linux/include/linux/slab.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
   4 *
   5 * (C) SGI 2006, Christoph Lameter
   6 *      Cleaned up and restructured to ease the addition of alternative
   7 *      implementations of SLAB allocators.
   8 * (C) Linux Foundation 2008-2013
   9 *      Unified interface for all slab allocators
  10 */
  11
  12#ifndef _LINUX_SLAB_H
  13#define _LINUX_SLAB_H
  14
  15#include <linux/gfp.h>
  16#include <linux/overflow.h>
  17#include <linux/types.h>
  18#include <linux/workqueue.h>
  19#include <linux/percpu-refcount.h>
  20
  21
  22/*
  23 * Flags to pass to kmem_cache_create().
  24 * The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
  25 */
  26/* DEBUG: Perform (expensive) checks on alloc/free */
  27#define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100U)
  28/* DEBUG: Red zone objs in a cache */
  29#define SLAB_RED_ZONE           ((slab_flags_t __force)0x00000400U)
  30/* DEBUG: Poison objects */
  31#define SLAB_POISON             ((slab_flags_t __force)0x00000800U)
  32/* Align objs on cache lines */
  33#define SLAB_HWCACHE_ALIGN      ((slab_flags_t __force)0x00002000U)
  34/* Use GFP_DMA memory */
  35#define SLAB_CACHE_DMA          ((slab_flags_t __force)0x00004000U)
  36/* Use GFP_DMA32 memory */
  37#define SLAB_CACHE_DMA32        ((slab_flags_t __force)0x00008000U)
  38/* DEBUG: Store the last owner for bug hunting */
  39#define SLAB_STORE_USER         ((slab_flags_t __force)0x00010000U)
  40/* Panic if kmem_cache_create() fails */
  41#define SLAB_PANIC              ((slab_flags_t __force)0x00040000U)
  42/*
  43 * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
  44 *
  45 * This delays freeing the SLAB page by a grace period, it does _NOT_
  46 * delay object freeing. This means that if you do kmem_cache_free()
  47 * that memory location is free to be reused at any time. Thus it may
  48 * be possible to see another object there in the same RCU grace period.
  49 *
  50 * This feature only ensures the memory location backing the object
  51 * stays valid, the trick to using this is relying on an independent
  52 * object validation pass. Something like:
  53 *
  54 *  rcu_read_lock()
  55 * again:
  56 *  obj = lockless_lookup(key);
  57 *  if (obj) {
  58 *    if (!try_get_ref(obj)) // might fail for free objects
  59 *      goto again;
  60 *
  61 *    if (obj->key != key) { // not the object we expected
  62 *      put_ref(obj);
  63 *      goto again;
  64 *    }
  65 *  }
  66 *  rcu_read_unlock();
  67 *
  68 * This is useful if we need to approach a kernel structure obliquely,
  69 * from its address obtained without the usual locking. We can lock
  70 * the structure to stabilize it and check it's still at the given address,
  71 * only if we can be sure that the memory has not been meanwhile reused
  72 * for some other kind of object (which our subsystem's lock might corrupt).
  73 *
  74 * rcu_read_lock before reading the address, then rcu_read_unlock after
  75 * taking the spinlock within the structure expected at that address.
