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 except per cpu partial list. The processor that froze the
  62 *   slab is the one who can perform list operations on the page. Other
  63 *   processors may put objects onto the freelist but the processor that
  64 *   froze the slab is the only one that can retrieve the objects from the
  65 *   page's freelist.
  66 *
  67 *   The list_lock protects the partial and full list on each node and
  68 *   the partial slab counter. If taken then no new slabs may be added or
  69 *   removed from the lists nor make the number of partial slabs be modified.
  70 *   (Note that the total number of slabs is an atomic value that may be
  71 *   modified without taking the list lock).
  72 *
  73 *   The list_lock is a centralized lock and thus we avoid taking it as
  74 *   much as possible. As long as SLUB does not have to handle partial
  75 *   slabs, operations can continue without any centralized lock. F.e.
  76 *   allocating a long series of objects that fill up slabs does not require
  77 *   the list lock.
  78 *   Interrupts are disabled during allocation and deallocation in order to
  79 *   make the slab allocator safe to use in the context of an irq. In addition
  80 *   interrupts are disabled to ensure that the processor does not change
  81 *   while handling per_cpu slabs, due to kernel preemption.
  82 *
  83 * SLUB assigns one slab for allocation to each processor.
  84 * Allocations only occur from these slabs called cpu slabs.
  85 *
  86 * Slabs with free elements are kept on a partial list and during regular
  87 * operations no list for full slabs is used. If an object in a full slab is
  88 * freed then the slab will show up again on the partial lists.
  89 * We track full slabs for debugging purposes though because otherwise we
  90 * cannot scan all objects.
  91 *
  92 * Slabs are freed when they become empty. Teardown and setup is
  93 * minimal so we rely on the page allocators per cpu caches for
  94 * fast frees and allocs.
  95 *
  96 * page->frozen		The slab is frozen and exempt from list processing.
  97 * 			This means that the slab is dedicated to a purpose
  98 * 			such as satisfying allocations for a specific
  99 * 			processor. Objects may be freed in the slab while
 100 * 			it is frozen but slab_free will then skip the usual
 101 * 			list operations. It is up to the processor holding
 102 * 			the slab to integrate the slab into the slab lists
 103 * 			when the slab is no longer needed.
 104 *
 105 * 			One use of this flag is to mark slabs that are
 106 * 			used for allocations. Then such a slab becomes a cpu
 107 * 			slab. The cpu slab may be equipped with an additional
 108 * 			freelist that allows lockless access to
 109 * 			free objects in addition to the regular freelist
 110 * 			that requires the slab lock.
 111 *
 112 * SLAB_DEBUG_FLAGS	Slab requires special handling due to debug
 113 * 			options set. This moves	slab handling out of
 114 * 			the fast path and disables lockless freelists.
 115 */
 116
 117#ifdef CONFIG_SLUB_DEBUG
 118#ifdef CONFIG_SLUB_DEBUG_ON
 119DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
 120#else
 121DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
 122#endif
 123#endif
 124
 125static inline bool kmem_cache_debug(struct kmem_cache *s)
 126{
 127	return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
 128}
 129
 130void *fixup_red_left(struct kmem_cache *s, void *p)
 131{
 132	if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
 133		p += s->red_left_pad;
 134
 135	return p;
 136}
 137
 138static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
 139{
 140#ifdef CONFIG_SLUB_CPU_PARTIAL
 141	return !kmem_cache_debug(s);
 142#else
 143	return false;
 144#endif
 145}
 146
 147/*
 148 * Issues still to be resolved:
 149 *
 150 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
 151 *
 152 * - Variable sizing of the per node arrays
 153 */
 154
 155/* Enable to test recovery from slab corruption on boot */
 156#undef SLUB_RESILIENCY_TEST
 157
 158/* Enable to log cmpxchg failures */
 159#undef SLUB_DEBUG_CMPXCHG
 160
 161/*
 162 * Mininum number of partial slabs. These will be left on the partial
 163 * lists even if they are empty. kmem_cache_shrink may reclaim them.
 164 */
 165#define MIN_PARTIAL 5
 166
 167/*
 168 * Maximum number of desirable partial slabs.
 169 * The existence of more partial slabs makes kmem_cache_shrink
 170 * sort the partial list by the number of objects in use.
 171 */
 172#define MAX_PARTIAL 10
 173
 174#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
 175				SLAB_POISON | SLAB_STORE_USER)
 176
 177/*
 178 * These debug flags cannot use CMPXCHG because there might be consistency
 179 * issues when checking or reading debug information
 180 */
 181#define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
 182				SLAB_TRACE)
 183
 184
 185/*
 186 * Debugging flags that require metadata to be stored in the slab.  These get
 187 * disabled when slub_debug=O is used and a cache's min order increases with
 188 * metadata.
 189 */
 190#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 191
 192#define OO_SHIFT	16
 193#define OO_MASK		((1 << OO_SHIFT) - 1)
 194#define MAX_OBJS_PER_PAGE	32767 /* since page.objects is u15 */
 195
 196/* Internal SLUB flags */
 197/* Poison object */
 198#define __OBJECT_POISON		((slab_flags_t __force)0x80000000U)
 199/* Use cmpxchg_double */
 200#define __CMPXCHG_DOUBLE	((slab_flags_t __force)0x40000000U)
 201
 202/*
 203 * Tracking user of a slab.
 204 */
 205#define TRACK_ADDRS_COUNT 16
 206struct track {
 207	unsigned long addr;	/* Called from address */
 208#ifdef CONFIG_STACKTRACE
 209	unsigned long addrs[TRACK_ADDRS_COUNT];	/* Called from address */
 210#endif
 211	int cpu;		/* Was running on cpu */
 212	int pid;		/* Pid context */
 213	unsigned long when;	/* When did the operation occur */
 214};
 215
 216enum track_item { TRACK_ALLOC, TRACK_FREE };
 217
 218#ifdef CONFIG_SYSFS
 219static int sysfs_slab_add(struct kmem_cache *);
 220static int sysfs_slab_alias(struct kmem_cache *, const char *);
 221#else
 222static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
 223static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
 224							{ return 0; }
 225#endif
 226
 
 
 
 
 
 
 227static inline void stat(const struct kmem_cache *s, enum stat_item si)
 228{
 229#ifdef CONFIG_SLUB_STATS
 230	/*
 231	 * The rmw is racy on a preemptible kernel but this is acceptable, so
 232	 * avoid this_cpu_add()'s irq-disable overhead.
 233	 */
 234	raw_cpu_inc(s->cpu_slab->stat[si]);
 235#endif
 236}
 237
 
 
 
 
 
 
 
 
 238/********************************************************************
 239 * 			Core slab cache functions
 240 *******************************************************************/
 241
 242/*
 243 * Returns freelist pointer (ptr). With hardening, this is obfuscated
 244 * with an XOR of the address where the pointer is held and a per-cache
 245 * random number.
 246 */
 247static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr,
 248				 unsigned long ptr_addr)
 249{
 250#ifdef CONFIG_SLAB_FREELIST_HARDENED
 251	/*
 252	 * When CONFIG_KASAN_SW_TAGS is enabled, ptr_addr might be tagged.
 253	 * Normally, this doesn't cause any issues, as both set_freepointer()
 254	 * and get_freepointer() are called with a pointer with the same tag.
 255	 * However, there are some issues with CONFIG_SLUB_DEBUG code. For
 256	 * example, when __free_slub() iterates over objects in a cache, it
 257	 * passes untagged pointers to check_object(). check_object() in turns
 258	 * calls get_freepointer() with an untagged pointer, which causes the
 259	 * freepointer to be restored incorrectly.
 260	 */
 261	return (void *)((unsigned long)ptr ^ s->random ^
 262			swab((unsigned long)kasan_reset_tag((void *)ptr_addr)));
 263#else
 264	return ptr;
 265#endif
 266}
 267
 268/* Returns the freelist pointer recorded at location ptr_addr. */
 269static inline void *freelist_dereference(const struct kmem_cache *s,
 270					 void *ptr_addr)
 271{
 272	return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr),
 273			    (unsigned long)ptr_addr);
 274}
 275
 276static inline void *get_freepointer(struct kmem_cache *s, void *object)
 277{
 
 278	return freelist_dereference(s, object + s->offset);
 279}
 280
 281static void prefetch_freepointer(const struct kmem_cache *s, void *object)
 282{
 283	prefetch(object + s->offset);
 284}
 285
 286static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
 287{
 288	unsigned long freepointer_addr;
 289	void *p;
 290
 291	if (!debug_pagealloc_enabled_static())
 292		return get_freepointer(s, object);
 293
 
 294	freepointer_addr = (unsigned long)object + s->offset;
 295	copy_from_kernel_nofault(&p, (void **)freepointer_addr, sizeof(p));
 296	return freelist_ptr(s, p, freepointer_addr);
 297}
 298
 299static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
 300{
 301	unsigned long freeptr_addr = (unsigned long)object + s->offset;
 302
 303#ifdef CONFIG_SLAB_FREELIST_HARDENED
 304	BUG_ON(object == fp); /* naive detection of double free or corruption */
 305#endif
 306
 
 307	*(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr);
 308}
 309
 310/* Loop over all objects in a slab */
 311#define for_each_object(__p, __s, __addr, __objects) \
 312	for (__p = fixup_red_left(__s, __addr); \
 313		__p < (__addr) + (__objects) * (__s)->size; \
 314		__p += (__s)->size)
 315
 316static inline unsigned int order_objects(unsigned int order, unsigned int size)
 317{
 318	return ((unsigned int)PAGE_SIZE << order) / size;
 319}
 320
 321static inline struct kmem_cache_order_objects oo_make(unsigned int order,
 322		unsigned int size)
 323{
 324	struct kmem_cache_order_objects x = {
 325		(order << OO_SHIFT) + order_objects(order, size)
 326	};
 327
 328	return x;
 329}
 330
 331static inline unsigned int oo_order(struct kmem_cache_order_objects x)
 332{
 333	return x.x >> OO_SHIFT;
 334}
 335
 336static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
 337{
 338	return x.x & OO_MASK;
 339}
 340
 341/*
 342 * Per slab locking using the pagelock
 343 */
 344static __always_inline void slab_lock(struct page *page)
 345{
 346	VM_BUG_ON_PAGE(PageTail(page), page);
 347	bit_spin_lock(PG_locked, &page->flags);
 348}
 349
 350static __always_inline void slab_unlock(struct page *page)
 351{
 352	VM_BUG_ON_PAGE(PageTail(page), page);
 353	__bit_spin_unlock(PG_locked, &page->flags);
 354}
 355
 356/* Interrupts must be disabled (for the fallback code to work right) */
 357static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 358		void *freelist_old, unsigned long counters_old,
 359		void *freelist_new, unsigned long counters_new,
 360		const char *n)
 361{
 362	VM_BUG_ON(!irqs_disabled());
 363#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
 364    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
 365	if (s->flags & __CMPXCHG_DOUBLE) {
 366		if (cmpxchg_double(&page->freelist, &page->counters,
 367				   freelist_old, counters_old,
 368				   freelist_new, counters_new))
 369			return true;
 370	} else
 371#endif
 372	{
 373		slab_lock(page);
 374		if (page->freelist == freelist_old &&
 375					page->counters == counters_old) {
 376			page->freelist = freelist_new;
 377			page->counters = counters_new;
 378			slab_unlock(page);
 379			return true;
 380		}
 381		slab_unlock(page);
 382	}
 383
 384	cpu_relax();
 385	stat(s, CMPXCHG_DOUBLE_FAIL);
 386
 387#ifdef SLUB_DEBUG_CMPXCHG
 388	pr_info("%s %s: cmpxchg double redo ", n, s->name);
 389#endif
 390
 391	return false;
 392}
 393
 394static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 395		void *freelist_old, unsigned long counters_old,
 396		void *freelist_new, unsigned long counters_new,
 397		const char *n)
 398{
 399#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
 400    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
 401	if (s->flags & __CMPXCHG_DOUBLE) {
 402		if (cmpxchg_double(&page->freelist, &page->counters,
 403				   freelist_old, counters_old,
 404				   freelist_new, counters_new))
 405			return true;
 406	} else
 407#endif
 408	{
 409		unsigned long flags;
 410
 411		local_irq_save(flags);
 412		slab_lock(page);
 413		if (page->freelist == freelist_old &&
 414					page->counters == counters_old) {
 415			page->freelist = freelist_new;
 416			page->counters = counters_new;
 417			slab_unlock(page);
 418			local_irq_restore(flags);
 419			return true;
 420		}
 421		slab_unlock(page);
 422		local_irq_restore(flags);
 423	}
 424
 425	cpu_relax();
 426	stat(s, CMPXCHG_DOUBLE_FAIL);
 427
 428#ifdef SLUB_DEBUG_CMPXCHG
 429	pr_info("%s %s: cmpxchg double redo ", n, s->name);
 430#endif
 431
 432	return false;
 433}
 434
 435#ifdef CONFIG_SLUB_DEBUG
 436static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
 437static DEFINE_SPINLOCK(object_map_lock);
 438
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 439/*
 440 * Determine a map of object in use on a page.
 441 *
 442 * Node listlock must be held to guarantee that the page does
 443 * not vanish from under us.
 444 */
 445static unsigned long *get_map(struct kmem_cache *s, struct page *page)
 446	__acquires(&object_map_lock)
 447{
 448	void *p;
 449	void *addr = page_address(page);
 450
 451	VM_BUG_ON(!irqs_disabled());
 452
 453	spin_lock(&object_map_lock);
 454
 455	bitmap_zero(object_map, page->objects);
 456
 457	for (p = page->freelist; p; p = get_freepointer(s, p))
 458		set_bit(__obj_to_index(s, addr, p), object_map);
 459
 460	return object_map;
 461}
 462
 463static void put_map(unsigned long *map) __releases(&object_map_lock)
 464{
 465	VM_BUG_ON(map != object_map);
 466	spin_unlock(&object_map_lock);
 467}
 468
 469static inline unsigned int size_from_object(struct kmem_cache *s)
 470{
 471	if (s->flags & SLAB_RED_ZONE)
 472		return s->size - s->red_left_pad;
 473
 474	return s->size;
 475}
 476
 477static inline void *restore_red_left(struct kmem_cache *s, void *p)
 478{
 479	if (s->flags & SLAB_RED_ZONE)
 480		p -= s->red_left_pad;
 481
 482	return p;
 483}
 484
 485/*
 486 * Debug settings:
 487 */
 488#if defined(CONFIG_SLUB_DEBUG_ON)
 489static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
 490#else
 491static slab_flags_t slub_debug;
 492#endif
 493
 494static char *slub_debug_string;
 495static int disable_higher_order_debug;
 496
 497/*
 498 * slub is about to manipulate internal object metadata.  This memory lies
 499 * outside the range of the allocated object, so accessing it would normally
 500 * be reported by kasan as a bounds error.  metadata_access_enable() is used
 501 * to tell kasan that these accesses are OK.
 502 */
 503static inline void metadata_access_enable(void)
 504{
 505	kasan_disable_current();
 506}
 507
 508static inline void metadata_access_disable(void)
 509{
 510	kasan_enable_current();
 511}
 512
 513/*
 514 * Object debugging
 515 */
 516
 517/* Verify that a pointer has an address that is valid within a slab page */
 518static inline int check_valid_pointer(struct kmem_cache *s,
 519				struct page *page, void *object)
 520{
 521	void *base;
 522
 523	if (!object)
 524		return 1;
 525
 526	base = page_address(page);
 527	object = kasan_reset_tag(object);
 528	object = restore_red_left(s, object);
 529	if (object < base || object >= base + page->objects * s->size ||
 530		(object - base) % s->size) {
 531		return 0;
 532	}
 533
 534	return 1;
 535}
 536
 537static void print_section(char *level, char *text, u8 *addr,
 538			  unsigned int length)
 539{
 540	metadata_access_enable();
 541	print_hex_dump(level, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
 542			length, 1);
 543	metadata_access_disable();
 544}
 545
 546/*
 547 * See comment in calculate_sizes().
 548 */
 549static inline bool freeptr_outside_object(struct kmem_cache *s)
 550{
 551	return s->offset >= s->inuse;
 552}
 553
 554/*
 555 * Return offset of the end of info block which is inuse + free pointer if
 556 * not overlapping with object.
 557 */
 558static inline unsigned int get_info_end(struct kmem_cache *s)
 559{
 560	if (freeptr_outside_object(s))
 561		return s->inuse + sizeof(void *);
 562	else
 563		return s->inuse;
 564}
 565
 566static struct track *get_track(struct kmem_cache *s, void *object,
 567	enum track_item alloc)
 568{
 569	struct track *p;
 570
 571	p = object + get_info_end(s);
 572
 573	return p + alloc;
 574}
 575
 576static void set_track(struct kmem_cache *s, void *object,
 577			enum track_item alloc, unsigned long addr)
 578{
 579	struct track *p = get_track(s, object, alloc);
 580
 581	if (addr) {
 582#ifdef CONFIG_STACKTRACE
 583		unsigned int nr_entries;
 584
 585		metadata_access_enable();
 586		nr_entries = stack_trace_save(p->addrs, TRACK_ADDRS_COUNT, 3);
 
 587		metadata_access_disable();
 588
 589		if (nr_entries < TRACK_ADDRS_COUNT)
 590			p->addrs[nr_entries] = 0;
 591#endif
 592		p->addr = addr;
 593		p->cpu = smp_processor_id();
 594		p->pid = current->pid;
 595		p->when = jiffies;
 596	} else {
 597		memset(p, 0, sizeof(struct track));
 598	}
 599}
 600
 601static void init_tracking(struct kmem_cache *s, void *object)
 602{
 603	if (!(s->flags & SLAB_STORE_USER))
 604		return;
 605
 606	set_track(s, object, TRACK_FREE, 0UL);
 607	set_track(s, object, TRACK_ALLOC, 0UL);
 608}
 609
 610static void print_track(const char *s, struct track *t, unsigned long pr_time)
 611{
 612	if (!t->addr)
 613		return;
 614
 615	pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
 616	       s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
 617#ifdef CONFIG_STACKTRACE
 618	{
 619		int i;
 620		for (i = 0; i < TRACK_ADDRS_COUNT; i++)
 621			if (t->addrs[i])
 622				pr_err("\t%pS\n", (void *)t->addrs[i]);
 623			else
 624				break;
 625	}
 626#endif
 627}
 628
 629void print_tracking(struct kmem_cache *s, void *object)
 630{
 631	unsigned long pr_time = jiffies;
 632	if (!(s->flags & SLAB_STORE_USER))
 633		return;
 634
 635	print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
 636	print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
 637}
 638
 639static void print_page_info(struct page *page)
 640{
 641	pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
 642	       page, page->objects, page->inuse, page->freelist, page->flags);
 
 643
 644}
 645
 646static void slab_bug(struct kmem_cache *s, char *fmt, ...)
 647{
 648	struct va_format vaf;
 649	va_list args;
 650
 651	va_start(args, fmt);
 652	vaf.fmt = fmt;
 653	vaf.va = &args;
 654	pr_err("=============================================================================\n");
 655	pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
 656	pr_err("-----------------------------------------------------------------------------\n\n");
 657
 658	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 659	va_end(args);
 660}
 661
 
 662static void slab_fix(struct kmem_cache *s, char *fmt, ...)
 663{
 664	struct va_format vaf;
 665	va_list args;
 666
 
 
 
 667	va_start(args, fmt);
 668	vaf.fmt = fmt;
 669	vaf.va = &args;
 670	pr_err("FIX %s: %pV\n", s->name, &vaf);
 671	va_end(args);
 672}
 673
 674static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
 675			       void **freelist, void *nextfree)
 676{
 677	if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
 678	    !check_valid_pointer(s, page, nextfree) && freelist) {
 679		object_err(s, page, *freelist, "Freechain corrupt");
 680		*freelist = NULL;
 681		slab_fix(s, "Isolate corrupted freechain");
 682		return true;
 683	}
 684
 685	return false;
 686}
 687
 688static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 689{
 690	unsigned int off;	/* Offset of last byte */
 691	u8 *addr = page_address(page);
 692
 693	print_tracking(s, p);
 694
 695	print_page_info(page);
 696
 697	pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
 698	       p, p - addr, get_freepointer(s, p));
 699
 700	if (s->flags & SLAB_RED_ZONE)
 701		print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
 702			      s->red_left_pad);
 703	else if (p > addr + 16)
 704		print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
 705
 706	print_section(KERN_ERR, "Object ", p,
 707		      min_t(unsigned int, s->object_size, PAGE_SIZE));
 708	if (s->flags & SLAB_RED_ZONE)
 709		print_section(KERN_ERR, "Redzone ", p + s->object_size,
 710			s->inuse - s->object_size);
 711
 712	off = get_info_end(s);
 713
 714	if (s->flags & SLAB_STORE_USER)
 715		off += 2 * sizeof(struct track);
 716
 717	off += kasan_metadata_size(s);
 718
 719	if (off != size_from_object(s))
 720		/* Beginning of the filler is the free pointer */
 721		print_section(KERN_ERR, "Padding ", p + off,
 722			      size_from_object(s) - off);
 723
 724	dump_stack();
 725}
 726
 727void object_err(struct kmem_cache *s, struct page *page,
 728			u8 *object, char *reason)
 729{
 
 
 
 730	slab_bug(s, "%s", reason);
 731	print_trailer(s, page, object);
 
 732}
 733
 734static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page,
 735			const char *fmt, ...)
 736{
 737	va_list args;
 738	char buf[100];
 739
 
 
 
 740	va_start(args, fmt);
 741	vsnprintf(buf, sizeof(buf), fmt, args);
 742	va_end(args);
 743	slab_bug(s, "%s", buf);
 744	print_page_info(page);
 745	dump_stack();
 
