// 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 <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 | SLAB_KASAN)

  #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
  ", 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
  ",
  				name, err);
  		else {

  			pr_warn("kmem_cache_create(%s) failed with error %d
  ",

  				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
  ",
  		       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
  ",

  					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
  ", 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!
  ",
  			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)
  ");
  #else
  	seq_puts(m, "slabinfo - version: 2.1
  ");
  #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, '
  ');
  }

  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, '
  ');

  }

  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, *s2;
  	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
  ");
  		return;
  	}
  
  	pr_info("Unreclaimable slab info:
  ");
  	pr_info("Name                      Used          Total
  ");
  
  	list_for_each_entry_safe(s, s2, &slab_caches, list) {

  		if (s->flags & SLAB_RECLAIM_ACCOUNT)

  			continue;
  
  		get_slabinfo(s, &sinfo);
  
  		if (sinfo.num_objs > 0)

  			pr_info("%-17s %10luKB %10luKB
  ", 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.  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_shadow(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);