Commit | Line | Data |
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0eb71a9d | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
7e1e7763 TG |
2 | /* |
3 | * Resizable, Scalable, Concurrent Hash Table | |
4 | * | |
ca26893f | 5 | * Copyright (c) 2015-2016 Herbert Xu <herbert@gondor.apana.org.au> |
b5e2c150 | 6 | * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch> |
7e1e7763 TG |
7 | * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net> |
8 | * | |
7e1e7763 | 9 | * Code partially derived from nft_hash |
dc0ee268 HX |
10 | * Rewritten with rehash code from br_multicast plus single list |
11 | * pointer as suggested by Josh Triplett | |
7e1e7763 TG |
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 | ||
3cf92222 | 21 | #include <linux/err.h> |
6626af69 | 22 | #include <linux/errno.h> |
31ccde2d | 23 | #include <linux/jhash.h> |
f89bd6f8 | 24 | #include <linux/list_nulls.h> |
97defe1e | 25 | #include <linux/workqueue.h> |
b2d09103 | 26 | #include <linux/rculist.h> |
8f0db018 | 27 | #include <linux/bit_spinlock.h> |
7e1e7763 | 28 | |
0eb71a9d | 29 | #include <linux/rhashtable-types.h> |
f89bd6f8 | 30 | /* |
8f0db018 N |
31 | * Objects in an rhashtable have an embedded struct rhash_head |
32 | * which is linked into as hash chain from the hash table - or one | |
33 | * of two or more hash tables when the rhashtable is being resized. | |
f89bd6f8 | 34 | * The end of the chain is marked with a special nulls marks which has |
8f0db018 N |
35 | * the least significant bit set but otherwise stores the address of |
36 | * the hash bucket. This allows us to be be sure we've found the end | |
37 | * of the right list. | |
38 | * The value stored in the hash bucket has BIT(2) used as a lock bit. | |
39 | * This bit must be atomically set before any changes are made to | |
40 | * the chain. To avoid dereferencing this pointer without clearing | |
41 | * the bit first, we use an opaque 'struct rhash_lock_head *' for the | |
42 | * pointer stored in the bucket. This struct needs to be defined so | |
43 | * that rcu_derefernce() works on it, but it has no content so a | |
44 | * cast is needed for it to be useful. This ensures it isn't | |
45 | * used by mistake with clearing the lock bit first. | |
f89bd6f8 | 46 | */ |
8f0db018 | 47 | struct rhash_lock_head {}; |
02fd97c3 | 48 | |
5f8ddeab FW |
49 | /* Maximum chain length before rehash |
50 | * | |
51 | * The maximum (not average) chain length grows with the size of the hash | |
52 | * table, at a rate of (log N)/(log log N). | |
53 | * | |
54 | * The value of 16 is selected so that even if the hash table grew to | |
55 | * 2^32 you would not expect the maximum chain length to exceed it | |
56 | * unless we are under attack (or extremely unlucky). | |
57 | * | |
58 | * As this limit is only to detect attacks, we don't need to set it to a | |
59 | * lower value as you'd need the chain length to vastly exceed 16 to have | |
60 | * any real effect on the system. | |
61 | */ | |
62 | #define RHT_ELASTICITY 16u | |
63 | ||
97defe1e TG |
64 | /** |
65 | * struct bucket_table - Table of hash buckets | |
66 | * @size: Number of hash buckets | |
da20420f | 67 | * @nest: Number of bits of first-level nested table. |
63d512d0 | 68 | * @rehash: Current bucket being rehashed |
988dfbd7 | 69 | * @hash_rnd: Random seed to fold into hash |
eddee5ba | 70 | * @walkers: List of active walkers |
9d901bc0 | 71 | * @rcu: RCU structure for freeing the table |
c4db8848 | 72 | * @future_tbl: Table under construction during rehashing |
da20420f | 73 | * @ntbl: Nested table used when out of memory. |
97defe1e TG |
74 | * @buckets: size * hash buckets |
75 | */ | |
7e1e7763 | 76 | struct bucket_table { |
63d512d0 | 77 | unsigned int size; |
da20420f | 78 | unsigned int nest; |
988dfbd7 | 79 | u32 hash_rnd; |
eddee5ba | 80 | struct list_head walkers; |
9d901bc0 | 81 | struct rcu_head rcu; |
b9ebafbe | 82 | |
c4db8848 HX |
83 | struct bucket_table __rcu *future_tbl; |
84 | ||
149212f0 N |
85 | struct lockdep_map dep_map; |
86 | ||
8f0db018 | 87 | struct rhash_lock_head __rcu *buckets[] ____cacheline_aligned_in_smp; |
7e1e7763 TG |
88 | }; |
89 | ||
8f0db018 N |
90 | /* |
91 | * We lock a bucket by setting BIT(1) in the pointer - this is always | |
92 | * zero in real pointers and in the nulls marker. | |
93 | * bit_spin_locks do not handle contention well, but the whole point | |
94 | * of the hashtable design is to achieve minimum per-bucket contention. | |
95 | * A nested hash table might not have a bucket pointer. In that case | |
96 | * we cannot get a lock. For remove and replace the bucket cannot be | |
97 | * interesting and doesn't need locking. | |
98 | * For insert we allocate the bucket if this is the last bucket_table, | |
99 | * and then take the lock. | |
100 | * Sometimes we unlock a bucket by writing a new pointer there. In that | |
101 | * case we don't need to unlock, but we do need to reset state such as | |
102 | * local_bh. For that we have rht_assign_unlock(). As rcu_assign_pointer() | |
103 | * provides the same release semantics that bit_spin_unlock() provides, | |
104 | * this is safe. | |
105 | */ | |
106 | ||
149212f0 N |
107 | static inline void rht_lock(struct bucket_table *tbl, |
108 | struct rhash_lock_head **bkt) | |
8f0db018 N |
109 | { |
110 | local_bh_disable(); | |
111 | bit_spin_lock(1, (unsigned long *)bkt); | |
149212f0 N |
112 | lock_map_acquire(&tbl->dep_map); |
113 | } | |
114 | ||
115 | static inline void rht_lock_nested(struct bucket_table *tbl, | |
116 | struct rhash_lock_head **bucket, | |
117 | unsigned int subclass) | |
118 | { | |
119 | local_bh_disable(); | |
120 | bit_spin_lock(1, (unsigned long *)bucket); | |
121 | lock_acquire_exclusive(&tbl->dep_map, subclass, 0, NULL, _THIS_IP_); | |
8f0db018 N |
122 | } |
123 | ||
149212f0 N |
124 | static inline void rht_unlock(struct bucket_table *tbl, |
125 | struct rhash_lock_head **bkt) | |
8f0db018 | 126 | { |
149212f0 | 127 | lock_map_release(&tbl->dep_map); |
8f0db018 N |
128 | bit_spin_unlock(1, (unsigned long *)bkt); |
129 | local_bh_enable(); | |
130 | } | |
131 | ||
149212f0 N |
132 | static inline void rht_assign_unlock(struct bucket_table *tbl, |
133 | struct rhash_lock_head **bkt, | |
8f0db018 N |
134 | struct rhash_head *obj) |
135 | { | |
136 | struct rhash_head **p = (struct rhash_head **)bkt; | |
137 | ||
149212f0 | 138 | lock_map_release(&tbl->dep_map); |
8f0db018 N |
139 | rcu_assign_pointer(*p, obj); |
140 | preempt_enable(); | |
141 | __release(bitlock); | |
