmem_cache *s, struct page *page,
4382 						unsigned long *map)
4383 {
4384 	void *p;
4385 	void *addr = page_address(page);
4386 
4387 	if (!check_slab(s, page) ||
4388 			!on_freelist(s, page, NULL))
4389 		return 0;
4390 
4391 	/* Now we know that a valid freelist exists */
4392 	bitmap_zero(map, page->objects);
4393 
4394 	get_map(s, page, map);
4395 	for_each_object(p, s, addr, page->objects) {
4396 		if (test_bit(slab_index(p, s, addr), map))
4397 			if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4398 				return 0;
4399 	}
4400 
4401 	for_each_object(p, s, addr, page->objects)
4402 		if (!test_bit(slab_index(p, s, addr), map))
4403 			if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4404 				return 0;
4405 	return 1;
4406 }
4407 
4408 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4409 						unsigned long *map)
4410 {
4411 	slab_lock(page);
4412 	validate_slab(s, page, map);
4413 	slab_unlock(page);
4414 }
4415 
4416 static int validate_slab_node(struct kmem_cache *s,
4417 		struct kmem_cache_node *n, unsigned long *map)
4418 {
4419 	unsigned long count = 0;
4420 	struct page *page;
4421 	unsigned long flags;
4422 
4423 	spin_lock_irqsave(&n->list_lock, flags);
4424 
4425 	list_for_each_entry(page, &n->partial, lru) {
4426 		validate_slab_slab(s, page, map);
4427 		count++;
4428 	}
4429 	if (count != n->nr_partial)
4430 		pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4431 		       s->name, count, n->nr_partial);
4432 
4433 	if (!(s->flags & SLAB_STORE_USER))
4434 		goto out;
4435 
4436 	list_for_each_entry(page, &n->full, lru) {
4437 		validate_slab_slab(s, page, map);
4438 		count++;
4439 	}
4440 	if (count != atomic_long_read(&n->nr_slabs))
4441 		pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4442 		       s->name, count, atomic_long_read(&n->nr_slabs));
4443 
4444 out:
4445 	spin_unlock_irqrestore(&n->list_lock, flags);
4446 	return count;
4447 }
4448 
4449 static long validate_slab_cache(struct kmem_cache *s)
4450 {
4451 	int node;
4452 	unsigned long count = 0;
4453 	struct kmem_cache_node *n;
4454 	unsigned long *map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL);
4455 
4456 	if (!map)
4457 		return -ENOMEM;
4458 
4459 	flush_all(s);
4460 	for_each_kmem_cache_node(s, node, n)
4461 		count += validate_slab_node(s, n, map);
4462 	bitmap_free(map);
4463 	return count;
4464 }
4465 /*
4466  * Generate lists of code addresses where slabcache objects are allocated
4467  * and freed.
4468  */
4469 
4470 struct location {
4471 	unsigned long count;
4472 	unsigned long addr;
4473 	long long sum_time;
4474 	long min_time;
4475 	long max_time;
4476 	long min_pid;
4477 	long max_pid;
4478 	DECLARE_BITMAP(cpus, NR_CPUS);
4479 	nodemask_t nodes;
4480 };
4481 
4482 struct loc_track {
4483 	unsigned long max;
4484 	unsigned long count;
4485 	struct location *loc;
4486 };
4487 
4488 static void free_loc_track(struct loc_track *t)
4489 {
4490 	if (t->max)
4491 		free_pages((unsigned long)t->loc,
4492 			get_order(sizeof(struct location) * t->max));
4493 }
4494 
4495 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4496 {
4497 	struct location *l;
4498 	int order;
4499 
4500 	order = get_order(sizeof(struct location) * max);
4501 
4502 	l = (void *)__get_free_pages(flags, order);
4503 	if (!l)
4504 		return 0;
4505 
4506 	if (t->count) {
4507 		memcpy(l, t->loc, sizeof(struct location) * t->count);
4508 		free_loc_track(t);
4509 	}
4510 	t->max = max;
4511 	t->loc = l;
4512 	return 1;
4513 }
4514 
4515 static int add_location(struct loc_track *t, struct kmem_cache *s,
4516 				const struct track *track)
4517 {
4518 	long start, end, pos;
4519 	struct location *l;
4520 	unsigned long caddr;
4521 	unsigned long age = jiffies - track->when;
4522 
4523 	start = -1;
4524 	end = t->count;
4525 
4526 	for ( ; ; ) {
4527 		pos = start + (end - start + 1) / 2;
4528 
4529 		/*
4530 		 * There is nothing at "end". If we end up there
4531 		 * we need to add something to before end.
4532 		 */
4533 		if (pos == end)
4534 			break;
4535 
4536 		caddr = t->loc[pos].addr;
4537 		if (track->addr == caddr) {
4538 
4539 			l = &t->loc[pos];
4540 			l->count++;
4541 			if (track->when) {
4542 				l->sum_time += age;
4543 				if (age < l->min_time)
4544 					l->min_time = age;
4545 				if (age > l->max_time)
4546 					l->max_time = age;
4547 
4548 				if (track->pid < l->min_pid)
4549 					l->min_pid = track->pid;
4550 				if (track->pid > l->max_pid)
4551 					l->max_pid = track->pid;
4552 
4553 				cpumask_set_cpu(track->cpu,
4554 						to_cpumask(l->cpus));
4555 			}
4556 			node_set(page_to_nid(virt_to_page(track)), l->nodes);
4557 			return 1;
4558 		}
4559 
4560 		if (track->addr < caddr)
4561 			end = pos;
4562 		else
4563 			start = pos;
4564 	}
4565 
4566 	/*
4567 	 * Not found. Insert new tracking element.