  76 *
  77 * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
  78 */
  79/* Defer freeing slabs to RCU */
  80#define SLAB_TYPESAFE_BY_RCU    ((slab_flags_t __force)0x00080000U)
  81/* Spread some memory over cpuset */
  82#define SLAB_MEM_SPREAD         ((slab_flags_t __force)0x00100000U)
  83/* Trace allocations and frees */
  84#define SLAB_TRACE              ((slab_flags_t __force)0x00200000U)
  85
  86/* Flag to prevent checks on free */
  87#ifdef CONFIG_DEBUG_OBJECTS
  88# define SLAB_DEBUG_OBJECTS     ((slab_flags_t __force)0x00400000U)
  89#else
  90# define SLAB_DEBUG_OBJECTS     0
  91#endif
  92
  93/* Avoid kmemleak tracing */
  94#define SLAB_NOLEAKTRACE        ((slab_flags_t __force)0x00800000U)
  95
  96/* Fault injection mark */
  97#ifdef CONFIG_FAILSLAB
  98# define SLAB_FAILSLAB          ((slab_flags_t __force)0x02000000U)
  99#else
 100# define SLAB_FAILSLAB          0
 101#endif
 102/* Account to memcg */
 103#ifdef CONFIG_MEMCG_KMEM
 104# define SLAB_ACCOUNT           ((slab_flags_t __force)0x04000000U)
 105#else
 106# define SLAB_ACCOUNT           0
 107#endif
 108
 109#ifdef CONFIG_KASAN
 110#define SLAB_KASAN              ((slab_flags_t __force)0x08000000U)
 111#else
 112#define SLAB_KASAN              0
 113#endif
 114
 115/* The following flags affect the page allocator grouping pages by mobility */
 116/* Objects are reclaimable */
 117#define SLAB_RECLAIM_ACCOUNT    ((slab_flags_t __force)0x00020000U)
 118#define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
 119
 120/* Slab deactivation flag */
 121#define SLAB_DEACTIVATED        ((slab_flags_t __force)0x10000000U)
 122
 123/*
 124 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
 125 *
 126 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
 127 *
 128 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
 129 * Both make kfree a no-op.
 130 */
 131#define ZERO_SIZE_PTR ((void *)16)
 132
 133#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
 134                                (unsigned long)ZERO_SIZE_PTR)
 135
 136#include <linux/kasan.h>
 137
 138struct mem_cgroup;
 139/*
 140 * struct kmem_cache related prototypes
 141 */
 142void __init kmem_cache_init(void);
 143bool slab_is_available(void);
 144
 145extern bool usercopy_fallback;
 146
 147struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
 148                        unsigned int align, slab_flags_t flags,
 149                        void (*ctor)(void *));
 150struct kmem_cache *kmem_cache_create_usercopy(const char *name,
 151                        unsigned int size, unsigned int align,
 152                        slab_flags_t flags,
 153                        unsigned int useroffset, unsigned int usersize,
 154                        void (*ctor)(void *));
 155void kmem_cache_destroy(struct kmem_cache *);
 156int kmem_cache_shrink(struct kmem_cache *);
 157
 158void memcg_create_kmem_cache(struct mem_cgroup *, struct kmem_cache *);
 159void memcg_deactivate_kmem_caches(struct mem_cgroup *, struct mem_cgroup *);
 160
 161/*
 162 * Please use this macro to create slab caches. Simply specify the
 163 * name of the structure and maybe some flags that are listed above.
 164 *
 165 * The alignment of the struct determines object alignment. If you
 166 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
 167 * then the objects will be properly aligned in SMP configurations.
 168 */
 169#define KMEM_CACHE(__struct, __flags)                                   \
 170                kmem_cache_create(#__struct, sizeof(struct __struct),   \
 171                        __alignof__(struct __struct), (__flags), NULL)
 172
 173/*
 174 * To whitelist a single field for copying to/from usercopy, use this
 175 * macro instead for KMEM_CACHE() above.
 176 */
 177#define KMEM_CACHE_USERCOPY(__struct, __flags, __field)                 \
 178                kmem_cache_create_usercopy(#__struct,                   \
 179                        sizeof(struct __struct),                        \
 180                        __alignof__(struct __struct), (__flags),        \
 181                        offsetof(struct __struct, __field),             \
 182                        sizeof_field(struct __struct, __field), NULL)
 183
 184/*
 185 * Common kmalloc functions provided by all allocators
 186 */
 187void * __must_check __krealloc(const void *, size_t, gfp_t);
 188void * __must_check krealloc(const void *, size_t, gfp_t);
 189void kfree(const void *);
 190void kzfree(const void *);
 191size_t __ksize(const void *);
 192size_t ksize(const void *);
 193
 194#ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
 195void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
 196                        bool to_user);
 197#else
 198static inline void __check_heap_object(const void *ptr, unsigned long n,
 199                                       struct page *page, bool to_user) { }
 200#endif
 201
 202/*
 203 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
 204 * alignment larger than the alignment of a 64-bit integer.
 205 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
 206 */
 207#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 208#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
 209#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 210#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
 211#else
 212#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
 213#endif
 214
 215/*
 216 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
 217 * Intended for arches that get misalignment faults even for 64 bit integer
 218 * aligned buffers.