 746}
 747
 748static void init_object(struct kmem_cache *s, void *object, u8 val)
 749{
 750	u8 *p = object;
 751
 752	if (s->flags & SLAB_RED_ZONE)
 753		memset(p - s->red_left_pad, val, s->red_left_pad);
 754
 755	if (s->flags & __OBJECT_POISON) {
 756		memset(p, POISON_FREE, s->object_size - 1);
 757		p[s->object_size - 1] = POISON_END;
 758	}
 759
 760	if (s->flags & SLAB_RED_ZONE)
 761		memset(p + s->object_size, val, s->inuse - s->object_size);
 762}
 763
 764static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
 765						void *from, void *to)
 766{
 767	slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
 768	memset(from, data, to - from);
 769}
 770
 771static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
 772			u8 *object, char *what,
 773			u8 *start, unsigned int value, unsigned int bytes)
 774{
 775	u8 *fault;
 776	u8 *end;
 777	u8 *addr = page_address(page);
 778
 779	metadata_access_enable();
 780	fault = memchr_inv(start, value, bytes);
 781	metadata_access_disable();
 782	if (!fault)
 783		return 1;
 784
 785	end = start + bytes;
 786	while (end > fault && end[-1] == value)
 787		end--;
 788
 
 
 
 789	slab_bug(s, "%s overwritten", what);
 790	pr_err("INFO: 0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
 791					fault, end - 1, fault - addr,
 792					fault[0], value);
 793	print_trailer(s, page, object);
 
 794
 
 795	restore_bytes(s, what, value, fault, end);
 796	return 0;
 797}
 798
 799/*
 800 * Object layout:
 801 *
 802 * object address
 803 * 	Bytes of the object to be managed.
 804 * 	If the freepointer may overlay the object then the free
 805 *	pointer is at the middle of the object.
 806 *
 807 * 	Poisoning uses 0x6b (POISON_FREE) and the last byte is
 808 * 	0xa5 (POISON_END)
 809 *
 810 * object + s->object_size
 811 * 	Padding to reach word boundary. This is also used for Redzoning.
 812 * 	Padding is extended by another word if Redzoning is enabled and
 813 * 	object_size == inuse.
 814 *
 815 * 	We fill with 0xbb (RED_INACTIVE) for inactive objects and with
 816 * 	0xcc (RED_ACTIVE) for objects in use.
 817 *
 818 * object + s->inuse
 819 * 	Meta data starts here.
 820 *
 821 * 	A. Free pointer (if we cannot overwrite object on free)
 822 * 	B. Tracking data for SLAB_STORE_USER
 823 * 	C. Padding to reach required alignment boundary or at mininum
 824 * 		one word if debugging is on to be able to detect writes
 825 * 		before the word boundary.
 826 *
 827 *	Padding is done using 0x5a (POISON_INUSE)
 828 *
 829 * object + s->size
 830 * 	Nothing is used beyond s->size.
 831 *
 832 * If slabcaches are merged then the object_size and inuse boundaries are mostly
 833 * ignored. And therefore no slab options that rely on these boundaries
 834 * may be used with merged slabcaches.
 835 */
 836
 837static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
 838{
 839	unsigned long off = get_info_end(s);	/* The end of info */
 840
 841	if (s->flags & SLAB_STORE_USER)
 842		/* We also have user information there */
 843		off += 2 * sizeof(struct track);
 844
 845	off += kasan_metadata_size(s);
 846
 847	if (size_from_object(s) == off)
 848		return 1;
 849
 850	return check_bytes_and_report(s, page, p, "Object padding",
 851			p + off, POISON_INUSE, size_from_object(s) - off);
 852}
 853
 854/* Check the pad bytes at the end of a slab page */
 855static int slab_pad_check(struct kmem_cache *s, struct page *page)
 856{
 857	u8 *start;
 858	u8 *fault;
 859	u8 *end;
 860	u8 *pad;
 861	int length;
 862	int remainder;
 863
 864	if (!(s->flags & SLAB_POISON))
 865		return 1;
 866
 867	start = page_address(page);
 868	length = page_size(page);
 869	end = start + length;
 870	remainder = length % s->size;
 871	if (!remainder)
 872		return 1;
 873
 874	pad = end - remainder;
 875	metadata_access_enable();
 876	fault = memchr_inv(pad, POISON_INUSE, remainder);
 877	metadata_access_disable();
 878	if (!fault)
 879		return 1;
 880	while (end > fault && end[-1] == POISON_INUSE)
 881		end--;
 882
 883	slab_err(s, page, "Padding overwritten. 0x%p-0x%p @offset=%tu",
 884			fault, end - 1, fault - start);
 885	print_section(KERN_ERR, "Padding ", pad, remainder);
 886
 887	restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
 888	return 0;
 889}
 890
 891static int check_object(struct kmem_cache *s, struct page *page,
 892					void *object, u8 val)
 893{
 894	u8 *p = object;
 895	u8 *endobject = object + s->object_size;
 896
 897	if (s->flags & SLAB_RED_ZONE) {
 898		if (!check_bytes_and_report(s, page, object, "Redzone",
 899			object - s->red_left_pad, val, s->red_left_pad))
 900			return 0;
 901
 902		if (!check_bytes_and_report(s, page, object, "Redzone",
 903			endobject, val, s->inuse - s->object_size))
 904			return 0;
 905	} else {
 906		if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
 907			check_bytes_and_report(s, page, p, "Alignment padding",
 908				endobject, POISON_INUSE,
 909				s->inuse - s->object_size);
 910		}
 911	}
 912
 913	if (s->flags & SLAB_POISON) {
 914		if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
 915			(!check_bytes_and_report(s, page, p, "Poison", p,
 916					POISON_FREE, s->object_size - 1) ||
 917			 !check_bytes_and_report(s, page, p, "Poison",
 918				p + s->object_size - 1, POISON_END, 1)))
 919			return 0;
 920		/*
 921		 * check_pad_bytes cleans up on its own.
 922		 */
 923		check_pad_bytes(s, page, p);
 924	}
 925
 926	if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE)
 927		/*
 928		 * Object and freepointer overlap. Cannot check
 929		 * freepointer while object is allocated.
 930		 */
 931		return 1;
 932
 933	/* Check free pointer validity */
 934	if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
 935		object_err(s, page, p, "Freepointer corrupt");
 936		/*
 937		 * No choice but to zap it and thus lose the remainder
 938		 * of the free objects in this slab. May cause
 939		 * another error because the object count is now wrong.
 940		 */
 941		set_freepointer(s, p, NULL);
 942		return 0;
 943	}
 944	return 1;
 945}
 946
 947static int check_slab(struct kmem_cache *s, struct page *page)
 948{
 949	int maxobj;
 950
 951	VM_BUG_ON(!irqs_disabled());
 952
 953	if (!PageSlab(page)) {
 954		slab_err(s, page, "Not a valid slab page");
 955		return 0;
 956	}
 957
 958	maxobj = order_objects(compound_order(page), s->size);
 959	if (page->objects > maxobj) {
 960		slab_err(s, page, "objects %u > max %u",
 961			page->objects, maxobj);
 962		return 0;
 963	}
 964	if (page->inuse > page->objects) {
 965		slab_err(s, page, "inuse %u > max %u",
 966			page->inuse, page->objects);
 967		return 0;
 968	}
 969	/* Slab_pad_check fixes things up after itself */
 970	slab_pad_check(s, page);
 971	return 1;
 972}
 973
 974/*
 975 * Determine if a certain object on a page is on the freelist. Must hold the
 976 * slab lock to guarantee that the chains are in a consistent state.
 977 */
 978static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
 979{
 980	int nr = 0;
 981	void *fp;
 982	void *object = NULL;
 983	int max_objects;
 984
 985	fp = page->freelist;
 986	while (fp && nr <= page->objects) {
 987		if (fp == search)
 988			return 1;
 989		if (!check_valid_pointer(s, page, fp)) {
 990			if (object) {
 991				object_err(s, page, object,
 992					"Freechain corrupt");
 993				set_freepointer(s, object, NULL);
 994			} else {
 995				slab_err(s, page, "Freepointer corrupt");
 996				page->freelist = NULL;
 997				page->inuse = page->objects;
 998				slab_fix(s, "Freelist cleared");
 999				return 0;
1000			}
1001			break;
1002		}
1003		object = fp;
1004		fp = get_freepointer(s, object);
1005		nr++;
1006	}
1007
1008	max_objects = order_objects(compound_order(page), s->size);
1009	if (max_objects > MAX_OBJS_PER_PAGE)
1010		max_objects = MAX_OBJS_PER_PAGE;
1011
1012	if (page->objects != max_objects) {
1013		slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
1014			 page->objects, max_objects);
1015		page->objects = max_objects;
1016		slab_fix(s, "Number of objects adjusted.");
1017	}
1018	if (page->inuse != page->objects - nr) {
1019		slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
1020			 page->inuse, page->objects - nr);
1021		page->inuse = page->objects - nr;
1022		slab_fix(s, "Object count adjusted.");
1023	}
1024	return search == NULL;
1025}
1026
1027static void trace(struct kmem_cache *s, struct page *page, void *object,
1028								int alloc)
1029{
1030	if (s->flags & SLAB_TRACE) {
1031		pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1032			s->name,
1033			alloc ? "alloc" : "free",
1034			object, page->inuse,
1035			page->freelist);
1036
1037		if (!alloc)
1038			print_section(KERN_INFO, "Object ", (void *)object,
1039					s->object_size);
1040
1041		dump_stack();
1042	}
1043}
1044
1045/*
1046 * Tracking of fully allocated slabs for debugging purposes.
1047 */
1048static void add_full(struct kmem_cache *s,
1049	struct kmem_cache_node *n, struct page *page)
1050{
1051	if (!(s->flags & SLAB_STORE_USER))
1052		return;
1053
1054	lockdep_assert_held(&n->list_lock);
1055	list_add(&page->slab_list, &n->full);
1056}
1057
1058static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
1059{
1060	if (!(s->flags & SLAB_STORE_USER))
1061		return;
1062
1063	lockdep_assert_held(&n->list_lock);
1064	list_del(&page->slab_list);
1065}
1066
1067/* Tracking of the number of slabs for debugging purposes */
1068static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1069{
1070	struct kmem_cache_node *n = get_node(s, node);
1071
1072	return atomic_long_read(&n->nr_slabs);
1073}
1074
1075static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1076{
1077	return atomic_long_read(&n->nr_slabs);
1078}
1079
1080static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1081{
1082	struct kmem_cache_node *n = get_node(s, node);
1083
1084	/*
1085	 * May be called early in order to allocate a slab for the
1086	 * kmem_cache_node structure. Solve the chicken-egg
1087	 * dilemma by deferring the increment of the count during
1088	 * bootstrap (see early_kmem_cache_node_alloc).
1089	 */
1090	if (likely(n)) {
1091		atomic_long_inc(&n->nr_slabs);
1092		atomic_long_add(objects, &n->total_objects);
1093	}
1094}
1095static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1096{
1097	struct kmem_cache_node *n = get_node(s, node);
1098
1099	atomic_long_dec(&n->nr_slabs);
1100	atomic_long_sub(objects, &n->total_objects);
1101}
1102
1103/* Object debug checks for alloc/free paths */
1104static void setup_object_debug(struct kmem_cache *s, struct page *page,
1105								void *object)
1106{
1107	if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
1108		return;
1109
1110	init_object(s, object, SLUB_RED_INACTIVE);
1111	init_tracking(s, object);
1112}
1113
1114static
1115void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr)
1116{
1117	if (!kmem_cache_debug_flags(s, SLAB_POISON))
1118		return;
1119
1120	metadata_access_enable();
1121	memset(addr, POISON_INUSE, page_size(page));
1122	metadata_access_disable();
1123}
1124
1125static inline int alloc_consistency_checks(struct kmem_cache *s,
1126					struct page *page, void *object)
1127{
1128	if (!check_slab(s, page))
1129		return 0;
1130
1131	if (!check_valid_pointer(s, page, object)) {
1132		object_err(s, page, object, "Freelist Pointer check fails");
1133		return 0;
1134	}
1135
1136	if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1137		return 0;
1138
1139	return 1;
1140}
1141
1142static noinline int alloc_debug_processing(struct kmem_cache *s,
1143					struct page *page,
1144					void *object, unsigned long addr)
1145{
1146	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1147		if (!alloc_consistency_checks(s, page, object))
1148			goto bad;
1149	}
1150
1151	/* Success perform special debug activities for allocs */
1152	if (s->flags & SLAB_STORE_USER)
1153		set_track(s, object, TRACK_ALLOC, addr);
1154	trace(s, page, object, 1);
1155	init_object(s, object, SLUB_RED_ACTIVE);
1156	return 1;
1157
1158bad:
1159	if (PageSlab(page)) {
1160		/*
1161		 * If this is a slab page then lets do the best we can
1162		 * to avoid issues in the future. Marking all objects
1163		 * as used avoids touching the remaining objects.
1164		 */
1165		slab_fix(s, "Marking all objects used");
1166		page->inuse = page->objects;
1167		page->freelist = NULL;
1168	}
1169	return 0;
1170}
1171
1172static inline int free_consistency_checks(struct kmem_cache *s,
1173		struct page *page, void *object, unsigned long addr)
1174{
1175	if (!check_valid_pointer(s, page, object)) {
1176		slab_err(s, page, "Invalid object pointer 0x%p", object);
1177		return 0;
1178	}
1179
1180	if (on_freelist(s, page, object)) {
1181		object_err(s, page, object, "Object already free");
1182		return 0;
1183	}
1184
1185	if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1186		return 0;
1187
1188	if (unlikely(s != page->slab_cache)) {
1189		if (!PageSlab(page)) {
1190			slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
1191				 object);
1192		} else if (!page->slab_cache) {
1193			pr_err("SLUB <none>: no slab for object 0x%p.\n",
1194			       object);
1195			dump_stack();
1196		} else
1197			object_err(s, page, object,
1198					"page slab pointer corrupt.");
1199		return 0;
1200	}
1201	return 1;
1202}
1203
1204/* Supports checking bulk free of a constructed freelist */
1205static noinline int free_debug_processing(
1206	struct kmem_cache *s, struct page *page,
1207	void *head, void *tail, int bulk_cnt,
1208	unsigned long addr)
1209{
1210	struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1211	void *object = head;
1212	int cnt = 0;
1213	unsigned long flags;
1214	int ret = 0;
1215
1216	spin_lock_irqsave(&n->list_lock, flags);
1217	slab_lock(page);
1218
1219	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1220		if (!check_slab(s, page))
1221			goto out;
1222	}
1223
1224next_object:
1225	cnt++;
1226
1227	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1228		if (!free_consistency_checks(s, page, object, addr))
1229			goto out;
1230	}
1231
1232	if (s->flags & SLAB_STORE_USER)
1233		set_track(s, object, TRACK_FREE, addr);
1234	trace(s, page, object, 0);
1235	/* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1236	init_object(s, object, SLUB_RED_INACTIVE);
1237
1238	/* Reached end of constructed freelist yet? */
1239	if (object != tail) {
1240		object = get_freepointer(s, object);
1241		goto next_object;
1242	}
1243	ret = 1;
1244
1245out:
1246	if (cnt != bulk_cnt)
1247		slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
1248			 bulk_cnt, cnt);
1249
1250	slab_unlock(page);
1251	spin_unlock_irqrestore(&n->list_lock, flags);
1252	if (!ret)
1253		slab_fix(s, "Object at 0x%p not freed", object);
1254	return ret;
1255}
1256
1257/*
1258 * Parse a block of slub_debug options. Blocks are delimited by ';'
1259 *
1260 * @str:    start of block
1261 * @flags:  returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
1262 * @slabs:  return start of list of slabs, or NULL when there's no list
1263 * @init:   assume this is initial parsing and not per-kmem-create parsing
1264 *
1265 * returns the start of next block if there's any, or NULL
1266 */
1267static char *
1268parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
1269{
1270	bool higher_order_disable = false;
1271
1272	/* Skip any completely empty blocks */
1273	while (*str && *str == ';')
1274		str++;
1275
1276	if (*str == ',') {
1277		/*
1278		 * No options but restriction on slabs. This means full
1279		 * debugging for slabs matching a pattern.
1280		 */
1281		*flags = DEBUG_DEFAULT_FLAGS;
1282		goto check_slabs;
1283	}
1284	*flags = 0;
1285
1286	/* Determine which debug features should be switched on */
1287	for (; *str && *str != ',' && *str != ';'; str++) {
1288		switch (tolower(*str)) {
1289		case '-':
1290			*flags = 0;
1291			break;
1292		case 'f':
1293			*flags |= SLAB_CONSISTENCY_CHECKS;
1294			break;
1295		case 'z':
1296			*flags |= SLAB_RED_ZONE;
1297			break;
1298		case 'p':
1299			*flags |= SLAB_POISON;
1300			break;
1301		case 'u':
1302			*flags |= SLAB_STORE_USER;
1303			break;
1304		case 't':
1305			*flags |= SLAB_TRACE;
1306			break;
1307		case 'a':
1308			*flags |= SLAB_FAILSLAB;
1309			break;
1310		case 'o':
1311			/*
1312			 * Avoid enabling debugging on caches if its minimum
1313			 * order would increase as a result.
1314			 */
1315			higher_order_disable = true;
1316			break;
1317		default:
1318			if (init)
1319				pr_err("slub_debug option '%c' unknown. skipped\n", *str);
1320		}
1321	}
1322check_slabs:
1323	if (*str == ',')
1324		*slabs = ++str;
1325	else
1326		*slabs = NULL;
1327
1328	/* Skip over the slab list */
1329	while (*str && *str != ';')
1330		str++;
1331
1332	/* Skip any completely empty blocks */
1333	while (*str && *str == ';')
1334		str++;
1335
1336	if (init && higher_order_disable)
1337		disable_higher_order_debug = 1;
1338
1339	if (*str)
1340		return str;
1341	else
1342		return NULL;
1343}
1344
1345static int __init setup_slub_debug(char *str)
1346{
1347	slab_flags_t flags;
 
1348	char *saved_str;
1349	char *slab_list;
1350	bool global_slub_debug_changed = false;
1351	bool slab_list_specified = false;
1352
1353	slub_debug = DEBUG_DEFAULT_FLAGS;
1354	if (*str++ != '=' || !*str)
1355		/*
1356		 * No options specified. Switch on full debugging.
1357		 */
1358		goto out;
1359
1360	saved_str = str;
1361	while (str) {
1362		str = parse_slub_debug_flags(str, &flags, &slab_list, true);
1363
1364		if (!slab_list) {
1365			slub_debug = flags;
1366			global_slub_debug_changed = true;
1367		} else {
1368			slab_list_specified = true;
1369		}
1370	}
1371
1372	/*
1373	 * For backwards compatibility, a single list of flags with list of
1374	 * slabs means debugging is only enabled for those slabs, so the global
1375	 * slub_debug should be 0. We can extended that to multiple lists as
 
1376	 * long as there is no option specifying flags without a slab list.
1377	 */
1378	if (slab_list_specified) {
1379		if (!global_slub_debug_changed)
1380			slub_debug = 0;
1381		slub_debug_string = saved_str;
1382	}
1383out:
 
1384	if (slub_debug != 0 || slub_debug_string)
1385		static_branch_enable(&slub_debug_enabled);
 
 
1386	if ((static_branch_unlikely(&init_on_alloc) ||
1387	     static_branch_unlikely(&init_on_free)) &&
1388	    (slub_debug & SLAB_POISON))
1389		pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
1390	return 1;
1391}
1392
1393__setup("slub_debug", setup_slub_debug);
1394
1395/*
1396 * kmem_cache_flags - apply debugging options to the cache
1397 * @object_size:	the size of an object without meta data
1398 * @flags:		flags to set
1399 * @name:		name of the cache
1400 * @ctor:		constructor function
1401 *
1402 * Debug option(s) are applied to @flags. In addition to the debug
1403 * option(s), if a slab name (or multiple) is specified i.e.
1404 * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
1405 * then only the select slabs will receive the debug option(s).
1406 */
1407slab_flags_t kmem_cache_flags(unsigned int object_size,
1408	slab_flags_t flags, const char *name,
1409	void (*ctor)(void *))
1410{
1411	char *iter;
1412	size_t len;
1413	char *next_block;
1414	slab_flags_t block_flags;
 
 
 
 
 
 
 
 
 
1415
1416	len = strlen(name);
1417	next_block = slub_debug_string;
1418	/* Go through all blocks of debug options, see if any matches our slab's name */
1419	while (next_block) {
1420		next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false);
1421		if (!iter)
1422			continue;
1423		/* Found a block that has a slab list, search it */
1424		while (*iter) {
1425			char *end, *glob;
1426			size_t cmplen;
1427
1428			end = strchrnul(iter, ',');
1429			if (next_block && next_block < end)
1430				end = next_block - 1;
1431
1432			glob = strnchr(iter, end - iter, '*');
1433			if (glob)
1434				cmplen = glob - iter;
1435			else
1436				cmplen = max_t(size_t, len, (end - iter));
1437
1438			if (!strncmp(name, iter, cmplen)) {
1439				flags |= block_flags;
1440				return flags;
1441			}
1442
1443			if (!*end || *end == ';')
1444				break;
1445			iter = end + 1;
1446		}
1447	}
1448
1449	return flags | slub_debug;
1450}
1451#else /* !CONFIG_SLUB_DEBUG */
1452static inline void setup_object_debug(struct kmem_cache *s,
1453			struct page *page, void *object) {}
1454static inline
1455void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr) {}
1456
1457static inline int alloc_debug_processing(struct kmem_cache *s,
1458	struct page *page, void *object, unsigned long addr) { return 0; }
1459
1460static inline int free_debug_processing(
1461	struct kmem_cache *s, struct page *page,
1462	void *head, void *tail, int bulk_cnt,
1463	unsigned long addr) { return 0; }
1464
1465static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1466			{ return 1; }
1467static inline int check_object(struct kmem_cache *s, struct page *page,
1468			void *object, u8 val) { return 1; }
1469static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1470					struct page *page) {}
1471static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1472					struct page *page) {}
1473slab_flags_t kmem_cache_flags(unsigned int object_size,
1474	slab_flags_t flags, const char *name,
1475	void (*ctor)(void *))
1476{
1477	return flags;
1478}
1479#define slub_debug 0
1480
1481#define disable_higher_order_debug 0
1482
1483static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1484							{ return 0; }
1485static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1486							{ return 0; }
1487static inline void inc_slabs_node(struct kmem_cache *s, int node,
1488							int objects) {}
1489static inline void dec_slabs_node(struct kmem_cache *s, int node,
1490							int objects) {}
1491
1492static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
1493			       void **freelist, void *nextfree)
1494{
1495	return false;
1496}
1497#endif /* CONFIG_SLUB_DEBUG */
1498
1499/*
1500 * Hooks for other subsystems that check memory allocations. In a typical
1501 * production configuration these hooks all should produce no code at all.
1502 */
1503static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1504{
1505	ptr = kasan_kmalloc_large(ptr, size, flags);
1506	/* As ptr might get tagged, call kmemleak hook after KASAN. */
1507	kmemleak_alloc(ptr, size, 1, flags);
1508	return ptr;
1509}
1510
1511static __always_inline void kfree_hook(void *x)
1512{
1513	kmemleak_free(x);
1514	kasan_kfree_large(x, _RET_IP_);
1515}
1516
1517static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x)
 
