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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_SLUB_DEF_H
3#define _LINUX_SLUB_DEF_H
4
5/*
6 * SLUB : A Slab allocator without object queues.
7 *
8 * (C) 2007 SGI, Christoph Lameter
9 */
10#include <linux/kfence.h>
11#include <linux/kobject.h>
12#include <linux/reciprocal_div.h>
13#include <linux/local_lock.h>
14
15enum stat_item {
16 ALLOC_FASTPATH, /* Allocation from cpu slab */
17 ALLOC_SLOWPATH, /* Allocation by getting a new cpu slab */
18 FREE_FASTPATH, /* Free to cpu slab */
19 FREE_SLOWPATH, /* Freeing not to cpu slab */
20 FREE_FROZEN, /* Freeing to frozen slab */
21 FREE_ADD_PARTIAL, /* Freeing moves slab to partial list */
22 FREE_REMOVE_PARTIAL, /* Freeing removes last object */
23 ALLOC_FROM_PARTIAL, /* Cpu slab acquired from node partial list */
24 ALLOC_SLAB, /* Cpu slab acquired from page allocator */
25 ALLOC_REFILL, /* Refill cpu slab from slab freelist */
26 ALLOC_NODE_MISMATCH, /* Switching cpu slab */
27 FREE_SLAB, /* Slab freed to the page allocator */
28 CPUSLAB_FLUSH, /* Abandoning of the cpu slab */
29 DEACTIVATE_FULL, /* Cpu slab was full when deactivated */
30 DEACTIVATE_EMPTY, /* Cpu slab was empty when deactivated */
31 DEACTIVATE_TO_HEAD, /* Cpu slab was moved to the head of partials */
32 DEACTIVATE_TO_TAIL, /* Cpu slab was moved to the tail of partials */
33 DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
34 DEACTIVATE_BYPASS, /* Implicit deactivation */
35 ORDER_FALLBACK, /* Number of times fallback was necessary */
36 CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
37 CMPXCHG_DOUBLE_FAIL, /* Number of times that cmpxchg double did not match */
38 CPU_PARTIAL_ALLOC, /* Used cpu partial on alloc */
39 CPU_PARTIAL_FREE, /* Refill cpu partial on free */
40 CPU_PARTIAL_NODE, /* Refill cpu partial from node partial */
41 CPU_PARTIAL_DRAIN, /* Drain cpu partial to node partial */
42 NR_SLUB_STAT_ITEMS
43};
44
45#ifndef CONFIG_SLUB_TINY
46/*
47 * When changing the layout, make sure freelist and tid are still compatible
48 * with this_cpu_cmpxchg_double() alignment requirements.
49 */
50struct kmem_cache_cpu {
51 union {
52 struct {
53 void **freelist; /* Pointer to next available object */
54 unsigned long tid; /* Globally unique transaction id */
55 };
56 freelist_aba_t freelist_tid;
57 };
58 struct slab *slab; /* The slab from which we are allocating */
59#ifdef CONFIG_SLUB_CPU_PARTIAL
60 struct slab *partial; /* Partially allocated frozen slabs */
61#endif
62 local_lock_t lock; /* Protects the fields above */
63#ifdef CONFIG_SLUB_STATS
64 unsigned stat[NR_SLUB_STAT_ITEMS];
65#endif
66};
67#endif /* CONFIG_SLUB_TINY */
68
69#ifdef CONFIG_SLUB_CPU_PARTIAL
70#define slub_percpu_partial(c) ((c)->partial)
71
72#define slub_set_percpu_partial(c, p) \
73({ \
74 slub_percpu_partial(c) = (p)->next; \
75})
76
77#define slub_percpu_partial_read_once(c) READ_ONCE(slub_percpu_partial(c))
78#else
79#define slub_percpu_partial(c) NULL
80
81#define slub_set_percpu_partial(c, p)
82
83#define slub_percpu_partial_read_once(c) NULL
84#endif // CONFIG_SLUB_CPU_PARTIAL
85
86/*
87 * Word size structure that can be atomically updated or read and that
88 * contains both the order and the number of objects that a slab of the
89 * given order would contain.
