]>
Commit | Line | Data |
---|---|---|
7e1e7763 TG |
1 | /* |
2 | * Resizable, Scalable, Concurrent Hash Table | |
3 | * | |
4 | * Copyright (c) 2014 Thomas Graf <tgraf@suug.ch> | |
5 | * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net> | |
6 | * | |
7 | * Based on the following paper by Josh Triplett, Paul E. McKenney | |
8 | * and Jonathan Walpole: | |
9 | * https://www.usenix.org/legacy/event/atc11/tech/final_files/Triplett.pdf | |
10 | * | |
11 | * Code partially derived from nft_hash | |
12 | * | |
13 | * This program is free software; you can redistribute it and/or modify | |
14 | * it under the terms of the GNU General Public License version 2 as | |
15 | * published by the Free Software Foundation. | |
16 | */ | |
17 | ||
18 | #ifndef _LINUX_RHASHTABLE_H | |
19 | #define _LINUX_RHASHTABLE_H | |
20 | ||
21 | #include <linux/rculist.h> | |
22 | ||
23 | struct rhash_head { | |
5300fdcb | 24 | struct rhash_head __rcu *next; |
7e1e7763 TG |
25 | }; |
26 | ||
27 | #define INIT_HASH_HEAD(ptr) ((ptr)->next = NULL) | |
28 | ||
29 | struct bucket_table { | |
30 | size_t size; | |
31 | struct rhash_head __rcu *buckets[]; | |
32 | }; | |
33 | ||
34 | typedef u32 (*rht_hashfn_t)(const void *data, u32 len, u32 seed); | |
35 | typedef u32 (*rht_obj_hashfn_t)(const void *data, u32 seed); | |
36 | ||
37 | struct rhashtable; | |
38 | ||
39 | /** | |
40 | * struct rhashtable_params - Hash table construction parameters | |
41 | * @nelem_hint: Hint on number of elements, should be 75% of desired size | |
42 | * @key_len: Length of key | |
43 | * @key_offset: Offset of key in struct to be hashed | |
44 | * @head_offset: Offset of rhash_head in struct to be hashed | |
45 | * @hash_rnd: Seed to use while hashing | |
46 | * @max_shift: Maximum number of shifts while expanding | |
94000176 | 47 | * @min_shift: Minimum number of shifts while shrinking |
7e1e7763 TG |
48 | * @hashfn: Function to hash key |
49 | * @obj_hashfn: Function to hash object | |
50 | * @grow_decision: If defined, may return true if table should expand | |
51 | * @shrink_decision: If defined, may return true if table should shrink | |
52 | * @mutex_is_held: Must return true if protecting mutex is held | |
53 | */ | |
54 | struct rhashtable_params { | |
55 | size_t nelem_hint; | |
56 | size_t key_len; | |
57 | size_t key_offset; | |
58 | size_t head_offset; | |
59 | u32 hash_rnd; | |
60 | size_t max_shift; | |
94000176 | 61 | size_t min_shift; |
7e1e7763 TG |
62 | rht_hashfn_t hashfn; |
63 | rht_obj_hashfn_t obj_hashfn; | |
64 | bool (*grow_decision)(const struct rhashtable *ht, | |
65 | size_t new_size); | |
66 | bool (*shrink_decision)(const struct rhashtable *ht, | |
67 | size_t new_size); | |
1b2f309d | 68 | #ifdef CONFIG_PROVE_LOCKING |
7b4ce235 HX |
69 | int (*mutex_is_held)(void *parent); |
70 | void *parent; | |
1b2f309d | 71 | #endif |
7e1e7763 TG |
72 | }; |
73 | ||
74 | /** | |
75 | * struct rhashtable - Hash table handle | |
76 | * @tbl: Bucket table | |
77 | * @nelems: Number of elements in table | |
78 | * @shift: Current size (1 << shift) | |
79 | * @p: Configuration parameters | |
80 | */ | |
81 | struct rhashtable { | |
82 | struct bucket_table __rcu *tbl; | |
83 | size_t nelems; | |
84 | size_t shift; | |
85 | struct rhashtable_params p; | |
86 | }; | |
87 | ||
88 | #ifdef CONFIG_PROVE_LOCKING | |
89 | int lockdep_rht_mutex_is_held(const struct rhashtable *ht); | |
88d6ed15 | 90 | int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash); |
7e1e7763 TG |
91 | #else |
92 | static inline int lockdep_rht_mutex_is_held(const struct rhashtable *ht) | |
93 | { | |
94 | return 1; | |
95 | } | |
88d6ed15 TG |
96 | |
97 | static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, | |
98 | u32 hash) | |
99 | { | |
100 | return 1; | |
101 | } | |
7e1e7763 TG |
102 | #endif /* CONFIG_PROVE_LOCKING */ |
103 | ||
104 | int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params); | |
105 | ||
6eba8224 TG |
106 | void rhashtable_insert(struct rhashtable *ht, struct rhash_head *node); |
107 | bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *node); | |
