Merge tag 'io_uring-5.11-2020-12-23' of git://git.kernel.dk/linux-block

[mirror_ubuntu-jammy-kernel.git] / mm / slab_common.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Slab allocator functions that are independent of the allocator strategy
 *
 * (C) 2012 Christoph Lameter <cl@linux.com>
 */
#include <linux/slab.h>

#include <linux/mm.h>
#include <linux/poison.h>
#include <linux/interrupt.h>
#include <linux/memory.h>
#include <linux/cache.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/uaccess.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/debugfs.h>
#include <linux/kasan.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/page.h>
#include <linux/memcontrol.h>

#define CREATE_TRACE_POINTS
#include <trace/events/kmem.h>

#include "internal.h"

#include "slab.h"

enum slab_state slab_state;
LIST_HEAD(slab_caches);
DEFINE_MUTEX(slab_mutex);
struct kmem_cache *kmem_cache;

#ifdef CONFIG_HARDENED_USERCOPY
bool usercopy_fallback __ro_after_init =
                IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK);
module_param(usercopy_fallback, bool, 0400);
MODULE_PARM_DESC(usercopy_fallback,
                "WARN instead of reject usercopy whitelist violations");
#endif

static LIST_HEAD(slab_caches_to_rcu_destroy);
static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
                    slab_caches_to_rcu_destroy_workfn);

/*
 * Set of flags that will prevent slab merging
 */
#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
                SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
                SLAB_FAILSLAB | kasan_never_merge())

#define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
                         SLAB_CACHE_DMA32 | SLAB_ACCOUNT)

/*
 * Merge control. If this is set then no merging of slab caches will occur.
 */
static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);

static int __init setup_slab_nomerge(char *str)
{
        slab_nomerge = true;
        return 1;
}

#ifdef CONFIG_SLUB
__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
#endif

__setup("slab_nomerge", setup_slab_nomerge);

/*
 * Determine the size of a slab object
 */
unsigned int kmem_cache_size(struct kmem_cache *s)
{
        return s->object_size;
}
EXPORT_SYMBOL(kmem_cache_size);

#ifdef CONFIG_DEBUG_VM
static int kmem_cache_sanity_check(const char *name, unsigned int size)
{
        if (!name || in_interrupt() || size < sizeof(void *) ||
                size > KMALLOC_MAX_SIZE) {
                pr_err("kmem_cache_create(%s) integrity check failed\n", name);
                return -EINVAL;
        }

        WARN_ON(strchr(name, ' '));     /* It confuses parsers */
        return 0;
}
#else
static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
{
        return 0;
}
#endif

void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p)
{
        size_t i;

        for (i = 0; i < nr; i++) {
                if (s)
                        kmem_cache_free(s, p[i]);
                else
                        kfree(p[i]);
        }
}

int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
                                                                void **p)
{
        size_t i;

        for (i = 0; i < nr; i++) {
                void *x = p[i] = kmem_cache_alloc(s, flags);
                if (!x) {
                        __kmem_cache_free_bulk(s, i, p);
                        return 0;
                }
        }
        return i;
}

/*
 * Figure out what the alignment of the objects will be given a set of
 * flags, a user specified alignment and the size of the objects.
 */
static unsigned int calculate_alignment(slab_flags_t flags,
                unsigned int align, unsigned int size)
{
        /*
         * If the user wants hardware cache aligned objects then follow that
         * suggestion if the object is sufficiently large.
         *
         * The hardware cache alignment cannot override the specified
         * alignment though. If that is greater then use it.
         */
        if (flags & SLAB_HWCACHE_ALIGN) {
                unsigned int ralign;

                ralign = cache_line_size();
                while (size <= ralign / 2)
                        ralign /= 2;
                align = max(align, ralign);
        }

        if (align < ARCH_SLAB_MINALIGN)
                align = ARCH_SLAB_MINALIGN;

        return ALIGN(align, sizeof(void *));
}

/*
 * Find a mergeable slab cache
 */
int slab_unmergeable(struct kmem_cache *s)
{
        if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
                return 1;

        if (s->ctor)
                return 1;

        if (s->usersize)
                return 1;