1518{
1519	kmemleak_free_recursive(x, s->flags);
1520
1521	/*
1522	 * Trouble is that we may no longer disable interrupts in the fast path
1523	 * So in order to make the debug calls that expect irqs to be
1524	 * disabled we need to disable interrupts temporarily.
1525	 */
1526#ifdef CONFIG_LOCKDEP
1527	{
1528		unsigned long flags;
1529
1530		local_irq_save(flags);
1531		debug_check_no_locks_freed(x, s->object_size);
1532		local_irq_restore(flags);
1533	}
1534#endif
1535	if (!(s->flags & SLAB_DEBUG_OBJECTS))
1536		debug_check_no_obj_freed(x, s->object_size);
1537
1538	/* Use KCSAN to help debug racy use-after-free. */
1539	if (!(s->flags & SLAB_TYPESAFE_BY_RCU))
1540		__kcsan_check_access(x, s->object_size,
1541				     KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
1542
1543	/* KASAN might put x into memory quarantine, delaying its reuse */
1544	return kasan_slab_free(s, x, _RET_IP_);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1545}
1546
1547static inline bool slab_free_freelist_hook(struct kmem_cache *s,
1548					   void **head, void **tail)
 
1549{
1550
1551	void *object;
1552	void *next = *head;
1553	void *old_tail = *tail ? *tail : *head;
1554	int rsize;
 
 
 
 
1555
1556	/* Head and tail of the reconstructed freelist */
1557	*head = NULL;
1558	*tail = NULL;
1559
1560	do {
1561		object = next;
1562		next = get_freepointer(s, object);
1563
1564		if (slab_want_init_on_free(s)) {
1565			/*
1566			 * Clear the object and the metadata, but don't touch
1567			 * the redzone.
1568			 */
1569			memset(object, 0, s->object_size);
1570			rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad
1571							   : 0;
1572			memset((char *)object + s->inuse, 0,
1573			       s->size - s->inuse - rsize);
1574
1575		}
1576		/* If object's reuse doesn't have to be delayed */
1577		if (!slab_free_hook(s, object)) {
1578			/* Move object to the new freelist */
1579			set_freepointer(s, object, *head);
1580			*head = object;
1581			if (!*tail)
1582				*tail = object;
 
 
 
 
 
 
1583		}
1584	} while (object != old_tail);
1585
1586	if (*head == *tail)
1587		*tail = NULL;
1588
1589	return *head != NULL;
1590}
1591
1592static void *setup_object(struct kmem_cache *s, struct page *page,
1593				void *object)
1594{
1595	setup_object_debug(s, page, object);
1596	object = kasan_init_slab_obj(s, object);
1597	if (unlikely(s->ctor)) {
1598		kasan_unpoison_object_data(s, object);
1599		s->ctor(object);
1600		kasan_poison_object_data(s, object);
1601	}
1602	return object;
1603}
1604
1605/*
1606 * Slab allocation and freeing
1607 */
1608static inline struct page *alloc_slab_page(struct kmem_cache *s,
1609		gfp_t flags, int node, struct kmem_cache_order_objects oo)
1610{
1611	struct page *page;
1612	unsigned int order = oo_order(oo);
1613
1614	if (node == NUMA_NO_NODE)
1615		page = alloc_pages(flags, order);
1616	else
1617		page = __alloc_pages_node(node, flags, order);
1618
1619	if (page)
1620		account_slab_page(page, order, s);
1621
1622	return page;
1623}
1624
1625#ifdef CONFIG_SLAB_FREELIST_RANDOM
1626/* Pre-initialize the random sequence cache */
1627static int init_cache_random_seq(struct kmem_cache *s)
1628{
1629	unsigned int count = oo_objects(s->oo);
1630	int err;
1631
1632	/* Bailout if already initialised */
1633	if (s->random_seq)
1634		return 0;
1635
1636	err = cache_random_seq_create(s, count, GFP_KERNEL);
1637	if (err) {
1638		pr_err("SLUB: Unable to initialize free list for %s\n",
1639			s->name);
1640		return err;
1641	}
1642
1643	/* Transform to an offset on the set of pages */
1644	if (s->random_seq) {
1645		unsigned int i;
1646
1647		for (i = 0; i < count; i++)
1648			s->random_seq[i] *= s->size;
1649	}
1650	return 0;
1651}
1652
1653/* Initialize each random sequence freelist per cache */
1654static void __init init_freelist_randomization(void)
1655{
1656	struct kmem_cache *s;
1657
1658	mutex_lock(&slab_mutex);
1659
1660	list_for_each_entry(s, &slab_caches, list)
1661		init_cache_random_seq(s);
1662
1663	mutex_unlock(&slab_mutex);
1664}
1665
1666/* Get the next entry on the pre-computed freelist randomized */
1667static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
1668				unsigned long *pos, void *start,
1669				unsigned long page_limit,
1670				unsigned long freelist_count)
1671{
1672	unsigned int idx;
1673
1674	/*
1675	 * If the target page allocation failed, the number of objects on the
1676	 * page might be smaller than the usual size defined by the cache.
1677	 */
1678	do {
1679		idx = s->random_seq[*pos];
1680		*pos += 1;
1681		if (*pos >= freelist_count)
1682			*pos = 0;
1683	} while (unlikely(idx >= page_limit));
1684
1685	return (char *)start + idx;
1686}
1687
1688/* Shuffle the single linked freelist based on a random pre-computed sequence */
1689static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1690{
1691	void *start;
1692	void *cur;
1693	void *next;
1694	unsigned long idx, pos, page_limit, freelist_count;
1695
1696	if (page->objects < 2 || !s->random_seq)
1697		return false;
1698
1699	freelist_count = oo_objects(s->oo);
1700	pos = get_random_int() % freelist_count;
1701
1702	page_limit = page->objects * s->size;
1703	start = fixup_red_left(s, page_address(page));
1704
1705	/* First entry is used as the base of the freelist */
1706	cur = next_freelist_entry(s, page, &pos, start, page_limit,
1707				freelist_count);
1708	cur = setup_object(s, page, cur);
1709	page->freelist = cur;
1710
1711	for (idx = 1; idx < page->objects; idx++) {
1712		next = next_freelist_entry(s, page, &pos, start, page_limit,
1713			freelist_count);
1714		next = setup_object(s, page, next);
1715		set_freepointer(s, cur, next);
1716		cur = next;
1717	}
1718	set_freepointer(s, cur, NULL);
1719
1720	return true;
1721}
1722#else
1723static inline int init_cache_random_seq(struct kmem_cache *s)
1724{
1725	return 0;
1726}
1727static inline void init_freelist_randomization(void) { }
1728static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1729{
1730	return false;
1731}
1732#endif /* CONFIG_SLAB_FREELIST_RANDOM */
1733
1734static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1735{
1736	struct page *page;
1737	struct kmem_cache_order_objects oo = s->oo;
1738	gfp_t alloc_gfp;
1739	void *start, *p, *next;
1740	int idx;
1741	bool shuffle;
1742
1743	flags &= gfp_allowed_mask;
1744
1745	if (gfpflags_allow_blocking(flags))
1746		local_irq_enable();
1747
1748	flags |= s->allocflags;
1749
1750	/*
1751	 * Let the initial higher-order allocation fail under memory pressure
1752	 * so we fall-back to the minimum order allocation.
1753	 */
1754	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1755	if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1756		alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
1757
1758	page = alloc_slab_page(s, alloc_gfp, node, oo);
1759	if (unlikely(!page)) {
1760		oo = s->min;
1761		alloc_gfp = flags;
1762		/*
1763		 * Allocation may have failed due to fragmentation.
1764		 * Try a lower order alloc if possible
1765		 */
1766		page = alloc_slab_page(s, alloc_gfp, node, oo);
1767		if (unlikely(!page))
1768			goto out;
1769		stat(s, ORDER_FALLBACK);
1770	}
1771
1772	page->objects = oo_objects(oo);
1773
 
 
1774	page->slab_cache = s;
1775	__SetPageSlab(page);
1776	if (page_is_pfmemalloc(page))
1777		SetPageSlabPfmemalloc(page);
1778
1779	kasan_poison_slab(page);
1780
1781	start = page_address(page);
1782
1783	setup_page_debug(s, page, start);
1784
1785	shuffle = shuffle_freelist(s, page);
1786
1787	if (!shuffle) {
1788		start = fixup_red_left(s, start);
1789		start = setup_object(s, page, start);
1790		page->freelist = start;
1791		for (idx = 0, p = start; idx < page->objects - 1; idx++) {
1792			next = p + s->size;
1793			next = setup_object(s, page, next);
1794			set_freepointer(s, p, next);
1795			p = next;
1796		}
1797		set_freepointer(s, p, NULL);
1798	}
1799
1800	page->inuse = page->objects;
1801	page->frozen = 1;
1802
1803out:
1804	if (gfpflags_allow_blocking(flags))
1805		local_irq_disable();
1806	if (!page)
1807		return NULL;
1808
1809	inc_slabs_node(s, page_to_nid(page), page->objects);
1810
1811	return page;
1812}
1813
1814static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1815{
1816	if (unlikely(flags & GFP_SLAB_BUG_MASK))
1817		flags = kmalloc_fix_flags(flags);
1818
1819	return allocate_slab(s,
1820		flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1821}
1822
1823static void __free_slab(struct kmem_cache *s, struct page *page)
1824{
1825	int order = compound_order(page);
1826	int pages = 1 << order;
1827
1828	if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
1829		void *p;
1830
1831		slab_pad_check(s, page);
1832		for_each_object(p, s, page_address(page),
1833						page->objects)
1834			check_object(s, page, p, SLUB_RED_INACTIVE);
1835	}
1836
1837	__ClearPageSlabPfmemalloc(page);
1838	__ClearPageSlab(page);
1839
1840	page->mapping = NULL;
1841	if (current->reclaim_state)
1842		current->reclaim_state->reclaimed_slab += pages;
1843	unaccount_slab_page(page, order, s);
1844	__free_pages(page, order);
1845}
1846
1847static void rcu_free_slab(struct rcu_head *h)
1848{
1849	struct page *page = container_of(h, struct page, rcu_head);
1850
1851	__free_slab(page->slab_cache, page);
1852}
1853
1854static void free_slab(struct kmem_cache *s, struct page *page)
1855{
1856	if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
1857		call_rcu(&page->rcu_head, rcu_free_slab);
1858	} else
1859		__free_slab(s, page);
1860}
1861
1862static void discard_slab(struct kmem_cache *s, struct page *page)
1863{
1864	dec_slabs_node(s, page_to_nid(page), page->objects);
1865	free_slab(s, page);
1866}
1867
1868/*
1869 * Management of partially allocated slabs.
1870 */
1871static inline void
1872__add_partial(struct kmem_cache_node *n, struct page *page, int tail)
1873{
1874	n->nr_partial++;
1875	if (tail == DEACTIVATE_TO_TAIL)
1876		list_add_tail(&page->slab_list, &n->partial);
1877	else
1878		list_add(&page->slab_list, &n->partial);
1879}
1880
1881static inline void add_partial(struct kmem_cache_node *n,
1882				struct page *page, int tail)
1883{
1884	lockdep_assert_held(&n->list_lock);
1885	__add_partial(n, page, tail);
1886}
1887
1888static inline void remove_partial(struct kmem_cache_node *n,
1889					struct page *page)
1890{
1891	lockdep_assert_held(&n->list_lock);
1892	list_del(&page->slab_list);
1893	n->nr_partial--;
1894}
1895
1896/*
1897 * Remove slab from the partial list, freeze it and
1898 * return the pointer to the freelist.
1899 *
1900 * Returns a list of objects or NULL if it fails.
1901 */
1902static inline void *acquire_slab(struct kmem_cache *s,
1903		struct kmem_cache_node *n, struct page *page,
1904		int mode, int *objects)
1905{
1906	void *freelist;
1907	unsigned long counters;
1908	struct page new;
1909
1910	lockdep_assert_held(&n->list_lock);
1911
1912	/*
1913	 * Zap the freelist and set the frozen bit.
1914	 * The old freelist is the list of objects for the
1915	 * per cpu allocation list.
1916	 */
1917	freelist = page->freelist;
1918	counters = page->counters;
1919	new.counters = counters;
1920	*objects = new.objects - new.inuse;
1921	if (mode) {
1922		new.inuse = page->objects;
1923		new.freelist = NULL;
1924	} else {
1925		new.freelist = freelist;
1926	}
1927
1928	VM_BUG_ON(new.frozen);
1929	new.frozen = 1;
1930
1931	if (!__cmpxchg_double_slab(s, page,
1932			freelist, counters,
1933			new.freelist, new.counters,
1934			"acquire_slab"))
1935		return NULL;
1936
1937	remove_partial(n, page);
1938	WARN_ON(!freelist);
1939	return freelist;
1940}
1941
1942static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1943static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1944
1945/*
1946 * Try to allocate a partial slab from a specific node.
1947 */
1948static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1949				struct kmem_cache_cpu *c, gfp_t flags)
1950{
1951	struct page *page, *page2;
1952	void *object = NULL;
1953	unsigned int available = 0;
1954	int objects;
1955
1956	/*
1957	 * Racy check. If we mistakenly see no partial slabs then we
1958	 * just allocate an empty slab. If we mistakenly try to get a
1959	 * partial slab and there is none available then get_partials()
1960	 * will return NULL.
1961	 */
1962	if (!n || !n->nr_partial)
1963		return NULL;
1964
1965	spin_lock(&n->list_lock);
1966	list_for_each_entry_safe(page, page2, &n->partial, slab_list) {
1967		void *t;
1968
1969		if (!pfmemalloc_match(page, flags))
1970			continue;
1971
1972		t = acquire_slab(s, n, page, object == NULL, &objects);
1973		if (!t)
1974			break;
1975
1976		available += objects;
1977		if (!object) {
1978			c->page = page;
1979			stat(s, ALLOC_FROM_PARTIAL);
1980			object = t;
1981		} else {
1982			put_cpu_partial(s, page, 0);
1983			stat(s, CPU_PARTIAL_NODE);
1984		}
1985		if (!kmem_cache_has_cpu_partial(s)
1986			|| available > slub_cpu_partial(s) / 2)
1987			break;
1988
1989	}
1990	spin_unlock(&n->list_lock);
1991	return object;
1992}
1993
1994/*
1995 * Get a page from somewhere. Search in increasing NUMA distances.
1996 */
1997static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1998		struct kmem_cache_cpu *c)
1999{
2000#ifdef CONFIG_NUMA
2001	struct zonelist *zonelist;
2002	struct zoneref *z;
2003	struct zone *zone;
2004	enum zone_type highest_zoneidx = gfp_zone(flags);
2005	void *object;
2006	unsigned int cpuset_mems_cookie;
2007
2008	/*
2009	 * The defrag ratio allows a configuration of the tradeoffs between
2010	 * inter node defragmentation and node local allocations. A lower
2011	 * defrag_ratio increases the tendency to do local allocations
2012	 * instead of attempting to obtain partial slabs from other nodes.
2013	 *
2014	 * If the defrag_ratio is set to 0 then kmalloc() always
2015	 * returns node local objects. If the ratio is higher then kmalloc()
2016	 * may return off node objects because partial slabs are obtained
2017	 * from other nodes and filled up.
2018	 *
2019	 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
2020	 * (which makes defrag_ratio = 1000) then every (well almost)
2021	 * allocation will first attempt to defrag slab caches on other nodes.
2022	 * This means scanning over all nodes to look for partial slabs which
2023	 * may be expensive if we do it every time we are trying to find a slab
2024	 * with available objects.
2025	 */
2026	if (!s->remote_node_defrag_ratio ||
2027			get_cycles() % 1024 > s->remote_node_defrag_ratio)
2028		return NULL;
2029
2030	do {
2031		cpuset_mems_cookie = read_mems_allowed_begin();
2032		zonelist = node_zonelist(mempolicy_slab_node(), flags);
2033		for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
2034			struct kmem_cache_node *n;
2035
2036			n = get_node(s, zone_to_nid(zone));
2037
2038			if (n && cpuset_zone_allowed(zone, flags) &&
2039					n->nr_partial > s->min_partial) {
2040				object = get_partial_node(s, n, c, flags);
2041				if (object) {
2042					/*
2043					 * Don't check read_mems_allowed_retry()
2044					 * here - if mems_allowed was updated in
2045					 * parallel, that was a harmless race
2046					 * between allocation and the cpuset
2047					 * update
2048					 */
2049					return object;
2050				}
2051			}
2052		}
2053	} while (read_mems_allowed_retry(cpuset_mems_cookie));
2054#endif	/* CONFIG_NUMA */
2055	return NULL;
2056}
2057
2058/*
2059 * Get a partial page, lock it and return it.
2060 */
2061static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
2062		struct kmem_cache_cpu *c)
2063{
2064	void *object;
2065	int searchnode = node;
2066
2067	if (node == NUMA_NO_NODE)
2068		searchnode = numa_mem_id();
2069
2070	object = get_partial_node(s, get_node(s, searchnode), c, flags);
2071	if (object || node != NUMA_NO_NODE)
2072		return object;
2073
2074	return get_any_partial(s, flags, c);
2075}
2076
2077#ifdef CONFIG_PREEMPTION
2078/*
2079 * Calculate the next globally unique transaction for disambiguation
2080 * during cmpxchg. The transactions start with the cpu number and are then
2081 * incremented by CONFIG_NR_CPUS.
2082 */
2083#define TID_STEP  roundup_pow_of_two(CONFIG_NR_CPUS)
2084#else
2085/*
2086 * No preemption supported therefore also no need to check for
2087 * different cpus.
2088 */
2089#define TID_STEP 1
2090#endif
2091
2092static inline unsigned long next_tid(unsigned long tid)
2093{
2094	return tid + TID_STEP;
2095}
2096
2097#ifdef SLUB_DEBUG_CMPXCHG
2098static inline unsigned int tid_to_cpu(unsigned long tid)
2099{
2100	return tid % TID_STEP;
2101}
2102
2103static inline unsigned long tid_to_event(unsigned long tid)
2104{
2105	return tid / TID_STEP;
2106}
2107#endif
2108
2109static inline unsigned int init_tid(int cpu)
2110{
2111	return cpu;
2112}
2113
2114static inline void note_cmpxchg_failure(const char *n,
2115		const struct kmem_cache *s, unsigned long tid)
2116{
2117#ifdef SLUB_DEBUG_CMPXCHG
2118	unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
2119
2120	pr_info("%s %s: cmpxchg redo ", n, s->name);
2121
2122#ifdef CONFIG_PREEMPTION
2123	if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
2124		pr_warn("due to cpu change %d -> %d\n",
2125			tid_to_cpu(tid), tid_to_cpu(actual_tid));
2126	else
2127#endif
2128	if (tid_to_event(tid) != tid_to_event(actual_tid))
2129		pr_warn("due to cpu running other code. Event %ld->%ld\n",
2130			tid_to_event(tid), tid_to_event(actual_tid));
2131	else
2132		pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2133			actual_tid, tid, next_tid(tid));
2134#endif
2135	stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2136}
2137
2138static void init_kmem_cache_cpus(struct kmem_cache *s)
2139{
2140	int cpu;
2141
2142	for_each_possible_cpu(cpu)
2143		per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
2144}
2145
2146/*
2147 * Remove the cpu slab
2148 */
2149static void deactivate_slab(struct kmem_cache *s, struct page *page,
2150				void *freelist, struct kmem_cache_cpu *c)
2151{
2152	enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
2153	struct kmem_cache_node *n = get_node(s, page_to_nid(page));
2154	int lock = 0;
2155	enum slab_modes l = M_NONE, m = M_NONE;
2156	void *nextfree;
2157	int tail = DEACTIVATE_TO_HEAD;
2158	struct page new;
2159	struct page old;
2160
2161	if (page->freelist) {
2162		stat(s, DEACTIVATE_REMOTE_FREES);
2163		tail = DEACTIVATE_TO_TAIL;
2164	}
2165
2166	/*
2167	 * Stage one: Free all available per cpu objects back
2168	 * to the page freelist while it is still frozen. Leave the
2169	 * last one.
2170	 *
2171	 * There is no need to take the list->lock because the page
2172	 * is still frozen.
2173	 */
2174	while (freelist && (nextfree = get_freepointer(s, freelist))) {
2175		void *prior;
2176		unsigned long counters;
 
2177
2178		/*
2179		 * If 'nextfree' is invalid, it is possible that the object at
2180		 * 'freelist' is already corrupted.  So isolate all objects
2181		 * starting at 'freelist'.
2182		 */
2183		if (freelist_corrupted(s, page, &freelist, nextfree))
2184			break;
2185
2186		do {
2187			prior = page->freelist;
2188			counters = page->counters;
2189			set_freepointer(s, freelist, prior);
2190			new.counters = counters;
2191			new.inuse--;
2192			VM_BUG_ON(!new.frozen);
2193
2194		} while (!__cmpxchg_double_slab(s, page,
2195			prior, counters,
2196			freelist, new.counters,
2197			"drain percpu freelist"));
2198
2199		freelist = nextfree;
2200	}
2201
2202	/*
2203	 * Stage two: Ensure that the page is unfrozen while the
2204	 * list presence reflects the actual number of objects
2205	 * during unfreeze.
 