90 */
91struct kmem_cache_order_objects {
92 unsigned int x;
93};
94
95/*
96 * Slab cache management.
97 */
98struct kmem_cache {
99#ifndef CONFIG_SLUB_TINY
100 struct kmem_cache_cpu __percpu *cpu_slab;
101#endif
102 /* Used for retrieving partial slabs, etc. */
103 slab_flags_t flags;
104 unsigned long min_partial;
105 unsigned int size; /* The size of an object including metadata */
106 unsigned int object_size;/* The size of an object without metadata */
107 struct reciprocal_value reciprocal_size;
108 unsigned int offset; /* Free pointer offset */
109#ifdef CONFIG_SLUB_CPU_PARTIAL
110 /* Number of per cpu partial objects to keep around */
111 unsigned int cpu_partial;
112 /* Number of per cpu partial slabs to keep around */
113 unsigned int cpu_partial_slabs;
114#endif
115 struct kmem_cache_order_objects oo;
116
117 /* Allocation and freeing of slabs */
118 struct kmem_cache_order_objects min;
119 gfp_t allocflags; /* gfp flags to use on each alloc */
120 int refcount; /* Refcount for slab cache destroy */
121 void (*ctor)(void *);
122 unsigned int inuse; /* Offset to metadata */
123 unsigned int align; /* Alignment */
124 unsigned int red_left_pad; /* Left redzone padding size */
125 const char *name; /* Name (only for display!) */
126 struct list_head list; /* List of slab caches */
127#ifdef CONFIG_SYSFS
128 struct kobject kobj; /* For sysfs */
129#endif
130#ifdef CONFIG_SLAB_FREELIST_HARDENED
131 unsigned long random;
132#endif
133
134#ifdef CONFIG_NUMA
135 /*
136 * Defragmentation by allocating from a remote node.
137 */
138 unsigned int remote_node_defrag_ratio;
139#endif
140
141#ifdef CONFIG_SLAB_FREELIST_RANDOM
142 unsigned int *random_seq;
143#endif
144
145#ifdef CONFIG_KASAN_GENERIC
146 struct kasan_cache kasan_info;
147#endif
148
149#ifdef CONFIG_HARDENED_USERCOPY
150 unsigned int useroffset; /* Usercopy region offset */
151 unsigned int usersize; /* Usercopy region size */
152#endif
153
154 struct kmem_cache_node *node[MAX_NUMNODES];
155};
156
157#if defined(CONFIG_SYSFS) && !defined(CONFIG_SLUB_TINY)
158#define SLAB_SUPPORTS_SYSFS
159void sysfs_slab_unlink(struct kmem_cache *);
160void sysfs_slab_release(struct kmem_cache *);
161#else
162static inline void sysfs_slab_unlink(struct kmem_cache *s)
163{
164}
165static inline void sysfs_slab_release(struct kmem_cache *s)
166{
167}
168#endif
169
170void *fixup_red_left(struct kmem_cache *s, void *p);
171
172static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *slab,
173 void *x) {
174 void *object = x - (x - slab_address(slab)) % cache->size;
175 void *last_object = slab_address(slab) +
176 (slab->objects - 1) * cache->size;
177 void *result = (unlikely(object > last_object)) ? last_object : object;
178
179 result = fixup_red_left(cache, result);
180 return result;
181}
182
183/* Determine object index from a given position */
184static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
185 void *addr, void *obj)
186{
187 return reciprocal_divide(kasan_reset_tag(obj) - addr,
188 cache->reciprocal_size);
189}
190
191static inline unsigned int obj_to_index(const struct kmem_cache *cache,
192 const struct slab *slab, void *obj)
193{
194 if (is_kfence_address(obj))
195 return 0;
196 return __obj_to_index(cache, slab_address(slab), obj);
197}
198
199static inline int objs_per_slab(const struct kmem_cache *cache,
200 const struct slab *slab)
201{
202 return slab->objects;
203}
204#endif /* _LINUX_SLUB_DEF_H */