142 | local_bh_enable(); | |
143 | } | |
144 | ||
145 | /* | |
146 | * If 'p' is a bucket head and might be locked: | |
147 | * rht_ptr() returns the address without the lock bit. | |
148 | * rht_ptr_locked() returns the address WITH the lock bit. | |
149 | */ | |
150 | static inline struct rhash_head __rcu *rht_ptr(const struct rhash_lock_head *p) | |
151 | { | |
152 | return (void *)(((unsigned long)p) & ~BIT(1)); | |
153 | } | |
154 | ||
155 | static inline struct rhash_lock_head __rcu *rht_ptr_locked(const | |
156 | struct rhash_head *p) | |
157 | { | |
158 | return (void *)(((unsigned long)p) | BIT(1)); | |
159 | } | |
160 | ||
82208d0d N |
161 | /* |
162 | * NULLS_MARKER() expects a hash value with the low | |
163 | * bits mostly likely to be significant, and it discards | |
164 | * the msb. | |
165 | * We git it an address, in which the bottom 2 bits are | |
166 | * always 0, and the msb might be significant. | |
167 | * So we shift the address down one bit to align with | |
168 | * expectations and avoid losing a significant bit. | |
169 | */ | |
170 | #define RHT_NULLS_MARKER(ptr) \ | |
171 | ((void *)NULLS_MARKER(((unsigned long) (ptr)) >> 1)) | |
9b4f64a2 | 172 | #define INIT_RHT_NULLS_HEAD(ptr) \ |
82208d0d | 173 | ((ptr) = RHT_NULLS_MARKER(&(ptr))) |
f89bd6f8 TG |
174 | |
175 | static inline bool rht_is_a_nulls(const struct rhash_head *ptr) | |
176 | { | |
177 | return ((unsigned long) ptr & 1); | |
178 | } | |
179 | ||
02fd97c3 HX |
180 | static inline void *rht_obj(const struct rhashtable *ht, |
181 | const struct rhash_head *he) | |
182 | { | |
183 | return (char *)he - ht->p.head_offset; | |
184 | } | |
185 | ||
186 | static inline unsigned int rht_bucket_index(const struct bucket_table *tbl, | |
187 | unsigned int hash) | |
188 | { | |
9f9a7077 | 189 | return hash & (tbl->size - 1); |
02fd97c3 HX |
190 | } |
191 | ||
2b860931 TH |
192 | static inline unsigned int rht_key_get_hash(struct rhashtable *ht, |
193 | const void *key, const struct rhashtable_params params, | |
194 | unsigned int hash_rnd) | |
02fd97c3 | 195 | { |
299e5c32 | 196 | unsigned int hash; |
de91b25c | 197 | |
31ccde2d HX |
198 | /* params must be equal to ht->p if it isn't constant. */ |
199 | if (!__builtin_constant_p(params.key_len)) | |
2b860931 | 200 | hash = ht->p.hashfn(key, ht->key_len, hash_rnd); |
31ccde2d | 201 | else if (params.key_len) { |
299e5c32 | 202 | unsigned int key_len = params.key_len; |
31ccde2d HX |
203 | |
204 | if (params.hashfn) | |
2b860931 | 205 | hash = params.hashfn(key, key_len, hash_rnd); |
31ccde2d | 206 | else if (key_len & (sizeof(u32) - 1)) |
2b860931 | 207 | hash = jhash(key, key_len, hash_rnd); |
31ccde2d | 208 | else |
2b860931 | 209 | hash = jhash2(key, key_len / sizeof(u32), hash_rnd); |
31ccde2d | 210 | } else { |
299e5c32 | 211 | unsigned int key_len = ht->p.key_len; |
31ccde2d HX |
212 | |
213 | if (params.hashfn) | |
2b860931 | 214 | hash = params.hashfn(key, key_len, hash_rnd); |
31ccde2d | 215 | else |
2b860931 | 216 | hash = jhash(key, key_len, hash_rnd); |
31ccde2d HX |
217 | } |
218 | ||
2b860931 TH |
219 | return hash; |
220 | } | |
221 | ||
222 | static inline unsigned int rht_key_hashfn( | |
223 | struct rhashtable *ht, const struct bucket_table *tbl, | |
224 | const void *key, const struct rhashtable_params params) | |
225 | { | |
226 | unsigned int hash = rht_key_get_hash(ht, key, params, tbl->hash_rnd); | |
227 | ||
31ccde2d | 228 | return rht_bucket_index(tbl, hash); |
02fd97c3 HX |
229 | } |
230 | ||
231 | static inline unsigned int rht_head_hashfn( | |
232 | struct rhashtable *ht, const struct bucket_table *tbl, | |
233 | const struct rhash_head *he, const struct rhashtable_params params) | |
234 | { | |
235 | const char *ptr = rht_obj(ht, he); | |
236 | ||
237 | return likely(params.obj_hashfn) ? | |
49f7b33e PM |
238 | rht_bucket_index(tbl, params.obj_hashfn(ptr, params.key_len ?: |
239 | ht->p.key_len, | |
240 | tbl->hash_rnd)) : | |
02fd97c3 HX |
241 | rht_key_hashfn(ht, tbl, ptr + params.key_offset, params); |
242 | } | |
243 | ||
244 | /** | |
245 | * rht_grow_above_75 - returns true if nelems > 0.75 * table-size | |
246 | * @ht: hash table | |
247 | * @tbl: current table | |
248 | */ | |
249 | static inline bool rht_grow_above_75(const struct rhashtable *ht, | |
250 | const struct bucket_table *tbl) | |
251 | { | |
252 | /* Expand table when exceeding 75% load */ | |
253 | return atomic_read(&ht->nelems) > (tbl->size / 4 * 3) && | |
254 | (!ht->p.max_size || tbl->size < ht->p.max_size); | |
255 | } | |
256 | ||
257 | /** | |
258 | * rht_shrink_below_30 - returns true if nelems < 0.3 * table-size | |
259 | * @ht: hash table | |
260 | * @tbl: current table | |
261 | */ | |
262 | static inline bool rht_shrink_below_30(const struct rhashtable *ht, | |
263 | const struct bucket_table *tbl) | |
264 | { | |
265 | /* Shrink table beneath 30% load */ | |
266 | return atomic_read(&ht->nelems) < (tbl->size * 3 / 10) && | |
267 | tbl->size > ht->p.min_size; | |
268 | } | |
269 | ||
ccd57b1b HX |
270 | /** |
271 | * rht_grow_above_100 - returns true if nelems > table-size | |
272 | * @ht: hash table | |
273 | * @tbl: current table | |
274 | */ | |
275 | static inline bool rht_grow_above_100(const struct rhashtable *ht, | |
276 | const struct bucket_table *tbl) | |
277 | { | |
1d8dc3d3 JB |
278 | return atomic_read(&ht->nelems) > tbl->size && |
279 | (!ht->p.max_size || tbl->size < ht->p.max_size); | |
ccd57b1b HX |
280 | } |
281 | ||
07ee0722 HX |
282 | /** |
283 | * rht_grow_above_max - returns true if table is above maximum | |
284 | * @ht: hash table | |
285 | * @tbl: current table | |
286 | */ | |
287 | static inline bool rht_grow_above_max(const struct rhashtable *ht, | |
288 | const struct bucket_table *tbl) | |
289 | { | |
6d684e54 | 290 | return atomic_read(&ht->nelems) >= ht->max_elems; |
07ee0722 HX |
291 | } |
292 | ||
7e1e7763 | 293 | #ifdef CONFIG_PROVE_LOCKING |
97defe1e | 294 | int lockdep_rht_mutex_is_held(struct rhashtable *ht); |
88d6ed15 | 295 | int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash); |
7e1e7763 | 296 | #else |
97defe1e | 297 | static inline int lockdep_rht_mutex_is_held(struct rhashtable *ht) |
7e1e7763 TG |
298 | { |
299 | return 1; | |
300 | } | |
88d6ed15 TG |
301 | |
302 | static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, | |
303 | u32 hash) | |
304 | { | |
305 | return 1; | |
306 | } | |
7e1e7763 TG |
307 | #endif /* CONFIG_PROVE_LOCKING */ |
308 | ||
ca26893f HX |
