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linux-sg2042/include/linux/slab.h

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
*
* (C) SGI 2006, Christoph Lameter
* Cleaned up and restructured to ease the addition of alternative
* implementations of SLAB allocators.
* (C) Linux Foundation 2008-2013
* Unified interface for all slab allocators
*/
#ifndef _LINUX_SLAB_H
#define _LINUX_SLAB_H
#include <linux/gfp.h>
#include <linux/overflow.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <linux/percpu-refcount.h>
/*
* Flags to pass to kmem_cache_create().
* The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
*/
/* DEBUG: Perform (expensive) checks on alloc/free */
#define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100U)
/* DEBUG: Red zone objs in a cache */
#define SLAB_RED_ZONE ((slab_flags_t __force)0x00000400U)
/* DEBUG: Poison objects */
#define SLAB_POISON ((slab_flags_t __force)0x00000800U)
/* Align objs on cache lines */
#define SLAB_HWCACHE_ALIGN ((slab_flags_t __force)0x00002000U)
/* Use GFP_DMA memory */
#define SLAB_CACHE_DMA ((slab_flags_t __force)0x00004000U)
/* Use GFP_DMA32 memory */
#define SLAB_CACHE_DMA32 ((slab_flags_t __force)0x00008000U)
/* DEBUG: Store the last owner for bug hunting */
#define SLAB_STORE_USER ((slab_flags_t __force)0x00010000U)
/* Panic if kmem_cache_create() fails */
#define SLAB_PANIC ((slab_flags_t __force)0x00040000U)
/*
* SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
*
* This delays freeing the SLAB page by a grace period, it does _NOT_
* delay object freeing. This means that if you do kmem_cache_free()
* that memory location is free to be reused at any time. Thus it may
* be possible to see another object there in the same RCU grace period.
*
* This feature only ensures the memory location backing the object
* stays valid, the trick to using this is relying on an independent
* object validation pass. Something like:
*
* rcu_read_lock()
* again:
* obj = lockless_lookup(key);
* if (obj) {
* if (!try_get_ref(obj)) // might fail for free objects
* goto again;
*
* if (obj->key != key) { // not the object we expected
* put_ref(obj);
* goto again;
* }
* }
* rcu_read_unlock();
*
* This is useful if we need to approach a kernel structure obliquely,
* from its address obtained without the usual locking. We can lock
* the structure to stabilize it and check it's still at the given address,
* only if we can be sure that the memory has not been meanwhile reused
* for some other kind of object (which our subsystem's lock might corrupt).
*
* rcu_read_lock before reading the address, then rcu_read_unlock after
* taking the spinlock within the structure expected at that address.
*
* Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
*/
/* Defer freeing slabs to RCU */
#define SLAB_TYPESAFE_BY_RCU ((slab_flags_t __force)0x00080000U)
/* Spread some memory over cpuset */
#define SLAB_MEM_SPREAD ((slab_flags_t __force)0x00100000U)
/* Trace allocations and frees */
#define SLAB_TRACE ((slab_flags_t __force)0x00200000U)
/* Flag to prevent checks on free */
#ifdef CONFIG_DEBUG_OBJECTS
# define SLAB_DEBUG_OBJECTS ((slab_flags_t __force)0x00400000U)
#else
# define SLAB_DEBUG_OBJECTS 0
#endif
/* Avoid kmemleak tracing */
#define SLAB_NOLEAKTRACE ((slab_flags_t __force)0x00800000U)
/* Fault injection mark */
#ifdef CONFIG_FAILSLAB
# define SLAB_FAILSLAB ((slab_flags_t __force)0x02000000U)
#else
# define SLAB_FAILSLAB 0
#endif
/* Account to memcg */
#ifdef CONFIG_MEMCG_KMEM
# define SLAB_ACCOUNT ((slab_flags_t __force)0x04000000U)
#else
# define SLAB_ACCOUNT 0
#endif
#ifdef CONFIG_KASAN
#define SLAB_KASAN ((slab_flags_t __force)0x08000000U)
#else
#define SLAB_KASAN 0
#endif
/* The following flags affect the page allocator grouping pages by mobility */
/* Objects are reclaimable */
#define SLAB_RECLAIM_ACCOUNT ((slab_flags_t __force)0x00020000U)
#define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
/* Slab deactivation flag */
#define SLAB_DEACTIVATED ((slab_flags_t __force)0x10000000U)
/*
* ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
*
* Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
*
* ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
* Both make kfree a no-op.