        /*
         * We may have set a slab to be unmergeable during bootstrap.
         */
        if (s->refcount < 0)
                return 1;

        return 0;
}

struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
                slab_flags_t flags, const char *name, void (*ctor)(void *))
{
        struct kmem_cache *s;

        if (slab_nomerge)
                return NULL;

        if (ctor)
                return NULL;

        size = ALIGN(size, sizeof(void *));
        align = calculate_alignment(flags, align, size);
        size = ALIGN(size, align);
        flags = kmem_cache_flags(size, flags, name, NULL);

        if (flags & SLAB_NEVER_MERGE)
                return NULL;

        list_for_each_entry_reverse(s, &slab_caches, list) {
                if (slab_unmergeable(s))
                        continue;

                if (size > s->size)
                        continue;

                if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
                        continue;
                /*
                 * Check if alignment is compatible.
                 * Courtesy of Adrian Drzewiecki
                 */
                if ((s->size & ~(align - 1)) != s->size)
                        continue;

                if (s->size - size >= sizeof(void *))
                        continue;

                if (IS_ENABLED(CONFIG_SLAB) && align &&
                        (align > s->align || s->align % align))
                        continue;

                return s;
        }
        return NULL;
}

static struct kmem_cache *create_cache(const char *name,
                unsigned int object_size, unsigned int align,
                slab_flags_t flags, unsigned int useroffset,
                unsigned int usersize, void (*ctor)(void *),
                struct kmem_cache *root_cache)
{
        struct kmem_cache *s;
        int err;

        if (WARN_ON(useroffset + usersize > object_size))
                useroffset = usersize = 0;

        err = -ENOMEM;
        s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
        if (!s)
                goto out;

        s->name = name;
        s->size = s->object_size = object_size;
        s->align = align;
        s->ctor = ctor;
        s->useroffset = useroffset;
        s->usersize = usersize;

        err = __kmem_cache_create(s, flags);
        if (err)
                goto out_free_cache;

        s->refcount = 1;
        list_add(&s->list, &slab_caches);
out:
        if (err)
                return ERR_PTR(err);
        return s;

out_free_cache:
        kmem_cache_free(kmem_cache, s);
        goto out;
}

/**
 * kmem_cache_create_usercopy - Create a cache with a region suitable
 * for copying to userspace
 * @name: A string which is used in /proc/slabinfo to identify this cache.
 * @size: The size of objects to be created in this cache.
 * @align: The required alignment for the objects.
 * @flags: SLAB flags
 * @useroffset: Usercopy region offset
 * @usersize: Usercopy region size
 * @ctor: A constructor for the objects.
 *
 * Cannot be called within a interrupt, but can be interrupted.
 * The @ctor is run when new pages are allocated by the cache.
 *
 * The flags are
 *
 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
 * to catch references to uninitialised memory.
 *
 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
 * for buffer overruns.
 *
 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
 * cacheline.  This can be beneficial if you're counting cycles as closely
 * as davem.
 *
 * Return: a pointer to the cache on success, NULL on failure.
 */
struct kmem_cache *
kmem_cache_create_usercopy(const char *name,
                  unsigned int size, unsigned int align,
                  slab_flags_t flags,
                  unsigned int useroffset, unsigned int usersize,
                  void (*ctor)(void *))
{
        struct kmem_cache *s = NULL;
        const char *cache_name;
        int err;

        get_online_cpus();
        get_online_mems();

        mutex_lock(&slab_mutex);

        err = kmem_cache_sanity_check(name, size);
        if (err) {
                goto out_unlock;
        }

        /* Refuse requests with allocator specific flags */
        if (flags & ~SLAB_FLAGS_PERMITTED) {
                err = -EINVAL;
                goto out_unlock;
        }

        /*
         * Some allocators will constraint the set of valid flags to a subset
         * of all flags. We expect them to define CACHE_CREATE_MASK in this
         * case, and we'll just provide them with a sanitized version of the
         * passed flags.
         */
        flags &= CACHE_CREATE_MASK;