4568 	 */
4569 	if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4570 		return 0;
4571 
4572 	l = t->loc + pos;
4573 	if (pos < t->count)
4574 		memmove(l + 1, l,
4575 			(t->count - pos) * sizeof(struct location));
4576 	t->count++;
4577 	l->count = 1;
4578 	l->addr = track->addr;
4579 	l->sum_time = age;
4580 	l->min_time = age;
4581 	l->max_time = age;
4582 	l->min_pid = track->pid;
4583 	l->max_pid = track->pid;
4584 	cpumask_clear(to_cpumask(l->cpus));
4585 	cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4586 	nodes_clear(l->nodes);
4587 	node_set(page_to_nid(virt_to_page(track)), l->nodes);
4588 	return 1;
4589 }
4590 
4591 static void process_slab(struct loc_track *t, struct kmem_cache *s,
4592 		struct page *page, enum track_item alloc,
4593 		unsigned long *map)
4594 {
4595 	void *addr = page_address(page);
4596 	void *p;
4597 
4598 	bitmap_zero(map, page->objects);
4599 	get_map(s, page, map);
4600 
4601 	for_each_object(p, s, addr, page->objects)
4602 		if (!test_bit(slab_index(p, s, addr), map))
4603 			add_location(t, s, get_track(s, p, alloc));
4604 }
4605 
4606 static int list_locations(struct kmem_cache *s, char *buf,
4607 					enum track_item alloc)
4608 {
4609 	int len = 0;
4610 	unsigned long i;
4611 	struct loc_track t = { 0, 0, NULL };
4612 	int node;
4613 	struct kmem_cache_node *n;
4614 	unsigned long *map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL);
4615 
4616 	if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4617 				     GFP_KERNEL)) {
4618 		bitmap_free(map);
4619 		return sprintf(buf, "Out of memory\n");
4620 	}
4621 	/* Push back cpu slabs */
4622 	flush_all(s);
4623 
4624 	for_each_kmem_cache_node(s, node, n) {
4625 		unsigned long flags;
4626 		struct page *page;
4627 
4628 		if (!atomic_long_read(&n->nr_slabs))
4629 			continue;
4630 
4631 		spin_lock_irqsave(&n->list_lock, flags);
4632 		list_for_each_entry(page, &n->partial, lru)
4633 			process_slab(&t, s, page, alloc, map);
4634 		list_for_each_entry(page, &n->full, lru)
4635 			process_slab(&t, s, page, alloc, map);
4636 		spin_unlock_irqrestore(&n->list_lock, flags);
4637 	}
4638 
4639 	for (i = 0; i < t.count; i++) {
4640 		struct location *l = &t.loc[i];
4641 
4642 		if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4643 			break;
4644 		len += sprintf(buf + len, "%7ld ", l->count);
4645 
4646 		if (l->addr)
4647 			len += sprintf(buf + len, "%pS", (void *)l->addr);
4648 		else
4649 			len += sprintf(buf + len, "<not-available>");
4650 
4651 		if (l->sum_time != l->min_time) {
4652 			len += sprintf(buf + len, " age=%ld/%ld/%ld",
4653 				l->min_time,
4654 				(long)div_u64(l->sum_time, l->count),
4655 				l->max_time);
4656 		} else
4657 			len += sprintf(buf + len, " age=%ld",
4658 				l->min_time);
4659 
4660 		if (l->min_pid != l->max_pid)
4661 			len += sprintf(buf + len, " pid=%ld-%ld",
4662 				l->min_pid, l->max_pid);
4663 		else
4664 			len += sprintf(buf + len, " pid=%ld",
4665 				l->min_pid);
4666 
4667 		if (num_online_cpus() > 1 &&
4668 				!cpumask_empty(to_cpumask(l->cpus)) &&
4669 				len < PAGE_SIZE - 60)
4670 			len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4671 					 " cpus=%*pbl",
4672 					 cpumask_pr_args(to_cpumask(l->cpus)));
4673 
4674 		if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4675 				len < PAGE_SIZE - 60)
4676 			len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4677 					 " nodes=%*pbl",
4678 					 nodemask_pr_args(&l->nodes));
4679 
4680 		len += sprintf(buf + len, "\n");
4681 	}
4682 
4683 	free_loc_track(&t);
4684 	bitmap_free(map);
4685 	if (!t.count)
4686 		len += sprintf(buf, "No data\n");
4687 	return len;
4688 }
4689 #endif
4690 
4691 #ifdef SLUB_RESILIENCY_TEST
4692 static void __init resiliency_test(void)
4693 {
4694 	u8 *p;
4695 	int type = KMALLOC_NORMAL;
4696 
4697 	BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4698 
4699 	pr_err("SLUB resiliency testing\n");
4700 	pr_err("-----------------------\n");
4701 	pr_err("A. Corruption after allocation\n");
4702 
4703 	p = kzalloc(16, GFP_KERNEL);
4704 	p[16] = 0x12;
4705 	pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4706 	       p + 16);
4707 
4708 	validate_slab_cache(kmalloc_caches[type][4]);
4709 
4710 	/* Hmmm... The next two are dangerous */
4711 	p = kzalloc(32, GFP_KERNEL);
4712 	p[32 + sizeof(void *)] = 0x34;
4713 	pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4714 	       p);
4715 	pr_err("If allocated object is overwritten then not detectable\n\n");
4716 
4717 	validate_slab_cache(kmalloc_caches[type][5]);
4718 	p = kzalloc(64, GFP_KERNEL);
4719 	p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4720 	*p = 0x56;
4721 	pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4722 	       p);
4723 	pr_err("If allocated object is overwritten then not detectable\n\n");
4724 	validate_slab_cache(kmalloc_caches[type][6]);
4725 
4726 	pr_err("\nB. Corruption after free\n");
4727 	p = kzalloc(128, GFP_KERNEL);
4728 	kfree(p);
4729 	*p = 0x78;
4730 	pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4731 	validate_slab_cache(kmalloc_caches[type][7]);
4732 
4733 	p = kzalloc(256, GFP_KERNEL);
4734 	kfree(p);
4735 	p[50] = 0x9a;
4736 	pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
4737 	validate_slab_cache(kmalloc_caches[type][8]);
4738 
4739 	p = kzalloc(512, GFP_KERNEL);
4740 	kfree(p);
4741 	p[512] = 0xab;
4742 	pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4743 	validate_slab_cache(kmalloc_caches[type][9]);