309 | void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, |
310 | struct rhash_head *obj); | |
7e1e7763 | 311 | |
246779dd HX |
312 | void rhashtable_walk_enter(struct rhashtable *ht, |
313 | struct rhashtable_iter *iter); | |
f2dba9c6 | 314 | void rhashtable_walk_exit(struct rhashtable_iter *iter); |
97a6ec4a TH |
315 | int rhashtable_walk_start_check(struct rhashtable_iter *iter) __acquires(RCU); |
316 | ||
317 | static inline void rhashtable_walk_start(struct rhashtable_iter *iter) | |
318 | { | |
319 | (void)rhashtable_walk_start_check(iter); | |
320 | } | |
321 | ||
f2dba9c6 | 322 | void *rhashtable_walk_next(struct rhashtable_iter *iter); |
2db54b47 | 323 | void *rhashtable_walk_peek(struct rhashtable_iter *iter); |
f2dba9c6 HX |
324 | void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases(RCU); |
325 | ||
6b6f302c TG |
326 | void rhashtable_free_and_destroy(struct rhashtable *ht, |
327 | void (*free_fn)(void *ptr, void *arg), | |
328 | void *arg); | |
97defe1e | 329 | void rhashtable_destroy(struct rhashtable *ht); |
7e1e7763 | 330 | |
8f0db018 N |
331 | struct rhash_lock_head __rcu **rht_bucket_nested(const struct bucket_table *tbl, |
332 | unsigned int hash); | |
333 | struct rhash_lock_head __rcu **__rht_bucket_nested(const struct bucket_table *tbl, | |
da20420f | 334 | unsigned int hash); |
8f0db018 N |
335 | struct rhash_lock_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht, |
336 | struct bucket_table *tbl, | |
337 | unsigned int hash); | |
da20420f | 338 | |
7e1e7763 TG |
339 | #define rht_dereference(p, ht) \ |
340 | rcu_dereference_protected(p, lockdep_rht_mutex_is_held(ht)) | |
341 | ||
342 | #define rht_dereference_rcu(p, ht) \ | |
343 | rcu_dereference_check(p, lockdep_rht_mutex_is_held(ht)) | |
344 | ||
88d6ed15 TG |
345 | #define rht_dereference_bucket(p, tbl, hash) \ |
346 | rcu_dereference_protected(p, lockdep_rht_bucket_is_held(tbl, hash)) | |
7e1e7763 | 347 | |
88d6ed15 TG |
348 | #define rht_dereference_bucket_rcu(p, tbl, hash) \ |
349 | rcu_dereference_check(p, lockdep_rht_bucket_is_held(tbl, hash)) | |
350 | ||
351 | #define rht_entry(tpos, pos, member) \ | |
352 | ({ tpos = container_of(pos, typeof(*tpos), member); 1; }) | |
7e1e7763 | 353 | |
8f0db018 | 354 | static inline struct rhash_lock_head __rcu *const *rht_bucket( |
da20420f HX |
355 | const struct bucket_table *tbl, unsigned int hash) |
356 | { | |
357 | return unlikely(tbl->nest) ? rht_bucket_nested(tbl, hash) : | |
358 | &tbl->buckets[hash]; | |
359 | } | |
360 | ||
8f0db018 | 361 | static inline struct rhash_lock_head __rcu **rht_bucket_var( |
da20420f HX |
362 | struct bucket_table *tbl, unsigned int hash) |
363 | { | |
ff302db9 | 364 | return unlikely(tbl->nest) ? __rht_bucket_nested(tbl, hash) : |
da20420f HX |
365 | &tbl->buckets[hash]; |
366 | } | |
367 | ||
8f0db018 | 368 | static inline struct rhash_lock_head __rcu **rht_bucket_insert( |
da20420f HX |
369 | struct rhashtable *ht, struct bucket_table *tbl, unsigned int hash) |
370 | { | |
371 | return unlikely(tbl->nest) ? rht_bucket_nested_insert(ht, tbl, hash) : | |
372 | &tbl->buckets[hash]; | |
373 | } | |
374 | ||
7e1e7763 | 375 | /** |
f7ad68bf | 376 | * rht_for_each_from - iterate over hash chain from given head |
88d6ed15 | 377 | * @pos: the &struct rhash_head to use as a loop cursor. |
f7ad68bf | 378 | * @head: the &struct rhash_head to start from |
88d6ed15 TG |
379 | * @tbl: the &struct bucket_table |
380 | * @hash: the hash value / bucket index | |
7e1e7763 | 381 | */ |
f7ad68bf | 382 | #define rht_for_each_from(pos, head, tbl, hash) \ |
88d6ed15 | 383 | for (pos = rht_dereference_bucket(head, tbl, hash); \ |
f89bd6f8 | 384 | !rht_is_a_nulls(pos); \ |
88d6ed15 TG |
385 | pos = rht_dereference_bucket((pos)->next, tbl, hash)) |
386 | ||
387 | /** | |
388 | * rht_for_each - iterate over hash chain | |
389 | * @pos: the &struct rhash_head to use as a loop cursor. | |
390 | * @tbl: the &struct bucket_table | |
391 | * @hash: the hash value / bucket index | |
392 | */ | |
393 | #define rht_for_each(pos, tbl, hash) \ | |
8f0db018 | 394 | rht_for_each_from(pos, rht_ptr(*rht_bucket(tbl, hash)), tbl, hash) |
88d6ed15 TG |
395 | |
396 | /** | |
f7ad68bf | 397 | * rht_for_each_entry_from - iterate over hash chain from given head |
88d6ed15 TG |
398 | * @tpos: the type * to use as a loop cursor. |
399 | * @pos: the &struct rhash_head to use as a loop cursor. | |
f7ad68bf | 400 | * @head: the &struct rhash_head to start from |
88d6ed15 TG |
401 | * @tbl: the &struct bucket_table |
402 | * @hash: the hash value / bucket index | |
403 | * @member: name of the &struct rhash_head within the hashable struct. | |
404 | */ | |
f7ad68bf | 405 | #define rht_for_each_entry_from(tpos, pos, head, tbl, hash, member) \ |
88d6ed15 | 406 | for (pos = rht_dereference_bucket(head, tbl, hash); \ |
f89bd6f8 | 407 | (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \ |
88d6ed15 | 408 | pos = rht_dereference_bucket((pos)->next, tbl, hash)) |
7e1e7763 TG |
409 | |
410 | /** | |
411 | * rht_for_each_entry - iterate over hash chain of given type | |
88d6ed15 TG |
412 | * @tpos: the type * to use as a loop cursor. |
413 | * @pos: the &struct rhash_head to use as a loop cursor. | |
414 | * @tbl: the &struct bucket_table | |
415 | * @hash: the hash value / bucket index | |
416 | * @member: name of the &struct rhash_head within the hashable struct. | |
7e1e7763 | 417 | */ |
88d6ed15 | 418 | #define rht_for_each_entry(tpos, pos, tbl, hash, member) \ |
8f0db018 | 419 | rht_for_each_entry_from(tpos, pos, rht_ptr(*rht_bucket(tbl, hash)), \ |
88d6ed15 | 420 | tbl, hash, member) |
7e1e7763 TG |
421 | |
422 | /** | |
423 | * rht_for_each_entry_safe - safely iterate over hash chain of given type | |
88d6ed15 TG |
424 | * @tpos: the type * to use as a loop cursor. |
425 | * @pos: the &struct rhash_head to use as a loop cursor. | |
426 | * @next: the &struct rhash_head to use as next in loop cursor. | |
427 | * @tbl: the &struct bucket_table | |
428 | * @hash: the hash value / bucket index | |
429 | * @member: name of the &struct rhash_head within the hashable struct. | |
7e1e7763 TG |
430 | * |
431 | * This hash chain list-traversal primitive allows for the looped code to | |
432 | * remove the loop cursor from the list. | |
433 | */ | |
da20420f | 434 | #define rht_for_each_entry_safe(tpos, pos, next, tbl, hash, member) \ |
8f0db018 N |
435 | for (pos = rht_dereference_bucket(rht_ptr(*rht_bucket(tbl, hash)), \ |
436 | tbl, hash), \ | |
da20420f HX |