7e1e7763 TG |
108 | |
109 | bool rht_grow_above_75(const struct rhashtable *ht, size_t new_size); | |
110 | bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size); | |
111 | ||
6eba8224 TG |
112 | int rhashtable_expand(struct rhashtable *ht); |
113 | int rhashtable_shrink(struct rhashtable *ht); | |
7e1e7763 TG |
114 | |
115 | void *rhashtable_lookup(const struct rhashtable *ht, const void *key); | |
8d24c0b4 | 116 | void *rhashtable_lookup_compare(const struct rhashtable *ht, const void *key, |
7e1e7763 TG |
117 | bool (*compare)(void *, void *), void *arg); |
118 | ||
119 | void rhashtable_destroy(const struct rhashtable *ht); | |
120 | ||
121 | #define rht_dereference(p, ht) \ | |
122 | rcu_dereference_protected(p, lockdep_rht_mutex_is_held(ht)) | |
123 | ||
124 | #define rht_dereference_rcu(p, ht) \ | |
125 | rcu_dereference_check(p, lockdep_rht_mutex_is_held(ht)) | |
126 | ||
88d6ed15 TG |
127 | #define rht_dereference_bucket(p, tbl, hash) \ |
128 | rcu_dereference_protected(p, lockdep_rht_bucket_is_held(tbl, hash)) | |
7e1e7763 | 129 | |
88d6ed15 TG |
130 | #define rht_dereference_bucket_rcu(p, tbl, hash) \ |
131 | rcu_dereference_check(p, lockdep_rht_bucket_is_held(tbl, hash)) | |
132 | ||
133 | #define rht_entry(tpos, pos, member) \ | |
134 | ({ tpos = container_of(pos, typeof(*tpos), member); 1; }) | |
7e1e7763 TG |
135 | |
136 | /** | |
88d6ed15 TG |
137 | * rht_for_each_continue - continue iterating over hash chain |
138 | * @pos: the &struct rhash_head to use as a loop cursor. | |
139 | * @head: the previous &struct rhash_head to continue from | |
140 | * @tbl: the &struct bucket_table | |
141 | * @hash: the hash value / bucket index | |
7e1e7763 | 142 | */ |
88d6ed15 TG |
143 | #define rht_for_each_continue(pos, head, tbl, hash) \ |
144 | for (pos = rht_dereference_bucket(head, tbl, hash); \ | |
7e1e7763 | 145 | pos; \ |
88d6ed15 TG |
146 | pos = rht_dereference_bucket((pos)->next, tbl, hash)) |
147 | ||
148 | /** | |
149 | * rht_for_each - iterate over hash chain | |
150 | * @pos: the &struct rhash_head to use as a loop cursor. | |
151 | * @tbl: the &struct bucket_table | |
152 | * @hash: the hash value / bucket index | |
153 | */ | |
154 | #define rht_for_each(pos, tbl, hash) \ | |
155 | rht_for_each_continue(pos, (tbl)->buckets[hash], tbl, hash) | |
156 | ||
157 | /** | |
158 | * rht_for_each_entry_continue - continue iterating over hash chain | |
159 | * @tpos: the type * to use as a loop cursor. | |
160 | * @pos: the &struct rhash_head to use as a loop cursor. | |
161 | * @head: the previous &struct rhash_head to continue from | |
162 | * @tbl: the &struct bucket_table | |
163 | * @hash: the hash value / bucket index | |
164 | * @member: name of the &struct rhash_head within the hashable struct. | |
165 | */ | |
166 | #define rht_for_each_entry_continue(tpos, pos, head, tbl, hash, member) \ | |
167 | for (pos = rht_dereference_bucket(head, tbl, hash); \ | |
168 | pos && rht_entry(tpos, pos, member); \ | |
169 | pos = rht_dereference_bucket((pos)->next, tbl, hash)) | |
7e1e7763 TG |
170 | |
171 | /** | |
172 | * rht_for_each_entry - iterate over hash chain of given type | |
88d6ed15 TG |
173 | * @tpos: the type * to use as a loop cursor. |
174 | * @pos: the &struct rhash_head to use as a loop cursor. | |
175 | * @tbl: the &struct bucket_table | |
176 | * @hash: the hash value / bucket index | |
177 | * @member: name of the &struct rhash_head within the hashable struct. | |
7e1e7763 | 178 | */ |
88d6ed15 TG |
179 | #define rht_for_each_entry(tpos, pos, tbl, hash, member) \ |
180 | rht_for_each_entry_continue(tpos, pos, (tbl)->buckets[hash], \ | |
181 | tbl, hash, member) | |
7e1e7763 TG |
182 | |
183 | /** | |
184 | * rht_for_each_entry_safe - safely iterate over hash chain of given type | |
88d6ed15 TG |
185 | * @tpos: the type * to use as a loop cursor. |
186 | * @pos: the &struct rhash_head to use as a loop cursor. | |
187 | * @next: the &struct rhash_head to use as next in loop cursor. | |
188 | * @tbl: the &struct bucket_table | |