 
2206	 *
2207	 * We setup the list membership and then perform a cmpxchg
2208	 * with the count. If there is a mismatch then the page
2209	 * is not unfrozen but the page is on the wrong list.
2210	 *
2211	 * Then we restart the process which may have to remove
2212	 * the page from the list that we just put it on again
2213	 * because the number of objects in the slab may have
2214	 * changed.
2215	 */
2216redo:
2217
2218	old.freelist = page->freelist;
2219	old.counters = page->counters;
2220	VM_BUG_ON(!old.frozen);
2221
2222	/* Determine target state of the slab */
2223	new.counters = old.counters;
2224	if (freelist) {
2225		new.inuse--;
2226		set_freepointer(s, freelist, old.freelist);
2227		new.freelist = freelist;
2228	} else
2229		new.freelist = old.freelist;
2230
2231	new.frozen = 0;
2232
2233	if (!new.inuse && n->nr_partial >= s->min_partial)
2234		m = M_FREE;
2235	else if (new.freelist) {
2236		m = M_PARTIAL;
2237		if (!lock) {
2238			lock = 1;
2239			/*
2240			 * Taking the spinlock removes the possibility
2241			 * that acquire_slab() will see a slab page that
2242			 * is frozen
2243			 */
2244			spin_lock(&n->list_lock);
2245		}
2246	} else {
2247		m = M_FULL;
2248		if (kmem_cache_debug(s) && !lock) {
2249			lock = 1;
2250			/*
2251			 * This also ensures that the scanning of full
2252			 * slabs from diagnostic functions will not see
2253			 * any frozen slabs.
2254			 */
2255			spin_lock(&n->list_lock);
2256		}
2257	}
2258
2259	if (l != m) {
2260		if (l == M_PARTIAL)
2261			remove_partial(n, page);
2262		else if (l == M_FULL)
2263			remove_full(s, n, page);
2264
2265		if (m == M_PARTIAL)
2266			add_partial(n, page, tail);
2267		else if (m == M_FULL)
2268			add_full(s, n, page);
2269	}
2270
2271	l = m;
2272	if (!__cmpxchg_double_slab(s, page,
2273				old.freelist, old.counters,
2274				new.freelist, new.counters,
2275				"unfreezing slab"))
2276		goto redo;
2277
2278	if (lock)
2279		spin_unlock(&n->list_lock);
2280
2281	if (m == M_PARTIAL)
2282		stat(s, tail);
2283	else if (m == M_FULL)
2284		stat(s, DEACTIVATE_FULL);
2285	else if (m == M_FREE) {
2286		stat(s, DEACTIVATE_EMPTY);
2287		discard_slab(s, page);
2288		stat(s, FREE_SLAB);
2289	}
2290
2291	c->page = NULL;
2292	c->freelist = NULL;
2293}
2294
2295/*
2296 * Unfreeze all the cpu partial slabs.
2297 *
2298 * This function must be called with interrupts disabled
2299 * for the cpu using c (or some other guarantee must be there
2300 * to guarantee no concurrent accesses).
2301 */
2302static void unfreeze_partials(struct kmem_cache *s,
2303		struct kmem_cache_cpu *c)
2304{
2305#ifdef CONFIG_SLUB_CPU_PARTIAL
2306	struct kmem_cache_node *n = NULL, *n2 = NULL;
2307	struct page *page, *discard_page = NULL;
2308
2309	while ((page = slub_percpu_partial(c))) {
2310		struct page new;
2311		struct page old;
2312
2313		slub_set_percpu_partial(c, page);
2314
2315		n2 = get_node(s, page_to_nid(page));
2316		if (n != n2) {
2317			if (n)
2318				spin_unlock(&n->list_lock);
2319
2320			n = n2;
2321			spin_lock(&n->list_lock);
2322		}
2323
2324		do {
2325
2326			old.freelist = page->freelist;
2327			old.counters = page->counters;
2328			VM_BUG_ON(!old.frozen);
2329
2330			new.counters = old.counters;
2331			new.freelist = old.freelist;
2332
2333			new.frozen = 0;
2334
2335		} while (!__cmpxchg_double_slab(s, page,
2336				old.freelist, old.counters,
2337				new.freelist, new.counters,
2338				"unfreezing slab"));
2339
2340		if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2341			page->next = discard_page;
2342			discard_page = page;
2343		} else {
2344			add_partial(n, page, DEACTIVATE_TO_TAIL);
2345			stat(s, FREE_ADD_PARTIAL);
2346		}
2347	}
2348
2349	if (n)
2350		spin_unlock(&n->list_lock);
2351
2352	while (discard_page) {
2353		page = discard_page;
2354		discard_page = discard_page->next;
2355
2356		stat(s, DEACTIVATE_EMPTY);
2357		discard_slab(s, page);
2358		stat(s, FREE_SLAB);
2359	}
2360#endif	/* CONFIG_SLUB_CPU_PARTIAL */
2361}
2362
2363/*
2364 * Put a page that was just frozen (in __slab_free|get_partial_node) into a
2365 * partial page slot if available.
2366 *
2367 * If we did not find a slot then simply move all the partials to the
2368 * per node partial list.
2369 */
2370static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
2371{
2372#ifdef CONFIG_SLUB_CPU_PARTIAL
2373	struct page *oldpage;
2374	int pages;
2375	int pobjects;
2376
2377	preempt_disable();
2378	do {
2379		pages = 0;
2380		pobjects = 0;
2381		oldpage = this_cpu_read(s->cpu_slab->partial);
2382
2383		if (oldpage) {
2384			pobjects = oldpage->pobjects;
2385			pages = oldpage->pages;
2386			if (drain && pobjects > slub_cpu_partial(s)) {
2387				unsigned long flags;
2388				/*
2389				 * partial array is full. Move the existing
2390				 * set to the per node partial list.
2391				 */
2392				local_irq_save(flags);
2393				unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2394				local_irq_restore(flags);
2395				oldpage = NULL;
2396				pobjects = 0;
2397				pages = 0;
2398				stat(s, CPU_PARTIAL_DRAIN);
2399			}
2400		}
2401
2402		pages++;
2403		pobjects += page->objects - page->inuse;
2404
2405		page->pages = pages;
2406		page->pobjects = pobjects;
2407		page->next = oldpage;
2408
2409	} while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2410								!= oldpage);
2411	if (unlikely(!slub_cpu_partial(s))) {
2412		unsigned long flags;
2413
2414		local_irq_save(flags);
2415		unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2416		local_irq_restore(flags);
2417	}
2418	preempt_enable();
2419#endif	/* CONFIG_SLUB_CPU_PARTIAL */
2420}
2421
2422static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2423{
2424	stat(s, CPUSLAB_FLUSH);
2425	deactivate_slab(s, c->page, c->freelist, c);
2426
2427	c->tid = next_tid(c->tid);
2428}
2429
2430/*
2431 * Flush cpu slab.
2432 *
2433 * Called from IPI handler with interrupts disabled.
2434 */
2435static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2436{
2437	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2438
2439	if (c->page)
2440		flush_slab(s, c);
2441
2442	unfreeze_partials(s, c);
2443}
2444
2445static void flush_cpu_slab(void *d)
2446{
2447	struct kmem_cache *s = d;
2448
2449	__flush_cpu_slab(s, smp_processor_id());
2450}
2451
2452static bool has_cpu_slab(int cpu, void *info)
2453{
2454	struct kmem_cache *s = info;
2455	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2456
2457	return c->page || slub_percpu_partial(c);
2458}
2459
2460static void flush_all(struct kmem_cache *s)
2461{
2462	on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1);
2463}
2464
2465/*
2466 * Use the cpu notifier to insure that the cpu slabs are flushed when
2467 * necessary.
2468 */
2469static int slub_cpu_dead(unsigned int cpu)
2470{
2471	struct kmem_cache *s;
2472	unsigned long flags;
2473
2474	mutex_lock(&slab_mutex);
2475	list_for_each_entry(s, &slab_caches, list) {
2476		local_irq_save(flags);
2477		__flush_cpu_slab(s, cpu);
2478		local_irq_restore(flags);
2479	}
2480	mutex_unlock(&slab_mutex);
2481	return 0;
2482}
2483
2484/*
2485 * Check if the objects in a per cpu structure fit numa
2486 * locality expectations.
2487 */
2488static inline int node_match(struct page *page, int node)
2489{
2490#ifdef CONFIG_NUMA
2491	if (node != NUMA_NO_NODE && page_to_nid(page) != node)
2492		return 0;
2493#endif
2494	return 1;
2495}
2496
2497#ifdef CONFIG_SLUB_DEBUG
2498static int count_free(struct page *page)
2499{
2500	return page->objects - page->inuse;
2501}
2502
2503static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2504{
2505	return atomic_long_read(&n->total_objects);
2506}
2507#endif /* CONFIG_SLUB_DEBUG */
2508
2509#if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2510static unsigned long count_partial(struct kmem_cache_node *n,
2511					int (*get_count)(struct page *))
2512{
2513	unsigned long flags;
2514	unsigned long x = 0;
2515	struct page *page;
2516
2517	spin_lock_irqsave(&n->list_lock, flags);
2518	list_for_each_entry(page, &n->partial, slab_list)
2519		x += get_count(page);
2520	spin_unlock_irqrestore(&n->list_lock, flags);
2521	return x;
2522}
2523#endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2524
2525static noinline void
2526slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2527{
2528#ifdef CONFIG_SLUB_DEBUG
2529	static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2530				      DEFAULT_RATELIMIT_BURST);
2531	int node;
2532	struct kmem_cache_node *n;
2533
2534	if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2535		return;
2536
2537	pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2538		nid, gfpflags, &gfpflags);
2539	pr_warn("  cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
2540		s->name, s->object_size, s->size, oo_order(s->oo),
2541		oo_order(s->min));
2542
2543	if (oo_order(s->min) > get_order(s->object_size))
2544		pr_warn("  %s debugging increased min order, use slub_debug=O to disable.\n",
2545			s->name);
2546
2547	for_each_kmem_cache_node(s, node, n) {
2548		unsigned long nr_slabs;
2549		unsigned long nr_objs;
2550		unsigned long nr_free;
2551
2552		nr_free  = count_partial(n, count_free);
2553		nr_slabs = node_nr_slabs(n);
2554		nr_objs  = node_nr_objs(n);
2555
2556		pr_warn("  node %d: slabs: %ld, objs: %ld, free: %ld\n",
2557			node, nr_slabs, nr_objs, nr_free);
2558	}
2559#endif
2560}
2561
2562static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2563			int node, struct kmem_cache_cpu **pc)
2564{
2565	void *freelist;
2566	struct kmem_cache_cpu *c = *pc;
2567	struct page *page;
2568
2569	WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
2570
2571	freelist = get_partial(s, flags, node, c);
2572
2573	if (freelist)
2574		return freelist;
2575
2576	page = new_slab(s, flags, node);
2577	if (page) {
2578		c = raw_cpu_ptr(s->cpu_slab);
2579		if (c->page)
2580			flush_slab(s, c);
2581
2582		/*
2583		 * No other reference to the page yet so we can
2584		 * muck around with it freely without cmpxchg
2585		 */
2586		freelist = page->freelist;
2587		page->freelist = NULL;
2588
2589		stat(s, ALLOC_SLAB);
2590		c->page = page;
2591		*pc = c;
2592	}
2593
2594	return freelist;
2595}
2596
2597static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2598{
2599	if (unlikely(PageSlabPfmemalloc(page)))
2600		return gfp_pfmemalloc_allowed(gfpflags);
2601
2602	return true;
2603}
2604
2605/*
2606 * Check the page->freelist of a page and either transfer the freelist to the
2607 * per cpu freelist or deactivate the page.
2608 *
2609 * The page is still frozen if the return value is not NULL.
2610 *
2611 * If this function returns NULL then the page has been unfrozen.
2612 *
2613 * This function must be called with interrupt disabled.
2614 */
2615static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2616{
2617	struct page new;
2618	unsigned long counters;
2619	void *freelist;
2620
2621	do {
2622		freelist = page->freelist;
2623		counters = page->counters;
2624
2625		new.counters = counters;
2626		VM_BUG_ON(!new.frozen);
2627
2628		new.inuse = page->objects;
2629		new.frozen = freelist != NULL;
2630
2631	} while (!__cmpxchg_double_slab(s, page,
2632		freelist, counters,
2633		NULL, new.counters,
2634		"get_freelist"));
2635
2636	return freelist;
2637}
2638
2639/*
2640 * Slow path. The lockless freelist is empty or we need to perform
2641 * debugging duties.
2642 *
2643 * Processing is still very fast if new objects have been freed to the
2644 * regular freelist. In that case we simply take over the regular freelist
2645 * as the lockless freelist and zap the regular freelist.
2646 *
2647 * If that is not working then we fall back to the partial lists. We take the
2648 * first element of the freelist as the object to allocate now and move the
2649 * rest of the freelist to the lockless freelist.
2650 *
2651 * And if we were unable to get a new slab from the partial slab lists then
2652 * we need to allocate a new slab. This is the slowest path since it involves
2653 * a call to the page allocator and the setup of a new slab.
2654 *
2655 * Version of __slab_alloc to use when we know that interrupts are
2656 * already disabled (which is the case for bulk allocation).
2657 */
2658static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2659			  unsigned long addr, struct kmem_cache_cpu *c)
2660{
2661	void *freelist;
2662	struct page *page;
2663
 
 
2664	page = c->page;
2665	if (!page) {
2666		/*
2667		 * if the node is not online or has no normal memory, just
2668		 * ignore the node constraint
2669		 */
2670		if (unlikely(node != NUMA_NO_NODE &&
2671			     !node_state(node, N_NORMAL_MEMORY)))
2672			node = NUMA_NO_NODE;
2673		goto new_slab;
2674	}
2675redo:
2676
2677	if (unlikely(!node_match(page, node))) {
2678		/*
2679		 * same as above but node_match() being false already
2680		 * implies node != NUMA_NO_NODE
2681		 */
2682		if (!node_state(node, N_NORMAL_MEMORY)) {
2683			node = NUMA_NO_NODE;
2684			goto redo;
2685		} else {
2686			stat(s, ALLOC_NODE_MISMATCH);
2687			deactivate_slab(s, page, c->freelist, c);
2688			goto new_slab;
2689		}
2690	}
2691
2692	/*
2693	 * By rights, we should be searching for a slab page that was
2694	 * PFMEMALLOC but right now, we are losing the pfmemalloc
2695	 * information when the page leaves the per-cpu allocator
2696	 */
2697	if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2698		deactivate_slab(s, page, c->freelist, c);
2699		goto new_slab;
2700	}
2701
2702	/* must check again c->freelist in case of cpu migration or IRQ */
2703	freelist = c->freelist;
2704	if (freelist)
2705		goto load_freelist;
2706
2707	freelist = get_freelist(s, page);
2708
2709	if (!freelist) {
2710		c->page = NULL;
2711		stat(s, DEACTIVATE_BYPASS);
2712		goto new_slab;
2713	}
2714
2715	stat(s, ALLOC_REFILL);
2716
2717load_freelist:
2718	/*
2719	 * freelist is pointing to the list of objects to be used.
2720	 * page is pointing to the page from which the objects are obtained.
2721	 * That page must be frozen for per cpu allocations to work.
2722	 */
2723	VM_BUG_ON(!c->page->frozen);
2724	c->freelist = get_freepointer(s, freelist);
2725	c->tid = next_tid(c->tid);
2726	return freelist;
2727
2728new_slab:
2729
2730	if (slub_percpu_partial(c)) {
2731		page = c->page = slub_percpu_partial(c);
2732		slub_set_percpu_partial(c, page);
2733		stat(s, CPU_PARTIAL_ALLOC);
2734		goto redo;
2735	}
2736
2737	freelist = new_slab_objects(s, gfpflags, node, &c);
2738
2739	if (unlikely(!freelist)) {
2740		slab_out_of_memory(s, gfpflags, node);
2741		return NULL;
2742	}
2743
2744	page = c->page;
2745	if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2746		goto load_freelist;
2747
2748	/* Only entered in the debug case */
2749	if (kmem_cache_debug(s) &&
2750			!alloc_debug_processing(s, page, freelist, addr))
2751		goto new_slab;	/* Slab failed checks. Next slab needed */
2752
2753	deactivate_slab(s, page, get_freepointer(s, freelist), c);
2754	return freelist;
2755}
2756
2757/*
2758 * Another one that disabled interrupt and compensates for possible
2759 * cpu changes by refetching the per cpu area pointer.
2760 */
2761static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2762			  unsigned long addr, struct kmem_cache_cpu *c)
2763{
2764	void *p;
2765	unsigned long flags;
2766
2767	local_irq_save(flags);
2768#ifdef CONFIG_PREEMPTION
2769	/*
2770	 * We may have been preempted and rescheduled on a different
2771	 * cpu before disabling interrupts. Need to reload cpu area
2772	 * pointer.
2773	 */
2774	c = this_cpu_ptr(s->cpu_slab);
2775#endif
2776
2777	p = ___slab_alloc(s, gfpflags, node, addr, c);
2778	local_irq_restore(flags);
2779	return p;
2780}
2781
2782/*
2783 * If the object has been wiped upon free, make sure it's fully initialized by
2784 * zeroing out freelist pointer.
2785 */
2786static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
2787						   void *obj)
2788{
2789	if (unlikely(slab_want_init_on_free(s)) && obj)
2790		memset((void *)((char *)obj + s->offset), 0, sizeof(void *));
 
2791}
2792
2793/*
2794 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2795 * have the fastpath folded into their functions. So no function call
2796 * overhead for requests that can be satisfied on the fastpath.
2797 *
2798 * The fastpath works by first checking if the lockless freelist can be used.
2799 * If not then __slab_alloc is called for slow processing.
2800 *
2801 * Otherwise we can simply pick the next object from the lockless free list.
2802 */
2803static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2804		gfp_t gfpflags, int node, unsigned long addr)
2805{
2806	void *object;
2807	struct kmem_cache_cpu *c;
2808	struct page *page;
2809	unsigned long tid;
2810	struct obj_cgroup *objcg = NULL;
 
2811
2812	s = slab_pre_alloc_hook(s, &objcg, 1, gfpflags);
2813	if (!s)
2814		return NULL;
 
 
 
 
 
2815redo:
2816	/*
2817	 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2818	 * enabled. We may switch back and forth between cpus while
2819	 * reading from one cpu area. That does not matter as long
2820	 * as we end up on the original cpu again when doing the cmpxchg.
2821	 *
2822	 * We should guarantee that tid and kmem_cache are retrieved on
2823	 * the same cpu. It could be different if CONFIG_PREEMPTION so we need
2824	 * to check if it is matched or not.
2825	 */
2826	do {
2827		tid = this_cpu_read(s->cpu_slab->tid);
2828		c = raw_cpu_ptr(s->cpu_slab);
2829	} while (IS_ENABLED(CONFIG_PREEMPTION) &&
2830		 unlikely(tid != READ_ONCE(c->tid)));
2831
2832	/*
2833	 * Irqless object alloc/free algorithm used here depends on sequence
2834	 * of fetching cpu_slab's data. tid should be fetched before anything
2835	 * on c to guarantee that object and page associated with previous tid
2836	 * won't be used with current tid. If we fetch tid first, object and
2837	 * page could be one associated with next tid and our alloc/free
2838	 * request will be failed. In this case, we will retry. So, no problem.
2839	 */
2840	barrier();
2841
2842	/*
2843	 * The transaction ids are globally unique per cpu and per operation on
2844	 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2845	 * occurs on the right processor and that there was no operation on the
2846	 * linked list in between.
2847	 */
2848
2849	object = c->freelist;
2850	page = c->page;
2851	if (unlikely(!object || !node_match(page, node))) {
2852		object = __slab_alloc(s, gfpflags, node, addr, c);
2853		stat(s, ALLOC_SLOWPATH);
2854	} else {
2855		void *next_object = get_freepointer_safe(s, object);
2856
2857		/*
2858		 * The cmpxchg will only match if there was no additional
2859		 * operation and if we are on the right processor.
2860		 *
2861		 * The cmpxchg does the following atomically (without lock
2862		 * semantics!)
2863		 * 1. Relocate first pointer to the current per cpu area.
2864		 * 2. Verify that tid and freelist have not been changed
2865		 * 3. If they were not changed replace tid and freelist
2866		 *
2867		 * Since this is without lock semantics the protection is only
2868		 * against code executing on this cpu *not* from access by
2869		 * other cpus.
2870		 */
2871		if (unlikely(!this_cpu_cmpxchg_double(
2872				s->cpu_slab->freelist, s->cpu_slab->tid,
2873				object, tid,
2874				next_object, next_tid(tid)))) {
2875
2876			note_cmpxchg_failure("slab_alloc", s, tid);
2877			goto redo;
2878		}
2879		prefetch_freepointer(s, next_object);
2880		stat(s, ALLOC_FASTPATH);
2881	}
2882
2883	maybe_wipe_obj_freeptr(s, object);
 