437 | next = !rht_is_a_nulls(pos) ? \ |
438 | rht_dereference_bucket(pos->next, tbl, hash) : NULL; \ | |
439 | (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \ | |
440 | pos = next, \ | |
441 | next = !rht_is_a_nulls(pos) ? \ | |
607954b0 | 442 | rht_dereference_bucket(pos->next, tbl, hash) : NULL) |
88d6ed15 TG |
443 | |
444 | /** | |
f7ad68bf | 445 | * rht_for_each_rcu_from - iterate over rcu hash chain from given head |
88d6ed15 | 446 | * @pos: the &struct rhash_head to use as a loop cursor. |
f7ad68bf | 447 | * @head: the &struct rhash_head to start from |
88d6ed15 TG |
448 | * @tbl: the &struct bucket_table |
449 | * @hash: the hash value / bucket index | |
450 | * | |
451 | * This hash chain list-traversal primitive may safely run concurrently with | |
452 | * the _rcu mutation primitives such as rhashtable_insert() as long as the | |
453 | * traversal is guarded by rcu_read_lock(). | |
454 | */ | |
f7ad68bf | 455 | #define rht_for_each_rcu_from(pos, head, tbl, hash) \ |
88d6ed15 TG |
456 | for (({barrier(); }), \ |
457 | pos = rht_dereference_bucket_rcu(head, tbl, hash); \ | |
f89bd6f8 | 458 | !rht_is_a_nulls(pos); \ |
88d6ed15 | 459 | pos = rcu_dereference_raw(pos->next)) |
7e1e7763 TG |
460 | |
461 | /** | |
462 | * rht_for_each_rcu - iterate over rcu hash chain | |
88d6ed15 TG |
463 | * @pos: the &struct rhash_head to use as a loop cursor. |
464 | * @tbl: the &struct bucket_table | |
465 | * @hash: the hash value / bucket index | |
7e1e7763 TG |
466 | * |
467 | * This hash chain list-traversal primitive may safely run concurrently with | |
88d6ed15 | 468 | * the _rcu mutation primitives such as rhashtable_insert() as long as the |
7e1e7763 TG |
469 | * traversal is guarded by rcu_read_lock(). |
470 | */ | |
8f0db018 N |
471 | #define rht_for_each_rcu(pos, tbl, hash) \ |
472 | for (({barrier(); }), \ | |
473 | pos = rht_ptr(rht_dereference_bucket_rcu( \ | |
474 | *rht_bucket(tbl, hash), tbl, hash)); \ | |
475 | !rht_is_a_nulls(pos); \ | |
476 | pos = rcu_dereference_raw(pos->next)) | |
88d6ed15 TG |
477 | |
478 | /** | |
f7ad68bf | 479 | * rht_for_each_entry_rcu_from - iterated over rcu hash chain from given head |
88d6ed15 TG |
480 | * @tpos: the type * to use as a loop cursor. |
481 | * @pos: the &struct rhash_head to use as a loop cursor. | |
f7ad68bf | 482 | * @head: the &struct rhash_head to start from |
88d6ed15 TG |
483 | * @tbl: the &struct bucket_table |
484 | * @hash: the hash value / bucket index | |
485 | * @member: name of the &struct rhash_head within the hashable struct. | |
486 | * | |
487 | * This hash chain list-traversal primitive may safely run concurrently with | |
488 | * the _rcu mutation primitives such as rhashtable_insert() as long as the | |
489 | * traversal is guarded by rcu_read_lock(). | |
490 | */ | |
f7ad68bf | 491 | #define rht_for_each_entry_rcu_from(tpos, pos, head, tbl, hash, member) \ |
88d6ed15 TG |
492 | for (({barrier(); }), \ |
493 | pos = rht_dereference_bucket_rcu(head, tbl, hash); \ | |
f89bd6f8 | 494 | (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \ |
88d6ed15 | 495 | pos = rht_dereference_bucket_rcu(pos->next, tbl, hash)) |
7e1e7763 TG |
496 | |
497 | /** | |
498 | * rht_for_each_entry_rcu - iterate over rcu hash chain of given type | |
88d6ed15 TG |
499 | * @tpos: the type * to use as a loop cursor. |
500 | * @pos: the &struct rhash_head to use as a loop cursor. | |
501 | * @tbl: the &struct bucket_table | |
502 | * @hash: the hash value / bucket index | |
503 | * @member: name of the &struct rhash_head within the hashable struct. | |
7e1e7763 TG |
504 | * |
505 | * This hash chain list-traversal primitive may safely run concurrently with | |
88d6ed15 | 506 | * the _rcu mutation primitives such as rhashtable_insert() as long as the |
7e1e7763 TG |
507 | * traversal is guarded by rcu_read_lock(). |
508 | */ | |
da20420f | 509 | #define rht_for_each_entry_rcu(tpos, pos, tbl, hash, member) \ |
8f0db018 N |
510 | rht_for_each_entry_rcu_from(tpos, pos, \ |
511 | rht_ptr(*rht_bucket(tbl, hash)), \ | |
88d6ed15 | 512 | tbl, hash, member) |
7e1e7763 | 513 | |
ca26893f HX |
514 | /** |
515 | * rhl_for_each_rcu - iterate over rcu hash table list | |
516 | * @pos: the &struct rlist_head to use as a loop cursor. | |
517 | * @list: the head of the list | |
518 | * | |
519 | * This hash chain list-traversal primitive should be used on the | |
520 | * list returned by rhltable_lookup. | |
521 | */ | |
522 | #define rhl_for_each_rcu(pos, list) \ | |
523 | for (pos = list; pos; pos = rcu_dereference_raw(pos->next)) | |
524 | ||
525 | /** | |
526 | * rhl_for_each_entry_rcu - iterate over rcu hash table list of given type | |
527 | * @tpos: the type * to use as a loop cursor. | |
528 | * @pos: the &struct rlist_head to use as a loop cursor. | |
529 | * @list: the head of the list | |
530 | * @member: name of the &struct rlist_head within the hashable struct. | |
531 | * | |
532 | * This hash chain list-traversal primitive should be used on the | |
533 | * list returned by rhltable_lookup. | |
534 | */ | |
535 | #define rhl_for_each_entry_rcu(tpos, pos, list, member) \ | |
536 | for (pos = list; pos && rht_entry(tpos, pos, member); \ | |
537 | pos = rcu_dereference_raw(pos->next)) | |
538 | ||
02fd97c3 HX |
539 | static inline int rhashtable_compare(struct rhashtable_compare_arg *arg, |
540 | const void *obj) | |
541 | { | |
542 | struct rhashtable *ht = arg->ht; | |
543 | const char *ptr = obj; | |
544 | ||
545 | return memcmp(ptr + ht->p.key_offset, arg->key, ht->p.key_len); | |
546 | } | |
547 | ||
ca26893f HX |
548 | /* Internal function, do not use. */ |
549 | static inline struct rhash_head *__rhashtable_lookup( | |
02fd97c3 HX |
550 | struct rhashtable *ht, const void *key, |
551 | const struct rhashtable_params params) | |
552 | { | |
553 | struct rhashtable_compare_arg arg = { | |
554 | .ht = ht, | |
555 | .key = key, | |
556 | }; | |
8f0db018 | 557 | struct rhash_lock_head __rcu * const *bkt; |
da20420f | 558 | struct bucket_table *tbl; |
02fd97c3 | 559 | struct rhash_head *he; |
299e5c32 | 560 | unsigned int hash; |
02fd97c3 | 561 | |
02fd97c3 HX |
562 | tbl = rht_dereference_rcu(ht->tbl, ht); |
563 | restart: | |
564 | hash = rht_key_hashfn(ht, tbl, key, params); | |
8f0db018 | 565 | bkt = rht_bucket(tbl, hash); |
82208d0d | 566 | do { |
8f0db018 N |
567 | he = rht_ptr(rht_dereference_bucket_rcu(*bkt, tbl, hash)); |
568 | rht_for_each_rcu_from(he, he, tbl, hash) { | |
82208d0d N |
569 | if (params.obj_cmpfn ? |
570 | params.obj_cmpfn(&arg, rht_obj(ht, he)) : | |