        /* Fail closed on bad usersize of useroffset values. */
        if (WARN_ON(!usersize && useroffset) ||
            WARN_ON(size < usersize || size - usersize < useroffset))
                usersize = useroffset = 0;

        if (!usersize)
                s = __kmem_cache_alias(name, size, align, flags, ctor);
        if (s)
                goto out_unlock;

        cache_name = kstrdup_const(name, GFP_KERNEL);
        if (!cache_name) {
                err = -ENOMEM;
                goto out_unlock;
        }

        s = create_cache(cache_name, size,
                         calculate_alignment(flags, align, size),
                         flags, useroffset, usersize, ctor, NULL);
        if (IS_ERR(s)) {
                err = PTR_ERR(s);
                kfree_const(cache_name);
        }

out_unlock:
        mutex_unlock(&slab_mutex);

        put_online_mems();
        put_online_cpus();

        if (err) {
                if (flags & SLAB_PANIC)
                        panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
                                name, err);
                else {
                        pr_warn("kmem_cache_create(%s) failed with error %d\n",
                                name, err);
                        dump_stack();
                }
                return NULL;
        }
        return s;
}
EXPORT_SYMBOL(kmem_cache_create_usercopy);

/**
 * kmem_cache_create - Create a cache.
 * @name: A string which is used in /proc/slabinfo to identify this cache.
 * @size: The size of objects to be created in this cache.
 * @align: The required alignment for the objects.
 * @flags: SLAB flags
 * @ctor: A constructor for the objects.
 *
 * Cannot be called within a interrupt, but can be interrupted.
 * The @ctor is run when new pages are allocated by the cache.
 *
 * The flags are
 *
 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
 * to catch references to uninitialised memory.
 *
 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
 * for buffer overruns.
 *
 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
 * cacheline.  This can be beneficial if you're counting cycles as closely
 * as davem.
 *
 * Return: a pointer to the cache on success, NULL on failure.
 */
struct kmem_cache *
kmem_cache_create(const char *name, unsigned int size, unsigned int align,
                slab_flags_t flags, void (*ctor)(void *))
{
        return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
                                          ctor);
}
EXPORT_SYMBOL(kmem_cache_create);

static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
{
        LIST_HEAD(to_destroy);
        struct kmem_cache *s, *s2;

        /*
         * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
         * @slab_caches_to_rcu_destroy list.  The slab pages are freed
         * through RCU and the associated kmem_cache are dereferenced
         * while freeing the pages, so the kmem_caches should be freed only
         * after the pending RCU operations are finished.  As rcu_barrier()
         * is a pretty slow operation, we batch all pending destructions
         * asynchronously.
         */
        mutex_lock(&slab_mutex);
        list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
        mutex_unlock(&slab_mutex);

        if (list_empty(&to_destroy))
                return;

        rcu_barrier();

        list_for_each_entry_safe(s, s2, &to_destroy, list) {
#ifdef SLAB_SUPPORTS_SYSFS
                sysfs_slab_release(s);
#else
                slab_kmem_cache_release(s);
#endif
        }
}

static int shutdown_cache(struct kmem_cache *s)
{
        /* free asan quarantined objects */
        kasan_cache_shutdown(s);

        if (__kmem_cache_shutdown(s) != 0)
                return -EBUSY;

        list_del(&s->list);

        if (s->flags & SLAB_TYPESAFE_BY_RCU) {
#ifdef SLAB_SUPPORTS_SYSFS
                sysfs_slab_unlink(s);
#endif
                list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
                schedule_work(&slab_caches_to_rcu_destroy_work);
        } else {
#ifdef SLAB_SUPPORTS_SYSFS
                sysfs_slab_unlink(s);
                sysfs_slab_release(s);
#else
                slab_kmem_cache_release(s);
#endif
        }

        return 0;
}

void slab_kmem_cache_release(struct kmem_cache *s)
{
        __kmem_cache_release(s);
        kfree_const(s->name);
        kmem_cache_free(kmem_cache, s);
}

void kmem_cache_destroy(struct kmem_cache *s)
{
        int err;

        if (unlikely(!s))
                return;

        get_online_cpus();
        get_online_mems();

        mutex_lock(&slab_mutex);

        s->refcount--;
        if (s->refcount)
                goto out_unlock;

        err = shutdown_cache(s);
        if (err) {
                pr_err("kmem_cache_destroy %s: Slab cache still has objects\n",
                       s->name);
                dump_stack();
        }
out_unlock:
        mutex_unlock(&slab_mutex);

        put_online_mems();
        put_online_cpus();
}
EXPORT_SYMBOL(kmem_cache_destroy);