2884
2885	if (unlikely(slab_want_init_on_alloc(gfpflags, s)) && object)
2886		memset(object, 0, s->object_size);
2887
2888	slab_post_alloc_hook(s, objcg, gfpflags, 1, &object);
2889
2890	return object;
2891}
2892
2893static __always_inline void *slab_alloc(struct kmem_cache *s,
2894		gfp_t gfpflags, unsigned long addr)
2895{
2896	return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2897}
2898
2899void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2900{
2901	void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2902
2903	trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2904				s->size, gfpflags);
2905
2906	return ret;
2907}
2908EXPORT_SYMBOL(kmem_cache_alloc);
2909
2910#ifdef CONFIG_TRACING
2911void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2912{
2913	void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2914	trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2915	ret = kasan_kmalloc(s, ret, size, gfpflags);
2916	return ret;
2917}
2918EXPORT_SYMBOL(kmem_cache_alloc_trace);
2919#endif
2920
2921#ifdef CONFIG_NUMA
2922void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2923{
2924	void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2925
2926	trace_kmem_cache_alloc_node(_RET_IP_, ret,
2927				    s->object_size, s->size, gfpflags, node);
2928
2929	return ret;
2930}
2931EXPORT_SYMBOL(kmem_cache_alloc_node);
2932
2933#ifdef CONFIG_TRACING
2934void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2935				    gfp_t gfpflags,
2936				    int node, size_t size)
2937{
2938	void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2939
2940	trace_kmalloc_node(_RET_IP_, ret,
2941			   size, s->size, gfpflags, node);
2942
2943	ret = kasan_kmalloc(s, ret, size, gfpflags);
2944	return ret;
2945}
2946EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2947#endif
2948#endif	/* CONFIG_NUMA */
2949
2950/*
2951 * Slow path handling. This may still be called frequently since objects
2952 * have a longer lifetime than the cpu slabs in most processing loads.
2953 *
2954 * So we still attempt to reduce cache line usage. Just take the slab
2955 * lock and free the item. If there is no additional partial page
2956 * handling required then we can return immediately.
2957 */
2958static void __slab_free(struct kmem_cache *s, struct page *page,
2959			void *head, void *tail, int cnt,
2960			unsigned long addr)
2961
2962{
2963	void *prior;
2964	int was_frozen;
2965	struct page new;
2966	unsigned long counters;
2967	struct kmem_cache_node *n = NULL;
2968	unsigned long flags;
2969
2970	stat(s, FREE_SLOWPATH);
2971
 
 
 
2972	if (kmem_cache_debug(s) &&
2973	    !free_debug_processing(s, page, head, tail, cnt, addr))
2974		return;
2975
2976	do {
2977		if (unlikely(n)) {
2978			spin_unlock_irqrestore(&n->list_lock, flags);
2979			n = NULL;
2980		}
2981		prior = page->freelist;
2982		counters = page->counters;
2983		set_freepointer(s, tail, prior);
2984		new.counters = counters;
2985		was_frozen = new.frozen;
2986		new.inuse -= cnt;
2987		if ((!new.inuse || !prior) && !was_frozen) {
2988
2989			if (kmem_cache_has_cpu_partial(s) && !prior) {
2990
2991				/*
2992				 * Slab was on no list before and will be
2993				 * partially empty
2994				 * We can defer the list move and instead
2995				 * freeze it.
2996				 */
2997				new.frozen = 1;
2998
2999			} else { /* Needs to be taken off a list */
3000
3001				n = get_node(s, page_to_nid(page));
3002				/*
3003				 * Speculatively acquire the list_lock.
3004				 * If the cmpxchg does not succeed then we may
3005				 * drop the list_lock without any processing.
3006				 *
3007				 * Otherwise the list_lock will synchronize with
3008				 * other processors updating the list of slabs.
3009				 */
3010				spin_lock_irqsave(&n->list_lock, flags);
3011
3012			}
3013		}
3014
3015	} while (!cmpxchg_double_slab(s, page,
3016		prior, counters,
3017		head, new.counters,
3018		"__slab_free"));
3019
3020	if (likely(!n)) {
3021
3022		/*
3023		 * If we just froze the page then put it onto the
3024		 * per cpu partial list.
3025		 */
3026		if (new.frozen && !was_frozen) {
 
 
 
 
 
 
3027			put_cpu_partial(s, page, 1);
3028			stat(s, CPU_PARTIAL_FREE);
3029		}
3030		/*
3031		 * The list lock was not taken therefore no list
3032		 * activity can be necessary.
3033		 */
3034		if (was_frozen)
3035			stat(s, FREE_FROZEN);
3036		return;
3037	}
3038
3039	if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
3040		goto slab_empty;
3041
3042	/*
3043	 * Objects left in the slab. If it was not on the partial list before
3044	 * then add it.
3045	 */
3046	if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
3047		remove_full(s, n, page);
3048		add_partial(n, page, DEACTIVATE_TO_TAIL);
3049		stat(s, FREE_ADD_PARTIAL);
3050	}
3051	spin_unlock_irqrestore(&n->list_lock, flags);
3052	return;
3053
3054slab_empty:
3055	if (prior) {
3056		/*
3057		 * Slab on the partial list.
3058		 */
3059		remove_partial(n, page);
3060		stat(s, FREE_REMOVE_PARTIAL);
3061	} else {
3062		/* Slab must be on the full list */
3063		remove_full(s, n, page);
3064	}
3065
3066	spin_unlock_irqrestore(&n->list_lock, flags);
3067	stat(s, FREE_SLAB);
3068	discard_slab(s, page);
3069}
3070
3071/*
3072 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
3073 * can perform fastpath freeing without additional function calls.
3074 *
3075 * The fastpath is only possible if we are freeing to the current cpu slab
3076 * of this processor. This typically the case if we have just allocated
3077 * the item before.
3078 *
3079 * If fastpath is not possible then fall back to __slab_free where we deal
3080 * with all sorts of special processing.
3081 *
3082 * Bulk free of a freelist with several objects (all pointing to the
3083 * same page) possible by specifying head and tail ptr, plus objects
3084 * count (cnt). Bulk free indicated by tail pointer being set.
3085 */
3086static __always_inline void do_slab_free(struct kmem_cache *s,
3087				struct page *page, void *head, void *tail,
3088				int cnt, unsigned long addr)
3089{
3090	void *tail_obj = tail ? : head;
3091	struct kmem_cache_cpu *c;
3092	unsigned long tid;
3093
3094	memcg_slab_free_hook(s, page, head);
 
 
3095redo:
3096	/*
3097	 * Determine the currently cpus per cpu slab.
3098	 * The cpu may change afterward. However that does not matter since
3099	 * data is retrieved via this pointer. If we are on the same cpu
3100	 * during the cmpxchg then the free will succeed.
3101	 */
3102	do {
3103		tid = this_cpu_read(s->cpu_slab->tid);
3104		c = raw_cpu_ptr(s->cpu_slab);
3105	} while (IS_ENABLED(CONFIG_PREEMPTION) &&
3106		 unlikely(tid != READ_ONCE(c->tid)));
3107
3108	/* Same with comment on barrier() in slab_alloc_node() */
3109	barrier();
3110
3111	if (likely(page == c->page)) {
3112		void **freelist = READ_ONCE(c->freelist);
3113
3114		set_freepointer(s, tail_obj, freelist);
3115
3116		if (unlikely(!this_cpu_cmpxchg_double(
3117				s->cpu_slab->freelist, s->cpu_slab->tid,
3118				freelist, tid,
3119				head, next_tid(tid)))) {
3120
3121			note_cmpxchg_failure("slab_free", s, tid);
3122			goto redo;
3123		}
3124		stat(s, FREE_FASTPATH);
3125	} else
3126		__slab_free(s, page, head, tail_obj, cnt, addr);
3127
3128}
3129
3130static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
3131				      void *head, void *tail, int cnt,
3132				      unsigned long addr)
3133{
3134	/*
3135	 * With KASAN enabled slab_free_freelist_hook modifies the freelist
3136	 * to remove objects, whose reuse must be delayed.
3137	 */
3138	if (slab_free_freelist_hook(s, &head, &tail))
3139		do_slab_free(s, page, head, tail, cnt, addr);
3140}
3141
3142#ifdef CONFIG_KASAN_GENERIC
3143void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
3144{
3145	do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
3146}
3147#endif
3148
3149void kmem_cache_free(struct kmem_cache *s, void *x)
3150{
3151	s = cache_from_obj(s, x);
3152	if (!s)
3153		return;
3154	slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
3155	trace_kmem_cache_free(_RET_IP_, x);
3156}
3157EXPORT_SYMBOL(kmem_cache_free);
3158
3159struct detached_freelist {
3160	struct page *page;
3161	void *tail;
3162	void *freelist;
3163	int cnt;
3164	struct kmem_cache *s;
3165};
3166
 
 
 
 
 
 
 
 
 
 
3167/*
3168 * This function progressively scans the array with free objects (with
3169 * a limited look ahead) and extract objects belonging to the same
3170 * page.  It builds a detached freelist directly within the given
3171 * page/objects.  This can happen without any need for
3172 * synchronization, because the objects are owned by running process.
3173 * The freelist is build up as a single linked list in the objects.
3174 * The idea is, that this detached freelist can then be bulk
3175 * transferred to the real freelist(s), but only requiring a single
3176 * synchronization primitive.  Look ahead in the array is limited due
3177 * to performance reasons.
3178 */
3179static inline
3180int build_detached_freelist(struct kmem_cache *s, size_t size,
3181			    void **p, struct detached_freelist *df)
3182{
3183	size_t first_skipped_index = 0;
3184	int lookahead = 3;
3185	void *object;
3186	struct page *page;
3187
3188	/* Always re-init detached_freelist */
3189	df->page = NULL;
3190
3191	do {
3192		object = p[--size];
3193		/* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
3194	} while (!object && size);
3195
3196	if (!object)
3197		return 0;
3198
3199	page = virt_to_head_page(object);
3200	if (!s) {
3201		/* Handle kalloc'ed objects */
3202		if (unlikely(!PageSlab(page))) {
3203			BUG_ON(!PageCompound(page));
3204			kfree_hook(object);
3205			__free_pages(page, compound_order(page));
3206			p[size] = NULL; /* mark object processed */
3207			return size;
3208		}
3209		/* Derive kmem_cache from object */
3210		df->s = page->slab_cache;
3211	} else {
3212		df->s = cache_from_obj(s, object); /* Support for memcg */
3213	}
3214
 
 
 
 
 
 
 
3215	/* Start new detached freelist */
3216	df->page = page;
3217	set_freepointer(df->s, object, NULL);
3218	df->tail = object;
3219	df->freelist = object;
3220	p[size] = NULL; /* mark object processed */
3221	df->cnt = 1;
3222
3223	while (size) {
3224		object = p[--size];
3225		if (!object)
3226			continue; /* Skip processed objects */
3227
3228		/* df->page is always set at this point */
3229		if (df->page == virt_to_head_page(object)) {
3230			/* Opportunity build freelist */
3231			set_freepointer(df->s, object, df->freelist);
3232			df->freelist = object;
3233			df->cnt++;
3234			p[size] = NULL; /* mark object processed */
3235
3236			continue;
3237		}
3238
3239		/* Limit look ahead search */
3240		if (!--lookahead)
3241			break;
3242
3243		if (!first_skipped_index)
3244			first_skipped_index = size + 1;
3245	}
3246
3247	return first_skipped_index;
3248}
3249
3250/* Note that interrupts must be enabled when calling this function. */
3251void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3252{
3253	if (WARN_ON(!size))
3254		return;
3255
 
3256	do {
3257		struct detached_freelist df;
3258
3259		size = build_detached_freelist(s, size, p, &df);
3260		if (!df.page)
3261			continue;
3262
3263		slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);
3264	} while (likely(size));
3265}
3266EXPORT_SYMBOL(kmem_cache_free_bulk);
3267
3268/* Note that interrupts must be enabled when calling this function. */
3269int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3270			  void **p)
3271{
3272	struct kmem_cache_cpu *c;
3273	int i;
3274	struct obj_cgroup *objcg = NULL;
3275
3276	/* memcg and kmem_cache debug support */
3277	s = slab_pre_alloc_hook(s, &objcg, size, flags);
3278	if (unlikely(!s))
3279		return false;
3280	/*
3281	 * Drain objects in the per cpu slab, while disabling local
3282	 * IRQs, which protects against PREEMPT and interrupts
3283	 * handlers invoking normal fastpath.
3284	 */
3285	local_irq_disable();
3286	c = this_cpu_ptr(s->cpu_slab);
3287
3288	for (i = 0; i < size; i++) {
3289		void *object = c->freelist;
3290
 
 
 
 
 
 
3291		if (unlikely(!object)) {
3292			/*
3293			 * We may have removed an object from c->freelist using
3294			 * the fastpath in the previous iteration; in that case,
3295			 * c->tid has not been bumped yet.
3296			 * Since ___slab_alloc() may reenable interrupts while
3297			 * allocating memory, we should bump c->tid now.
3298			 */
3299			c->tid = next_tid(c->tid);
3300
3301			/*
3302			 * Invoking slow path likely have side-effect
3303			 * of re-populating per CPU c->freelist
3304			 */
3305			p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3306					    _RET_IP_, c);
3307			if (unlikely(!p[i]))
3308				goto error;
3309
3310			c = this_cpu_ptr(s->cpu_slab);
3311			maybe_wipe_obj_freeptr(s, p[i]);
3312
3313			continue; /* goto for-loop */
3314		}
3315		c->freelist = get_freepointer(s, object);
3316		p[i] = object;
3317		maybe_wipe_obj_freeptr(s, p[i]);
3318	}
3319	c->tid = next_tid(c->tid);
3320	local_irq_enable();
3321
3322	/* Clear memory outside IRQ disabled fastpath loop */
3323	if (unlikely(slab_want_init_on_alloc(flags, s))) {
3324		int j;
3325
3326		for (j = 0; j < i; j++)
3327			memset(p[j], 0, s->object_size);
3328	}
3329
3330	/* memcg and kmem_cache debug support */
3331	slab_post_alloc_hook(s, objcg, flags, size, p);
3332	return i;
3333error:
3334	local_irq_enable();
3335	slab_post_alloc_hook(s, objcg, flags, i, p);
3336	__kmem_cache_free_bulk(s, i, p);
3337	return 0;
3338}
3339EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3340
3341
3342/*
3343 * Object placement in a slab is made very easy because we always start at
3344 * offset 0. If we tune the size of the object to the alignment then we can
3345 * get the required alignment by putting one properly sized object after
3346 * another.
3347 *
3348 * Notice that the allocation order determines the sizes of the per cpu
3349 * caches. Each processor has always one slab available for allocations.
3350 * Increasing the allocation order reduces the number of times that slabs
3351 * must be moved on and off the partial lists and is therefore a factor in
3352 * locking overhead.
3353 */
3354
3355/*
3356 * Mininum / Maximum order of slab pages. This influences locking overhead
3357 * and slab fragmentation. A higher order reduces the number of partial slabs
3358 * and increases the number of allocations possible without having to
3359 * take the list_lock.
3360 */
3361static unsigned int slub_min_order;
3362static unsigned int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3363static unsigned int slub_min_objects;
3364
3365/*
3366 * Calculate the order of allocation given an slab object size.
3367 *
3368 * The order of allocation has significant impact on performance and other
3369 * system components. Generally order 0 allocations should be preferred since
3370 * order 0 does not cause fragmentation in the page allocator. Larger objects
3371 * be problematic to put into order 0 slabs because there may be too much
3372 * unused space left. We go to a higher order if more than 1/16th of the slab
3373 * would be wasted.
3374 *
3375 * In order to reach satisfactory performance we must ensure that a minimum
3376 * number of objects is in one slab. Otherwise we may generate too much
3377 * activity on the partial lists which requires taking the list_lock. This is
3378 * less a concern for large slabs though which are rarely used.
3379 *
3380 * slub_max_order specifies the order where we begin to stop considering the
3381 * number of objects in a slab as critical. If we reach slub_max_order then
3382 * we try to keep the page order as low as possible. So we accept more waste
3383 * of space in favor of a small page order.
3384 *
3385 * Higher order allocations also allow the placement of more objects in a
3386 * slab and thereby reduce object handling overhead. If the user has
3387 * requested a higher mininum order then we start with that one instead of
3388 * the smallest order which will fit the object.
3389 */
3390static inline unsigned int slab_order(unsigned int size,
3391		unsigned int min_objects, unsigned int max_order,
3392		unsigned int fract_leftover)
3393{
3394	unsigned int min_order = slub_min_order;
3395	unsigned int order;
3396
3397	if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
3398		return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3399
3400	for (order = max(min_order, (unsigned int)get_order(min_objects * size));
3401			order <= max_order; order++) {
3402
3403		unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
3404		unsigned int rem;
3405
3406		rem = slab_size % size;
3407
3408		if (rem <= slab_size / fract_leftover)
3409			break;
3410	}
3411
3412	return order;
3413}
3414
3415static inline int calculate_order(unsigned int size)
3416{
3417	unsigned int order;
3418	unsigned int min_objects;
3419	unsigned int max_objects;
 
3420
3421	/*
3422	 * Attempt to find best configuration for a slab. This
3423	 * works by first attempting to generate a layout with
3424	 * the best configuration and backing off gradually.
3425	 *
3426	 * First we increase the acceptable waste in a slab. Then
3427	 * we reduce the minimum objects required in a slab.
3428	 */
3429	min_objects = slub_min_objects;
3430	if (!min_objects)
3431		min_objects = 4 * (fls(nr_cpu_ids) + 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
3432	max_objects = order_objects(slub_max_order, size);
3433	min_objects = min(min_objects, max_objects);
3434
3435	while (min_objects > 1) {
3436		unsigned int fraction;
3437
3438		fraction = 16;
3439		while (fraction >= 4) {
3440			order = slab_order(size, min_objects,
3441					slub_max_order, fraction);
3442			if (order <= slub_max_order)
3443				return order;
3444			fraction /= 2;
3445		}
3446		min_objects--;
3447	}
3448
3449	/*
3450	 * We were unable to place multiple objects in a slab. Now
3451	 * lets see if we can place a single object there.
3452	 */
3453	order = slab_order(size, 1, slub_max_order, 1);
3454	if (order <= slub_max_order)
3455		return order;
3456
3457	/*
3458	 * Doh this slab cannot be placed using slub_max_order.
3459	 */
3460	order = slab_order(size, 1, MAX_ORDER, 1);
3461	if (order < MAX_ORDER)
3462		return order;
3463	return -ENOSYS;
3464}
3465
3466static void
3467init_kmem_cache_node(struct kmem_cache_node *n)
3468{
3469	n->nr_partial = 0;
3470	spin_lock_init(&n->list_lock);
3471	INIT_LIST_HEAD(&n->partial);
3472#ifdef CONFIG_SLUB_DEBUG
3473	atomic_long_set(&n->nr_slabs, 0);
3474	atomic_long_set(&n->total_objects, 0);
3475	INIT_LIST_HEAD(&n->full);
3476#endif
3477}
3478
3479static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3480{
3481	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3482			KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3483
3484	/*
3485	 * Must align to double word boundary for the double cmpxchg
3486	 * instructions to work; see __pcpu_double_call_return_bool().
3487	 */
3488	s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3489				     2 * sizeof(void *));
3490
3491	if (!s->cpu_slab)
3492		return 0;
3493
3494	init_kmem_cache_cpus(s);
3495
3496	return 1;
3497}
3498
3499static struct kmem_cache *kmem_cache_node;
3500
3501/*
3502 * No kmalloc_node yet so do it by hand. We know that this is the first
3503 * slab on the node for this slabcache. There are no concurrent accesses
3504 * possible.
3505 *
3506 * Note that this function only works on the kmem_cache_node
3507 * when allocating for the kmem_cache_node. This is used for bootstrapping
3508 * memory on a fresh node that has no slab structures yet.
3509 */
3510static void early_kmem_cache_node_alloc(int node)
3511{
3512	struct page *page;
3513	struct kmem_cache_node *n;
3514
3515	BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3516
3517	page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3518
3519	BUG_ON(!page);
3520	if (page_to_nid(page) != node) {
3521		pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3522		pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3523	}
3524
3525	n = page->freelist;
3526	BUG_ON(!n);
3527#ifdef CONFIG_SLUB_DEBUG
3528	init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3529	init_tracking(kmem_cache_node, n);
3530#endif
3531	n = kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node),
3532		      GFP_KERNEL);
3533	page->freelist = get_freepointer(kmem_cache_node, n);
3534	page->inuse = 1;
3535	page->frozen = 0;
3536	kmem_cache_node->node[node] = n;
3537	init_kmem_cache_node(n);
3538	inc_slabs_node(kmem_cache_node, node, page->objects);
3539
3540	/*
3541	 * No locks need to be taken here as it has just been
3542	 * initialized and there is no concurrent access.
3543	 */
3544	__add_partial(n, page, DEACTIVATE_TO_HEAD);
3545}
3546
3547static void free_kmem_cache_nodes(struct kmem_cache *s)
3548{
3549	int node;
3550	struct kmem_cache_node *n;
3551
3552	for_each_kmem_cache_node(s, node, n) {
3553		s->node[node] = NULL;
3554		kmem_cache_free(kmem_cache_node, n);
3555	}
3556}
3557
3558void __kmem_cache_release(struct kmem_cache *s)
3559{
3560	cache_random_seq_destroy(s);
3561	free_percpu(s->cpu_slab);
3562	free_kmem_cache_nodes(s);
3563}
3564
3565static int init_kmem_cache_nodes(struct kmem_cache *s)
3566{
3567	int node;
3568
3569	for_each_node_state(node, N_NORMAL_MEMORY) {
3570		struct kmem_cache_node *n;
3571
3572		if (slab_state == DOWN) {
3573			early_kmem_cache_node_alloc(node);
3574			continue;
3575		}
3576		n = kmem_cache_alloc_node(kmem_cache_node,
3577						GFP_KERNEL, node);
3578
3579		if (!n) {
3580			free_kmem_cache_nodes(s);
3581			return 0;
3582		}
3583
3584		init_kmem_cache_node(n);
3585		s->node[node] = n;
3586	}
3587	return 1;
3588}
3589
3590static void set_min_partial(struct kmem_cache *s, unsigned long min)
3591{
3592	if (min < MIN_PARTIAL)
3593		min = MIN_PARTIAL;
3594	else if (min > MAX_PARTIAL)
3595		min = MAX_PARTIAL;
3596	s->min_partial = min;
3597}
3598
3599static void set_cpu_partial(struct kmem_cache *s)
3600{
3601#ifdef CONFIG_SLUB_CPU_PARTIAL
3602	/*
3603	 * cpu_partial determined the maximum number of objects kept in the
3604	 * per cpu partial lists of a processor.
3605	 *
3606	 * Per cpu partial lists mainly contain slabs that just have one
3607	 * object freed. If they are used for allocation then they can be
3608	 * filled up again with minimal effort. The slab will never hit the
3609	 * per node partial lists and therefore no locking will be required.
3610	 *
3611	 * This setting also determines
3612	 *
3613	 * A) The number of objects from per cpu partial slabs dumped to the
3614	 *    per node list when we reach the limit.
3615	 * B) The number of objects in cpu partial slabs to extract from the
3616	 *    per node list when we run out of per cpu objects. We only fetch
3617	 *    50% to keep some capacity around for frees.
3618	 */
3619	if (!kmem_cache_has_cpu_partial(s))
3620		slub_set_cpu_partial(s, 0);
3621	else if (s->size >= PAGE_SIZE)
3622		slub_set_cpu_partial(s, 2);
3623	else if (s->size >= 1024)
3624		slub_set_cpu_partial(s, 6);
3625	else if (s->size >= 256)
3626		slub_set_cpu_partial(s, 13);
3627	else
3628		slub_set_cpu_partial(s, 30);
3629#endif
3630}
3631
3632/*
3633 * calculate_sizes() determines the order and the distribution of data within
3634 * a slab object.
3635 */
3636static int calculate_sizes(struct kmem_cache *s, int forced_order)
3637{
3638	slab_flags_t flags = s->flags;
3639	unsigned int size = s->object_size;
3640	unsigned int freepointer_area;
3641	unsigned int order;
3642
3643	/*
3644	 * Round up object size to the next word boundary. We can only
3645	 * place the free pointer at word boundaries and this determines
3646	 * the possible location of the free pointer.
3647	 */
3648	size = ALIGN(size, sizeof(void *));
3649	/*
3650	 * This is the area of the object where a freepointer can be
3651	 * safely written. If redzoning adds more to the inuse size, we
3652	 * can't use that portion for writing the freepointer, so
3653	 * s->offset must be limited within this for the general case.
3654	 */
3655	freepointer_area = size;
3656
3657#ifdef CONFIG_SLUB_DEBUG
3658	/*
3659	 * Determine if we can poison the object itself. If the user of
3660	 * the slab may touch the object after free or before allocation
3661	 * then we should never poison the object itself.
3662	 */
3663	if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
3664			!s->ctor)
3665		s->flags |= __OBJECT_POISON;
3666	else
3667		s->flags &= ~__OBJECT_POISON;
3668
3669
3670	/*
3671	 * If we are Redzoning then check if there is some space between the
3672	 * end of the object and the free pointer. If not then add an
3673	 * additional word to have some bytes to store Redzone information.
3674	 */
3675	if ((flags & SLAB_RED_ZONE) && size == s->object_size)
3676		size += sizeof(void *);
3677#endif
3678
3679	/*
3680	 * With that we have determined the number of bytes in actual use
3681	 * by the object. This is the potential offset to the free pointer.
3682	 */
3683	s->inuse = size;
3684
3685	if (((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
3686		s->ctor)) {
 