*/
#define ZERO_SIZE_PTR ((void *)16)
#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
(unsigned long)ZERO_SIZE_PTR)
#include <linux/kasan.h>
struct mem_cgroup;
/*
* struct kmem_cache related prototypes
*/
void __init kmem_cache_init(void);
bool slab_is_available(void);
extern bool usercopy_fallback;
struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
unsigned int align, slab_flags_t flags,
void (*ctor)(void *));
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 *));
void kmem_cache_destroy(struct kmem_cache *);
int kmem_cache_shrink(struct kmem_cache *);
/*
* Please use this macro to create slab caches. Simply specify the
* name of the structure and maybe some flags that are listed above.
*
* The alignment of the struct determines object alignment. If you
* f.e. add ____cacheline_aligned_in_smp to the struct declaration
* then the objects will be properly aligned in SMP configurations.
*/
#define KMEM_CACHE(__struct, __flags) \
kmem_cache_create(#__struct, sizeof(struct __struct), \
__alignof__(struct __struct), (__flags), NULL)
/*
* To whitelist a single field for copying to/from usercopy, use this
* macro instead for KMEM_CACHE() above.
*/
#define KMEM_CACHE_USERCOPY(__struct, __flags, __field) \
kmem_cache_create_usercopy(#__struct, \
sizeof(struct __struct), \
__alignof__(struct __struct), (__flags), \
offsetof(struct __struct, __field), \
sizeof_field(struct __struct, __field), NULL)
/*
* Common kmalloc functions provided by all allocators
*/
void * __must_check krealloc(const void *, size_t, gfp_t);
void kfree(const void *);
void kfree_sensitive(const void *);
size_t __ksize(const void *);
size_t ksize(const void *);
#ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
bool to_user);
#else
static inline void __check_heap_object(const void *ptr, unsigned long n,
struct page *page, bool to_user) { }
#endif
/*
* Some archs want to perform DMA into kmalloc caches and need a guaranteed
* alignment larger than the alignment of a 64-bit integer.
* Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
*/
#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
#else
#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
#endif
/*
* Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
* Intended for arches that get misalignment faults even for 64 bit integer
* aligned buffers.
*/
#ifndef ARCH_SLAB_MINALIGN
#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
#endif
/*
* kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
* pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
* aligned pointers.
*/
#define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
#define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
#define __assume_page_alignment __assume_aligned(PAGE_SIZE)
/*
* Kmalloc array related definitions
*/
#ifdef CONFIG_SLAB
/*
* The largest kmalloc size supported by the SLAB allocators is
* 32 megabyte (2^25) or the maximum allocatable page order if that is
* less than 32 MB.
*
* WARNING: Its not easy to increase this value since the allocators have
* to do various tricks to work around compiler limitations in order to
* ensure proper constant folding.
*/
#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
(MAX_ORDER + PAGE_SHIFT - 1) : 25)
#define KMALLOC_SHIFT_MAX KMALLOC_SHIFT_HIGH
#ifndef KMALLOC_SHIFT_LOW
#define KMALLOC_SHIFT_LOW 5
#endif
#endif
#ifdef CONFIG_SLUB
/*
* SLUB directly allocates requests fitting in to an order-1 page
* (PAGE_SIZE*2). Larger requests are passed to the page allocator.
*/
#define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1)
#define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
#ifndef KMALLOC_SHIFT_LOW
#define KMALLOC_SHIFT_LOW 3
#endif
#endif
#ifdef CONFIG_SLOB
/*
* SLOB passes all requests larger than one page to the page allocator.
* No kmalloc array is necessary since objects of different sizes can
* be allocated from the same page.
*/
#define KMALLOC_SHIFT_HIGH PAGE_SHIFT
#define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
#ifndef KMALLOC_SHIFT_LOW
#define KMALLOC_SHIFT_LOW 3
#endif
#endif
/* Maximum allocatable size */
#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX)
/* Maximum size for which we actually use a slab cache */
#define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH)
/* Maximum order allocatable via the slab allocator */
#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
/*
* Kmalloc subsystem.
*/
#ifndef KMALLOC_MIN_SIZE
#define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
#endif
/*
* This restriction comes from byte sized index implementation.
* Page size is normally 2^12 bytes and, in this case, if we want to use
* byte sized index which can represent 2^8 entries, the size of the object
* should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
* If minimum size of kmalloc is less than 16, we use it as minimum object
* size and give up to use byte sized index.
*/
#define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \
(KMALLOC_MIN_SIZE) : 16)
/*
* Whenever changing this, take care of that kmalloc_type() and
* create_kmalloc_caches() still work as intended.
*/
enum kmalloc_cache_type {
KMALLOC_NORMAL = 0,
KMALLOC_RECLAIM,
#ifdef CONFIG_ZONE_DMA
KMALLOC_DMA,
#endif
NR_KMALLOC_TYPES
};
#ifndef CONFIG_SLOB
extern struct kmem_cache *
kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
{
#ifdef CONFIG_ZONE_DMA
/*
* The most common case is KMALLOC_NORMAL, so test for it
* with a single branch for both flags.
