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
14 enum stat_item {
15 ALLOC_FASTPATH, /* Allocation from cpu slab */
16 ALLOC_SLOWPATH, /* Allocation by getting a new cpu slab */
17 FREE_FASTPATH, /* Free to cpu slab */
18 FREE_SLOWPATH, /* Freeing not to cpu slab */
19 FREE_FROZEN, /* Freeing to frozen slab */
20 FREE_ADD_PARTIAL, /* Freeing moves slab to partial list */
21 FREE_REMOVE_PARTIAL, /* Freeing removes last object */
22 ALLOC_FROM_PARTIAL, /* Cpu slab acquired from node partial list */
23 ALLOC_SLAB, /* Cpu slab acquired from page allocator */
24 ALLOC_REFILL, /* Refill cpu slab from slab freelist */
25 ALLOC_NODE_MISMATCH, /* Switching cpu slab */
26 FREE_SLAB, /* Slab freed to the page allocator */
27 CPUSLAB_FLUSH, /* Abandoning of the cpu slab */
28 DEACTIVATE_FULL, /* Cpu slab was full when deactivated */
29 DEACTIVATE_EMPTY, /* Cpu slab was empty when deactivated */
30 DEACTIVATE_TO_HEAD, /* Cpu slab was moved to the head of partials */
31 DEACTIVATE_TO_TAIL, /* Cpu slab was moved to the tail of partials */
32 DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
33 DEACTIVATE_BYPASS, /* Implicit deactivation */
34 ORDER_FALLBACK, /* Number of times fallback was necessary */
35 CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
36 CMPXCHG_DOUBLE_FAIL, /* Number of times that cmpxchg double did not match */
37 CPU_PARTIAL_ALLOC, /* Used cpu partial on alloc */
38 CPU_PARTIAL_FREE, /* Refill cpu partial on free */
39 CPU_PARTIAL_NODE, /* Refill cpu partial from node partial */
40 CPU_PARTIAL_DRAIN, /* Drain cpu partial to node partial */
41 NR_SLUB_STAT_ITEMS };
42
43 struct kmem_cache_cpu {
44 void **freelist; /* Pointer to next available object */
45 unsigned long tid; /* Globally unique transaction id */
46 struct page *page; /* The slab from which we are allocating */
47 #ifdef CONFIG_SLUB_CPU_PARTIAL
48 struct page *partial; /* Partially allocated frozen slabs */
49 #endif
50 #ifdef CONFIG_SLUB_STATS
51 unsigned stat[NR_SLUB_STAT_ITEMS];
52 #endif
53 };
54
55 #ifdef CONFIG_SLUB_CPU_PARTIAL
56 #define slub_percpu_partial(c) ((c)->partial)
57
58 #define slub_set_percpu_partial(c, p) \
59 ({ \
60 slub_percpu_partial(c) = (p)->next; \
61 })
62
63 #define slub_percpu_partial_read_once(c) READ_ONCE(slub_percpu_partial(c))
64 #else
65 #define slub_percpu_partial(c) NULL
66
67 #define slub_set_percpu_partial(c, p)
68
69 #define slub_percpu_partial_read_once(c) NULL
70 #endif // CONFIG_SLUB_CPU_PARTIAL
71
72 /*
73 * Word size structure that can be atomically updated or read and that
74 * contains both the order and the number of objects that a slab of the
75 * given order would contain.
76 */
77 struct kmem_cache_order_objects {
78 unsigned int x;
79 };
80
81 /*
82 * Slab cache management.