/**
 * kmem_cache_shrink - Shrink a cache.
 * @cachep: The cache to shrink.
 *
 * Releases as many slabs as possible for a cache.
 * To help debugging, a zero exit status indicates all slabs were released.
 *
 * Return: %0 if all slabs were released, non-zero otherwise
 */
int kmem_cache_shrink(struct kmem_cache *cachep)
{
        int ret;

        get_online_cpus();
        get_online_mems();
        kasan_cache_shrink(cachep);
        ret = __kmem_cache_shrink(cachep);
        put_online_mems();
        put_online_cpus();
        return ret;
}
EXPORT_SYMBOL(kmem_cache_shrink);

bool slab_is_available(void)
{
        return slab_state >= UP;
}

#ifndef CONFIG_SLOB
/* Create a cache during boot when no slab services are available yet */
void __init create_boot_cache(struct kmem_cache *s, const char *name,
                unsigned int size, slab_flags_t flags,
                unsigned int useroffset, unsigned int usersize)
{
        int err;
        unsigned int align = ARCH_KMALLOC_MINALIGN;

        s->name = name;
        s->size = s->object_size = size;

        /*
         * For power of two sizes, guarantee natural alignment for kmalloc
         * caches, regardless of SL*B debugging options.
         */
        if (is_power_of_2(size))
                align = max(align, size);
        s->align = calculate_alignment(flags, align, size);

        s->useroffset = useroffset;
        s->usersize = usersize;

        err = __kmem_cache_create(s, flags);

        if (err)
                panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
                                        name, size, err);

        s->refcount = -1;       /* Exempt from merging for now */
}

struct kmem_cache *__init create_kmalloc_cache(const char *name,
                unsigned int size, slab_flags_t flags,
                unsigned int useroffset, unsigned int usersize)
{
        struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);

        if (!s)
                panic("Out of memory when creating slab %s\n", name);

        create_boot_cache(s, name, size, flags, useroffset, usersize);
        list_add(&s->list, &slab_caches);
        s->refcount = 1;
        return s;
}

struct kmem_cache *
kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init =
{ /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ };
EXPORT_SYMBOL(kmalloc_caches);

/*
 * Conversion table for small slabs sizes / 8 to the index in the
 * kmalloc array. This is necessary for slabs < 192 since we have non power
 * of two cache sizes there. The size of larger slabs can be determined using
 * fls.
 */
static u8 size_index[24] __ro_after_init = {
        3,      /* 8 */
        4,      /* 16 */
        5,      /* 24 */
        5,      /* 32 */
        6,      /* 40 */
        6,      /* 48 */
        6,      /* 56 */
        6,      /* 64 */
        1,      /* 72 */
        1,      /* 80 */
        1,      /* 88 */
        1,      /* 96 */
        7,      /* 104 */
        7,      /* 112 */
        7,      /* 120 */
        7,      /* 128 */
        2,      /* 136 */
        2,      /* 144 */
        2,      /* 152 */
        2,      /* 160 */
        2,      /* 168 */
        2,      /* 176 */
        2,      /* 184 */
        2       /* 192 */
};

static inline unsigned int size_index_elem(unsigned int bytes)
{
        return (bytes - 1) / 8;
}

