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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 page *page; /* The slab from which we are allocating */
52#ifdef CONFIG_SLUB_CPU_PARTIAL
53 struct page *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#endif
103 struct kmem_cache_order_objects oo;
104
105 /* Allocation and freeing of slabs */
106 struct kmem_cache_order_objects max;
107 struct kmem_cache_order_objects min;
108 gfp_t allocflags; /* gfp flags to use on each alloc */
109 int refcount; /* Refcount for slab cache destroy */
110 void (*ctor)(void *);
111 unsigned int inuse; /* Offset to metadata */
112 unsigned int align; /* Alignment */
113 unsigned int red_left_pad; /* Left redzone padding size */
114 const char *name; /* Name (only for display!) */
115 struct list_head list; /* List of slab caches */
116#ifdef CONFIG_SYSFS
117 struct kobject kobj; /* For sysfs */
118#endif
119#ifdef CONFIG_SLAB_FREELIST_HARDENED
120 unsigned long random;
121#endif
122
123#ifdef CONFIG_NUMA
124 /*
125 * Defragmentation by allocating from a remote node.
126 */
127 unsigned int remote_node_defrag_ratio;
128#endif
129
130#ifdef CONFIG_SLAB_FREELIST_RANDOM
131 unsigned int *random_seq;
132#endif
133
134#ifdef CONFIG_KASAN
135 struct kasan_cache kasan_info;
136#endif
137
138 unsigned int useroffset; /* Usercopy region offset */
139 unsigned int usersize; /* Usercopy region size */
140
141 struct kmem_cache_node *node[MAX_NUMNODES];
142};
143
144#ifdef CONFIG_SLUB_CPU_PARTIAL
145#define slub_cpu_partial(s) ((s)->cpu_partial)
146#define slub_set_cpu_partial(s, n) \
147({ \
148 slub_cpu_partial(s) = (n); \
149})
150#else
151#define slub_cpu_partial(s) (0)
152#define slub_set_cpu_partial(s, n)
153#endif /* CONFIG_SLUB_CPU_PARTIAL */
154
155#ifdef CONFIG_SYSFS
156#define SLAB_SUPPORTS_SYSFS
157void sysfs_slab_unlink(struct kmem_cache *);
158void sysfs_slab_release(struct kmem_cache *);
159#else
160static inline void sysfs_slab_unlink(struct kmem_cache *s)
161{
162}
163static inline void sysfs_slab_release(struct kmem_cache *s)
164{
165}
166#endif
167
168void object_err(struct kmem_cache *s, struct page *page,
169 u8 *object, char *reason);
170
171void *fixup_red_left(struct kmem_cache *s, void *p);
172
173static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
174 void *x) {
175 void *object = x - (x - page_address(page)) % cache->size;
176 void *last_object = page_address(page) +
177 (page->objects - 1) * cache->size;
178 void *result = (unlikely(object > last_object)) ? last_object : object;
179
180 result = fixup_red_left(cache, result);
181 return result;
182}
183
184/* Determine object index from a given position */
185static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
186 void *addr, void *obj)
187{
188 return reciprocal_divide(kasan_reset_tag(obj) - addr,
189 cache->reciprocal_size);
190}
191
192static inline unsigned int obj_to_index(const struct kmem_cache *cache,
193 const struct page *page, void *obj)
194{
195 if (is_kfence_address(obj))
196 return 0;
197 return __obj_to_index(cache, page_address(page), obj);
198}
199
200static inline int objs_per_slab_page(const struct kmem_cache *cache,
201 const struct page *page)
202{
203 return page->objects;
204}
205#endif /* _LINUX_SLUB_DEF_H */