83 */
84 struct kmem_cache {
85 struct kmem_cache_cpu __percpu *cpu_slab;
86 /* Used for retrieving partial slabs, etc. */
87 slab_flags_t flags;
88 unsigned long min_partial;
89 unsigned int size; /* The size of an object including metadata */
90 unsigned int object_size;/* The size of an object without metadata */
91 struct reciprocal_value reciprocal_size;
92 unsigned int offset; /* Free pointer offset */
93 #ifdef CONFIG_SLUB_CPU_PARTIAL
94 /* Number of per cpu partial objects to keep around */
95 unsigned int cpu_partial;
96 #endif
97 struct kmem_cache_order_objects oo;
98
99 /* Allocation and freeing of slabs */
100 struct kmem_cache_order_objects max;
101 struct kmem_cache_order_objects min;
102 gfp_t allocflags; /* gfp flags to use on each alloc */
103 int refcount; /* Refcount for slab cache destroy */
104 void (*ctor)(void *);
105 unsigned int inuse; /* Offset to metadata */
106 unsigned int align; /* Alignment */
107 unsigned int red_left_pad; /* Left redzone padding size */
108 const char *name; /* Name (only for display!) */
109 struct list_head list; /* List of slab caches */
110 #ifdef CONFIG_SYSFS
111 struct kobject kobj; /* For sysfs */
112 #endif
113 #ifdef CONFIG_SLAB_FREELIST_HARDENED
114 unsigned long random;
115 #endif
116
117 #ifdef CONFIG_NUMA
118 /*
119 * Defragmentation by allocating from a remote node.
120 */
121 unsigned int remote_node_defrag_ratio;
122 #endif
123
124 #ifdef CONFIG_SLAB_FREELIST_RANDOM
125 unsigned int *random_seq;
126 #endif
127
128 #ifdef CONFIG_KASAN
129 struct kasan_cache kasan_info;
130 #endif
131
132 unsigned int useroffset; /* Usercopy region offset */
133 unsigned int usersize; /* Usercopy region size */
134
135 struct kmem_cache_node *node[MAX_NUMNODES];
136 };
137
138 #ifdef CONFIG_SLUB_CPU_PARTIAL
139 #define slub_cpu_partial(s) ((s)->cpu_partial)
140 #define slub_set_cpu_partial(s, n) \
141 ({ \
142 slub_cpu_partial(s) = (n); \
143 })
144 #else
145 #define slub_cpu_partial(s) (0)
146 #define slub_set_cpu_partial(s, n)
147 #endif /* CONFIG_SLUB_CPU_PARTIAL */
148
149 #ifdef CONFIG_SYSFS
150 #define SLAB_SUPPORTS_SYSFS
151 void sysfs_slab_unlink(struct kmem_cache *);
152 void sysfs_slab_release(struct kmem_cache *);
153 #else
sysfs_slab_unlink(struct kmem_cache * s)154 static inline void sysfs_slab_unlink(struct kmem_cache *s)
155 {
156 }
sysfs_slab_release(struct kmem_cache * s)157 static inline void sysfs_slab_release(struct kmem_cache *s)
158 {
159 }
160 #endif
161
162 void object_err(struct kmem_cache *s, struct page *page,
163 u8 *object, char *reason);
164
165 void *fixup_red_left(struct kmem_cache *s, void *p);
166
nearest_obj(struct kmem_cache * cache,struct page * page,void * x)167 static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
168 void *x) {
169 void *object = x - (x - page_address(page)) % cache->size;
170 void *last_object = page_address(page) +
171 (page->objects - 1) * cache->size;
172 void *result = (unlikely(object > last_object)) ? last_object : object;
173
174 result = fixup_red_left(cache, result);
175 return result;
176 }
177
178 /* Determine object index from a given position */
__obj_to_index(const struct kmem_cache * cache,void * addr,void * obj)179 static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
180 void *addr, void *obj)
181 {
182 return reciprocal_divide(kasan_reset_tag(obj) - addr,
183 cache->reciprocal_size);
184 }
185
obj_to_index(const struct kmem_cache * cache,const struct page * page,void * obj)186 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
187 const struct page *page, void *obj)
188 {
189 if (is_kfence_address(obj))
190 return 0;
191 return __obj_to_index(cache, page_address(page), obj);
192 }
193
objs_per_slab_page(const struct kmem_cache * cache,const struct page * page)194 static inline int objs_per_slab_page(const struct kmem_cache *cache,
195 const struct page *page)
196 {
197 return page->objects;
198 }
199 #endif /* _LINUX_SLUB_DEF_H */
200