/*
 * Find the kmem_cache structure that serves a given size of
 * allocation
 */
struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
{
        unsigned int index;

        if (size <= 192) {
                if (!size)
                        return ZERO_SIZE_PTR;

                index = size_index[size_index_elem(size)];
        } else {
                if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE))
                        return NULL;
                index = fls(size - 1);
        }

        return kmalloc_caches[kmalloc_type(flags)][index];
}

#ifdef CONFIG_ZONE_DMA
#define INIT_KMALLOC_INFO(__size, __short_size)                 \
{                                                               \
        .name[KMALLOC_NORMAL]  = "kmalloc-" #__short_size,      \
        .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size,  \
        .name[KMALLOC_DMA]     = "dma-kmalloc-" #__short_size,  \
        .size = __size,                                         \
}
#else
#define INIT_KMALLOC_INFO(__size, __short_size)                 \
{                                                               \
        .name[KMALLOC_NORMAL]  = "kmalloc-" #__short_size,      \
        .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size,  \
        .size = __size,                                         \
}
#endif

/*
 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
 * kmalloc-67108864.
 */
const struct kmalloc_info_struct kmalloc_info[] __initconst = {
        INIT_KMALLOC_INFO(0, 0),
        INIT_KMALLOC_INFO(96, 96),
        INIT_KMALLOC_INFO(192, 192),
        INIT_KMALLOC_INFO(8, 8),
        INIT_KMALLOC_INFO(16, 16),
        INIT_KMALLOC_INFO(32, 32),
        INIT_KMALLOC_INFO(64, 64),
        INIT_KMALLOC_INFO(128, 128),
        INIT_KMALLOC_INFO(256, 256),
        INIT_KMALLOC_INFO(512, 512),
        INIT_KMALLOC_INFO(1024, 1k),
        INIT_KMALLOC_INFO(2048, 2k),
        INIT_KMALLOC_INFO(4096, 4k),
        INIT_KMALLOC_INFO(8192, 8k),
        INIT_KMALLOC_INFO(16384, 16k),
        INIT_KMALLOC_INFO(32768, 32k),
        INIT_KMALLOC_INFO(65536, 64k),
        INIT_KMALLOC_INFO(131072, 128k),
        INIT_KMALLOC_INFO(262144, 256k),
        INIT_KMALLOC_INFO(524288, 512k),
        INIT_KMALLOC_INFO(1048576, 1M),
        INIT_KMALLOC_INFO(2097152, 2M),
        INIT_KMALLOC_INFO(4194304, 4M),
        INIT_KMALLOC_INFO(8388608, 8M),
        INIT_KMALLOC_INFO(16777216, 16M),
        INIT_KMALLOC_INFO(33554432, 32M),
        INIT_KMALLOC_INFO(67108864, 64M)
};

/*
 * Patch up the size_index table if we have strange large alignment
 * requirements for the kmalloc array. This is only the case for
 * MIPS it seems. The standard arches will not generate any code here.
 *
 * Largest permitted alignment is 256 bytes due to the way we
 * handle the index determination for the smaller caches.
 *
 * Make sure that nothing crazy happens if someone starts tinkering
 * around with ARCH_KMALLOC_MINALIGN
 */
void __init setup_kmalloc_cache_index_table(void)
{
        unsigned int i;

        BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
                (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));

        for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
                unsigned int elem = size_index_elem(i);

                if (elem >= ARRAY_SIZE(size_index))
                        break;
                size_index[elem] = KMALLOC_SHIFT_LOW;
        }

        if (KMALLOC_MIN_SIZE >= 64) {
                /*
                 * The 96 byte size cache is not used if the alignment
                 * is 64 byte.
                 */
                for (i = 64 + 8; i <= 96; i += 8)
                        size_index[size_index_elem(i)] = 7;

        }

        if (KMALLOC_MIN_SIZE >= 128) {
                /*
                 * The 192 byte sized cache is not used if the alignment
                 * is 128 byte. Redirect kmalloc to use the 256 byte cache
                 * instead.
                 */
                for (i = 128 + 8; i <= 192; i += 8)
                        size_index[size_index_elem(i)] = 8;
        }
}

static void __init
new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
{
        if (type == KMALLOC_RECLAIM)
                flags |= SLAB_RECLAIM_ACCOUNT;

        kmalloc_caches[type][idx] = create_kmalloc_cache(
                                        kmalloc_info[idx].name[type],
                                        kmalloc_info[idx].size, flags, 0,
                                        kmalloc_info[idx].size);
}