4744 }
4745 #else
4746 #ifdef CONFIG_SYSFS
4747 static void resiliency_test(void) {};
4748 #endif
4749 #endif
4750 
4751 #ifdef CONFIG_SYSFS
4752 enum slab_stat_type {
4753 	SL_ALL,			/* All slabs */
4754 	SL_PARTIAL,		/* Only partially allocated slabs */
4755 	SL_CPU,			/* Only slabs used for cpu caches */
4756 	SL_OBJECTS,		/* Determine allocated objects not slabs */
4757 	SL_TOTAL		/* Determine object capacity not slabs */
4758 };
4759 
4760 #define SO_ALL		(1 << SL_ALL)
4761 #define SO_PARTIAL	(1 << SL_PARTIAL)
4762 #define SO_CPU		(1 << SL_CPU)
4763 #define SO_OBJECTS	(1 << SL_OBJECTS)
4764 #define SO_TOTAL	(1 << SL_TOTAL)
4765 
4766 #ifdef CONFIG_MEMCG
4767 static bool memcg_sysfs_enabled = IS_ENABLED(CONFIG_SLUB_MEMCG_SYSFS_ON);
4768 
4769 static int __init setup_slub_memcg_sysfs(char *str)
4770 {
4771 	int v;
4772 
4773 	if (get_option(&str, &v) > 0)
4774 		memcg_sysfs_enabled = v;
4775 
4776 	return 1;
4777 }
4778 
4779 __setup("slub_memcg_sysfs=", setup_slub_memcg_sysfs);
4780 #endif
4781 
4782 static ssize_t show_slab_objects(struct kmem_cache *s,
4783 			    char *buf, unsigned long flags)
4784 {
4785 	unsigned long total = 0;
4786 	int node;
4787 	int x;
4788 	unsigned long *nodes;
4789 
4790 	nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
4791 	if (!nodes)
4792 		return -ENOMEM;
4793 
4794 	if (flags & SO_CPU) {
4795 		int cpu;
4796 
4797 		for_each_possible_cpu(cpu) {
4798 			struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4799 							       cpu);
4800 			int node;
4801 			struct page *page;
4802 
4803 			page = READ_ONCE(c->page);
4804 			if (!page)
4805 				continue;
4806 
4807 			node = page_to_nid(page);
4808 			if (flags & SO_TOTAL)
4809 				x = page->objects;
4810 			else if (flags & SO_OBJECTS)
4811 				x = page->inuse;
4812 			else
4813 				x = 1;
4814 
4815 			total += x;
4816 			nodes[node] += x;
4817 
4818 			page = slub_percpu_partial_read_once(c);
4819 			if (page) {
4820 				node = page_to_nid(page);
4821 				if (flags & SO_TOTAL)
4822 					WARN_ON_ONCE(1);
4823 				else if (flags & SO_OBJECTS)
4824 					WARN_ON_ONCE(1);
4825 				else
4826 					x = page->pages;
4827 				total += x;
4828 				nodes[node] += x;
4829 			}
4830 		}
4831 	}
4832 
4833 	get_online_mems();
4834 #ifdef CONFIG_SLUB_DEBUG
4835 	if (flags & SO_ALL) {
4836 		struct kmem_cache_node *n;
4837 
4838 		for_each_kmem_cache_node(s, node, n) {
4839 
4840 			if (flags & SO_TOTAL)
4841 				x = atomic_long_read(&n->total_objects);
4842 			else if (flags & SO_OBJECTS)
4843 				x = atomic_long_read(&n->total_objects) -
4844 					count_partial(n, count_free);
4845 			else
4846 				x = atomic_long_read(&n->nr_slabs);
4847 			total += x;
4848 			nodes[node] += x;
4849 		}
4850 
4851 	} else
4852 #endif
4853 	if (flags & SO_PARTIAL) {
4854 		struct kmem_cache_node *n;
4855 
4856 		for_each_kmem_cache_node(s, node, n) {
4857 			if (flags & SO_TOTAL)
4858 				x = count_partial(n, count_total);
4859 			else if (flags & SO_OBJECTS)
4860 				x = count_partial(n, count_inuse);
4861 			else
4862 				x = n->nr_partial;
4863 			total += x;
4864 			nodes[node] += x;
4865 		}
4866 	}
4867 	x = sprintf(buf, "%lu", total);
4868 #ifdef CONFIG_NUMA
4869 	for (node = 0; node < nr_node_ids; node++)
4870 		if (nodes[node])
4871 			x += sprintf(buf + x, " N%d=%lu",
4872 					node, nodes[node]);
4873 #endif
4874 	put_online_mems();
4875 	kfree(nodes);
4876 	return x + sprintf(buf + x, "\n");
4877 }
4878 
4879 #ifdef CONFIG_SLUB_DEBUG
4880 static int any_slab_objects(struct kmem_cache *s)
4881 {
4882 	int node;
4883 	struct kmem_cache_node *n;
4884 
4885 	for_each_kmem_cache_node(s, node, n)
4886 		if (atomic_long_read(&n->total_objects))
4887 			return 1;
4888 
4889 	return 0;
4890 }
4891 #endif
4892 
4893 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4894 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4895 
4896 struct slab_attribute {
4897 	struct attribute attr;
4898 	ssize_t (*show)(struct kmem_cache *s, char *buf);
4899 	ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4900 };
4901 
4902 #define SLAB_ATTR_RO(_name) \
4903 	static struct slab_attribute _name##_attr = \
4904 	__ATTR(_name, 0400, _name##_show, NULL)
4905 
4906 #define SLAB_ATTR(_name) \
4907 	static struct slab_attribute _name##_attr =  \
4908 	__ATTR(_name, 0600, _name##_show, _name##_store)
4909 
4910 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4911 {
4912 	return sprintf(buf, "%u\n", s->size);
4913 }
4914 SLAB_ATTR_RO(slab_size);
4915 
4916 static ssize_t align_show(struct kmem_cache *s, char *buf)
4917 {
4918 	return sprintf(buf, "%u\n", s->align);
4919 }
4920 SLAB_ATTR_RO(align);
4921 
4922 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4923 {
4924 	return sprintf(buf, "%u\n", s->object_size);
4925 }
4926 SLAB_ATTR_RO(object_size);
4927 
4928 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4929 {
4930 	return sprintf(buf, "%u\n", oo_objects(s->oo));
4931 }
4932 SLAB_ATTR_RO(objs_per_slab);
4933 
4934 static ssize_t order_store(struct kmem_cache *s,
4935 				const char *buf, size_t length)
4936 {
4937 	unsigned int order;
4938 	int err;
4939 
4940 	err = kstrtouint(buf, 10, &order);
4941 	if (err)
4942 		return err;
4943 
4944 	if (order > slub_max_order || order < slub_min_order)
4945 		return -EINVAL;
4946 
4947 	calculate_sizes(s, order);
4948 	return length;
4949 }
4950 
4951 static ssize_t order_show(struct kmem_cache *s, char *buf)