 219 */
 220#ifndef ARCH_SLAB_MINALIGN
 221#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 222#endif
 223
 224/*
 225 * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
 226 * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
 227 * aligned pointers.
 228 */
 229#define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
 230#define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
 231#define __assume_page_alignment __assume_aligned(PAGE_SIZE)
 232
 233/*
 234 * Kmalloc array related definitions
 235 */
 236
 237#ifdef CONFIG_SLAB
 238/*
 239 * The largest kmalloc size supported by the SLAB allocators is
 240 * 32 megabyte (2^25) or the maximum allocatable page order if that is
 241 * less than 32 MB.
 242 *
 243 * WARNING: Its not easy to increase this value since the allocators have
 244 * to do various tricks to work around compiler limitations in order to
 245 * ensure proper constant folding.
 246 */
 247#define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
 248                                (MAX_ORDER + PAGE_SHIFT - 1) : 25)
 249#define KMALLOC_SHIFT_MAX       KMALLOC_SHIFT_HIGH
 250#ifndef KMALLOC_SHIFT_LOW
 251#define KMALLOC_SHIFT_LOW       5
 252#endif
 253#endif
 254
 255#ifdef CONFIG_SLUB
 256/*
 257 * SLUB directly allocates requests fitting in to an order-1 page
 258 * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
 259 */
 260#define KMALLOC_SHIFT_HIGH      (PAGE_SHIFT + 1)
 261#define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
 262#ifndef KMALLOC_SHIFT_LOW
 263#define KMALLOC_SHIFT_LOW       3
 264#endif
 265#endif
 266
 267#ifdef CONFIG_SLOB
 268/*
 269 * SLOB passes all requests larger than one page to the page allocator.
 270 * No kmalloc array is necessary since objects of different sizes can
 271 * be allocated from the same page.
 272 */
 273#define KMALLOC_SHIFT_HIGH      PAGE_SHIFT
 274#define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
 275#ifndef KMALLOC_SHIFT_LOW
 276#define KMALLOC_SHIFT_LOW       3
 277#endif
 278#endif
 279
 280/* Maximum allocatable size */
 281#define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_MAX)
 282/* Maximum size for which we actually use a slab cache */
 283#define KMALLOC_MAX_CACHE_SIZE  (1UL << KMALLOC_SHIFT_HIGH)
 284/* Maximum order allocatable via the slab allocagtor */
 285#define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
 286
 287/*
 288 * Kmalloc subsystem.
 289 */
 290#ifndef KMALLOC_MIN_SIZE
 291#define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
 292#endif
 293
 294/*
 295 * This restriction comes from byte sized index implementation.
 296 * Page size is normally 2^12 bytes and, in this case, if we want to use
 297 * byte sized index which can represent 2^8 entries, the size of the object
 298 * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
 299 * If minimum size of kmalloc is less than 16, we use it as minimum object
 300 * size and give up to use byte sized index.
 301 */
 302#define SLAB_OBJ_MIN_SIZE      (KMALLOC_MIN_SIZE < 16 ? \
 303                               (KMALLOC_MIN_SIZE) : 16)
 304
 305/*
 306 * Whenever changing this, take care of that kmalloc_type() and
 307 * create_kmalloc_caches() still work as intended.
 308 */
 309enum kmalloc_cache_type {
 310        KMALLOC_NORMAL = 0,
 311        KMALLOC_RECLAIM,
 312#ifdef CONFIG_ZONE_DMA
 313        KMALLOC_DMA,
 314#endif
 315        NR_KMALLOC_TYPES
 316};
 317
 318#ifndef CONFIG_SLOB
 319extern struct kmem_cache *
 320kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
 321
 322static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
 323{
 324#ifdef CONFIG_ZONE_DMA
 325        /*
 326         * The most common case is KMALLOC_NORMAL, so test for it
 327         * with a single branch for both flags.
 328         */
 329        if (likely((flags & (__GFP_DMA | __GFP_RECLAIMABLE)) == 0))
 330                return KMALLOC_NORMAL;
 331
 332        /*
 333         * At least one of the flags has to be set. If both are, __GFP_DMA
 334         * is more important.