3687		/*
3688		 * Relocate free pointer after the object if it is not
3689		 * permitted to overwrite the first word of the object on
3690		 * kmem_cache_free.
3691		 *
3692		 * This is the case if we do RCU, have a constructor or
3693		 * destructor or are poisoning the objects.
 
3694		 *
3695		 * The assumption that s->offset >= s->inuse means free
3696		 * pointer is outside of the object is used in the
3697		 * freeptr_outside_object() function. If that is no
3698		 * longer true, the function needs to be modified.
3699		 */
3700		s->offset = size;
3701		size += sizeof(void *);
3702	} else if (freepointer_area > sizeof(void *)) {
3703		/*
3704		 * Store freelist pointer near middle of object to keep
3705		 * it away from the edges of the object to avoid small
3706		 * sized over/underflows from neighboring allocations.
3707		 */
3708		s->offset = ALIGN(freepointer_area / 2, sizeof(void *));
3709	}
3710
3711#ifdef CONFIG_SLUB_DEBUG
3712	if (flags & SLAB_STORE_USER)
3713		/*
3714		 * Need to store information about allocs and frees after
3715		 * the object.
3716		 */
3717		size += 2 * sizeof(struct track);
3718#endif
3719
3720	kasan_cache_create(s, &size, &s->flags);
3721#ifdef CONFIG_SLUB_DEBUG
3722	if (flags & SLAB_RED_ZONE) {
3723		/*
3724		 * Add some empty padding so that we can catch
3725		 * overwrites from earlier objects rather than let
3726		 * tracking information or the free pointer be
3727		 * corrupted if a user writes before the start
3728		 * of the object.
3729		 */
3730		size += sizeof(void *);
3731
3732		s->red_left_pad = sizeof(void *);
3733		s->red_left_pad = ALIGN(s->red_left_pad, s->align);
3734		size += s->red_left_pad;
3735	}
3736#endif
3737
3738	/*
3739	 * SLUB stores one object immediately after another beginning from
3740	 * offset 0. In order to align the objects we have to simply size
3741	 * each object to conform to the alignment.
3742	 */
3743	size = ALIGN(size, s->align);
3744	s->size = size;
3745	s->reciprocal_size = reciprocal_value(size);
3746	if (forced_order >= 0)
3747		order = forced_order;
3748	else
3749		order = calculate_order(size);
3750
3751	if ((int)order < 0)
3752		return 0;
3753
3754	s->allocflags = 0;
3755	if (order)
3756		s->allocflags |= __GFP_COMP;
3757
3758	if (s->flags & SLAB_CACHE_DMA)
3759		s->allocflags |= GFP_DMA;
3760
3761	if (s->flags & SLAB_CACHE_DMA32)
3762		s->allocflags |= GFP_DMA32;
3763
3764	if (s->flags & SLAB_RECLAIM_ACCOUNT)
3765		s->allocflags |= __GFP_RECLAIMABLE;
3766
3767	/*
3768	 * Determine the number of objects per slab
3769	 */
3770	s->oo = oo_make(order, size);
3771	s->min = oo_make(get_order(size), size);
3772	if (oo_objects(s->oo) > oo_objects(s->max))
3773		s->max = s->oo;
3774
3775	return !!oo_objects(s->oo);
3776}
3777
3778static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
3779{
3780	s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3781#ifdef CONFIG_SLAB_FREELIST_HARDENED
3782	s->random = get_random_long();
3783#endif
3784
3785	if (!calculate_sizes(s, -1))
3786		goto error;
3787	if (disable_higher_order_debug) {
3788		/*
3789		 * Disable debugging flags that store metadata if the min slab
3790		 * order increased.
3791		 */
3792		if (get_order(s->size) > get_order(s->object_size)) {
3793			s->flags &= ~DEBUG_METADATA_FLAGS;
3794			s->offset = 0;
3795			if (!calculate_sizes(s, -1))
3796				goto error;
3797		}
3798	}
3799
3800#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3801    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3802	if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
3803		/* Enable fast mode */
3804		s->flags |= __CMPXCHG_DOUBLE;
3805#endif
3806
3807	/*
3808	 * The larger the object size is, the more pages we want on the partial
3809	 * list to avoid pounding the page allocator excessively.
3810	 */
3811	set_min_partial(s, ilog2(s->size) / 2);
3812
3813	set_cpu_partial(s);
3814
3815#ifdef CONFIG_NUMA
3816	s->remote_node_defrag_ratio = 1000;
3817#endif
3818
3819	/* Initialize the pre-computed randomized freelist if slab is up */
3820	if (slab_state >= UP) {
3821		if (init_cache_random_seq(s))
3822			goto error;
3823	}
3824
3825	if (!init_kmem_cache_nodes(s))
3826		goto error;
3827
3828	if (alloc_kmem_cache_cpus(s))
3829		return 0;
3830
3831	free_kmem_cache_nodes(s);
3832error:
 
3833	return -EINVAL;
3834}
3835
3836static void list_slab_objects(struct kmem_cache *s, struct page *page,
3837			      const char *text)
3838{
3839#ifdef CONFIG_SLUB_DEBUG
3840	void *addr = page_address(page);
3841	unsigned long *map;
3842	void *p;
3843
3844	slab_err(s, page, text, s->name);
3845	slab_lock(page);
3846
3847	map = get_map(s, page);
3848	for_each_object(p, s, addr, page->objects) {
3849
3850		if (!test_bit(__obj_to_index(s, addr, p), map)) {
3851			pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
3852			print_tracking(s, p);
3853		}
3854	}
3855	put_map(map);
3856	slab_unlock(page);
3857#endif
3858}
3859
3860/*
3861 * Attempt to free all partial slabs on a node.
3862 * This is called from __kmem_cache_shutdown(). We must take list_lock
3863 * because sysfs file might still access partial list after the shutdowning.
3864 */
3865static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3866{
3867	LIST_HEAD(discard);
3868	struct page *page, *h;
3869
3870	BUG_ON(irqs_disabled());
3871	spin_lock_irq(&n->list_lock);
3872	list_for_each_entry_safe(page, h, &n->partial, slab_list) {
3873		if (!page->inuse) {
3874			remove_partial(n, page);
3875			list_add(&page->slab_list, &discard);
3876		} else {
3877			list_slab_objects(s, page,
3878			  "Objects remaining in %s on __kmem_cache_shutdown()");
3879		}
3880	}
3881	spin_unlock_irq(&n->list_lock);
3882
3883	list_for_each_entry_safe(page, h, &discard, slab_list)
3884		discard_slab(s, page);
3885}
3886
3887bool __kmem_cache_empty(struct kmem_cache *s)
3888{
3889	int node;
3890	struct kmem_cache_node *n;
3891
3892	for_each_kmem_cache_node(s, node, n)
3893		if (n->nr_partial || slabs_node(s, node))
3894			return false;
3895	return true;
3896}
3897
3898/*
3899 * Release all resources used by a slab cache.
3900 */
3901int __kmem_cache_shutdown(struct kmem_cache *s)
3902{
3903	int node;
3904	struct kmem_cache_node *n;
3905
3906	flush_all(s);
3907	/* Attempt to free all objects */
3908	for_each_kmem_cache_node(s, node, n) {
3909		free_partial(s, n);
3910		if (n->nr_partial || slabs_node(s, node))
3911			return 1;
3912	}
3913	return 0;
3914}
3915
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3916/********************************************************************
3917 *		Kmalloc subsystem
3918 *******************************************************************/
3919
3920static int __init setup_slub_min_order(char *str)
3921{
3922	get_option(&str, (int *)&slub_min_order);
3923
3924	return 1;
3925}
3926
3927__setup("slub_min_order=", setup_slub_min_order);
3928
3929static int __init setup_slub_max_order(char *str)
3930{
3931	get_option(&str, (int *)&slub_max_order);
3932	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
3933
3934	return 1;
3935}
3936
3937__setup("slub_max_order=", setup_slub_max_order);
3938
3939static int __init setup_slub_min_objects(char *str)
3940{
3941	get_option(&str, (int *)&slub_min_objects);
3942
3943	return 1;
3944}
3945
3946__setup("slub_min_objects=", setup_slub_min_objects);
3947
3948void *__kmalloc(size_t size, gfp_t flags)
3949{
3950	struct kmem_cache *s;
3951	void *ret;
3952
3953	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3954		return kmalloc_large(size, flags);
3955
3956	s = kmalloc_slab(size, flags);
3957
3958	if (unlikely(ZERO_OR_NULL_PTR(s)))
3959		return s;
3960
3961	ret = slab_alloc(s, flags, _RET_IP_);
3962
3963	trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3964
3965	ret = kasan_kmalloc(s, ret, size, flags);
3966
3967	return ret;
3968}
3969EXPORT_SYMBOL(__kmalloc);
3970
3971#ifdef CONFIG_NUMA
3972static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3973{
3974	struct page *page;
3975	void *ptr = NULL;
3976	unsigned int order = get_order(size);
3977
3978	flags |= __GFP_COMP;
3979	page = alloc_pages_node(node, flags, order);
3980	if (page) {
3981		ptr = page_address(page);
3982		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
3983				    PAGE_SIZE << order);
3984	}
3985
3986	return kmalloc_large_node_hook(ptr, size, flags);
3987}
3988
3989void *__kmalloc_node(size_t size, gfp_t flags, int node)
3990{
3991	struct kmem_cache *s;
3992	void *ret;
3993
3994	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3995		ret = kmalloc_large_node(size, flags, node);
3996
3997		trace_kmalloc_node(_RET_IP_, ret,
3998				   size, PAGE_SIZE << get_order(size),
3999				   flags, node);
4000
4001		return ret;
4002	}
4003
4004	s = kmalloc_slab(size, flags);
4005
4006	if (unlikely(ZERO_OR_NULL_PTR(s)))
4007		return s;
4008
4009	ret = slab_alloc_node(s, flags, node, _RET_IP_);
4010
4011	trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
4012
4013	ret = kasan_kmalloc(s, ret, size, flags);
4014
4015	return ret;
4016}
4017EXPORT_SYMBOL(__kmalloc_node);
4018#endif	/* CONFIG_NUMA */
4019
4020#ifdef CONFIG_HARDENED_USERCOPY
4021/*
4022 * Rejects incorrectly sized objects and objects that are to be copied
4023 * to/from userspace but do not fall entirely within the containing slab
4024 * cache's usercopy region.
4025 *
4026 * Returns NULL if check passes, otherwise const char * to name of cache
4027 * to indicate an error.
4028 */
4029void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
4030			 bool to_user)
4031{
4032	struct kmem_cache *s;
4033	unsigned int offset;
4034	size_t object_size;
 
4035
4036	ptr = kasan_reset_tag(ptr);
4037
4038	/* Find object and usable object size. */
4039	s = page->slab_cache;
4040
4041	/* Reject impossible pointers. */
4042	if (ptr < page_address(page))
4043		usercopy_abort("SLUB object not in SLUB page?!", NULL,
4044			       to_user, 0, n);
4045
4046	/* Find offset within object. */
4047	offset = (ptr - page_address(page)) % s->size;
 
 
 
4048
4049	/* Adjust for redzone and reject if within the redzone. */
4050	if (kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
4051		if (offset < s->red_left_pad)
4052			usercopy_abort("SLUB object in left red zone",
4053				       s->name, to_user, offset, n);
4054		offset -= s->red_left_pad;
4055	}
4056
4057	/* Allow address range falling entirely within usercopy region. */
4058	if (offset >= s->useroffset &&
4059	    offset - s->useroffset <= s->usersize &&
4060	    n <= s->useroffset - offset + s->usersize)
4061		return;
4062
4063	/*
4064	 * If the copy is still within the allocated object, produce
4065	 * a warning instead of rejecting the copy. This is intended
4066	 * to be a temporary method to find any missing usercopy
4067	 * whitelists.
4068	 */
4069	object_size = slab_ksize(s);
4070	if (usercopy_fallback &&
4071	    offset <= object_size && n <= object_size - offset) {
4072		usercopy_warn("SLUB object", s->name, to_user, offset, n);
4073		return;
4074	}
4075
4076	usercopy_abort("SLUB object", s->name, to_user, offset, n);
4077}
4078#endif /* CONFIG_HARDENED_USERCOPY */
4079
4080size_t __ksize(const void *object)
4081{
4082	struct page *page;
4083
4084	if (unlikely(object == ZERO_SIZE_PTR))
4085		return 0;
4086
4087	page = virt_to_head_page(object);
4088
4089	if (unlikely(!PageSlab(page))) {
4090		WARN_ON(!PageCompound(page));
4091		return page_size(page);
4092	}
4093
4094	return slab_ksize(page->slab_cache);
4095}
4096EXPORT_SYMBOL(__ksize);
4097
4098void kfree(const void *x)
4099{
4100	struct page *page;
4101	void *object = (void *)x;
4102
4103	trace_kfree(_RET_IP_, x);
4104
4105	if (unlikely(ZERO_OR_NULL_PTR(x)))
4106		return;
4107
4108	page = virt_to_head_page(x);
4109	if (unlikely(!PageSlab(page))) {
4110		unsigned int order = compound_order(page);
4111
4112		BUG_ON(!PageCompound(page));
4113		kfree_hook(object);
4114		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
4115				    -(PAGE_SIZE << order));
4116		__free_pages(page, order);
4117		return;
4118	}
4119	slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
4120}
4121EXPORT_SYMBOL(kfree);
4122
4123#define SHRINK_PROMOTE_MAX 32
4124
4125/*
4126 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
4127 * up most to the head of the partial lists. New allocations will then
4128 * fill those up and thus they can be removed from the partial lists.
4129 *
4130 * The slabs with the least items are placed last. This results in them
4131 * being allocated from last increasing the chance that the last objects
4132 * are freed in them.
4133 */
4134int __kmem_cache_shrink(struct kmem_cache *s)
4135{
4136	int node;
4137	int i;
4138	struct kmem_cache_node *n;
4139	struct page *page;
4140	struct page *t;
4141	struct list_head discard;
4142	struct list_head promote[SHRINK_PROMOTE_MAX];
4143	unsigned long flags;
4144	int ret = 0;
4145
4146	flush_all(s);
4147	for_each_kmem_cache_node(s, node, n) {
4148		INIT_LIST_HEAD(&discard);
4149		for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
4150			INIT_LIST_HEAD(promote + i);
4151
4152		spin_lock_irqsave(&n->list_lock, flags);
4153
4154		/*
4155		 * Build lists of slabs to discard or promote.
4156		 *
4157		 * Note that concurrent frees may occur while we hold the
4158		 * list_lock. page->inuse here is the upper limit.
4159		 */
4160		list_for_each_entry_safe(page, t, &n->partial, slab_list) {
4161			int free = page->objects - page->inuse;
4162
4163			/* Do not reread page->inuse */
4164			barrier();
4165
4166			/* We do not keep full slabs on the list */
4167			BUG_ON(free <= 0);
4168
4169			if (free == page->objects) {
4170				list_move(&page->slab_list, &discard);
4171				n->nr_partial--;
4172			} else if (free <= SHRINK_PROMOTE_MAX)
4173				list_move(&page->slab_list, promote + free - 1);
4174		}
4175
4176		/*
4177		 * Promote the slabs filled up most to the head of the
4178		 * partial list.
4179		 */
4180		for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
4181			list_splice(promote + i, &n->partial);
4182
4183		spin_unlock_irqrestore(&n->list_lock, flags);
4184
4185		/* Release empty slabs */
4186		list_for_each_entry_safe(page, t, &discard, slab_list)
4187			discard_slab(s, page);
4188
4189		if (slabs_node(s, node))
4190			ret = 1;
4191	}
4192
4193	return ret;
4194}
4195
4196static int slab_mem_going_offline_callback(void *arg)
4197{
4198	struct kmem_cache *s;
4199
4200	mutex_lock(&slab_mutex);
4201	list_for_each_entry(s, &slab_caches, list)
4202		__kmem_cache_shrink(s);
4203	mutex_unlock(&slab_mutex);
4204
4205	return 0;
4206}
4207
4208static void slab_mem_offline_callback(void *arg)
4209{
4210	struct kmem_cache_node *n;
4211	struct kmem_cache *s;
4212	struct memory_notify *marg = arg;
4213	int offline_node;
4214
4215	offline_node = marg->status_change_nid_normal;
4216
4217	/*
4218	 * If the node still has available memory. we need kmem_cache_node
4219	 * for it yet.
4220	 */
4221	if (offline_node < 0)
4222		return;
4223
4224	mutex_lock(&slab_mutex);
4225	list_for_each_entry(s, &slab_caches, list) {
4226		n = get_node(s, offline_node);
4227		if (n) {
4228			/*
4229			 * if n->nr_slabs > 0, slabs still exist on the node
4230			 * that is going down. We were unable to free them,
4231			 * and offline_pages() function shouldn't call this
4232			 * callback. So, we must fail.
4233			 */
4234			BUG_ON(slabs_node(s, offline_node));
4235
4236			s->node[offline_node] = NULL;
4237			kmem_cache_free(kmem_cache_node, n);
4238		}
4239	}
4240	mutex_unlock(&slab_mutex);
4241}
4242
4243static int slab_mem_going_online_callback(void *arg)
4244{
4245	struct kmem_cache_node *n;
4246	struct kmem_cache *s;
4247	struct memory_notify *marg = arg;
4248	int nid = marg->status_change_nid_normal;
4249	int ret = 0;
4250
4251	/*
4252	 * If the node's memory is already available, then kmem_cache_node is
4253	 * already created. Nothing to do.
4254	 */
4255	if (nid < 0)
4256		return 0;
4257
4258	/*
4259	 * We are bringing a node online. No memory is available yet. We must
4260	 * allocate a kmem_cache_node structure in order to bring the node
4261	 * online.
4262	 */
4263	mutex_lock(&slab_mutex);
4264	list_for_each_entry(s, &slab_caches, list) {
4265		/*
 
 
 
 
 
 
4266		 * XXX: kmem_cache_alloc_node will fallback to other nodes
4267		 *      since memory is not yet available from the node that
4268		 *      is brought up.
4269		 */
4270		n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
4271		if (!n) {
4272			ret = -ENOMEM;
4273			goto out;
4274		}
4275		init_kmem_cache_node(n);
4276		s->node[nid] = n;
4277	}
 