4952 {
4953 	return sprintf(buf, "%u\n", oo_order(s->oo));
4954 }
4955 SLAB_ATTR(order);
4956 
4957 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4958 {
4959 	return sprintf(buf, "%lu\n", s->min_partial);
4960 }
4961 
4962 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4963 				 size_t length)
4964 {
4965 	unsigned long min;
4966 	int err;
4967 
4968 	err = kstrtoul(buf, 10, &min);
4969 	if (err)
4970 		return err;
4971 
4972 	set_min_partial(s, min);
4973 	return length;
4974 }
4975 SLAB_ATTR(min_partial);
4976 
4977 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4978 {
4979 	return sprintf(buf, "%u\n", slub_cpu_partial(s));
4980 }
4981 
4982 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4983 				 size_t length)
4984 {
4985 	unsigned int objects;
4986 	int err;
4987 
4988 	err = kstrtouint(buf, 10, &objects);
4989 	if (err)
4990 		return err;
4991 	if (objects && !kmem_cache_has_cpu_partial(s))
4992 		return -EINVAL;
4993 
4994 	slub_set_cpu_partial(s, objects);
4995 	flush_all(s);
4996 	return length;
4997 }
4998 SLAB_ATTR(cpu_partial);
4999 
5000 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
5001 {
5002 	if (!s->ctor)
5003 		return 0;
5004 	return sprintf(buf, "%pS\n", s->ctor);
5005 }
5006 SLAB_ATTR_RO(ctor);
5007 
5008 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
5009 {
5010 	return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
5011 }
5012 SLAB_ATTR_RO(aliases);
5013 
5014 static ssize_t partial_show(struct kmem_cache *s, char *buf)
5015 {
5016 	return show_slab_objects(s, buf, SO_PARTIAL);
5017 }
5018 SLAB_ATTR_RO(partial);
5019 
5020 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
5021 {
5022 	return show_slab_objects(s, buf, SO_CPU);
5023 }
5024 SLAB_ATTR_RO(cpu_slabs);
5025 
5026 static ssize_t objects_show(struct kmem_cache *s, char *buf)
5027 {
5028 	return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
5029 }
5030 SLAB_ATTR_RO(objects);
5031 
5032 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
5033 {
5034 	return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
5035 }
5036 SLAB_ATTR_RO(objects_partial);
5037 
5038 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
5039 {
5040 	int objects = 0;
5041 	int pages = 0;
5042 	int cpu;
5043 	int len;
5044 
5045 	for_each_online_cpu(cpu) {
5046 		struct page *page;
5047 
5048 		page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5049 
5050 		if (page) {
5051 			pages += page->pages;
5052 			objects += page->pobjects;
5053 		}
5054 	}
5055 
5056 	len = sprintf(buf, "%d(%d)", objects, pages);
5057 
5058 #ifdef CONFIG_SMP
5059 	for_each_online_cpu(cpu) {
5060 		struct page *page;
5061 
5062 		page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5063 
5064 		if (page && len < PAGE_SIZE - 20)
5065 			len += sprintf(buf + len, " C%d=%d(%d)", cpu,
5066 				page->pobjects, page->pages);
5067 	}
5068 #endif
5069 	return len + sprintf(buf + len, "\n");
5070 }
5071 SLAB_ATTR_RO(slabs_cpu_partial);
5072 
5073 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
5074 {
5075 	return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
5076 }
5077 
5078 static ssize_t reclaim_account_store(struct kmem_cache *s,
5079 				const char *buf, size_t length)
5080 {
5081 	s->flags &= ~SLAB_RECLAIM_ACCOUNT;
5082 	if (buf[0] == '1')
5083 		s->flags |= SLAB_RECLAIM_ACCOUNT;
5084 	return length;
5085 }
5086 SLAB_ATTR(reclaim_account);
5087 
5088 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
5089 {
5090 	return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
5091 }
5092 SLAB_ATTR_RO(hwcache_align);
5093 
5094 #ifdef CONFIG_ZONE_DMA
5095 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
5096 {
5097 	return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
5098 }
5099 SLAB_ATTR_RO(cache_dma);
5100 #endif
5101 
5102 static ssize_t usersize_show(struct kmem_cache *s, char *buf)
5103 {
5104 	return sprintf(buf, "%u\n", s->usersize);
5105 }
5106 SLAB_ATTR_RO(usersize);
5107 
5108 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
5109 {
5110 	return sprintf(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
5111 }
5112 SLAB_ATTR_RO(destroy_by_rcu);
5113 
5114 #ifdef CONFIG_SLUB_DEBUG
5115 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
5116 {
5117 	return show_slab_objects(s, buf, SO_ALL);
5118 }
5119 SLAB_ATTR_RO(slabs);
5120 
5121 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
5122 {
5123 	return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
5124 }
5125 SLAB_ATTR_RO(total_objects);
5126 
5127 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
5128 {
5129 	return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
5130 }
5131 
5132 static ssize_t sanity_checks_store(struct kmem_cache *s,
5133 				const char *buf, size_t length)
5134 {
5135 	s->flags &= ~SLAB_CONSISTENCY_CHECKS;
5136 	if (buf[0] == '1') {
5137 		s->flags &= ~__CMPXCHG_DOUBLE;
5138 		s->flags |= SLAB_CONSISTENCY_CHECKS;
5139 	}
5140 	return length;
5141 }
5142 SLAB_ATTR(sanity_checks);
5143 
5144 static ssize_t trace_show(struct kmem_cache *s, char *buf)
5145 {
5146 	return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
5147 }
5148 
5149 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
5150 							size_t length)
5151 {
5152 	/*
5153 	 * Tracing a merged cache is going to give confusing results
5154 	 * as well as cause other issues like converting a mergeable
5155 	 * cache into an umergeable one.