 335         */
 336        return flags & __GFP_DMA ? KMALLOC_DMA : KMALLOC_RECLAIM;
 337#else
 338        return flags & __GFP_RECLAIMABLE ? KMALLOC_RECLAIM : KMALLOC_NORMAL;
 339#endif
 340}
 341
 342/*
 343 * Figure out which kmalloc slab an allocation of a certain size
 344 * belongs to.
 345 * 0 = zero alloc
 346 * 1 =  65 .. 96 bytes
 347 * 2 = 129 .. 192 bytes
 348 * n = 2^(n-1)+1 .. 2^n
 349 */
 350static __always_inline unsigned int kmalloc_index(size_t size)
 351{
 352        if (!size)
 353                return 0;
 354
 355        if (size <= KMALLOC_MIN_SIZE)
 356                return KMALLOC_SHIFT_LOW;
 357
 358        if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
 359                return 1;
 360        if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
 361                return 2;
 362        if (size <=          8) return 3;
 363        if (size <=         16) return 4;
 364        if (size <=         32) return 5;
 365        if (size <=         64) return 6;
 366        if (size <=        128) return 7;
 367        if (size <=        256) return 8;
 368        if (size <=        512) return 9;
 369        if (size <=       1024) return 10;
 370        if (size <=   2 * 1024) return 11;
 371        if (size <=   4 * 1024) return 12;
 372        if (size <=   8 * 1024) return 13;
 373        if (size <=  16 * 1024) return 14;
 374        if (size <=  32 * 1024) return 15;
 375        if (size <=  64 * 1024) return 16;
 376        if (size <= 128 * 1024) return 17;
 377        if (size <= 256 * 1024) return 18;
 378        if (size <= 512 * 1024) return 19;
 379        if (size <= 1024 * 1024) return 20;
 380        if (size <=  2 * 1024 * 1024) return 21;
 381        if (size <=  4 * 1024 * 1024) return 22;
 382        if (size <=  8 * 1024 * 1024) return 23;
 383        if (size <=  16 * 1024 * 1024) return 24;
 384        if (size <=  32 * 1024 * 1024) return 25;
 385        if (size <=  64 * 1024 * 1024) return 26;
 386        BUG();
 387
 388        /* Will never be reached. Needed because the compiler may complain */
 389        return -1;
 390}
 391#endif /* !CONFIG_SLOB */
 392
 393void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
 394void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __assume_slab_alignment __malloc;
 395void kmem_cache_free(struct kmem_cache *, void *);
 396
 397/*
 398 * Bulk allocation and freeing operations. These are accelerated in an
 399 * allocator specific way to avoid taking locks repeatedly or building
 400 * metadata structures unnecessarily.
 401 *
 402 * Note that interrupts must be enabled when calling these functions.
 403 */
 404void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
 405int kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
 406
 407/*
 408 * Caller must not use kfree_bulk() on memory not originally allocated
 409 * by kmalloc(), because the SLOB allocator cannot handle this.
 410 */
 411static __always_inline void kfree_bulk(size_t size, void **p)
 412{
 413        kmem_cache_free_bulk(NULL, size, p);
 414}
 415
 416#ifdef CONFIG_NUMA
 417void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
 418void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node) __assume_slab_alignment __malloc;
 419#else
 420static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
 421{
 422        return __kmalloc(size, flags);
 423}
 424
 425static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
 426{
 427        return kmem_cache_alloc(s, flags);
 428}
 429#endif
 430
 431#ifdef CONFIG_TRACING
 432extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t) __assume_slab_alignment __malloc;
 433
 434#ifdef CONFIG_NUMA
 435extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 436                                           gfp_t gfpflags,
 437                                           int node, size_t size) __assume_slab_alignment __malloc;
 438#else
 439static __always_inline void *
 440kmem_cache_alloc_node_trace(struct kmem_cache *s,
 441                              gfp_t gfpflags,
 442                              int node, size_t size)
 443{
 444        return kmem_cache_alloc_trace(s, gfpflags, size);
 445}
 446#endif /* CONFIG_NUMA */
 447
 448#else /* CONFIG_TRACING */
 449static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
 450                gfp_t flags, size_t size)
 451{
 452        void *ret = kmem_cache_alloc(s, flags);
 453
 454        ret = kasan_kmalloc(s, ret, size, flags);
 455        return ret;
 456}
 457
 458static __always_inline void *
 459kmem_cache_alloc_node_trace(struct kmem_cache *s,
 460                              gfp_t gfpflags,
 461                              int node, size_t size)
 462{
 463        void *ret = kmem_cache_alloc_node(s, gfpflags, node);
 464
 465        ret = kasan_kmalloc(s, ret, size, gfpflags);
 466        return ret;
 467}
 468#endif /* CONFIG_TRACING */
 469
 470extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
 471
 472#ifdef CONFIG_TRACING
 473extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
 474#else
 475static __always_inline void *
 476kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 477{
 478        return kmalloc_order(size, flags, order);
 479}
 480#endif
 481
 482static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 483{
 484        unsigned int order = get_order(size);
 485        return kmalloc_order_trace(size, flags, order);
 486}
 487
 488/**
 489 * kmalloc - allocate memory
 490 * @size: how many bytes of memory are required.