571 | rhashtable_compare(&arg, rht_obj(ht, he))) | |
572 | continue; | |
573 | return he; | |
574 | } | |
575 | /* An object might have been moved to a different hash chain, | |
576 | * while we walk along it - better check and retry. | |
577 | */ | |
8f0db018 | 578 | } while (he != RHT_NULLS_MARKER(bkt)); |
02fd97c3 HX |
579 | |
580 | /* Ensure we see any new tables. */ | |
581 | smp_rmb(); | |
582 | ||
583 | tbl = rht_dereference_rcu(tbl->future_tbl, ht); | |
584 | if (unlikely(tbl)) | |
585 | goto restart; | |
02fd97c3 HX |
586 | |
587 | return NULL; | |
588 | } | |
589 | ||
ca26893f HX |
590 | /** |
591 | * rhashtable_lookup - search hash table | |
592 | * @ht: hash table | |
593 | * @key: the pointer to the key | |
594 | * @params: hash table parameters | |
595 | * | |
596 | * Computes the hash value for the key and traverses the bucket chain looking | |
597 | * for a entry with an identical key. The first matching entry is returned. | |
598 | * | |
599 | * This must only be called under the RCU read lock. | |
600 | * | |
601 | * Returns the first entry on which the compare function returned true. | |
602 | */ | |
603 | static inline void *rhashtable_lookup( | |
604 | struct rhashtable *ht, const void *key, | |
605 | const struct rhashtable_params params) | |
606 | { | |
607 | struct rhash_head *he = __rhashtable_lookup(ht, key, params); | |
608 | ||
609 | return he ? rht_obj(ht, he) : NULL; | |
610 | } | |
611 | ||
612 | /** | |
613 | * rhashtable_lookup_fast - search hash table, without RCU read lock | |
614 | * @ht: hash table | |
615 | * @key: the pointer to the key | |
616 | * @params: hash table parameters | |
617 | * | |
618 | * Computes the hash value for the key and traverses the bucket chain looking | |
619 | * for a entry with an identical key. The first matching entry is returned. | |
620 | * | |
621 | * Only use this function when you have other mechanisms guaranteeing | |
622 | * that the object won't go away after the RCU read lock is released. | |
623 | * | |
624 | * Returns the first entry on which the compare function returned true. | |
625 | */ | |
626 | static inline void *rhashtable_lookup_fast( | |
627 | struct rhashtable *ht, const void *key, | |
628 | const struct rhashtable_params params) | |
629 | { | |
630 | void *obj; | |
631 | ||
632 | rcu_read_lock(); | |
633 | obj = rhashtable_lookup(ht, key, params); | |
634 | rcu_read_unlock(); | |
635 | ||
636 | return obj; | |
637 | } | |
638 | ||
639 | /** | |
640 | * rhltable_lookup - search hash list table | |
641 | * @hlt: hash table | |
642 | * @key: the pointer to the key | |
643 | * @params: hash table parameters | |
644 | * | |
645 | * Computes the hash value for the key and traverses the bucket chain looking | |
646 | * for a entry with an identical key. All matching entries are returned | |
647 | * in a list. | |
648 | * | |
649 | * This must only be called under the RCU read lock. | |
650 | * | |
651 | * Returns the list of entries that match the given key. | |
652 | */ | |
653 | static inline struct rhlist_head *rhltable_lookup( | |
654 | struct rhltable *hlt, const void *key, | |
655 | const struct rhashtable_params params) | |
656 | { | |
657 | struct rhash_head *he = __rhashtable_lookup(&hlt->ht, key, params); | |
658 | ||
659 | return he ? container_of(he, struct rhlist_head, rhead) : NULL; | |
660 | } | |
661 | ||
5ca8cc5b PNA |
662 | /* Internal function, please use rhashtable_insert_fast() instead. This |
663 | * function returns the existing element already in hashes in there is a clash, | |
664 | * otherwise it returns an error via ERR_PTR(). | |
665 | */ | |
666 | static inline void *__rhashtable_insert_fast( | |
02fd97c3 | 667 | struct rhashtable *ht, const void *key, struct rhash_head *obj, |
ca26893f | 668 | const struct rhashtable_params params, bool rhlist) |
02fd97c3 HX |
669 | { |
670 | struct rhashtable_compare_arg arg = { | |
671 | .ht = ht, | |
672 | .key = key, | |
673 | }; | |
8f0db018 | 674 | struct rhash_lock_head __rcu **bkt; |
ca26893f HX |
675 | struct rhash_head __rcu **pprev; |
676 | struct bucket_table *tbl; | |
02fd97c3 | 677 | struct rhash_head *head; |
299e5c32 | 678 | unsigned int hash; |
ca26893f HX |
679 | int elasticity; |
680 | void *data; | |
02fd97c3 HX |
681 | |
682 | rcu_read_lock(); | |
683 | ||
684 | tbl = rht_dereference_rcu(ht->tbl, ht); | |
ca26893f | 685 | hash = rht_head_hashfn(ht, tbl, obj, params); |
8f0db018 N |
686 | elasticity = RHT_ELASTICITY; |
687 | bkt = rht_bucket_insert(ht, tbl, hash); | |
688 | data = ERR_PTR(-ENOMEM); | |
689 | if (!bkt) | |
690 | goto out; | |
691 | pprev = NULL; | |
149212f0 | 692 | rht_lock(tbl, bkt); |
02fd97c3 | 693 | |
c0690016 | 694 | if (unlikely(rcu_access_pointer(tbl->future_tbl))) { |
ca26893f | 695 | slow_path: |
149212f0 | 696 | rht_unlock(tbl, bkt); |
ca26893f HX |
697 | rcu_read_unlock(); |
698 | return rhashtable_insert_slow(ht, key, obj); | |
b824478b HX |
699 | } |
700 | ||
8f0db018 | 701 | rht_for_each_from(head, rht_ptr(*bkt), tbl, hash) { |
ca26893f HX |
702 | struct rhlist_head *plist; |
703 | struct rhlist_head *list; | |
704 | ||
705 | elasticity--; | |
706 | if (!key || | |
707 | (params.obj_cmpfn ? | |
708 | params.obj_cmpfn(&arg, rht_obj(ht, head)) : | |
d3dcf8eb PB |
709 | rhashtable_compare(&arg, rht_obj(ht, head)))) { |
710 | pprev = &head->next; | |
ca26893f | 711 | continue; |
d3dcf8eb | 712 | } |
ca26893f HX |
713 | |
714 | data = rht_obj(ht, head); | |
3cf92222 | 715 | |
ca26893f | 716 | if (!rhlist) |
8f0db018 | 717 | goto out_unlock; |
5ca8cc5b | 718 | |
02fd97c3 | 719 | |
ca26893f HX |
720 | list = container_of(obj, struct rhlist_head, rhead); |
721 | plist = container_of(head, struct rhlist_head, rhead); | |
07ee0722 | 722 | |
ca26893f HX |
723 | RCU_INIT_POINTER(list->next, plist); |
724 | head = rht_dereference_bucket(head->next, tbl, hash); | |
725 | RCU_INIT_POINTER(list->rhead.next, head); | |
8f0db018 N |
726 | if (pprev) { |
727 | rcu_assign_pointer(*pprev, obj); | |
149212f0 | 728 | rht_unlock(tbl, bkt); |
8f0db018 | 729 | } else |
149212f0 | 730 | rht_assign_unlock(tbl, bkt, obj); |
8f0db018 N |
731 | data = NULL; |
732 | goto out; | |
ccd57b1b | 733 | } |
02fd97c3 | 734 | |
ca26893f HX |
735 | if (elasticity <= 0) |
736 | goto slow_path; | |
737 | ||
738 | data = ERR_PTR(-E2BIG); | |
739 | if (unlikely(rht_grow_above_max(ht, tbl))) | |
8f0db018 | 740 | goto out_unlock; |
ca26893f HX |
741 | |
742 | if (unlikely(rht_grow_above_100(ht, tbl))) | |
