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7e1e7763 TG |
1 | /* |
2 | * Resizable, Scalable, Concurrent Hash Table | |
3 | * | |
ca26893f | 4 | * Copyright (c) 2015-2016 Herbert Xu <herbert@gondor.apana.org.au> |
b5e2c150 | 5 | * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch> |
7e1e7763 TG |
6 | * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net> |
7 | * | |
7e1e7763 | 8 | * Code partially derived from nft_hash |
dc0ee268 HX |
9 | * Rewritten with rehash code from br_multicast plus single list |
10 | * pointer as suggested by Josh Triplett | |
7e1e7763 TG |
11 | * |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License version 2 as | |
14 | * published by the Free Software Foundation. | |
15 | */ | |
16 | ||
17 | #ifndef _LINUX_RHASHTABLE_H | |
18 | #define _LINUX_RHASHTABLE_H | |
19 | ||
07ee0722 | 20 | #include <linux/atomic.h> |
f2dba9c6 | 21 | #include <linux/compiler.h> |
3cf92222 | 22 | #include <linux/err.h> |
6626af69 | 23 | #include <linux/errno.h> |
31ccde2d | 24 | #include <linux/jhash.h> |
f89bd6f8 | 25 | #include <linux/list_nulls.h> |
97defe1e | 26 | #include <linux/workqueue.h> |
86b35b64 | 27 | #include <linux/mutex.h> |
b2d09103 | 28 | #include <linux/rculist.h> |
7e1e7763 | 29 | |
f89bd6f8 TG |
30 | /* |
31 | * The end of the chain is marked with a special nulls marks which has | |
32 | * the following format: | |
33 | * | |
34 | * +-------+-----------------------------------------------------+-+ | |
35 | * | Base | Hash |1| | |
36 | * +-------+-----------------------------------------------------+-+ | |
37 | * | |
38 | * Base (4 bits) : Reserved to distinguish between multiple tables. | |
39 | * Specified via &struct rhashtable_params.nulls_base. | |
40 | * Hash (27 bits): Full hash (unmasked) of first element added to bucket | |
41 | * 1 (1 bit) : Nulls marker (always set) | |
42 | * | |
43 | * The remaining bits of the next pointer remain unused for now. | |
44 | */ | |
45 | #define RHT_BASE_BITS 4 | |
46 | #define RHT_HASH_BITS 27 | |
47 | #define RHT_BASE_SHIFT RHT_HASH_BITS | |
48 | ||
02fd97c3 HX |
49 | /* Base bits plus 1 bit for nulls marker */ |
50 | #define RHT_HASH_RESERVED_SPACE (RHT_BASE_BITS + 1) | |
51 | ||
5f8ddeab FW |
52 | /* Maximum chain length before rehash |
53 | * | |
54 | * The maximum (not average) chain length grows with the size of the hash | |
55 | * table, at a rate of (log N)/(log log N). | |
56 | * | |
57 | * The value of 16 is selected so that even if the hash table grew to | |
58 | * 2^32 you would not expect the maximum chain length to exceed it | |
59 | * unless we are under attack (or extremely unlucky). | |
60 | * | |
61 | * As this limit is only to detect attacks, we don't need to set it to a | |
62 | * lower value as you'd need the chain length to vastly exceed 16 to have | |
63 | * any real effect on the system. | |
64 | */ | |
65 | #define RHT_ELASTICITY 16u | |
66 | ||
7e1e7763 | 67 | struct rhash_head { |
5300fdcb | 68 | struct rhash_head __rcu *next; |
7e1e7763 TG |
69 | }; |
70 | ||
ca26893f HX |
71 | struct rhlist_head { |
72 | struct rhash_head rhead; | |
73 | struct rhlist_head __rcu *next; | |
74 | }; | |
75 | ||
97defe1e TG |
76 | /** |
77 | * struct bucket_table - Table of hash buckets | |
78 | * @size: Number of hash buckets | |
da20420f | 79 | * @nest: Number of bits of first-level nested table. |
63d512d0 | 80 | * @rehash: Current bucket being rehashed |