 
 
 
 
4278out:
4279	mutex_unlock(&slab_mutex);
4280	return ret;
4281}
4282
4283static int slab_memory_callback(struct notifier_block *self,
4284				unsigned long action, void *arg)
4285{
4286	int ret = 0;
4287
4288	switch (action) {
4289	case MEM_GOING_ONLINE:
4290		ret = slab_mem_going_online_callback(arg);
4291		break;
4292	case MEM_GOING_OFFLINE:
4293		ret = slab_mem_going_offline_callback(arg);
4294		break;
4295	case MEM_OFFLINE:
4296	case MEM_CANCEL_ONLINE:
4297		slab_mem_offline_callback(arg);
4298		break;
4299	case MEM_ONLINE:
4300	case MEM_CANCEL_OFFLINE:
4301		break;
4302	}
4303	if (ret)
4304		ret = notifier_from_errno(ret);
4305	else
4306		ret = NOTIFY_OK;
4307	return ret;
4308}
4309
4310static struct notifier_block slab_memory_callback_nb = {
4311	.notifier_call = slab_memory_callback,
4312	.priority = SLAB_CALLBACK_PRI,
4313};
4314
4315/********************************************************************
4316 *			Basic setup of slabs
4317 *******************************************************************/
4318
4319/*
4320 * Used for early kmem_cache structures that were allocated using
4321 * the page allocator. Allocate them properly then fix up the pointers
4322 * that may be pointing to the wrong kmem_cache structure.
4323 */
4324
4325static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4326{
4327	int node;
4328	struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4329	struct kmem_cache_node *n;
4330
4331	memcpy(s, static_cache, kmem_cache->object_size);
4332
4333	/*
4334	 * This runs very early, and only the boot processor is supposed to be
4335	 * up.  Even if it weren't true, IRQs are not up so we couldn't fire
4336	 * IPIs around.
4337	 */
4338	__flush_cpu_slab(s, smp_processor_id());
4339	for_each_kmem_cache_node(s, node, n) {
4340		struct page *p;
4341
4342		list_for_each_entry(p, &n->partial, slab_list)
4343			p->slab_cache = s;
4344
4345#ifdef CONFIG_SLUB_DEBUG
4346		list_for_each_entry(p, &n->full, slab_list)
4347			p->slab_cache = s;
4348#endif
4349	}
4350	list_add(&s->list, &slab_caches);
4351	return s;
4352}
4353
4354void __init kmem_cache_init(void)
4355{
4356	static __initdata struct kmem_cache boot_kmem_cache,
4357		boot_kmem_cache_node;
 
4358
4359	if (debug_guardpage_minorder())
4360		slub_max_order = 0;
4361
 
 
 
 
4362	kmem_cache_node = &boot_kmem_cache_node;
4363	kmem_cache = &boot_kmem_cache;
4364
 
 
 
 
 
 
 
4365	create_boot_cache(kmem_cache_node, "kmem_cache_node",
4366		sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
4367
4368	register_hotmemory_notifier(&slab_memory_callback_nb);
4369
4370	/* Able to allocate the per node structures */
4371	slab_state = PARTIAL;
4372
4373	create_boot_cache(kmem_cache, "kmem_cache",
4374			offsetof(struct kmem_cache, node) +
4375				nr_node_ids * sizeof(struct kmem_cache_node *),
4376		       SLAB_HWCACHE_ALIGN, 0, 0);
4377
4378	kmem_cache = bootstrap(&boot_kmem_cache);
4379	kmem_cache_node = bootstrap(&boot_kmem_cache_node);
4380
4381	/* Now we can use the kmem_cache to allocate kmalloc slabs */
4382	setup_kmalloc_cache_index_table();
4383	create_kmalloc_caches(0);
4384
4385	/* Setup random freelists for each cache */
4386	init_freelist_randomization();
4387
4388	cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
4389				  slub_cpu_dead);
4390
4391	pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
4392		cache_line_size(),
4393		slub_min_order, slub_max_order, slub_min_objects,
4394		nr_cpu_ids, nr_node_ids);
4395}
4396
4397void __init kmem_cache_init_late(void)
4398{
4399}
4400
4401struct kmem_cache *
4402__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
4403		   slab_flags_t flags, void (*ctor)(void *))
4404{
4405	struct kmem_cache *s;
4406
4407	s = find_mergeable(size, align, flags, name, ctor);
4408	if (s) {
4409		s->refcount++;
4410
4411		/*
4412		 * Adjust the object sizes so that we clear
4413		 * the complete object on kzalloc.
4414		 */
4415		s->object_size = max(s->object_size, size);
4416		s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
4417
4418		if (sysfs_slab_alias(s, name)) {
4419			s->refcount--;
4420			s = NULL;
4421		}
4422	}
4423
4424	return s;
4425}
4426
4427int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
4428{
4429	int err;
4430
4431	err = kmem_cache_open(s, flags);
4432	if (err)
4433		return err;
4434
4435	/* Mutex is not taken during early boot */
4436	if (slab_state <= UP)
4437		return 0;
4438
4439	err = sysfs_slab_add(s);
4440	if (err)
4441		__kmem_cache_release(s);
 
 
4442
4443	return err;
 
 
 
4444}
4445
4446void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4447{
4448	struct kmem_cache *s;
4449	void *ret;
4450
4451	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4452		return kmalloc_large(size, gfpflags);
4453
4454	s = kmalloc_slab(size, gfpflags);
4455
4456	if (unlikely(ZERO_OR_NULL_PTR(s)))
4457		return s;
4458
4459	ret = slab_alloc(s, gfpflags, caller);
4460
4461	/* Honor the call site pointer we received. */
4462	trace_kmalloc(caller, ret, size, s->size, gfpflags);
4463
4464	return ret;
4465}
4466EXPORT_SYMBOL(__kmalloc_track_caller);
4467
4468#ifdef CONFIG_NUMA
4469void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4470					int node, unsigned long caller)
4471{
4472	struct kmem_cache *s;
4473	void *ret;
4474
4475	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4476		ret = kmalloc_large_node(size, gfpflags, node);
4477
4478		trace_kmalloc_node(caller, ret,
4479				   size, PAGE_SIZE << get_order(size),
4480				   gfpflags, node);
4481
4482		return ret;
4483	}
4484
4485	s = kmalloc_slab(size, gfpflags);
4486
4487	if (unlikely(ZERO_OR_NULL_PTR(s)))
4488		return s;
4489
4490	ret = slab_alloc_node(s, gfpflags, node, caller);
4491
4492	/* Honor the call site pointer we received. */
4493	trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4494
4495	return ret;
4496}
4497EXPORT_SYMBOL(__kmalloc_node_track_caller);
4498#endif
4499
4500#ifdef CONFIG_SYSFS
4501static int count_inuse(struct page *page)
4502{
4503	return page->inuse;
4504}
4505
4506static int count_total(struct page *page)
4507{
4508	return page->objects;
4509}
4510#endif
4511
4512#ifdef CONFIG_SLUB_DEBUG
4513static void validate_slab(struct kmem_cache *s, struct page *page)
4514{
4515	void *p;
4516	void *addr = page_address(page);
4517	unsigned long *map;
4518
4519	slab_lock(page);
4520
4521	if (!check_slab(s, page) || !on_freelist(s, page, NULL))
4522		goto unlock;
4523
4524	/* Now we know that a valid freelist exists */
4525	map = get_map(s, page);
4526	for_each_object(p, s, addr, page->objects) {
4527		u8 val = test_bit(__obj_to_index(s, addr, p), map) ?
4528			 SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
4529
4530		if (!check_object(s, page, p, val))
4531			break;
4532	}
4533	put_map(map);
4534unlock:
4535	slab_unlock(page);
4536}
4537
4538static int validate_slab_node(struct kmem_cache *s,
4539		struct kmem_cache_node *n)
4540{
4541	unsigned long count = 0;
4542	struct page *page;
4543	unsigned long flags;
4544
4545	spin_lock_irqsave(&n->list_lock, flags);
4546
4547	list_for_each_entry(page, &n->partial, slab_list) {
4548		validate_slab(s, page);
4549		count++;
4550	}
4551	if (count != n->nr_partial)
4552		pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4553		       s->name, count, n->nr_partial);
 
 
4554
4555	if (!(s->flags & SLAB_STORE_USER))
4556		goto out;
4557
4558	list_for_each_entry(page, &n->full, slab_list) {
4559		validate_slab(s, page);
4560		count++;
4561	}
4562	if (count != atomic_long_read(&n->nr_slabs))
4563		pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4564		       s->name, count, atomic_long_read(&n->nr_slabs));
 
 
4565
4566out:
4567	spin_unlock_irqrestore(&n->list_lock, flags);
4568	return count;
4569}
4570
4571static long validate_slab_cache(struct kmem_cache *s)
4572{
4573	int node;
4574	unsigned long count = 0;
4575	struct kmem_cache_node *n;
4576
4577	flush_all(s);
4578	for_each_kmem_cache_node(s, node, n)
4579		count += validate_slab_node(s, n);
4580
4581	return count;
4582}
 
 
 
4583/*
4584 * Generate lists of code addresses where slabcache objects are allocated
4585 * and freed.
4586 */
4587
4588struct location {
4589	unsigned long count;
4590	unsigned long addr;
4591	long long sum_time;
4592	long min_time;
4593	long max_time;
4594	long min_pid;
4595	long max_pid;
4596	DECLARE_BITMAP(cpus, NR_CPUS);
4597	nodemask_t nodes;
4598};
4599
4600struct loc_track {
4601	unsigned long max;
4602	unsigned long count;
4603	struct location *loc;
4604};
4605
 
 
4606static void free_loc_track(struct loc_track *t)
4607{
4608	if (t->max)
4609		free_pages((unsigned long)t->loc,
4610			get_order(sizeof(struct location) * t->max));
4611}
4612
4613static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4614{
4615	struct location *l;
4616	int order;
4617
4618	order = get_order(sizeof(struct location) * max);
4619
4620	l = (void *)__get_free_pages(flags, order);
4621	if (!l)
4622		return 0;
4623
4624	if (t->count) {
4625		memcpy(l, t->loc, sizeof(struct location) * t->count);
4626		free_loc_track(t);
4627	}
4628	t->max = max;
4629	t->loc = l;
4630	return 1;
4631}
4632
4633static int add_location(struct loc_track *t, struct kmem_cache *s,
4634				const struct track *track)
4635{
4636	long start, end, pos;
4637	struct location *l;
4638	unsigned long caddr;
4639	unsigned long age = jiffies - track->when;
4640
4641	start = -1;
4642	end = t->count;
4643
4644	for ( ; ; ) {
4645		pos = start + (end - start + 1) / 2;
4646
4647		/*
4648		 * There is nothing at "end". If we end up there
4649		 * we need to add something to before end.
4650		 */
4651		if (pos == end)
4652			break;
4653
4654		caddr = t->loc[pos].addr;
4655		if (track->addr == caddr) {
4656
4657			l = &t->loc[pos];
4658			l->count++;
4659			if (track->when) {
4660				l->sum_time += age;
4661				if (age < l->min_time)
4662					l->min_time = age;
4663				if (age > l->max_time)
4664					l->max_time = age;
4665
4666				if (track->pid < l->min_pid)
4667					l->min_pid = track->pid;
4668				if (track->pid > l->max_pid)
4669					l->max_pid = track->pid;
4670
4671				cpumask_set_cpu(track->cpu,
4672						to_cpumask(l->cpus));
4673			}
4674			node_set(page_to_nid(virt_to_page(track)), l->nodes);
4675			return 1;
4676		}
4677
4678		if (track->addr < caddr)
4679			end = pos;
4680		else
4681			start = pos;
4682	}
4683
4684	/*
4685	 * Not found. Insert new tracking element.
4686	 */
4687	if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4688		return 0;
4689
4690	l = t->loc + pos;
4691	if (pos < t->count)
4692		memmove(l + 1, l,
4693			(t->count - pos) * sizeof(struct location));
4694	t->count++;
4695	l->count = 1;
4696	l->addr = track->addr;
4697	l->sum_time = age;
4698	l->min_time = age;
4699	l->max_time = age;
4700	l->min_pid = track->pid;
4701	l->max_pid = track->pid;
4702	cpumask_clear(to_cpumask(l->cpus));
4703	cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4704	nodes_clear(l->nodes);
4705	node_set(page_to_nid(virt_to_page(track)), l->nodes);
4706	return 1;
4707}
4708
4709static void process_slab(struct loc_track *t, struct kmem_cache *s,
4710		struct page *page, enum track_item alloc)
4711{
4712	void *addr = page_address(page);
4713	void *p;
4714	unsigned long *map;
4715
4716	map = get_map(s, page);
4717	for_each_object(p, s, addr, page->objects)
4718		if (!test_bit(__obj_to_index(s, addr, p), map))
4719			add_location(t, s, get_track(s, p, alloc));
4720	put_map(map);
4721}
4722
4723static int list_locations(struct kmem_cache *s, char *buf,
4724					enum track_item alloc)
4725{
4726	int len = 0;
4727	unsigned long i;
4728	struct loc_track t = { 0, 0, NULL };
4729	int node;
4730	struct kmem_cache_node *n;
4731
4732	if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4733			     GFP_KERNEL)) {
4734		return sprintf(buf, "Out of memory\n");
4735	}
4736	/* Push back cpu slabs */
4737	flush_all(s);
4738
4739	for_each_kmem_cache_node(s, node, n) {
4740		unsigned long flags;
4741		struct page *page;
4742
4743		if (!atomic_long_read(&n->nr_slabs))
4744			continue;
4745
4746		spin_lock_irqsave(&n->list_lock, flags);
4747		list_for_each_entry(page, &n->partial, slab_list)
4748			process_slab(&t, s, page, alloc);
4749		list_for_each_entry(page, &n->full, slab_list)
4750			process_slab(&t, s, page, alloc);
4751		spin_unlock_irqrestore(&n->list_lock, flags);
4752	}
4753
4754	for (i = 0; i < t.count; i++) {
4755		struct location *l = &t.loc[i];
4756
4757		if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4758			break;
4759		len += sprintf(buf + len, "%7ld ", l->count);
4760
4761		if (l->addr)
4762			len += sprintf(buf + len, "%pS", (void *)l->addr);
4763		else
4764			len += sprintf(buf + len, "<not-available>");
4765
4766		if (l->sum_time != l->min_time) {
4767			len += sprintf(buf + len, " age=%ld/%ld/%ld",
4768				l->min_time,
4769				(long)div_u64(l->sum_time, l->count),
4770				l->max_time);
4771		} else
4772			len += sprintf(buf + len, " age=%ld",
4773				l->min_time);
4774
4775		if (l->min_pid != l->max_pid)
4776			len += sprintf(buf + len, " pid=%ld-%ld",
4777				l->min_pid, l->max_pid);
4778		else
4779			len += sprintf(buf + len, " pid=%ld",
4780				l->min_pid);
4781
4782		if (num_online_cpus() > 1 &&
4783				!cpumask_empty(to_cpumask(l->cpus)) &&
4784				len < PAGE_SIZE - 60)
4785			len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4786					 " cpus=%*pbl",
4787					 cpumask_pr_args(to_cpumask(l->cpus)));
4788
4789		if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4790				len < PAGE_SIZE - 60)
4791			len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4792					 " nodes=%*pbl",
4793					 nodemask_pr_args(&l->nodes));
4794
4795		len += sprintf(buf + len, "\n");
4796	}
4797
4798	free_loc_track(&t);
4799	if (!t.count)
4800		len += sprintf(buf, "No data\n");
4801	return len;
4802}
4803#endif	/* CONFIG_SLUB_DEBUG */
4804
4805#ifdef SLUB_RESILIENCY_TEST
4806static void __init resiliency_test(void)
4807{
4808	u8 *p;
4809	int type = KMALLOC_NORMAL;
4810
4811	BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4812
4813	pr_err("SLUB resiliency testing\n");
4814	pr_err("-----------------------\n");
4815	pr_err("A. Corruption after allocation\n");
4816
4817	p = kzalloc(16, GFP_KERNEL);
4818	p[16] = 0x12;
4819	pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4820	       p + 16);
4821
4822	validate_slab_cache(kmalloc_caches[type][4]);
4823
4824	/* Hmmm... The next two are dangerous */
4825	p = kzalloc(32, GFP_KERNEL);
4826	p[32 + sizeof(void *)] = 0x34;
4827	pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4828	       p);
4829	pr_err("If allocated object is overwritten then not detectable\n\n");
4830
4831	validate_slab_cache(kmalloc_caches[type][5]);
4832	p = kzalloc(64, GFP_KERNEL);
4833	p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4834	*p = 0x56;
4835	pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4836	       p);
4837	pr_err("If allocated object is overwritten then not detectable\n\n");
4838	validate_slab_cache(kmalloc_caches[type][6]);
4839
4840	pr_err("\nB. Corruption after free\n");
4841	p = kzalloc(128, GFP_KERNEL);
4842	kfree(p);
4843	*p = 0x78;
4844	pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4845	validate_slab_cache(kmalloc_caches[type][7]);
4846
4847	p = kzalloc(256, GFP_KERNEL);
4848	kfree(p);
4849	p[50] = 0x9a;
4850	pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
4851	validate_slab_cache(kmalloc_caches[type][8]);
4852
4853	p = kzalloc(512, GFP_KERNEL);
4854	kfree(p);
4855	p[512] = 0xab;
4856	pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4857	validate_slab_cache(kmalloc_caches[type][9]);
4858}
4859#else
4860#ifdef CONFIG_SYSFS
4861static void resiliency_test(void) {};
4862#endif
4863#endif	/* SLUB_RESILIENCY_TEST */
4864
4865#ifdef CONFIG_SYSFS
4866enum slab_stat_type {
4867	SL_ALL,			/* All slabs */
4868	SL_PARTIAL,		/* Only partially allocated slabs */
4869	SL_CPU,			/* Only slabs used for cpu caches */
4870	SL_OBJECTS,		/* Determine allocated objects not slabs */
4871	SL_TOTAL		/* Determine object capacity not slabs */
4872};
4873
4874#define SO_ALL		(1 << SL_ALL)
4875#define SO_PARTIAL	(1 << SL_PARTIAL)
4876#define SO_CPU		(1 << SL_CPU)
4877#define SO_OBJECTS	(1 << SL_OBJECTS)
4878#define SO_TOTAL	(1 << SL_TOTAL)
4879
4880#ifdef CONFIG_MEMCG
4881static bool memcg_sysfs_enabled = IS_ENABLED(CONFIG_SLUB_MEMCG_SYSFS_ON);
4882
4883static int __init setup_slub_memcg_sysfs(char *str)
4884{
4885	int v;
4886
4887	if (get_option(&str, &v) > 0)
4888		memcg_sysfs_enabled = v;
4889
4890	return 1;
4891}
4892
4893__setup("slub_memcg_sysfs=", setup_slub_memcg_sysfs);
4894#endif
4895
4896static ssize_t show_slab_objects(struct kmem_cache *s,
4897			    char *buf, unsigned long flags)
4898{
4899	unsigned long total = 0;
4900	int node;
4901	int x;
4902	unsigned long *nodes;
 
4903
4904	nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
4905	if (!nodes)
4906		return -ENOMEM;
4907
4908	if (flags & SO_CPU) {
4909		int cpu;
4910
4911		for_each_possible_cpu(cpu) {
4912			struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4913							       cpu);
4914			int node;
4915			struct page *page;
4916
4917			page = READ_ONCE(c->page);
4918			if (!page)
4919				continue;
4920
4921			node = page_to_nid(page);
4922			if (flags & SO_TOTAL)
4923				x = page->objects;
4924			else if (flags & SO_OBJECTS)
4925				x = page->inuse;
4926			else
4927				x = 1;
4928
4929			total += x;
4930			nodes[node] += x;
4931
4932			page = slub_percpu_partial_read_once(c);
4933			if (page) {
4934				node = page_to_nid(page);
4935				if (flags & SO_TOTAL)
4936					WARN_ON_ONCE(1);
4937				else if (flags & SO_OBJECTS)
4938					WARN_ON_ONCE(1);
4939				else
4940					x = page->pages;
4941				total += x;
4942				nodes[node] += x;
4943			}
4944		}
4945	}
4946
4947	/*
4948	 * It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
4949	 * already held which will conflict with an existing lock order:
4950	 *
4951	 * mem_hotplug_lock->slab_mutex->kernfs_mutex
4952	 *
4953	 * We don't really need mem_hotplug_lock (to hold off
4954	 * slab_mem_going_offline_callback) here because slab's memory hot
4955	 * unplug code doesn't destroy the kmem_cache->node[] data.
4956	 */
4957
4958#ifdef CONFIG_SLUB_DEBUG
4959	if (flags & SO_ALL) {
4960		struct kmem_cache_node *n;
4961
4962		for_each_kmem_cache_node(s, node, n) {
4963
4964			if (flags & SO_TOTAL)
4965				x = atomic_long_read(&n->total_objects);
4966			else if (flags & SO_OBJECTS)
4967				x = atomic_long_read(&n->total_objects) -
4968					count_partial(n, count_free);
4969			else
4970				x = atomic_long_read(&n->nr_slabs);
4971			total += x;
4972			nodes[node] += x;
4973		}
4974
4975	} else
4976#endif
4977	if (flags & SO_PARTIAL) {
4978		struct kmem_cache_node *n;
4979
4980		for_each_kmem_cache_node(s, node, n) {
4981			if (flags & SO_TOTAL)
4982				x = count_partial(n, count_total);
4983			else if (flags & SO_OBJECTS)
4984				x = count_partial(n, count_inuse);
4985			else
4986				x = n->nr_partial;
4987			total += x;
4988			nodes[node] += x;
4989		}
4990	}
4991	x = sprintf(buf, "%lu", total);
 