189 | * @hash: the hash value / bucket index | |
190 | * @member: name of the &struct rhash_head within the hashable struct. | |
7e1e7763 TG |
191 | * |
192 | * This hash chain list-traversal primitive allows for the looped code to | |
193 | * remove the loop cursor from the list. | |
194 | */ | |
88d6ed15 TG |
195 | #define rht_for_each_entry_safe(tpos, pos, next, tbl, hash, member) \ |
196 | for (pos = rht_dereference_bucket((tbl)->buckets[hash], tbl, hash), \ | |
197 | next = pos ? rht_dereference_bucket(pos->next, tbl, hash) \ | |
198 | : NULL; \ | |
199 | pos && rht_entry(tpos, pos, member); \ | |
200 | pos = next) | |
201 | ||
202 | /** | |
203 | * rht_for_each_rcu_continue - continue iterating over rcu hash chain | |
204 | * @pos: the &struct rhash_head to use as a loop cursor. | |
205 | * @head: the previous &struct rhash_head to continue from | |
206 | * @tbl: the &struct bucket_table | |
207 | * @hash: the hash value / bucket index | |
208 | * | |
209 | * This hash chain list-traversal primitive may safely run concurrently with | |
210 | * the _rcu mutation primitives such as rhashtable_insert() as long as the | |
211 | * traversal is guarded by rcu_read_lock(). | |
212 | */ | |
213 | #define rht_for_each_rcu_continue(pos, head, tbl, hash) \ | |
214 | for (({barrier(); }), \ | |
215 | pos = rht_dereference_bucket_rcu(head, tbl, hash); \ | |
216 | pos; \ | |
217 | pos = rcu_dereference_raw(pos->next)) | |
7e1e7763 TG |
218 | |
219 | /** | |
220 | * rht_for_each_rcu - iterate over rcu hash chain | |
88d6ed15 TG |
221 | * @pos: the &struct rhash_head to use as a loop cursor. |
222 | * @tbl: the &struct bucket_table | |
223 | * @hash: the hash value / bucket index | |
7e1e7763 TG |
224 | * |
225 | * This hash chain list-traversal primitive may safely run concurrently with | |
88d6ed15 | 226 | * the _rcu mutation primitives such as rhashtable_insert() as long as the |
7e1e7763 TG |
227 | * traversal is guarded by rcu_read_lock(). |
228 | */ | |
88d6ed15 TG |
229 | #define rht_for_each_rcu(pos, tbl, hash) \ |
230 | rht_for_each_rcu_continue(pos, (tbl)->buckets[hash], tbl, hash) | |
231 | ||
232 | /** | |
233 | * rht_for_each_entry_rcu_continue - continue iterating over rcu hash chain | |
234 | * @tpos: the type * to use as a loop cursor. | |
235 | * @pos: the &struct rhash_head to use as a loop cursor. | |
236 | * @head: the previous &struct rhash_head to continue from | |
237 | * @tbl: the &struct bucket_table | |
238 | * @hash: the hash value / bucket index | |
239 | * @member: name of the &struct rhash_head within the hashable struct. | |
240 | * | |
241 | * This hash chain list-traversal primitive may safely run concurrently with | |
242 | * the _rcu mutation primitives such as rhashtable_insert() as long as the | |
243 | * traversal is guarded by rcu_read_lock(). | |
244 | */ | |
245 | #define rht_for_each_entry_rcu_continue(tpos, pos, head, tbl, hash, member) \ | |
246 | for (({barrier(); }), \ | |
247 | pos = rht_dereference_bucket_rcu(head, tbl, hash); \ | |
248 | pos && rht_entry(tpos, pos, member); \ | |
249 | pos = rht_dereference_bucket_rcu(pos->next, tbl, hash)) | |
7e1e7763 TG |
250 | |
251 | /** | |
252 | * rht_for_each_entry_rcu - iterate over rcu hash chain of given type | |
88d6ed15 TG |
253 | * @tpos: the type * to use as a loop cursor. |
254 | * @pos: the &struct rhash_head to use as a loop cursor. | |
255 | * @tbl: the &struct bucket_table | |
256 | * @hash: the hash value / bucket index | |
257 | * @member: name of the &struct rhash_head within the hashable struct. | |
7e1e7763 TG |
258 | * |
259 | * This hash chain list-traversal primitive may safely run concurrently with | |
88d6ed15 | 260 | * the _rcu mutation primitives such as rhashtable_insert() as long as the |
7e1e7763 TG |
261 | * traversal is guarded by rcu_read_lock(). |
262 | */ | |
88d6ed15 TG |
263 | #define rht_for_each_entry_rcu(tpos, pos, tbl, hash, member) \ |
264 | rht_for_each_entry_rcu_continue(tpos, pos, (tbl)->buckets[hash],\ | |
265 | tbl, hash, member) | |
7e1e7763 TG |
266 | |
267 | #endif /* _LINUX_RHASHTABLE_H */ |