988dfbd7 | 81 | * @hash_rnd: Random seed to fold into hash |
97defe1e TG |
82 | * @locks_mask: Mask to apply before accessing locks[] |
83 | * @locks: Array of spinlocks protecting individual buckets | |
eddee5ba | 84 | * @walkers: List of active walkers |
9d901bc0 | 85 | * @rcu: RCU structure for freeing the table |
c4db8848 | 86 | * @future_tbl: Table under construction during rehashing |
da20420f | 87 | * @ntbl: Nested table used when out of memory. |
97defe1e TG |
88 | * @buckets: size * hash buckets |
89 | */ | |
7e1e7763 | 90 | struct bucket_table { |
63d512d0 | 91 | unsigned int size; |
da20420f | 92 | unsigned int nest; |
63d512d0 | 93 | unsigned int rehash; |
988dfbd7 | 94 | u32 hash_rnd; |
b9ebafbe ED |
95 | unsigned int locks_mask; |
96 | spinlock_t *locks; | |
eddee5ba | 97 | struct list_head walkers; |
9d901bc0 | 98 | struct rcu_head rcu; |
b9ebafbe | 99 | |
c4db8848 HX |
100 | struct bucket_table __rcu *future_tbl; |
101 | ||
da20420f | 102 | struct rhash_head __rcu *buckets[] ____cacheline_aligned_in_smp; |
7e1e7763 TG |
103 | }; |
104 | ||
02fd97c3 HX |
105 | /** |
106 | * struct rhashtable_compare_arg - Key for the function rhashtable_compare | |
107 | * @ht: Hash table | |
108 | * @key: Key to compare against | |
109 | */ | |
110 | struct rhashtable_compare_arg { | |
111 | struct rhashtable *ht; | |
112 | const void *key; | |
113 | }; | |
114 | ||
7e1e7763 | 115 | typedef u32 (*rht_hashfn_t)(const void *data, u32 len, u32 seed); |
49f7b33e | 116 | typedef u32 (*rht_obj_hashfn_t)(const void *data, u32 len, u32 seed); |
02fd97c3 HX |
117 | typedef int (*rht_obj_cmpfn_t)(struct rhashtable_compare_arg *arg, |
118 | const void *obj); | |
7e1e7763 TG |
119 | |
120 | struct rhashtable; | |
121 | ||
122 | /** | |
123 | * struct rhashtable_params - Hash table construction parameters | |
124 | * @nelem_hint: Hint on number of elements, should be 75% of desired size | |
125 | * @key_len: Length of key | |
126 | * @key_offset: Offset of key in struct to be hashed | |
127 | * @head_offset: Offset of rhash_head in struct to be hashed | |
c2e213cf HX |
128 | * @max_size: Maximum size while expanding |
129 | * @min_size: Minimum size while shrinking | |
895a6072 | 130 | * @locks_mul: Number of bucket locks to allocate per cpu (default: 32) |
48e75b43 FW |
131 | * @automatic_shrinking: Enable automatic shrinking of tables |
132 | * @nulls_base: Base value to generate nulls marker | |
31ccde2d | 133 | * @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash) |
7e1e7763 | 134 | * @obj_hashfn: Function to hash object |
02fd97c3 | 135 | * @obj_cmpfn: Function to compare key with object |
7e1e7763 TG |
136 | */ |
137 | struct rhashtable_params { | |
48e75b43 FW |
138 | u16 nelem_hint; |
139 | u16 key_len; | |
140 | u16 key_offset; | |
141 | u16 head_offset; | |
c2e213cf | 142 | unsigned int max_size; |
48e75b43 | 143 | u16 min_size; |
b5e2c150 | 144 | bool automatic_shrinking; |
48e75b43 FW |
145 | u8 locks_mul; |
146 | u32 nulls_base; | |
7e1e7763 TG |
147 | rht_hashfn_t hashfn; |
148 | rht_obj_hashfn_t obj_hashfn; | |
02fd97c3 | 149 | rht_obj_cmpfn_t obj_cmpfn; |
7e1e7763 TG |
150 | }; |
151 | ||
152 | /** | |
153 | * struct rhashtable - Hash table handle | |
154 | * @tbl: Bucket table | |
155 | * @nelems: Number of elements in table | |
31ccde2d | 156 | * @key_len: Key length for hashfn |
7e1e7763 | 157 | * @p: Configuration parameters |
6d684e54 | 158 | * @max_elems: Maximum number of elements in table |