5156 	 */
5157 	if (s->refcount > 1)
5158 		return -EINVAL;
5159 
5160 	s->flags &= ~SLAB_TRACE;
5161 	if (buf[0] == '1') {
5162 		s->flags &= ~__CMPXCHG_DOUBLE;
5163 		s->flags |= SLAB_TRACE;
5164 	}
5165 	return length;
5166 }
5167 SLAB_ATTR(trace);
5168 
5169 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5170 {
5171 	return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5172 }
5173 
5174 static ssize_t red_zone_store(struct kmem_cache *s,
5175 				const char *buf, size_t length)
5176 {
5177 	if (any_slab_objects(s))
5178 		return -EBUSY;
5179 
5180 	s->flags &= ~SLAB_RED_ZONE;
5181 	if (buf[0] == '1') {
5182 		s->flags |= SLAB_RED_ZONE;
5183 	}
5184 	calculate_sizes(s, -1);
5185 	return length;
5186 }
5187 SLAB_ATTR(red_zone);
5188 
5189 static ssize_t poison_show(struct kmem_cache *s, char *buf)
5190 {
5191 	return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
5192 }
5193 
5194 static ssize_t poison_store(struct kmem_cache *s,
5195 				const char *buf, size_t length)
5196 {
5197 	if (any_slab_objects(s))
5198 		return -EBUSY;
5199 
5200 	s->flags &= ~SLAB_POISON;
5201 	if (buf[0] == '1') {
5202 		s->flags |= SLAB_POISON;
5203 	}
5204 	calculate_sizes(s, -1);
5205 	return length;
5206 }
5207 SLAB_ATTR(poison);
5208 
5209 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5210 {
5211 	return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5212 }
5213 
5214 static ssize_t store_user_store(struct kmem_cache *s,
5215 				const char *buf, size_t length)
5216 {
5217 	if (any_slab_objects(s))
5218 		return -EBUSY;
5219 
5220 	s->flags &= ~SLAB_STORE_USER;
5221 	if (buf[0] == '1') {
5222 		s->flags &= ~__CMPXCHG_DOUBLE;
5223 		s->flags |= SLAB_STORE_USER;
5224 	}
5225 	calculate_sizes(s, -1);
5226 	return length;
5227 }
5228 SLAB_ATTR(store_user);
5229 
5230 static ssize_t validate_show(struct kmem_cache *s, char *buf)
5231 {
5232 	return 0;
5233 }
5234 
5235 static ssize_t validate_store(struct kmem_cache *s,
5236 			const char *buf, size_t length)
5237 {
5238 	int ret = -EINVAL;
5239 
5240 	if (buf[0] == '1') {
5241 		ret = validate_slab_cache(s);
5242 		if (ret >= 0)
5243 			ret = length;
5244 	}
5245 	return ret;
5246 }
5247 SLAB_ATTR(validate);
5248 
5249 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
5250 {
5251 	if (!(s->flags & SLAB_STORE_USER))
5252 		return -ENOSYS;
5253 	return list_locations(s, buf, TRACK_ALLOC);
5254 }
5255 SLAB_ATTR_RO(alloc_calls);
5256 
5257 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
5258 {
5259 	if (!(s->flags & SLAB_STORE_USER))
5260 		return -ENOSYS;
5261 	return list_locations(s, buf, TRACK_FREE);
5262 }
5263 SLAB_ATTR_RO(free_calls);
5264 #endif /* CONFIG_SLUB_DEBUG */
5265 
5266 #ifdef CONFIG_FAILSLAB
5267 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5268 {
5269 	return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5270 }
5271 
5272 static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
5273 							size_t length)
5274 {
5275 	if (s->refcount > 1)
5276 		return -EINVAL;
5277 
5278 	s->flags &= ~SLAB_FAILSLAB;
5279 	if (buf[0] == '1')
5280 		s->flags |= SLAB_FAILSLAB;
5281 	return length;
5282 }
5283 SLAB_ATTR(failslab);
5284 #endif
5285 
5286 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5287 {
5288 	return 0;
5289 }
5290 
5291 static ssize_t shrink_store(struct kmem_cache *s,
5292 			const char *buf, size_t length)
5293 {
5294 	if (buf[0] == '1')
5295 		kmem_cache_shrink(s);
5296 	else
5297 		return -EINVAL;
5298 	return length;
5299 }
5300 SLAB_ATTR(shrink);
5301 
5302 #ifdef CONFIG_NUMA
5303 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5304 {
5305 	return sprintf(buf, "%u\n", s->remote_node_defrag_ratio / 10);
5306 }
5307 
5308 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5309 				const char *buf, size_t length)
5310 {
5311 	unsigned int ratio;
5312 	int err;
5313 
5314 	err = kstrtouint(buf, 10, &ratio);
5315 	if (err)
5316 		return err;
5317 	if (ratio > 100)
5318 		return -ERANGE;
5319 
5320 	s->remote_node_defrag_ratio = ratio * 10;
5321 
5322 	return length;
5323 }
5324 SLAB_ATTR(remote_node_defrag_ratio);
5325 #endif
5326 
5327 #ifdef CONFIG_SLUB_STATS
5328 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5329 {
5330 	unsigned long sum  = 0;
5331 	int cpu;
5332 	int len;
5333 	int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
5334 
5335 	if (!data)
5336 		return -ENOMEM;
5337 
5338 	for_each_online_cpu(cpu) {
5339 		unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5340 
5341 		data[cpu] = x;
5342 		sum += x;
5343 	}
5344 
5345 	len = sprintf(buf, "%lu", sum);
5346 
5347 #ifdef CONFIG_SMP
5348 	for_each_online_cpu(cpu) {
5349 		if (data[cpu] && len < PAGE_SIZE - 20)
5350 			len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
5351 	}
5352 #endif
5353 	kfree(data);
5354 	return len + sprintf(buf + len, "\n");
5355 }
5356 
5357 static void clear_stat(struct kmem_cache *s, enum stat_item si)
5358 {
5359 	int cpu;
5360 
5361 	for_each_online_cpu(cpu)
5362 		per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5363 }
5364 
5365 #define STAT_ATTR(si, text) 					\
5366 static ssize_t text##_show(struct kmem_cache *s, char *buf)	\
5367 {								\
5368 	return show_stat(s, buf, si);				\
5369 }								\