*/
if (likely((flags & (__GFP_DMA | __GFP_RECLAIMABLE)) == 0))
return KMALLOC_NORMAL;
/*
* At least one of the flags has to be set. If both are, __GFP_DMA
* is more important.
*/
return flags & __GFP_DMA ? KMALLOC_DMA : KMALLOC_RECLAIM;
#else
return flags & __GFP_RECLAIMABLE ? KMALLOC_RECLAIM : KMALLOC_NORMAL;
#endif
}
/*
* Figure out which kmalloc slab an allocation of a certain size
* belongs to.
* 0 = zero alloc
* 1 = 65 .. 96 bytes
* 2 = 129 .. 192 bytes
* n = 2^(n-1)+1 .. 2^n
*/
static __always_inline unsigned int kmalloc_index(size_t size)
{
if (!size)
return 0;
if (size <= KMALLOC_MIN_SIZE)
return KMALLOC_SHIFT_LOW;
if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
return 1;
if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
return 2;
if (size <= 8) return 3;
if (size <= 16) return 4;
if (size <= 32) return 5;
if (size <= 64) return 6;
if (size <= 128) return 7;
if (size <= 256) return 8;
if (size <= 512) return 9;
if (size <= 1024) return 10;
if (size <= 2 * 1024) return 11;
if (size <= 4 * 1024) return 12;
if (size <= 8 * 1024) return 13;
if (size <= 16 * 1024) return 14;
if (size <= 32 * 1024) return 15;
if (size <= 64 * 1024) return 16;
if (size <= 128 * 1024) return 17;
if (size <= 256 * 1024) return 18;
if (size <= 512 * 1024) return 19;
if (size <= 1024 * 1024) return 20;
if (size <= 2 * 1024 * 1024) return 21;
if (size <= 4 * 1024 * 1024) return 22;
if (size <= 8 * 1024 * 1024) return 23;
if (size <= 16 * 1024 * 1024) return 24;
if (size <= 32 * 1024 * 1024) return 25;
if (size <= 64 * 1024 * 1024) return 26;
BUG();
/* Will never be reached. Needed because the compiler may complain */
return -1;
}
#endif /* !CONFIG_SLOB */
void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __assume_slab_alignment __malloc;
void kmem_cache_free(struct kmem_cache *, void *);
/*
* Bulk allocation and freeing operations. These are accelerated in an
* allocator specific way to avoid taking locks repeatedly or building
* metadata structures unnecessarily.
*
* Note that interrupts must be enabled when calling these functions.
*/
void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
int kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
/*
* Caller must not use kfree_bulk() on memory not originally allocated
* by kmalloc(), because the SLOB allocator cannot handle this.
*/
static __always_inline void kfree_bulk(size_t size, void **p)
{
kmem_cache_free_bulk(NULL, size, p);
}
#ifdef CONFIG_NUMA
void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node) __assume_slab_alignment __malloc;
#else
static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
{
return __kmalloc(size, flags);
}
static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
{
return kmem_cache_alloc(s, flags);
}
#endif
#ifdef CONFIG_TRACING
extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t) __assume_slab_alignment __malloc;
#ifdef CONFIG_NUMA
extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
gfp_t gfpflags,
int node, size_t size) __assume_slab_alignment __malloc;
#else
static __always_inline void *
kmem_cache_alloc_node_trace(struct kmem_cache *s,
gfp_t gfpflags,
int node, size_t size)
{
return kmem_cache_alloc_trace(s, gfpflags, size);
}
#endif /* CONFIG_NUMA */
#else /* CONFIG_TRACING */
static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
gfp_t flags, size_t size)
{
void *ret = kmem_cache_alloc(s, flags);
ret = kasan_kmalloc(s, ret, size, flags);
return ret;
}
static __always_inline void *
kmem_cache_alloc_node_trace(struct kmem_cache *s,
gfp_t gfpflags,
int node, size_t size)
{
void *ret = kmem_cache_alloc_node(s, gfpflags, node);
ret = kasan_kmalloc(s, ret, size, gfpflags);
return ret;
}
#endif /* CONFIG_TRACING */
extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
#ifdef CONFIG_TRACING
extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
#else
static __always_inline void *
kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
{
return kmalloc_order(size, flags, order);
}
#endif
static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
{
unsigned int order = get_order(size);
return kmalloc_order_trace(size, flags, order);
}
/**
* kmalloc - allocate memory
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate.
*
* kmalloc is the normal method of allocating memory
* for objects smaller than page size in the kernel.
*
* The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
* bytes. For @size of power of two bytes, the alignment is also guaranteed
* to be at least to the size.
*
* The @flags argument may be one of the GFP flags defined at
* include/linux/gfp.h and described at
* :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
*
* The recommended usage of the @flags is described at
* :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>`
*
* Below is a brief outline of the most useful GFP flags
*
* %GFP_KERNEL
* Allocate normal kernel ram. May sleep.