/*
 * Create the kmalloc array. Some of the regular kmalloc arrays
 * may already have been created because they were needed to
 * enable allocations for slab creation.
 */
void __init create_kmalloc_caches(slab_flags_t flags)
{
        int i;
        enum kmalloc_cache_type type;

        for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
                for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
                        if (!kmalloc_caches[type][i])
                                new_kmalloc_cache(i, type, flags);

                        /*
                         * Caches that are not of the two-to-the-power-of size.
                         * These have to be created immediately after the
                         * earlier power of two caches
                         */
                        if (KMALLOC_MIN_SIZE <= 32 && i == 6 &&
                                        !kmalloc_caches[type][1])
                                new_kmalloc_cache(1, type, flags);
                        if (KMALLOC_MIN_SIZE <= 64 && i == 7 &&
                                        !kmalloc_caches[type][2])
                                new_kmalloc_cache(2, type, flags);
                }
        }

        /* Kmalloc array is now usable */
        slab_state = UP;

#ifdef CONFIG_ZONE_DMA
        for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
                struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];

                if (s) {
                        kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
                                kmalloc_info[i].name[KMALLOC_DMA],
                                kmalloc_info[i].size,
                                SLAB_CACHE_DMA | flags, 0,
                                kmalloc_info[i].size);
                }
        }
#endif
}
#endif /* !CONFIG_SLOB */

gfp_t kmalloc_fix_flags(gfp_t flags)
{
        gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;

        flags &= ~GFP_SLAB_BUG_MASK;
        pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
                        invalid_mask, &invalid_mask, flags, &flags);
        dump_stack();

        return flags;
}

/*
 * To avoid unnecessary overhead, we pass through large allocation requests
 * directly to the page allocator. We use __GFP_COMP, because we will need to
 * know the allocation order to free the pages properly in kfree.
 */
void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
{
        void *ret = NULL;
        struct page *page;

        if (unlikely(flags & GFP_SLAB_BUG_MASK))
                flags = kmalloc_fix_flags(flags);

        flags |= __GFP_COMP;
        page = alloc_pages(flags, order);
        if (likely(page)) {
                ret = page_address(page);
                mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
                                    PAGE_SIZE << order);
        }
        ret = kasan_kmalloc_large(ret, size, flags);
        /* As ret might get tagged, call kmemleak hook after KASAN. */
        kmemleak_alloc(ret, size, 1, flags);
        return ret;
}
EXPORT_SYMBOL(kmalloc_order);

#ifdef CONFIG_TRACING
void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
{
        void *ret = kmalloc_order(size, flags, order);
        trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
        return ret;
}
EXPORT_SYMBOL(kmalloc_order_trace);
#endif

#ifdef CONFIG_SLAB_FREELIST_RANDOM
/* Randomize a generic freelist */
static void freelist_randomize(struct rnd_state *state, unsigned int *list,
                               unsigned int count)
{
        unsigned int rand;
        unsigned int i;

        for (i = 0; i < count; i++)
                list[i] = i;

        /* Fisher-Yates shuffle */
        for (i = count - 1; i > 0; i--) {
                rand = prandom_u32_state(state);
                rand %= (i + 1);
                swap(list[i], list[rand]);
        }
}

/* Create a random sequence per cache */
int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
                                    gfp_t gfp)
{
        struct rnd_state state;

        if (count < 2 || cachep->random_seq)
                return 0;

        cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
        if (!cachep->random_seq)
                return -ENOMEM;

        /* Get best entropy at this stage of boot */
        prandom_seed_state(&state, get_random_long());

        freelist_randomize(&state, cachep->random_seq, count);
        return 0;
}

/* Destroy the per-cache random freelist sequence */
void cache_random_seq_destroy(struct kmem_cache *cachep)
{
        kfree(cachep->random_seq);
        cachep->random_seq = NULL;
}
#endif /* CONFIG_SLAB_FREELIST_RANDOM */