5370 static ssize_t text##_store(struct kmem_cache *s,		\
5371 				const char *buf, size_t length)	\
5372 {								\
5373 	if (buf[0] != '0')					\
5374 		return -EINVAL;					\
5375 	clear_stat(s, si);					\
5376 	return length;						\
5377 }								\
5378 SLAB_ATTR(text);						\
5379 
5380 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5381 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5382 STAT_ATTR(FREE_FASTPATH, free_fastpath);
5383 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5384 STAT_ATTR(FREE_FROZEN, free_frozen);
5385 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5386 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5387 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5388 STAT_ATTR(ALLOC_SLAB, alloc_slab);
5389 STAT_ATTR(ALLOC_REFILL, alloc_refill);
5390 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5391 STAT_ATTR(FREE_SLAB, free_slab);
5392 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5393 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5394 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5395 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5396 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5397 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5398 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5399 STAT_ATTR(ORDER_FALLBACK, order_fallback);
5400 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5401 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5402 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5403 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5404 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5405 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5406 #endif
5407 
5408 static struct attribute *slab_attrs[] = {
5409 	&slab_size_attr.attr,
5410 	&object_size_attr.attr,
5411 	&objs_per_slab_attr.attr,
5412 	&order_attr.attr,
5413 	&min_partial_attr.attr,
5414 	&cpu_partial_attr.attr,
5415 	&objects_attr.attr,
5416 	&objects_partial_attr.attr,
5417 	&partial_attr.attr,
5418 	&cpu_slabs_attr.attr,
5419 	&ctor_attr.attr,
5420 	&aliases_attr.attr,
5421 	&align_attr.attr,
5422 	&hwcache_align_attr.attr,
5423 	&reclaim_account_attr.attr,
5424 	&destroy_by_rcu_attr.attr,
5425 	&shrink_attr.attr,
5426 	&slabs_cpu_partial_attr.attr,
5427 #ifdef CONFIG_SLUB_DEBUG
5428 	&total_objects_attr.attr,
5429 	&slabs_attr.attr,
5430 	&sanity_checks_attr.attr,
5431 	&trace_attr.attr,
5432 	&red_zone_attr.attr,
5433 	&poison_attr.attr,
5434 	&store_user_attr.attr,
5435 	&validate_attr.attr,
5436 	&alloc_calls_attr.attr,
5437 	&free_calls_attr.attr,
5438 #endif
5439 #ifdef CONFIG_ZONE_DMA
5440 	&cache_dma_attr.attr,
5441 #endif
5442 #ifdef CONFIG_NUMA
5443 	&remote_node_defrag_ratio_attr.attr,
5444 #endif
5445 #ifdef CONFIG_SLUB_STATS
5446 	&alloc_fastpath_attr.attr,
5447 	&alloc_slowpath_attr.attr,
5448 	&free_fastpath_attr.attr,
5449 	&free_slowpath_attr.attr,
5450 	&free_frozen_attr.attr,
5451 	&free_add_partial_attr.attr,
5452 	&free_remove_partial_attr.attr,
5453 	&alloc_from_partial_attr.attr,
5454 	&alloc_slab_attr.attr,
5455 	&alloc_refill_attr.attr,
5456 	&alloc_node_mismatch_attr.attr,
5457 	&free_slab_attr.attr,
5458 	&cpuslab_flush_attr.attr,
5459 	&deactivate_full_attr.attr,
5460 	&deactivate_empty_attr.attr,
5461 	&deactivate_to_head_attr.attr,
5462 	&deactivate_to_tail_attr.attr,
5463 	&deactivate_remote_frees_attr.attr,
5464 	&deactivate_bypass_attr.attr,
5465 	&order_fallback_attr.attr,
5466 	&cmpxchg_double_fail_attr.attr,
5467 	&cmpxchg_double_cpu_fail_attr.attr,
5468 	&cpu_partial_alloc_attr.attr,
5469 	&cpu_partial_free_attr.attr,
5470 	&cpu_partial_node_attr.attr,
5471 	&cpu_partial_drain_attr.attr,
5472 #endif
5473 #ifdef CONFIG_FAILSLAB
5474 	&failslab_attr.attr,
5475 #endif
5476 	&usersize_attr.attr,
5477 
5478 	NULL
5479 };
5480 
5481 static const struct attribute_group slab_attr_group = {
5482 	.attrs = slab_attrs,
5483 };
5484 
5485 static ssize_t slab_attr_show(struct kobject *kobj,
5486 				struct attribute *attr,
5487 				char *buf)
5488 {
5489 	struct slab_attribute *attribute;
5490 	struct kmem_cache *s;
5491 	int err;
5492 
5493 	attribute = to_slab_attr(attr);
5494 	s = to_slab(kobj);
5495 
5496 	if (!attribute->show)
5497 		return -EIO;
5498 
5499 	err = attribute->show(s, buf);
5500 
5501 	return err;
5502 }
5503 
5504 static ssize_t slab_attr_store(struct kobject *kobj,
5505 				struct attribute *attr,
5506 				const char *buf, size_t len)
5507 {
5508 	struct slab_attribute *attribute;
5509 	struct kmem_cache *s;
5510 	int err;
5511 
5512 	attribute = to_slab_attr(attr);
5513 	s = to_slab(kobj);
5514 
5515 	if (!attribute->store)
5516 		return -EIO;
5517 
5518 	err = attribute->store(s, buf, len);
5519 #ifdef CONFIG_MEMCG
5520 	if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
5521 		struct kmem_cache *c;
5522 
5523 		mutex_lock(&slab_mutex);
5524 		if (s->max_attr_size < len)
5525 			s->max_attr_size = len;
5526 
5527 		/*
5528 		 * This is a best effort propagation, so this function's return
5529 		 * value will be determined by the parent cache only. This is
5530 		 * basically because not all attributes will have a well
5531 		 * defined semantics for rollbacks - most of the actions will
5532 		 * have permanent effects.