*
* %GFP_NOWAIT
* Allocation will not sleep.
*
* %GFP_ATOMIC
* Allocation will not sleep. May use emergency pools.
*
* %GFP_HIGHUSER
* Allocate memory from high memory on behalf of user.
*
* Also it is possible to set different flags by OR'ing
* in one or more of the following additional @flags:
*
* %__GFP_HIGH
* This allocation has high priority and may use emergency pools.
*
* %__GFP_NOFAIL
* Indicate that this allocation is in no way allowed to fail
* (think twice before using).
*
* %__GFP_NORETRY
* If memory is not immediately available,
* then give up at once.
*
* %__GFP_NOWARN
* If allocation fails, don't issue any warnings.
*
* %__GFP_RETRY_MAYFAIL
* Try really hard to succeed the allocation but fail
* eventually.
*/
static __always_inline void *kmalloc(size_t size, gfp_t flags)
{
if (__builtin_constant_p(size)) {
#ifndef CONFIG_SLOB
unsigned int index;
#endif
if (size > KMALLOC_MAX_CACHE_SIZE)
return kmalloc_large(size, flags);
#ifndef CONFIG_SLOB
index = kmalloc_index(size);
if (!index)
return ZERO_SIZE_PTR;
return kmem_cache_alloc_trace(
kmalloc_caches[kmalloc_type(flags)][index],
flags, size);
#endif
}
return __kmalloc(size, flags);
}
static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
{
#ifndef CONFIG_SLOB
if (__builtin_constant_p(size) &&
size <= KMALLOC_MAX_CACHE_SIZE) {
unsigned int i = kmalloc_index(size);
if (!i)
return ZERO_SIZE_PTR;
return kmem_cache_alloc_node_trace(
kmalloc_caches[kmalloc_type(flags)][i],
flags, node, size);
}
#endif
return __kmalloc_node(size, flags, node);
}
/**
* kmalloc_array - allocate memory for an array.
* @n: number of elements.
* @size: element size.
* @flags: the type of memory to allocate (see kmalloc).
*/
static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
{
size_t bytes;
if (unlikely(check_mul_overflow(n, size, &bytes)))
return NULL;
if (__builtin_constant_p(n) && __builtin_constant_p(size))
return kmalloc(bytes, flags);
return __kmalloc(bytes, flags);
}
/**
* kcalloc - allocate memory for an array. The memory is set to zero.
* @n: number of elements.
* @size: element size.
* @flags: the type of memory to allocate (see kmalloc).
*/
static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
{
return kmalloc_array(n, size, flags | __GFP_ZERO);
}
/*
* kmalloc_track_caller is a special version of kmalloc that records the
* calling function of the routine calling it for slab leak tracking instead
* of just the calling function (confusing, eh?).
* It's useful when the call to kmalloc comes from a widely-used standard
* allocator where we care about the real place the memory allocation
* request comes from.
*/
extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
#define kmalloc_track_caller(size, flags) \
__kmalloc_track_caller(size, flags, _RET_IP_)
static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
int node)
{
size_t bytes;
if (unlikely(check_mul_overflow(n, size, &bytes)))
return NULL;
if (__builtin_constant_p(n) && __builtin_constant_p(size))
return kmalloc_node(bytes, flags, node);
return __kmalloc_node(bytes, flags, node);
}
static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
{
return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
}
#ifdef CONFIG_NUMA
extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
#define kmalloc_node_track_caller(size, flags, node) \
__kmalloc_node_track_caller(size, flags, node, \
_RET_IP_)
#else /* CONFIG_NUMA */
#define kmalloc_node_track_caller(size, flags, node) \
kmalloc_track_caller(size, flags)
#endif /* CONFIG_NUMA */
/*
* Shortcuts
*/
static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
{
return kmem_cache_alloc(k, flags | __GFP_ZERO);
}
/**
* kzalloc - allocate memory. The memory is set to zero.
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate (see kmalloc).
*/
static inline void *kzalloc(size_t size, gfp_t flags)
{
return kmalloc(size, flags | __GFP_ZERO);
}
/**
* kzalloc_node - allocate zeroed memory from a particular memory node.
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate (see kmalloc).
* @node: memory node from which to allocate
*/
static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
{
return kmalloc_node(size, flags | __GFP_ZERO, node);
}
unsigned int kmem_cache_size(struct kmem_cache *s);
void __init kmem_cache_init_late(void);
#if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
int slab_prepare_cpu(unsigned int cpu);
int slab_dead_cpu(unsigned int cpu);
#else
#define slab_prepare_cpu NULL
#define slab_dead_cpu NULL
#endif
#endif /* _LINUX_SLAB_H */
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