743 | goto slow_path; | |
02fd97c3 | 744 | |
8f0db018 N |
745 | /* Inserting at head of list makes unlocking free. */ |
746 | head = rht_ptr(rht_dereference_bucket(*bkt, tbl, hash)); | |
02fd97c3 HX |
747 | |
748 | RCU_INIT_POINTER(obj->next, head); | |
ca26893f HX |
749 | if (rhlist) { |
750 | struct rhlist_head *list; | |
751 | ||
752 | list = container_of(obj, struct rhlist_head, rhead); | |
753 | RCU_INIT_POINTER(list->next, NULL); | |
754 | } | |
02fd97c3 | 755 | |
02fd97c3 | 756 | atomic_inc(&ht->nelems); |
149212f0 | 757 | rht_assign_unlock(tbl, bkt, obj); |
8f0db018 | 758 | |
02fd97c3 HX |
759 | if (rht_grow_above_75(ht, tbl)) |
760 | schedule_work(&ht->run_work); | |
761 | ||
ca26893f | 762 | data = NULL; |
02fd97c3 | 763 | out: |
02fd97c3 HX |
764 | rcu_read_unlock(); |
765 | ||
ca26893f | 766 | return data; |
8f0db018 N |
767 | |
768 | out_unlock: | |
149212f0 | 769 | rht_unlock(tbl, bkt); |
8f0db018 | 770 | goto out; |
02fd97c3 HX |
771 | } |
772 | ||
773 | /** | |
774 | * rhashtable_insert_fast - insert object into hash table | |
775 | * @ht: hash table | |
776 | * @obj: pointer to hash head inside object | |
777 | * @params: hash table parameters | |
778 | * | |
8f0db018 | 779 | * Will take the per bucket bitlock to protect against mutual mutations |
02fd97c3 | 780 | * on the same bucket. Multiple insertions may occur in parallel unless |
8f0db018 | 781 | * they map to the same bucket. |
02fd97c3 HX |
782 | * |
783 | * It is safe to call this function from atomic context. | |
784 | * | |
0c6f69a5 N |
785 | * Will trigger an automatic deferred table resizing if residency in the |
786 | * table grows beyond 70%. | |
02fd97c3 HX |
787 | */ |
788 | static inline int rhashtable_insert_fast( | |
789 | struct rhashtable *ht, struct rhash_head *obj, | |
790 | const struct rhashtable_params params) | |
791 | { | |
5ca8cc5b PNA |
792 | void *ret; |
793 | ||
ca26893f | 794 | ret = __rhashtable_insert_fast(ht, NULL, obj, params, false); |
5ca8cc5b PNA |
795 | if (IS_ERR(ret)) |
796 | return PTR_ERR(ret); | |
797 | ||
798 | return ret == NULL ? 0 : -EEXIST; | |
02fd97c3 HX |
799 | } |
800 | ||
ca26893f HX |
801 | /** |
802 | * rhltable_insert_key - insert object into hash list table | |
803 | * @hlt: hash list table | |
804 | * @key: the pointer to the key | |
805 | * @list: pointer to hash list head inside object | |
806 | * @params: hash table parameters | |
807 | * | |
8f0db018 | 808 | * Will take the per bucket bitlock to protect against mutual mutations |
ca26893f | 809 | * on the same bucket. Multiple insertions may occur in parallel unless |
8f0db018 | 810 | * they map to the same bucket. |
ca26893f HX |
811 | * |
812 | * It is safe to call this function from atomic context. | |
813 | * | |
0c6f69a5 N |
814 | * Will trigger an automatic deferred table resizing if residency in the |
815 | * table grows beyond 70%. | |
ca26893f HX |
816 | */ |
817 | static inline int rhltable_insert_key( | |
818 | struct rhltable *hlt, const void *key, struct rhlist_head *list, | |
819 | const struct rhashtable_params params) | |
820 | { | |
821 | return PTR_ERR(__rhashtable_insert_fast(&hlt->ht, key, &list->rhead, | |
822 | params, true)); | |
823 | } | |
824 | ||
825 | /** | |
826 | * rhltable_insert - insert object into hash list table | |
827 | * @hlt: hash list table | |
828 | * @list: pointer to hash list head inside object | |
829 | * @params: hash table parameters | |
830 | * | |
8f0db018 | 831 | * Will take the per bucket bitlock to protect against mutual mutations |
ca26893f | 832 | * on the same bucket. Multiple insertions may occur in parallel unless |
8f0db018 | 833 | * they map to the same bucket. |
ca26893f HX |
834 | * |
835 | * It is safe to call this function from atomic context. | |
836 | * | |
0c6f69a5 N |
837 | * Will trigger an automatic deferred table resizing if residency in the |
838 | * table grows beyond 70%. | |
ca26893f HX |
839 | */ |
840 | static inline int rhltable_insert( | |
841 | struct rhltable *hlt, struct rhlist_head *list, | |
842 | const struct rhashtable_params params) | |
843 | { | |
844 | const char *key = rht_obj(&hlt->ht, &list->rhead); | |
845 | ||
846 | key += params.key_offset; | |
847 | ||
848 | return rhltable_insert_key(hlt, key, list, params); | |
849 | } | |
850 | ||
02fd97c3 HX |
851 | /** |
852 | * rhashtable_lookup_insert_fast - lookup and insert object into hash table | |
853 | * @ht: hash table | |
854 | * @obj: pointer to hash head inside object | |
855 | * @params: hash table parameters | |
856 | * | |
02fd97c3 HX |
857 | * This lookup function may only be used for fixed key hash table (key_len |
858 | * parameter set). It will BUG() if used inappropriately. | |
859 | * | |
860 | * It is safe to call this function from atomic context. | |
861 | * | |
0c6f69a5 N |
862 | * Will trigger an automatic deferred table resizing if residency in the |
863 | * table grows beyond 70%. | |
02fd97c3 HX |
864 | */ |
865 | static inline int rhashtable_lookup_insert_fast( | |
866 | struct rhashtable *ht, struct rhash_head *obj, | |
867 | const struct rhashtable_params params) | |
868 | { | |
869 | const char *key = rht_obj(ht, obj); | |
5ca8cc5b | 870 | void *ret; |
02fd97c3 HX |
871 | |
872 | BUG_ON(ht->p.obj_hashfn); | |
873 | ||
ca26893f HX |
874 | ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params, |
875 | false); | |
5ca8cc5b PNA |
876 | if (IS_ERR(ret)) |
877 | return PTR_ERR(ret); | |
878 | ||
879 | return ret == NULL ? 0 : -EEXIST; | |
02fd97c3 HX |
880 | } |
881 | ||
f9fe1c12 AG |
882 | /** |
883 | * rhashtable_lookup_get_insert_fast - lookup and insert object into hash table | |
884 | * @ht: hash table | |
885 | * @obj: pointer to hash head inside object | |
886 | * @params: hash table parameters | |
887 | * | |
888 | * Just like rhashtable_lookup_insert_fast(), but this function returns the | |
889 | * object if it exists, NULL if it did not and the insertion was successful, | |
890 | * and an ERR_PTR otherwise. | |
891 | */ | |
892 | static inline void *rhashtable_lookup_get_insert_fast( | |
893 | struct rhashtable *ht, struct rhash_head *obj, | |
894 | const struct rhashtable_params params) | |
895 | { | |
896 | const char *key = rht_obj(ht, obj); | |
897 | ||
898 | BUG_ON(ht->p.obj_hashfn); | |
899 | ||
900 | return __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params, | |
901 | false); | |
902 | } | |
903 | ||
02fd97c3 HX |
904 | /** |
905 | * rhashtable_lookup_insert_key - search and insert object to hash table | |
906 | * with explicit key | |