5533 		 *
5534 		 * Returning the error value of any of the children that fail
5535 		 * is not 100 % defined, in the sense that users seeing the
5536 		 * error code won't be able to know anything about the state of
5537 		 * the cache.
5538 		 *
5539 		 * Only returning the error code for the parent cache at least
5540 		 * has well defined semantics. The cache being written to
5541 		 * directly either failed or succeeded, in which case we loop
5542 		 * through the descendants with best-effort propagation.
5543 		 */
5544 		for_each_memcg_cache(c, s)
5545 			attribute->store(c, buf, len);
5546 		mutex_unlock(&slab_mutex);
5547 	}
5548 #endif
5549 	return err;
5550 }
5551 
5552 static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5553 {
5554 #ifdef CONFIG_MEMCG
5555 	int i;
5556 	char *buffer = NULL;
5557 	struct kmem_cache *root_cache;
5558 
5559 	if (is_root_cache(s))
5560 		return;
5561 
5562 	root_cache = s->memcg_params.root_cache;
5563 
5564 	/*
5565 	 * This mean this cache had no attribute written. Therefore, no point
5566 	 * in copying default values around
5567 	 */
5568 	if (!root_cache->max_attr_size)
5569 		return;
5570 
5571 	for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5572 		char mbuf[64];
5573 		char *buf;
5574 		struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5575 		ssize_t len;
5576 
5577 		if (!attr || !attr->store || !attr->show)
5578 			continue;
5579 
5580 		/*
5581 		 * It is really bad that we have to allocate here, so we will
5582 		 * do it only as a fallback. If we actually allocate, though,
5583 		 * we can just use the allocated buffer until the end.
5584 		 *
5585 		 * Most of the slub attributes will tend to be very small in
5586 		 * size, but sysfs allows buffers up to a page, so they can
5587 		 * theoretically happen.
5588 		 */
5589 		if (buffer)
5590 			buf = buffer;
5591 		else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
5592 			buf = mbuf;
5593 		else {
5594 			buffer = (char *) get_zeroed_page(GFP_KERNEL);
5595 			if (WARN_ON(!buffer))
5596 				continue;
5597 			buf = buffer;
5598 		}
5599 
5600 		len = attr->show(root_cache, buf);
5601 		if (len > 0)
5602 			attr->store(s, buf, len);
5603 	}
5604 
5605 	if (buffer)
5606 		free_page((unsigned long)buffer);
5607 #endif
5608 }
5609 
5610 static void kmem_cache_release(struct kobject *k)
5611 {
5612 	slab_kmem_cache_release(to_slab(k));
5613 }
5614 
5615 static const struct sysfs_ops slab_sysfs_ops = {
5616 	.show = slab_attr_show,
5617 	.store = slab_attr_store,
5618 };
5619 
5620 static struct kobj_type slab_ktype = {
5621 	.sysfs_ops = &slab_sysfs_ops,
5622 	.release = kmem_cache_release,
5623 };
5624 
5625 static int uevent_filter(struct kset *kset, struct kobject *kobj)
5626 {
5627 	struct kobj_type *ktype = get_ktype(kobj);
5628 
5629 	if (ktype == &slab_ktype)
5630 		return 1;
5631 	return 0;
5632 }
5633 
5634 static const struct kset_uevent_ops slab_uevent_ops = {
5635 	.filter = uevent_filter,
5636 };
5637 
5638 static struct kset *slab_kset;
5639 
5640 static inline struct kset *cache_kset(struct kmem_cache *s)
5641 {
5642 #ifdef CONFIG_MEMCG
5643 	if (!is_root_cache(s))
5644 		return s->memcg_params.root_cache->memcg_kset;
5645 #endif
5646 	return slab_kset;
5647 }
5648 
5649 #define ID_STR_LENGTH 64
5650 
5651 /* Create a unique string id for a slab cache:
5652  *
5653  * Format	:[flags-]size
5654  */
5655 static char *create_unique_id(struct kmem_cache *s)
5656 {
5657 	char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5658 	char *p = name;
5659 
5660 	BUG_ON(!name);
5661 
5662 	*p++ = ':';
5663 	/*
5664 	 * First flags affecting slabcache operations. We will only
5665 	 * get here for aliasable slabs so we do not need to support
5666 	 * too many flags. The flags here must cover all flags that
5667 	 * are matched during merging to guarantee that the id is
5668 	 * unique.
5669 	 */
5670 	if (s->flags & SLAB_CACHE_DMA)
5671 		*p++ = 'd';
5672 	if (s->flags & SLAB_RECLAIM_ACCOUNT)
5673 		*p++ = 'a';
5674 	if (s->flags & SLAB_CONSISTENCY_CHECKS)
5675 		*p++ = 'F';
5676 	if (s->flags & SLAB_ACCOUNT)
5677 		*p++ = 'A';
5678 	if (p != name + 1)
5679 		*p++ = '-';
5680 	p += sprintf(p, "%07u", s->size);
5681 
5682 	BUG_ON(p > name + ID_STR_LENGTH - 1);
5683 	return name;
5684 }
5685 
5686 static void sysfs_slab_remove_workfn(struct work_struct *work)
5687 {
5688 	struct kmem_cache *s =
5689 		container_of(work, struct kmem_cache, kobj_remove_work);
5690 
5691 	if (!s->kobj.state_in_sysfs)
5692 		/*
5693 		 * For a memcg cache, this may be called during
5694 		 * deactivation and again on shutdown.  Remove only once.
5695 		 * A cache is never shut down before deactivation is
5696 		 * complete, so no need to worry about synchronization.