 491 * @flags: the type of memory to allocate.
 492 *
 493 * kmalloc is the normal method of allocating memory
 494 * for objects smaller than page size in the kernel.
 495 *
 496 * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
 497 * bytes. For @size of power of two bytes, the alignment is also guaranteed
 498 * to be at least to the size.
 499 *
 500 * The @flags argument may be one of the GFP flags defined at
 501 * include/linux/gfp.h and described at
 502 * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
 503 *
 504 * The recommended usage of the @flags is described at
 505 * :ref:`Documentation/core-api/memory-allocation.rst <memory-allocation>`
 506 *
 507 * Below is a brief outline of the most useful GFP flags
 508 *
 509 * %GFP_KERNEL
 510 *      Allocate normal kernel ram. May sleep.
 511 *
 512 * %GFP_NOWAIT
 513 *      Allocation will not sleep.
 514 *
 515 * %GFP_ATOMIC
 516 *      Allocation will not sleep.  May use emergency pools.
 517 *
 518 * %GFP_HIGHUSER
 519 *      Allocate memory from high memory on behalf of user.
 520 *
 521 * Also it is possible to set different flags by OR'ing
 522 * in one or more of the following additional @flags:
 523 *
 524 * %__GFP_HIGH
 525 *      This allocation has high priority and may use emergency pools.
 526 *
 527 * %__GFP_NOFAIL
 528 *      Indicate that this allocation is in no way allowed to fail
 529 *      (think twice before using).
 530 *
 531 * %__GFP_NORETRY
 532 *      If memory is not immediately available,
 533 *      then give up at once.
 534 *
 535 * %__GFP_NOWARN
 536 *      If allocation fails, don't issue any warnings.
 537 *
 538 * %__GFP_RETRY_MAYFAIL
 539 *      Try really hard to succeed the allocation but fail
 540 *      eventually.
 541 */
 542static __always_inline void *kmalloc(size_t size, gfp_t flags)
 543{
 544        if (__builtin_constant_p(size)) {
 545#ifndef CONFIG_SLOB
 546                unsigned int index;
 547#endif
 548                if (size > KMALLOC_MAX_CACHE_SIZE)
 549                        return kmalloc_large(size, flags);
 550#ifndef CONFIG_SLOB
 551                index = kmalloc_index(size);
 552
 553                if (!index)
 554                        return ZERO_SIZE_PTR;
 555
 556                return kmem_cache_alloc_trace(
 557                                kmalloc_caches[kmalloc_type(flags)][index],
 558                                flags, size);
 559#endif
 560        }
 561        return __kmalloc(size, flags);
 562}
 563
 564/*
 565 * Determine size used for the nth kmalloc cache.