907 | * @ht: hash table | |
908 | * @key: key | |
909 | * @obj: pointer to hash head inside object | |
910 | * @params: hash table parameters | |
911 | * | |
02fd97c3 HX |
912 | * Lookups may occur in parallel with hashtable mutations and resizing. |
913 | * | |
0c6f69a5 N |
914 | * Will trigger an automatic deferred table resizing if residency in the |
915 | * table grows beyond 70%. | |
02fd97c3 HX |
916 | * |
917 | * Returns zero on success. | |
918 | */ | |
919 | static inline int rhashtable_lookup_insert_key( | |
920 | struct rhashtable *ht, const void *key, struct rhash_head *obj, | |
921 | const struct rhashtable_params params) | |
5ca8cc5b PNA |
922 | { |
923 | void *ret; | |
924 | ||
925 | BUG_ON(!ht->p.obj_hashfn || !key); | |
926 | ||
ca26893f | 927 | ret = __rhashtable_insert_fast(ht, key, obj, params, false); |
5ca8cc5b PNA |
928 | if (IS_ERR(ret)) |
929 | return PTR_ERR(ret); | |
930 | ||
931 | return ret == NULL ? 0 : -EEXIST; | |
932 | } | |
933 | ||
934 | /** | |
935 | * rhashtable_lookup_get_insert_key - lookup and insert object into hash table | |
936 | * @ht: hash table | |
937 | * @obj: pointer to hash head inside object | |
938 | * @params: hash table parameters | |
939 | * @data: pointer to element data already in hashes | |
940 | * | |
941 | * Just like rhashtable_lookup_insert_key(), but this function returns the | |
942 | * object if it exists, NULL if it does not and the insertion was successful, | |
943 | * and an ERR_PTR otherwise. | |
944 | */ | |
945 | static inline void *rhashtable_lookup_get_insert_key( | |
946 | struct rhashtable *ht, const void *key, struct rhash_head *obj, | |
947 | const struct rhashtable_params params) | |
02fd97c3 HX |
948 | { |
949 | BUG_ON(!ht->p.obj_hashfn || !key); | |
950 | ||
ca26893f | 951 | return __rhashtable_insert_fast(ht, key, obj, params, false); |
02fd97c3 HX |
952 | } |
953 | ||
ac833bdd | 954 | /* Internal function, please use rhashtable_remove_fast() instead */ |
ca26893f | 955 | static inline int __rhashtable_remove_fast_one( |
02fd97c3 | 956 | struct rhashtable *ht, struct bucket_table *tbl, |
ca26893f HX |
957 | struct rhash_head *obj, const struct rhashtable_params params, |
958 | bool rhlist) | |
02fd97c3 | 959 | { |
8f0db018 | 960 | struct rhash_lock_head __rcu **bkt; |
02fd97c3 HX |
961 | struct rhash_head __rcu **pprev; |
962 | struct rhash_head *he; | |
299e5c32 | 963 | unsigned int hash; |
02fd97c3 HX |
964 | int err = -ENOENT; |
965 | ||
966 | hash = rht_head_hashfn(ht, tbl, obj, params); | |
8f0db018 N |
967 | bkt = rht_bucket_var(tbl, hash); |
968 | if (!bkt) | |
969 | return -ENOENT; | |
970 | pprev = NULL; | |
149212f0 | 971 | rht_lock(tbl, bkt); |
02fd97c3 | 972 | |
8f0db018 | 973 | rht_for_each_from(he, rht_ptr(*bkt), tbl, hash) { |
ca26893f HX |
974 | struct rhlist_head *list; |
975 | ||
976 | list = container_of(he, struct rhlist_head, rhead); | |
977 | ||
02fd97c3 | 978 | if (he != obj) { |
ca26893f HX |
979 | struct rhlist_head __rcu **lpprev; |
980 | ||
02fd97c3 | 981 | pprev = &he->next; |
ca26893f HX |
982 | |
983 | if (!rhlist) | |
984 | continue; | |
985 | ||
986 | do { | |
987 | lpprev = &list->next; | |
988 | list = rht_dereference_bucket(list->next, | |
989 | tbl, hash); | |
990 | } while (list && obj != &list->rhead); | |
991 | ||
992 | if (!list) | |
993 | continue; | |
994 | ||
995 | list = rht_dereference_bucket(list->next, tbl, hash); | |
996 | RCU_INIT_POINTER(*lpprev, list); | |
997 | err = 0; | |
998 | break; | |
02fd97c3 HX |
999 | } |
1000 | ||
ca26893f HX |
1001 | obj = rht_dereference_bucket(obj->next, tbl, hash); |
1002 | err = 1; | |
1003 | ||
1004 | if (rhlist) { | |
1005 | list = rht_dereference_bucket(list->next, tbl, hash); | |
1006 | if (list) { | |
1007 | RCU_INIT_POINTER(list->rhead.next, obj); | |
1008 | obj = &list->rhead; | |
1009 | err = 0; | |
1010 | } | |
1011 | } | |
1012 | ||
8f0db018 N |
1013 | if (pprev) { |
1014 | rcu_assign_pointer(*pprev, obj); | |
149212f0 | 1015 | rht_unlock(tbl, bkt); |
8f0db018 | 1016 | } else { |
149212f0 | 1017 | rht_assign_unlock(tbl, bkt, obj); |
8f0db018 N |
1018 | } |
1019 | goto unlocked; | |
02fd97c3 HX |
1020 | } |
1021 | ||
149212f0 | 1022 | rht_unlock(tbl, bkt); |
8f0db018 | 1023 | unlocked: |
ca26893f HX |
1024 | if (err > 0) { |
1025 | atomic_dec(&ht->nelems); | |
1026 | if (unlikely(ht->p.automatic_shrinking && | |
1027 | rht_shrink_below_30(ht, tbl))) | |
1028 | schedule_work(&ht->run_work); | |
1029 | err = 0; | |
1030 | } | |
1031 | ||
02fd97c3 HX |
1032 | return err; |
1033 | } | |
1034 | ||
ca26893f HX |
1035 | /* Internal function, please use rhashtable_remove_fast() instead */ |
1036 | static inline int __rhashtable_remove_fast( | |
02fd97c3 | 1037 | struct rhashtable *ht, struct rhash_head *obj, |
ca26893f | 1038 | const struct rhashtable_params params, bool rhlist) |
02fd97c3 HX |
1039 | { |
1040 | struct bucket_table *tbl; | |
1041 | int err; | |
1042 | ||
1043 | rcu_read_lock(); | |
1044 | ||
1045 | tbl = rht_dereference_rcu(ht->tbl, ht); | |
1046 | ||
1047 | /* Because we have already taken (and released) the bucket | |
1048 | * lock in old_tbl, if we find that future_tbl is not yet | |
1049 | * visible then that guarantees the entry to still be in | |
1050 | * the old tbl if it exists. | |
1051 | */ | |
ca26893f HX |
1052 | while ((err = __rhashtable_remove_fast_one(ht, tbl, obj, params, |
1053 | rhlist)) && | |
02fd97c3 HX |
1054 | (tbl = rht_dereference_rcu(tbl->future_tbl, ht))) |
1055 | ; | |
1056 | ||
02fd97c3 HX |
1057 | rcu_read_unlock(); |
1058 | ||
1059 | return err; | |
1060 | } | |
1061 | ||
ca26893f HX |
1062 | /** |
1063 | * rhashtable_remove_fast - remove object from hash table | |
1064 | * @ht: hash table | |
1065 | * @obj: pointer to hash head inside object | |
1066 | * @params: hash table parameters | |
1067 | * | |
1068 | * Since the hash chain is single linked, the removal operation needs to | |
1069 | * walk the bucket chain upon removal. The removal operation is thus | |
1070 | * considerable slow if the hash table is not correctly sized. | |
1071 | * | |
0c6f69a5 N |
1072 | * Will automatically shrink the table if permitted when residency drops |
1073 | * below 30%. | |
ca26893f HX |
1074 | * |
1075 | * Returns zero on success, -ENOENT if the entry could not be found. | |
1076 | */ | |
1077 | static inline int rhashtable_remove_fast( | |
1078 | struct rhashtable *ht, struct rhash_head *obj, | |
1079 | const struct rhashtable_params params) | |
1080 | { | |