5697 		 */
5698 		goto out;
5699 
5700 #ifdef CONFIG_MEMCG
5701 	kset_unregister(s->memcg_kset);
5702 #endif
5703 	kobject_uevent(&s->kobj, KOBJ_REMOVE);
5704 out:
5705 	kobject_put(&s->kobj);
5706 }
5707 
5708 static int sysfs_slab_add(struct kmem_cache *s)
5709 {
5710 	int err;
5711 	const char *name;
5712 	struct kset *kset = cache_kset(s);
5713 	int unmergeable = slab_unmergeable(s);
5714 
5715 	INIT_WORK(&s->kobj_remove_work, sysfs_slab_remove_workfn);
5716 
5717 	if (!kset) {
5718 		kobject_init(&s->kobj, &slab_ktype);
5719 		return 0;
5720 	}
5721 
5722 	if (!unmergeable && disable_higher_order_debug &&
5723 			(slub_debug & DEBUG_METADATA_FLAGS))
5724 		unmergeable = 1;
5725 
5726 	if (unmergeable) {
5727 		/*
5728 		 * Slabcache can never be merged so we can use the name proper.
5729 		 * This is typically the case for debug situations. In that
5730 		 * case we can catch duplicate names easily.
5731 		 */
5732 		sysfs_remove_link(&slab_kset->kobj, s->name);
5733 		name = s->name;
5734 	} else {
5735 		/*
5736 		 * Create a unique name for the slab as a target
5737 		 * for the symlinks.
5738 		 */
5739 		name = create_unique_id(s);
5740 	}
5741 
5742 	s->kobj.kset = kset;
5743 	err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5744 	if (err)
5745 		goto out;
5746 
5747 	err = sysfs_create_group(&s->kobj, &slab_attr_group);
5748 	if (err)
5749 		goto out_del_kobj;
5750 
5751 #ifdef CONFIG_MEMCG
5752 	if (is_root_cache(s) && memcg_sysfs_enabled) {
5753 		s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj);
5754 		if (!s->memcg_kset) {
5755 			err = -ENOMEM;
5756 			goto out_del_kobj;
5757 		}
5758 	}
5759 #endif
5760 
5761 	kobject_uevent(&s->kobj, KOBJ_ADD);
5762 	if (!unmergeable) {
5763 		/* Setup first alias */
5764 		sysfs_slab_alias(s, s->name);
5765 	}
5766 out:
5767 	if (!unmergeable)
5768 		kfree(name);
5769 	return err;
5770 out_del_kobj:
5771 	kobject_del(&s->kobj);
5772 	goto out;
5773 }
5774 
5775 static void sysfs_slab_remove(struct kmem_cache *s)
5776 {
5777 	if (slab_state < FULL)
5778 		/*
5779 		 * Sysfs has not been setup yet so no need to remove the
5780 		 * cache from sysfs.
5781 		 */
5782 		return;
5783 
5784 	kobject_get(&s->kobj);
5785 	schedule_work(&s->kobj_remove_work);
5786 }
5787 
5788 void sysfs_slab_unlink(struct kmem_cache *s)
5789 {
5790 	if (slab_state >= FULL)
5791 		kobject_del(&s->kobj);
5792 }
5793 
5794 void sysfs_slab_release(struct kmem_cache *s)
5795 {
5796 	if (slab_state >= FULL)
5797 		kobject_put(&s->kobj);
5798 }
5799 
5800 /*
5801  * Need to buffer aliases during bootup until sysfs becomes
5802  * available lest we lose that information.
5803  */
5804 struct saved_alias {
5805 	struct kmem_cache *s;
5806 	const char *name;
5807 	struct saved_alias *next;
5808 };
5809 
5810 static struct saved_alias *alias_list;
5811 
5812 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5813 {
5814 	struct saved_alias *al;
5815 
5816 	if (slab_state == FULL) {
5817 		/*
5818 		 * If we have a leftover link then remove it.
5819 		 */
5820 		sysfs_remove_link(&slab_kset->kobj, name);
5821 		return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5822 	}
5823 
5824 	al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5825 	if (!al)
5826 		return -ENOMEM;
5827 
5828 	al->s = s;
5829 	al->name = name;
5830 	al->next = alias_list;
5831 	alias_list = al;
5832 	return 0;
5833 }
5834 
5835 static int __init slab_sysfs_init(void)
5836 {
5837 	struct kmem_cache *s;
5838 	int err;
5839 
5840 	mutex_lock(&slab_mutex);
5841 
5842 	slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5843 	if (!slab_kset) {
5844 		mutex_unlock(&slab_mutex);
5845 		pr_err("Cannot register slab subsystem.\n");
5846 		return -ENOSYS;
5847 	}
5848 
5849 	slab_state = FULL;
5850 
5851 	list_for_each_entry(s, &slab_caches, list) {
5852 		err = sysfs_slab_add(s);
5853 		if (err)
5854 			pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5855 			       s->name);
5856 	}
5857 
5858 	while (alias_list) {
5859 		struct saved_alias *al = alias_list;
5860 
5861 		alias_list = alias_list->next;
5862 		err = sysfs_slab_alias(al->s, al->name);
5863 		if (err)
5864 			pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5865 			       al->name);
5866 		kfree(al);
5867 	}
5868 
5869 	mutex_unlock(&slab_mutex);
5870 	resiliency_test();
5871 	return 0;
5872 }
5873 
5874 __initcall(slab_sysfs_init);
5875 #endif /* CONFIG_SYSFS */
5876 
5877 /*
5878  * The /proc/slabinfo ABI
5879  */
5880 #ifdef CONFIG_SLUB_DEBUG
5881 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5882 {
5883 	unsigned long nr_slabs = 0;
5884 	unsigned long nr_objs = 0;
5885 	unsigned long nr_free = 0;
5886 	int node;
5887 	struct kmem_cache_node *n;
5888 
5889 	for_each_kmem_cache_node(s, node, n) {
5890 		nr_slabs += node_nr_slabs(n);
5891 		nr_objs += node_nr_objs(n);
5892 		nr_free += count_partial(n, count_free);
5893 	}
5894 
5895 	sinfo->active_objs = nr_objs - nr_free;
5896 	sinfo->num_objs = nr_objs;
5897 	sinfo->active_slabs = nr_slabs;
5898 	sinfo->num_slabs = nr_slabs;
5899 	sinfo->objects_per_slab = oo_objects(s->oo);
5900 	sinfo->cache_order = oo_order(s->oo);
5901 }
5902 
5903 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5904 {
5905 }
5906 
5907 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5908 		       size_t count, loff_t *ppos)
5909 {
5910 	return -EIO;
5911 }
5912 #endif /* CONFIG_SLUB_DEBUG */
5913