#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
#ifdef CONFIG_SLAB
#define SLABINFO_RIGHTS (0600)
#else
#define SLABINFO_RIGHTS (0400)
#endif

static void print_slabinfo_header(struct seq_file *m)
{
        /*
         * Output format version, so at least we can change it
         * without _too_ many complaints.
         */
#ifdef CONFIG_DEBUG_SLAB
        seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
#else
        seq_puts(m, "slabinfo - version: 2.1\n");
#endif
        seq_puts(m, "# name            <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
        seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
        seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
#ifdef CONFIG_DEBUG_SLAB
        seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
        seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
#endif
        seq_putc(m, '\n');
}

void *slab_start(struct seq_file *m, loff_t *pos)
{
        mutex_lock(&slab_mutex);
        return seq_list_start(&slab_caches, *pos);
}

void *slab_next(struct seq_file *m, void *p, loff_t *pos)
{
        return seq_list_next(p, &slab_caches, pos);
}

void slab_stop(struct seq_file *m, void *p)
{
        mutex_unlock(&slab_mutex);
}

static void cache_show(struct kmem_cache *s, struct seq_file *m)
{
        struct slabinfo sinfo;

        memset(&sinfo, 0, sizeof(sinfo));
        get_slabinfo(s, &sinfo);

        seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
                   s->name, sinfo.active_objs, sinfo.num_objs, s->size,
                   sinfo.objects_per_slab, (1 << sinfo.cache_order));

        seq_printf(m, " : tunables %4u %4u %4u",
                   sinfo.limit, sinfo.batchcount, sinfo.shared);
        seq_printf(m, " : slabdata %6lu %6lu %6lu",
                   sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
        slabinfo_show_stats(m, s);
        seq_putc(m, '\n');
}

static int slab_show(struct seq_file *m, void *p)
{
        struct kmem_cache *s = list_entry(p, struct kmem_cache, list);

        if (p == slab_caches.next)
                print_slabinfo_header(m);
        cache_show(s, m);
        return 0;
}

void dump_unreclaimable_slab(void)
{
        struct kmem_cache *s;
        struct slabinfo sinfo;

        /*
         * Here acquiring slab_mutex is risky since we don't prefer to get
         * sleep in oom path. But, without mutex hold, it may introduce a
         * risk of crash.
         * Use mutex_trylock to protect the list traverse, dump nothing
         * without acquiring the mutex.
         */
        if (!mutex_trylock(&slab_mutex)) {
                pr_warn("excessive unreclaimable slab but cannot dump stats\n");
                return;
        }

        pr_info("Unreclaimable slab info:\n");
        pr_info("Name                      Used          Total\n");

        list_for_each_entry(s, &slab_caches, list) {
                if (s->flags & SLAB_RECLAIM_ACCOUNT)
                        continue;

                get_slabinfo(s, &sinfo);

                if (sinfo.num_objs > 0)
                        pr_info("%-17s %10luKB %10luKB\n", s->name,
                                (sinfo.active_objs * s->size) / 1024,
                                (sinfo.num_objs * s->size) / 1024);
        }
        mutex_unlock(&slab_mutex);
}

#if defined(CONFIG_MEMCG_KMEM)
int memcg_slab_show(struct seq_file *m, void *p)
{
        /*
         * Deprecated.
         * Please, take a look at tools/cgroup/slabinfo.py .
         */
        return 0;
}
#endif

/*
 * slabinfo_op - iterator that generates /proc/slabinfo
 *
 * Output layout:
 * cache-name
 * num-active-objs
 * total-objs
 * object size
 * num-active-slabs
 * total-slabs
 * num-pages-per-slab
 * + further values on SMP and with statistics enabled
 */
static const struct seq_operations slabinfo_op = {
        .start = slab_start,
        .next = slab_next,
        .stop = slab_stop,
        .show = slab_show,
};

static int slabinfo_open(struct inode *inode, struct file *file)
{
        return seq_open(file, &slabinfo_op);
}

static const struct proc_ops slabinfo_proc_ops = {
        .proc_flags     = PROC_ENTRY_PERMANENT,
        .proc_open      = slabinfo_open,
        .proc_read      = seq_read,
        .proc_write     = slabinfo_write,
        .proc_lseek     = seq_lseek,
        .proc_release   = seq_release,
};

static int __init slab_proc_init(void)
{
        proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops);
        return 0;
}
module_init(slab_proc_init);

#endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */

static __always_inline void *__do_krealloc(const void *p, size_t new_size,
                                           gfp_t flags)
{
        void *ret;
        size_t ks;

        ks = ksize(p);

        if (ks >= new_size) {
                p = kasan_krealloc((void *)p, new_size, flags);
                return (void *)p;
        }

        ret = kmalloc_track_caller(new_size, flags);
        if (ret && p)
                memcpy(ret, p, ks);

        return ret;
}

/**
 * krealloc - reallocate memory. The contents will remain unchanged.
 * @p: object to reallocate memory for.
 * @new_size: how many bytes of memory are required.
 * @flags: the type of memory to allocate.
 *
 * The contents of the object pointed to are preserved up to the
 * lesser of the new and old sizes (__GFP_ZERO flag is effectively ignored).
 * If @p is %NULL, krealloc() behaves exactly like kmalloc().  If @new_size
 * is 0 and @p is not a %NULL pointer, the object pointed to is freed.
 *
 * Return: pointer to the allocated memory or %NULL in case of error
 */
void *krealloc(const void *p, size_t new_size, gfp_t flags)
{
        void *ret;

        if (unlikely(!new_size)) {
                kfree(p);
                return ZERO_SIZE_PTR;
        }

        ret = __do_krealloc(p, new_size, flags);
        if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
                kfree(p);

        return ret;
}
EXPORT_SYMBOL(krealloc);

/**
 * kfree_sensitive - Clear sensitive information in memory before freeing
 * @p: object to free memory of
 *
 * The memory of the object @p points to is zeroed before freed.
 * If @p is %NULL, kfree_sensitive() does nothing.
 *
 * Note: this function zeroes the whole allocated buffer which can be a good
 * deal bigger than the requested buffer size passed to kmalloc(). So be
 * careful when using this function in performance sensitive code.
 */
void kfree_sensitive(const void *p)
{
        size_t ks;
        void *mem = (void *)p;

        ks = ksize(mem);
        if (ks)
                memzero_explicit(mem, ks);
        kfree(mem);
}
EXPORT_SYMBOL(kfree_sensitive);

/**
 * ksize - get the actual amount of memory allocated for a given object
 * @objp: Pointer to the object
 *
 * kmalloc may internally round up allocations and return more memory
 * than requested. ksize() can be used to determine the actual amount of
 * memory allocated. The caller may use this additional memory, even though
 * a smaller amount of memory was initially specified with the kmalloc call.
 * The caller must guarantee that objp points to a valid object previously
 * allocated with either kmalloc() or kmem_cache_alloc(). The object
 * must not be freed during the duration of the call.
 *
 * Return: size of the actual memory used by @objp in bytes
 */
size_t ksize(const void *objp)
{
        size_t size;

        /*
         * We need to check that the pointed to object is valid, and only then
         * unpoison the shadow memory below. We use __kasan_check_read(), to
         * generate a more useful report at the time ksize() is called (rather
         * than later where behaviour is undefined due to potential
         * use-after-free or double-free).
         *
         * If the pointed to memory is invalid we return 0, to avoid users of
         * ksize() writing to and potentially corrupting the memory region.
         *
         * We want to perform the check before __ksize(), to avoid potentially
         * crashing in __ksize() due to accessing invalid metadata.
         */
        if (unlikely(ZERO_OR_NULL_PTR(objp)) || !__kasan_check_read(objp, 1))
                return 0;

        size = __ksize(objp);
        /*
         * We assume that ksize callers could use whole allocated area,
         * so we need to unpoison this area.
         */
        kasan_unpoison_range(objp, size);
        return size;
}
EXPORT_SYMBOL(ksize);

/* Tracepoints definitions. */
EXPORT_TRACEPOINT_SYMBOL(kmalloc);
EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
EXPORT_TRACEPOINT_SYMBOL(kfree);
EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);

int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
{
        if (__should_failslab(s, gfpflags))
                return -ENOMEM;
        return 0;
}
ALLOW_ERROR_INJECTION(should_failslab, ERRNO);