1081 | return __rhashtable_remove_fast(ht, obj, params, false); | |
1082 | } | |
1083 | ||
1084 | /** | |
1085 | * rhltable_remove - remove object from hash list table | |
1086 | * @hlt: hash list table | |
1087 | * @list: pointer to hash list head inside object | |
1088 | * @params: hash table parameters | |
1089 | * | |
1090 | * Since the hash chain is single linked, the removal operation needs to | |
1091 | * walk the bucket chain upon removal. The removal operation is thus | |
1092 | * considerable slow if the hash table is not correctly sized. | |
1093 | * | |
0c6f69a5 N |
1094 | * Will automatically shrink the table if permitted when residency drops |
1095 | * below 30% | |
ca26893f HX |
1096 | * |
1097 | * Returns zero on success, -ENOENT if the entry could not be found. | |
1098 | */ | |
1099 | static inline int rhltable_remove( | |
1100 | struct rhltable *hlt, struct rhlist_head *list, | |
1101 | const struct rhashtable_params params) | |
1102 | { | |
1103 | return __rhashtable_remove_fast(&hlt->ht, &list->rhead, params, true); | |
1104 | } | |
1105 | ||
3502cad7 TH |
1106 | /* Internal function, please use rhashtable_replace_fast() instead */ |
1107 | static inline int __rhashtable_replace_fast( | |
1108 | struct rhashtable *ht, struct bucket_table *tbl, | |
1109 | struct rhash_head *obj_old, struct rhash_head *obj_new, | |
1110 | const struct rhashtable_params params) | |
1111 | { | |
8f0db018 | 1112 | struct rhash_lock_head __rcu **bkt; |
3502cad7 TH |
1113 | struct rhash_head __rcu **pprev; |
1114 | struct rhash_head *he; | |
3502cad7 TH |
1115 | unsigned int hash; |
1116 | int err = -ENOENT; | |
1117 | ||
1118 | /* Minimally, the old and new objects must have same hash | |
1119 | * (which should mean identifiers are the same). | |
1120 | */ | |
1121 | hash = rht_head_hashfn(ht, tbl, obj_old, params); | |
1122 | if (hash != rht_head_hashfn(ht, tbl, obj_new, params)) | |
1123 | return -EINVAL; | |
1124 | ||
8f0db018 N |
1125 | bkt = rht_bucket_var(tbl, hash); |
1126 | if (!bkt) | |
1127 | return -ENOENT; | |
3502cad7 | 1128 | |
8f0db018 | 1129 | pprev = NULL; |
149212f0 | 1130 | rht_lock(tbl, bkt); |
3502cad7 | 1131 | |
8f0db018 | 1132 | rht_for_each_from(he, rht_ptr(*bkt), tbl, hash) { |
3502cad7 TH |
1133 | if (he != obj_old) { |
1134 | pprev = &he->next; | |
1135 | continue; | |
1136 | } | |
1137 | ||
1138 | rcu_assign_pointer(obj_new->next, obj_old->next); | |
8f0db018 N |
1139 | if (pprev) { |
1140 | rcu_assign_pointer(*pprev, obj_new); | |
149212f0 | 1141 | rht_unlock(tbl, bkt); |
8f0db018 | 1142 | } else { |
149212f0 | 1143 | rht_assign_unlock(tbl, bkt, obj_new); |
8f0db018 | 1144 | } |
3502cad7 | 1145 | err = 0; |
8f0db018 | 1146 | goto unlocked; |
3502cad7 | 1147 | } |
3502cad7 | 1148 | |
149212f0 | 1149 | rht_unlock(tbl, bkt); |
8f0db018 N |
1150 | |
1151 | unlocked: | |
3502cad7 TH |
1152 | return err; |
1153 | } | |
1154 | ||
1155 | /** | |
1156 | * rhashtable_replace_fast - replace an object in hash table | |
1157 | * @ht: hash table | |
1158 | * @obj_old: pointer to hash head inside object being replaced | |
1159 | * @obj_new: pointer to hash head inside object which is new | |
1160 | * @params: hash table parameters | |
1161 | * | |
1162 | * Replacing an object doesn't affect the number of elements in the hash table | |
1163 | * or bucket, so we don't need to worry about shrinking or expanding the | |
1164 | * table here. | |
1165 | * | |
1166 | * Returns zero on success, -ENOENT if the entry could not be found, | |
1167 | * -EINVAL if hash is not the same for the old and new objects. | |
1168 | */ | |
1169 | static inline int rhashtable_replace_fast( | |
1170 | struct rhashtable *ht, struct rhash_head *obj_old, | |
1171 | struct rhash_head *obj_new, | |
1172 | const struct rhashtable_params params) | |
1173 | { | |
1174 | struct bucket_table *tbl; | |
1175 | int err; | |
1176 | ||
1177 | rcu_read_lock(); | |
1178 | ||
1179 | tbl = rht_dereference_rcu(ht->tbl, ht); | |
1180 | ||
1181 | /* Because we have already taken (and released) the bucket | |
1182 | * lock in old_tbl, if we find that future_tbl is not yet | |
1183 | * visible then that guarantees the entry to still be in | |
1184 | * the old tbl if it exists. | |
1185 | */ | |
1186 | while ((err = __rhashtable_replace_fast(ht, tbl, obj_old, | |
1187 | obj_new, params)) && | |
1188 | (tbl = rht_dereference_rcu(tbl->future_tbl, ht))) | |
1189 | ; | |
1190 | ||
1191 | rcu_read_unlock(); | |
1192 | ||
1193 | return err; | |
1194 | } | |
1195 | ||
ca26893f HX |
1196 | /** |
1197 | * rhltable_walk_enter - Initialise an iterator | |
1198 | * @hlt: Table to walk over | |
1199 | * @iter: Hash table Iterator | |
1200 | * | |
1201 | * This function prepares a hash table walk. | |
1202 | * | |
1203 | * Note that if you restart a walk after rhashtable_walk_stop you | |
1204 | * may see the same object twice. Also, you may miss objects if | |
1205 | * there are removals in between rhashtable_walk_stop and the next | |
1206 | * call to rhashtable_walk_start. | |
1207 | * | |
1208 | * For a completely stable walk you should construct your own data | |
1209 | * structure outside the hash table. | |
1210 | * | |
82266e98 N |
1211 | * This function may be called from any process context, including |
1212 | * non-preemptable context, but cannot be called from softirq or | |
1213 | * hardirq context. | |
ca26893f HX |
1214 | * |
1215 | * You must call rhashtable_walk_exit after this function returns. | |
1216 | */ | |
1217 | static inline void rhltable_walk_enter(struct rhltable *hlt, | |
1218 | struct rhashtable_iter *iter) | |
1219 | { | |
1220 | return rhashtable_walk_enter(&hlt->ht, iter); | |
1221 | } | |
1222 | ||
1223 | /** | |
1224 | * rhltable_free_and_destroy - free elements and destroy hash list table | |
1225 | * @hlt: the hash list table to destroy | |
1226 | * @free_fn: callback to release resources of element | |
1227 | * @arg: pointer passed to free_fn | |
1228 | * | |
1229 | * See documentation for rhashtable_free_and_destroy. | |
1230 | */ | |
1231 | static inline void rhltable_free_and_destroy(struct rhltable *hlt, | |
1232 | void (*free_fn)(void *ptr, | |
1233 | void *arg), | |
1234 | void *arg) | |
1235 | { | |
1236 | return rhashtable_free_and_destroy(&hlt->ht, free_fn, arg); | |
1237 | } | |
1238 | ||
1239 | static inline void rhltable_destroy(struct rhltable *hlt) | |
1240 | { | |
1241 | return rhltable_free_and_destroy(hlt, NULL, NULL); | |
1242 | } | |
1243 | ||
7e1e7763 | 1244 | #endif /* _LINUX_RHASHTABLE_H */ |