4992#ifdef CONFIG_NUMA
4993	for (node = 0; node < nr_node_ids; node++)
4994		if (nodes[node])
4995			x += sprintf(buf + x, " N%d=%lu",
4996					node, nodes[node]);
 
4997#endif
 
4998	kfree(nodes);
4999	return x + sprintf(buf + x, "\n");
 
5000}
5001
5002#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
5003#define to_slab(n) container_of(n, struct kmem_cache, kobj)
5004
5005struct slab_attribute {
5006	struct attribute attr;
5007	ssize_t (*show)(struct kmem_cache *s, char *buf);
5008	ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
5009};
5010
5011#define SLAB_ATTR_RO(_name) \
5012	static struct slab_attribute _name##_attr = \
5013	__ATTR(_name, 0400, _name##_show, NULL)
5014
5015#define SLAB_ATTR(_name) \
5016	static struct slab_attribute _name##_attr =  \
5017	__ATTR(_name, 0600, _name##_show, _name##_store)
5018
5019static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
5020{
5021	return sprintf(buf, "%u\n", s->size);
5022}
5023SLAB_ATTR_RO(slab_size);
5024
5025static ssize_t align_show(struct kmem_cache *s, char *buf)
5026{
5027	return sprintf(buf, "%u\n", s->align);
5028}
5029SLAB_ATTR_RO(align);
5030
5031static ssize_t object_size_show(struct kmem_cache *s, char *buf)
5032{
5033	return sprintf(buf, "%u\n", s->object_size);
5034}
5035SLAB_ATTR_RO(object_size);
5036
5037static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
5038{
5039	return sprintf(buf, "%u\n", oo_objects(s->oo));
5040}
5041SLAB_ATTR_RO(objs_per_slab);
5042
5043static ssize_t order_show(struct kmem_cache *s, char *buf)
5044{
5045	return sprintf(buf, "%u\n", oo_order(s->oo));
5046}
5047SLAB_ATTR_RO(order);
5048
5049static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
5050{
5051	return sprintf(buf, "%lu\n", s->min_partial);
5052}
5053
5054static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
5055				 size_t length)
5056{
5057	unsigned long min;
5058	int err;
5059
5060	err = kstrtoul(buf, 10, &min);
5061	if (err)
5062		return err;
5063
5064	set_min_partial(s, min);
5065	return length;
5066}
5067SLAB_ATTR(min_partial);
5068
5069static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
5070{
5071	return sprintf(buf, "%u\n", slub_cpu_partial(s));
5072}
5073
5074static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
5075				 size_t length)
5076{
5077	unsigned int objects;
5078	int err;
5079
5080	err = kstrtouint(buf, 10, &objects);
5081	if (err)
5082		return err;
5083	if (objects && !kmem_cache_has_cpu_partial(s))
5084		return -EINVAL;
5085
5086	slub_set_cpu_partial(s, objects);
5087	flush_all(s);
5088	return length;
5089}
5090SLAB_ATTR(cpu_partial);
5091
5092static ssize_t ctor_show(struct kmem_cache *s, char *buf)
5093{
5094	if (!s->ctor)
5095		return 0;
5096	return sprintf(buf, "%pS\n", s->ctor);
5097}
5098SLAB_ATTR_RO(ctor);
5099
5100static ssize_t aliases_show(struct kmem_cache *s, char *buf)
5101{
5102	return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
5103}
5104SLAB_ATTR_RO(aliases);
5105
5106static ssize_t partial_show(struct kmem_cache *s, char *buf)
5107{
5108	return show_slab_objects(s, buf, SO_PARTIAL);
5109}
5110SLAB_ATTR_RO(partial);
5111
5112static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
5113{
5114	return show_slab_objects(s, buf, SO_CPU);
5115}
5116SLAB_ATTR_RO(cpu_slabs);
5117
5118static ssize_t objects_show(struct kmem_cache *s, char *buf)
5119{
5120	return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
5121}
5122SLAB_ATTR_RO(objects);
5123
5124static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
5125{
5126	return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
5127}
5128SLAB_ATTR_RO(objects_partial);
5129
5130static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
5131{
5132	int objects = 0;
5133	int pages = 0;
5134	int cpu;
5135	int len;
5136
5137	for_each_online_cpu(cpu) {
5138		struct page *page;
5139
5140		page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5141
5142		if (page) {
5143			pages += page->pages;
5144			objects += page->pobjects;
5145		}
5146	}
5147
5148	len = sprintf(buf, "%d(%d)", objects, pages);
5149
5150#ifdef CONFIG_SMP
5151	for_each_online_cpu(cpu) {
5152		struct page *page;
5153
5154		page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5155
5156		if (page && len < PAGE_SIZE - 20)
5157			len += sprintf(buf + len, " C%d=%d(%d)", cpu,
5158				page->pobjects, page->pages);
5159	}
5160#endif
5161	return len + sprintf(buf + len, "\n");
 
 
5162}
5163SLAB_ATTR_RO(slabs_cpu_partial);
5164
5165static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
5166{
5167	return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
5168}
5169SLAB_ATTR_RO(reclaim_account);
5170
5171static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
5172{
5173	return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
5174}
5175SLAB_ATTR_RO(hwcache_align);
5176
5177#ifdef CONFIG_ZONE_DMA
5178static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
5179{
5180	return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
5181}
5182SLAB_ATTR_RO(cache_dma);
5183#endif
5184
5185static ssize_t usersize_show(struct kmem_cache *s, char *buf)
5186{
5187	return sprintf(buf, "%u\n", s->usersize);
5188}
5189SLAB_ATTR_RO(usersize);
5190
5191static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
5192{
5193	return sprintf(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
5194}
5195SLAB_ATTR_RO(destroy_by_rcu);
5196
5197#ifdef CONFIG_SLUB_DEBUG
5198static ssize_t slabs_show(struct kmem_cache *s, char *buf)
5199{
5200	return show_slab_objects(s, buf, SO_ALL);
5201}
5202SLAB_ATTR_RO(slabs);
5203
5204static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
5205{
5206	return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
5207}
5208SLAB_ATTR_RO(total_objects);
5209
5210static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
5211{
5212	return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
5213}
5214SLAB_ATTR_RO(sanity_checks);
5215
5216static ssize_t trace_show(struct kmem_cache *s, char *buf)
5217{
5218	return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
5219}
5220SLAB_ATTR_RO(trace);
5221
5222static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5223{
5224	return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5225}
5226
5227SLAB_ATTR_RO(red_zone);
5228
5229static ssize_t poison_show(struct kmem_cache *s, char *buf)
5230{
5231	return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
5232}
5233
5234SLAB_ATTR_RO(poison);
5235
5236static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5237{
5238	return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5239}
5240
5241SLAB_ATTR_RO(store_user);
5242
5243static ssize_t validate_show(struct kmem_cache *s, char *buf)
5244{
5245	return 0;
5246}
5247
5248static ssize_t validate_store(struct kmem_cache *s,
5249			const char *buf, size_t length)
5250{
5251	int ret = -EINVAL;
5252
5253	if (buf[0] == '1') {
5254		ret = validate_slab_cache(s);
5255		if (ret >= 0)
5256			ret = length;
5257	}
5258	return ret;
5259}
5260SLAB_ATTR(validate);
5261
5262static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
5263{
5264	if (!(s->flags & SLAB_STORE_USER))
5265		return -ENOSYS;
5266	return list_locations(s, buf, TRACK_ALLOC);
5267}
5268SLAB_ATTR_RO(alloc_calls);
5269
5270static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
5271{
5272	if (!(s->flags & SLAB_STORE_USER))
5273		return -ENOSYS;
5274	return list_locations(s, buf, TRACK_FREE);
5275}
5276SLAB_ATTR_RO(free_calls);
5277#endif /* CONFIG_SLUB_DEBUG */
5278
5279#ifdef CONFIG_FAILSLAB
5280static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5281{
5282	return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5283}
5284SLAB_ATTR_RO(failslab);
5285#endif
5286
5287static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5288{
5289	return 0;
5290}
5291
5292static ssize_t shrink_store(struct kmem_cache *s,
5293			const char *buf, size_t length)
5294{
5295	if (buf[0] == '1')
5296		kmem_cache_shrink(s);
5297	else
5298		return -EINVAL;
5299	return length;
5300}
5301SLAB_ATTR(shrink);
5302
5303#ifdef CONFIG_NUMA
5304static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5305{
5306	return sprintf(buf, "%u\n", s->remote_node_defrag_ratio / 10);
5307}
5308
5309static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5310				const char *buf, size_t length)
5311{
5312	unsigned int ratio;
5313	int err;
5314
5315	err = kstrtouint(buf, 10, &ratio);
5316	if (err)
5317		return err;
5318	if (ratio > 100)
5319		return -ERANGE;
5320
5321	s->remote_node_defrag_ratio = ratio * 10;
5322
5323	return length;
5324}
5325SLAB_ATTR(remote_node_defrag_ratio);
5326#endif
5327
5328#ifdef CONFIG_SLUB_STATS
5329static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5330{
5331	unsigned long sum  = 0;
5332	int cpu;
5333	int len;
5334	int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
5335
5336	if (!data)
5337		return -ENOMEM;
5338
5339	for_each_online_cpu(cpu) {
5340		unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5341
5342		data[cpu] = x;
5343		sum += x;
5344	}
5345
5346	len = sprintf(buf, "%lu", sum);
5347
5348#ifdef CONFIG_SMP
5349	for_each_online_cpu(cpu) {
5350		if (data[cpu] && len < PAGE_SIZE - 20)
5351			len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
 
5352	}
5353#endif
5354	kfree(data);
5355	return len + sprintf(buf + len, "\n");
 
 
5356}
5357
5358static void clear_stat(struct kmem_cache *s, enum stat_item si)
5359{
5360	int cpu;
5361
5362	for_each_online_cpu(cpu)
5363		per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5364}
5365
5366#define STAT_ATTR(si, text) 					\
5367static ssize_t text##_show(struct kmem_cache *s, char *buf)	\
5368{								\
5369	return show_stat(s, buf, si);				\
5370}								\
5371static ssize_t text##_store(struct kmem_cache *s,		\
5372				const char *buf, size_t length)	\
5373{								\
5374	if (buf[0] != '0')					\
5375		return -EINVAL;					\
5376	clear_stat(s, si);					\
5377	return length;						\
5378}								\
5379SLAB_ATTR(text);						\
5380
5381STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5382STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5383STAT_ATTR(FREE_FASTPATH, free_fastpath);
5384STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5385STAT_ATTR(FREE_FROZEN, free_frozen);
5386STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5387STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5388STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5389STAT_ATTR(ALLOC_SLAB, alloc_slab);
5390STAT_ATTR(ALLOC_REFILL, alloc_refill);
5391STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5392STAT_ATTR(FREE_SLAB, free_slab);
5393STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5394STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5395STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5396STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5397STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5398STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5399STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5400STAT_ATTR(ORDER_FALLBACK, order_fallback);
5401STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5402STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5403STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5404STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5405STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5406STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5407#endif	/* CONFIG_SLUB_STATS */
5408
5409static struct attribute *slab_attrs[] = {
5410	&slab_size_attr.attr,
5411	&object_size_attr.attr,
5412	&objs_per_slab_attr.attr,
5413	&order_attr.attr,
5414	&min_partial_attr.attr,
5415	&cpu_partial_attr.attr,
5416	&objects_attr.attr,
5417	&objects_partial_attr.attr,
5418	&partial_attr.attr,
5419	&cpu_slabs_attr.attr,
5420	&ctor_attr.attr,
5421	&aliases_attr.attr,
5422	&align_attr.attr,
5423	&hwcache_align_attr.attr,
5424	&reclaim_account_attr.attr,
5425	&destroy_by_rcu_attr.attr,
5426	&shrink_attr.attr,
5427	&slabs_cpu_partial_attr.attr,
5428#ifdef CONFIG_SLUB_DEBUG
5429	&total_objects_attr.attr,
5430	&slabs_attr.attr,
5431	&sanity_checks_attr.attr,
5432	&trace_attr.attr,
5433	&red_zone_attr.attr,
5434	&poison_attr.attr,
5435	&store_user_attr.attr,
5436	&validate_attr.attr,
5437	&alloc_calls_attr.attr,
5438	&free_calls_attr.attr,
5439#endif
5440#ifdef CONFIG_ZONE_DMA
5441	&cache_dma_attr.attr,
5442#endif
5443#ifdef CONFIG_NUMA
5444	&remote_node_defrag_ratio_attr.attr,
5445#endif
5446#ifdef CONFIG_SLUB_STATS
5447	&alloc_fastpath_attr.attr,
5448	&alloc_slowpath_attr.attr,
5449	&free_fastpath_attr.attr,
5450	&free_slowpath_attr.attr,
5451	&free_frozen_attr.attr,
5452	&free_add_partial_attr.attr,
5453	&free_remove_partial_attr.attr,
5454	&alloc_from_partial_attr.attr,
5455	&alloc_slab_attr.attr,
5456	&alloc_refill_attr.attr,
5457	&alloc_node_mismatch_attr.attr,
5458	&free_slab_attr.attr,
5459	&cpuslab_flush_attr.attr,
5460	&deactivate_full_attr.attr,
5461	&deactivate_empty_attr.attr,
5462	&deactivate_to_head_attr.attr,
5463	&deactivate_to_tail_attr.attr,
5464	&deactivate_remote_frees_attr.attr,
5465	&deactivate_bypass_attr.attr,
5466	&order_fallback_attr.attr,
5467	&cmpxchg_double_fail_attr.attr,
5468	&cmpxchg_double_cpu_fail_attr.attr,
5469	&cpu_partial_alloc_attr.attr,
5470	&cpu_partial_free_attr.attr,
5471	&cpu_partial_node_attr.attr,
5472	&cpu_partial_drain_attr.attr,
5473#endif
5474#ifdef CONFIG_FAILSLAB
5475	&failslab_attr.attr,
5476#endif
5477	&usersize_attr.attr,
5478
5479	NULL
5480};
5481
5482static const struct attribute_group slab_attr_group = {
5483	.attrs = slab_attrs,
5484};
5485
5486static ssize_t slab_attr_show(struct kobject *kobj,
5487				struct attribute *attr,
5488				char *buf)
5489{
5490	struct slab_attribute *attribute;
5491	struct kmem_cache *s;
5492	int err;
5493
5494	attribute = to_slab_attr(attr);
5495	s = to_slab(kobj);
5496
5497	if (!attribute->show)
5498		return -EIO;
5499
5500	err = attribute->show(s, buf);
5501
5502	return err;
5503}
5504
5505static ssize_t slab_attr_store(struct kobject *kobj,
5506				struct attribute *attr,
5507				const char *buf, size_t len)
5508{
5509	struct slab_attribute *attribute;
5510	struct kmem_cache *s;
5511	int err;
5512
5513	attribute = to_slab_attr(attr);
5514	s = to_slab(kobj);
5515
5516	if (!attribute->store)
5517		return -EIO;
5518
5519	err = attribute->store(s, buf, len);
5520	return err;
5521}
5522
5523static void kmem_cache_release(struct kobject *k)
5524{
5525	slab_kmem_cache_release(to_slab(k));
5526}
5527
5528static const struct sysfs_ops slab_sysfs_ops = {
5529	.show = slab_attr_show,
5530	.store = slab_attr_store,
5531};
5532
5533static struct kobj_type slab_ktype = {
5534	.sysfs_ops = &slab_sysfs_ops,
5535	.release = kmem_cache_release,
5536};
5537
5538static struct kset *slab_kset;
5539
5540static inline struct kset *cache_kset(struct kmem_cache *s)
5541{
5542	return slab_kset;
5543}
5544
5545#define ID_STR_LENGTH 64
5546
5547/* Create a unique string id for a slab cache:
5548 *
5549 * Format	:[flags-]size
5550 */
5551static char *create_unique_id(struct kmem_cache *s)
5552{
5553	char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5554	char *p = name;
5555
5556	BUG_ON(!name);
5557
5558	*p++ = ':';
5559	/*
5560	 * First flags affecting slabcache operations. We will only
5561	 * get here for aliasable slabs so we do not need to support
5562	 * too many flags. The flags here must cover all flags that
5563	 * are matched during merging to guarantee that the id is
5564	 * unique.
5565	 */
5566	if (s->flags & SLAB_CACHE_DMA)
5567		*p++ = 'd';
5568	if (s->flags & SLAB_CACHE_DMA32)
5569		*p++ = 'D';
5570	if (s->flags & SLAB_RECLAIM_ACCOUNT)
5571		*p++ = 'a';
5572	if (s->flags & SLAB_CONSISTENCY_CHECKS)
5573		*p++ = 'F';
5574	if (s->flags & SLAB_ACCOUNT)
5575		*p++ = 'A';
5576	if (p != name + 1)
5577		*p++ = '-';
5578	p += sprintf(p, "%07u", s->size);
5579
5580	BUG_ON(p > name + ID_STR_LENGTH - 1);
5581	return name;
5582}
5583
5584static int sysfs_slab_add(struct kmem_cache *s)
5585{
5586	int err;
5587	const char *name;
5588	struct kset *kset = cache_kset(s);
5589	int unmergeable = slab_unmergeable(s);
5590
5591	if (!kset) {
5592		kobject_init(&s->kobj, &slab_ktype);
5593		return 0;
5594	}
5595
5596	if (!unmergeable && disable_higher_order_debug &&
5597			(slub_debug & DEBUG_METADATA_FLAGS))
5598		unmergeable = 1;
5599
5600	if (unmergeable) {
5601		/*
5602		 * Slabcache can never be merged so we can use the name proper.
5603		 * This is typically the case for debug situations. In that
5604		 * case we can catch duplicate names easily.
5605		 */
5606		sysfs_remove_link(&slab_kset->kobj, s->name);
5607		name = s->name;
5608	} else {
5609		/*
5610		 * Create a unique name for the slab as a target
5611		 * for the symlinks.
5612		 */
5613		name = create_unique_id(s);
5614	}
5615
5616	s->kobj.kset = kset;
5617	err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5618	if (err) {
5619		kobject_put(&s->kobj);
5620		goto out;
5621	}
5622
5623	err = sysfs_create_group(&s->kobj, &slab_attr_group);
5624	if (err)
5625		goto out_del_kobj;
5626
5627	if (!unmergeable) {
5628		/* Setup first alias */
5629		sysfs_slab_alias(s, s->name);
5630	}
5631out:
5632	if (!unmergeable)
5633		kfree(name);
5634	return err;
5635out_del_kobj:
5636	kobject_del(&s->kobj);
5637	goto out;
5638}
5639
5640void sysfs_slab_unlink(struct kmem_cache *s)
5641{
5642	if (slab_state >= FULL)
5643		kobject_del(&s->kobj);
5644}
5645
5646void sysfs_slab_release(struct kmem_cache *s)
5647{
5648	if (slab_state >= FULL)
5649		kobject_put(&s->kobj);
5650}
5651
5652/*
5653 * Need to buffer aliases during bootup until sysfs becomes
5654 * available lest we lose that information.
5655 */
5656struct saved_alias {
5657	struct kmem_cache *s;
5658	const char *name;
5659	struct saved_alias *next;
5660};
5661
5662static struct saved_alias *alias_list;
5663
5664static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5665{
5666	struct saved_alias *al;
5667
5668	if (slab_state == FULL) {
5669		/*
5670		 * If we have a leftover link then remove it.
5671		 */
5672		sysfs_remove_link(&slab_kset->kobj, name);
5673		return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5674	}
5675
5676	al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5677	if (!al)
5678		return -ENOMEM;
5679
5680	al->s = s;
5681	al->name = name;
5682	al->next = alias_list;
5683	alias_list = al;
5684	return 0;
5685}
5686
5687static int __init slab_sysfs_init(void)
5688{
5689	struct kmem_cache *s;
5690	int err;
5691
5692	mutex_lock(&slab_mutex);
5693
5694	slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
5695	if (!slab_kset) {
5696		mutex_unlock(&slab_mutex);
5697		pr_err("Cannot register slab subsystem.\n");
5698		return -ENOSYS;
5699	}
5700
5701	slab_state = FULL;
5702
5703	list_for_each_entry(s, &slab_caches, list) {
5704		err = sysfs_slab_add(s);
5705		if (err)
5706			pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5707			       s->name);
5708	}
5709
5710	while (alias_list) {
5711		struct saved_alias *al = alias_list;
5712
5713		alias_list = alias_list->next;
5714		err = sysfs_slab_alias(al->s, al->name);
5715		if (err)
5716			pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5717			       al->name);
5718		kfree(al);
5719	}
5720
5721	mutex_unlock(&slab_mutex);
5722	resiliency_test();
5723	return 0;
5724}
5725
5726__initcall(slab_sysfs_init);
5727#endif /* CONFIG_SYSFS */
5728
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5729/*
5730 * The /proc/slabinfo ABI
5731 */
5732#ifdef CONFIG_SLUB_DEBUG
5733void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5734{
5735	unsigned long nr_slabs = 0;
5736	unsigned long nr_objs = 0;
5737	unsigned long nr_free = 0;
5738	int node;
5739	struct kmem_cache_node *n;
5740
5741	for_each_kmem_cache_node(s, node, n) {
5742		nr_slabs += node_nr_slabs(n);
5743		nr_objs += node_nr_objs(n);
5744		nr_free += count_partial(n, count_free);
5745	}
5746
5747	sinfo->active_objs = nr_objs - nr_free;
5748	sinfo->num_objs = nr_objs;
5749	sinfo->active_slabs = nr_slabs;
5750	sinfo->num_slabs = nr_slabs;
5751	sinfo->objects_per_slab = oo_objects(s->oo);
5752	sinfo->cache_order = oo_order(s->oo);
5753}
5754
5755void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5756{
5757}
5758
5759ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5760		       size_t count, loff_t *ppos)
5761{
5762	return -EIO;
5763}
5764#endif /* CONFIG_SLUB_DEBUG */