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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 * When changing the layout, make sure freelist and tid are still compatible
46 * with this_cpu_cmpxchg_double() alignment requirements.
47 */
48struct kmem_cache_cpu {
49 void **freelist; /* Pointer to next available object */
50 unsigned long tid; /* Globally unique transaction id */
51 struct slab *slab; /* The slab from which we are allocating */
52#ifdef CONFIG_SLUB_CPU_PARTIAL
53 struct slab *partial; /* Partially allocated frozen slabs */
54#endif
55 local_lock_t lock; /* Protects the fields above */
56#ifdef CONFIG_SLUB_STATS
57 unsigned stat[NR_SLUB_STAT_ITEMS];
58#endif
59};
60
61#ifdef CONFIG_SLUB_CPU_PARTIAL
62#define slub_percpu_partial(c) ((c)->partial)
63
64#define slub_set_percpu_partial(c, p) \
65({ \
66 slub_percpu_partial(c) = (p)->next; \
67})
68
69#define slub_percpu_partial_read_once(c) READ_ONCE(slub_percpu_partial(c))
70#else
71#define slub_percpu_partial(c) NULL
72
73#define slub_set_percpu_partial(c, p)
74
75#define slub_percpu_partial_read_once(c) NULL
76#endif // CONFIG_SLUB_CPU_PARTIAL
77
78/*
79 * Word size structure that can be atomically updated or read and that
80 * contains both the order and the number of objects that a slab of the
81 * given order would contain.
82 */
83struct kmem_cache_order_objects {
84 unsigned int x;
85};
86
87/*
88 * Slab cache management.
89 */
90struct kmem_cache {
91 struct kmem_cache_cpu __percpu *cpu_slab;
92 /* Used for retrieving partial slabs, etc. */
93 slab_flags_t flags;
94 unsigned long min_partial;
95 unsigned int size; /* The size of an object including metadata */
96 unsigned int object_size;/* The size of an object without metadata */
97 struct reciprocal_value reciprocal_size;
98 unsigned int offset; /* Free pointer offset */
99#ifdef CONFIG_SLUB_CPU_PARTIAL
100 /* Number of per cpu partial objects to keep around */
101 unsigned int cpu_partial;
102 /* Number of per cpu partial slabs to keep around */
103 unsigned int cpu_partial_slabs;
104#endif
105 struct kmem_cache_order_objects oo;
106
107 /* Allocation and freeing of slabs */
108 struct kmem_cache_order_objects max;
109 struct kmem_cache_order_objects min;
110 gfp_t allocflags; /* gfp flags to use on each alloc */
111 int refcount; /* Refcount for slab cache destroy */
112 void (*ctor)(void *);
113 unsigned int inuse; /* Offset to metadata */
114 unsigned int align; /* Alignment */
115 unsigned int red_left_pad; /* Left redzone padding size */
116 const char *name; /* Name (only for display!) */
117 struct list_head list; /* List of slab caches */
118#ifdef CONFIG_SYSFS
119 struct kobject kobj; /* For sysfs */
120#endif
121#ifdef CONFIG_SLAB_FREELIST_HARDENED
122 unsigned long random;
123#endif
124
125#ifdef CONFIG_NUMA
126 /*
127 * Defragmentation by allocating from a remote node.
128 */
129 unsigned int remote_node_defrag_ratio;
130#endif
131
132#ifdef CONFIG_SLAB_FREELIST_RANDOM
133 unsigned int *random_seq;
134#endif
135
136#ifdef CONFIG_KASAN
137 struct kasan_cache kasan_info;
138#endif
139
140 unsigned int useroffset; /* Usercopy region offset */
141 unsigned int usersize; /* Usercopy region size */
142
143 struct kmem_cache_node *node[MAX_NUMNODES];
144};
145
146#ifdef CONFIG_SYSFS
147#define SLAB_SUPPORTS_SYSFS
148void sysfs_slab_unlink(struct kmem_cache *);
149void sysfs_slab_release(struct kmem_cache *);
150#else
151static inline void sysfs_slab_unlink(struct kmem_cache *s)
152{
153}
154static inline void sysfs_slab_release(struct kmem_cache *s)
155{
156}
157#endif
158
159void *fixup_red_left(struct kmem_cache *s, void *p);
160
161static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *slab,
162 void *x) {
163 void *object = x - (x - slab_address(slab)) % cache->size;
164 void *last_object = slab_address(slab) +
165 (slab->objects - 1) * cache->size;
166 void *result = (unlikely(object > last_object)) ? last_object : object;
167
168 result = fixup_red_left(cache, result);
169 return result;
170}
171
172/* Determine object index from a given position */
173static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
174 void *addr, void *obj)
175{
176 return reciprocal_divide(kasan_reset_tag(obj) - addr,
177 cache->reciprocal_size);
178}
179
180static inline unsigned int obj_to_index(const struct kmem_cache *cache,
181 const struct slab *slab, void *obj)
182{
183 if (is_kfence_address(obj))
184 return 0;
185 return __obj_to_index(cache, slab_address(slab), obj);
186}
187
188static inline int objs_per_slab(const struct kmem_cache *cache,
189 const struct slab *slab)
190{
191 return slab->objects;
192}
193#endif /* _LINUX_SLUB_DEF_H */