 566 * return size or 0 if a kmalloc cache for that
 567 * size does not exist
 568 */
 569static __always_inline unsigned int kmalloc_size(unsigned int n)
 570{
 571#ifndef CONFIG_SLOB
 572        if (n > 2)
 573                return 1U << n;
 574
 575        if (n == 1 && KMALLOC_MIN_SIZE <= 32)
 576                return 96;
 577
 578        if (n == 2 && KMALLOC_MIN_SIZE <= 64)
 579                return 192;
 580#endif
 581        return 0;
 582}
 583
 584static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 585{
 586#ifndef CONFIG_SLOB
 587        if (__builtin_constant_p(size) &&
 588                size <= KMALLOC_MAX_CACHE_SIZE) {
 589                unsigned int i = kmalloc_index(size);
 590
 591                if (!i)
 592                        return ZERO_SIZE_PTR;
 593
 594                return kmem_cache_alloc_node_trace(
 595                                kmalloc_caches[kmalloc_type(flags)][i],
 596                                                flags, node, size);
 597        }
 598#endif
 599        return __kmalloc_node(size, flags, node);
 600}
 601
 602int memcg_update_all_caches(int num_memcgs);
 603
 604/**
 605 * kmalloc_array - allocate memory for an array.
 606 * @n: number of elements.
 607 * @size: element size.
 608 * @flags: the type of memory to allocate (see kmalloc).
 609 */
 610static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
 611{
 612        size_t bytes;
 613
 614        if (unlikely(check_mul_overflow(n, size, &bytes)))
 615                return NULL;
 616        if (__builtin_constant_p(n) && __builtin_constant_p(size))
 617                return kmalloc(bytes, flags);
 618        return __kmalloc(bytes, flags);
 619}
 620
 621/**
 622 * kcalloc - allocate memory for an array. The memory is set to zero.
 623 * @n: number of elements.
 624 * @size: element size.
 625 * @flags: the type of memory to allocate (see kmalloc).
 626 */
 627static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
 628{
 629        return kmalloc_array(n, size, flags | __GFP_ZERO);
 630}
 631
 632/*
 633 * kmalloc_track_caller is a special version of kmalloc that records the
 634 * calling function of the routine calling it for slab leak tracking instead
 635 * of just the calling function (confusing, eh?).
 636 * It's useful when the call to kmalloc comes from a widely-used standard
 637 * allocator where we care about the real place the memory allocation
 638 * request comes from.
 639 */
 640extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
 641#define kmalloc_track_caller(size, flags) \
 642        __kmalloc_track_caller(size, flags, _RET_IP_)
 643
 644static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
 645                                       int node)
 646{
 647        size_t bytes;
 648
 649        if (unlikely(check_mul_overflow(n, size, &bytes)))
 650                return NULL;
 651        if (__builtin_constant_p(n) && __builtin_constant_p(size))
 652                return kmalloc_node(bytes, flags, node);
 653        return __kmalloc_node(bytes, flags, node);
 654}
 655
 656static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
 657{
 658        return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
 659}
 660
 661
 662#ifdef CONFIG_NUMA
 663extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
 664#define kmalloc_node_track_caller(size, flags, node) \
 665        __kmalloc_node_track_caller(size, flags, node, \
 666                        _RET_IP_)
 667
 668#else /* CONFIG_NUMA */
 669
 670#define kmalloc_node_track_caller(size, flags, node) \
 671        kmalloc_track_caller(size, flags)
 672
 673#endif /* CONFIG_NUMA */
 674
 675/*
 676 * Shortcuts
 677 */
 678static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
 679{
 680        return kmem_cache_alloc(k, flags | __GFP_ZERO);
 681}
 682
 683/**
 684 * kzalloc - allocate memory. The memory is set to zero.
 685 * @size: how many bytes of memory are required.
 686 * @flags: the type of memory to allocate (see kmalloc).
 687 */
 688static inline void *kzalloc(size_t size, gfp_t flags)
 689{
 690        return kmalloc(size, flags | __GFP_ZERO);
 691}
 692
 693/**
 694 * kzalloc_node - allocate zeroed memory from a particular memory node.
 695 * @size: how many bytes of memory are required.
 696 * @flags: the type of memory to allocate (see kmalloc).
 697 * @node: memory node from which to allocate
 698 */
 699static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
 700{
 701        return kmalloc_node(size, flags | __GFP_ZERO, node);
 702}
 703
 704unsigned int kmem_cache_size(struct kmem_cache *s);
 705void __init kmem_cache_init_late(void);
 706
 707#if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
 708int slab_prepare_cpu(unsigned int cpu);
 709int slab_dead_cpu(unsigned int cpu);
 710#else
 711#define slab_prepare_cpu        NULL
 712#define slab_dead_cpu           NULL
 713#endif
 714
 715#endif  /* _LINUX_SLAB_H */
 716