ca26893f | 159 | * @rhlist: True if this is an rhltable |
97defe1e TG |
160 | * @run_work: Deferred worker to expand/shrink asynchronously |
161 | * @mutex: Mutex to protect current/future table swapping | |
ba7c95ea | 162 | * @lock: Spin lock to protect walker list |
7e1e7763 TG |
163 | */ |
164 | struct rhashtable { | |
165 | struct bucket_table __rcu *tbl; | |
97defe1e | 166 | atomic_t nelems; |
31ccde2d | 167 | unsigned int key_len; |
7e1e7763 | 168 | struct rhashtable_params p; |
6d684e54 | 169 | unsigned int max_elems; |
ca26893f | 170 | bool rhlist; |
57699a40 | 171 | struct work_struct run_work; |
97defe1e | 172 | struct mutex mutex; |
ba7c95ea | 173 | spinlock_t lock; |
7e1e7763 TG |
174 | }; |
175 | ||
ca26893f HX |
176 | /** |
177 | * struct rhltable - Hash table with duplicate objects in a list | |
178 | * @ht: Underlying rhtable | |
179 | */ | |
180 | struct rhltable { | |
181 | struct rhashtable ht; | |
182 | }; | |
183 | ||
f2dba9c6 HX |
184 | /** |
185 | * struct rhashtable_walker - Hash table walker | |
186 | * @list: List entry on list of walkers | |
eddee5ba | 187 | * @tbl: The table that we were walking over |
f2dba9c6 HX |
188 | */ |
189 | struct rhashtable_walker { | |
190 | struct list_head list; | |
eddee5ba | 191 | struct bucket_table *tbl; |
f2dba9c6 HX |
192 | }; |
193 | ||
194 | /** | |
ca26893f | 195 | * struct rhashtable_iter - Hash table iterator |
f2dba9c6 HX |
196 | * @ht: Table to iterate through |
197 | * @p: Current pointer | |
ca26893f | 198 | * @list: Current hash list pointer |
f2dba9c6 HX |
199 | * @walker: Associated rhashtable walker |
200 | * @slot: Current slot | |
201 | * @skip: Number of entries to skip in slot | |
202 | */ | |
203 | struct rhashtable_iter { | |
204 | struct rhashtable *ht; | |
205 | struct rhash_head *p; | |
ca26893f | 206 | struct rhlist_head *list; |
246779dd | 207 | struct rhashtable_walker walker; |
f2dba9c6 HX |
208 | unsigned int slot; |
209 | unsigned int skip; | |
2db54b47 | 210 | bool end_of_table; |
f2dba9c6 HX |
211 | }; |
212 | ||
f89bd6f8 TG |
213 | static inline unsigned long rht_marker(const struct rhashtable *ht, u32 hash) |
214 | { | |
215 | return NULLS_MARKER(ht->p.nulls_base + hash); | |
216 | } | |
217 | ||
218 | #define INIT_RHT_NULLS_HEAD(ptr, ht, hash) \ | |
219 | ((ptr) = (typeof(ptr)) rht_marker(ht, hash)) | |
220 | ||
221 | static inline bool rht_is_a_nulls(const struct rhash_head *ptr) | |
222 | { | |
223 | return ((unsigned long) ptr & 1); | |
224 | } | |
225 | ||
226 | static inline unsigned long rht_get_nulls_value(const struct rhash_head *ptr) | |
227 | { | |
228 | return ((unsigned long) ptr) >> 1; | |
229 | } | |
230 | ||
02fd97c3 HX |
231 | static inline void *rht_obj(const struct rhashtable *ht, |
232 | const struct rhash_head *he) | |
233 | { | |
234 | return (char *)he - ht->p.head_offset; | |
235 | } | |
236 | ||
237 | static inline unsigned int rht_bucket_index(const struct bucket_table *tbl, | |
238 | unsigned int hash) | |
239 | { | |
240 | return (hash >> RHT_HASH_RESERVED_SPACE) & (tbl->size - 1); | |
241 | } | |
242 | ||
2b860931 TH |
243 | static inline unsigned int rht_key_get_hash(struct rhashtable *ht, |
244 | const void *key, const struct rhashtable_params params, | |
245 | unsigned int hash_rnd) | |
02fd97c3 | 246 | { |
299e5c32 | 247 | unsigned int hash; |
de91b25c | 248 | |
31ccde2d HX |
249 | /* params must be equal to ht->p if it isn't constant. */ |
250 | if (!__builtin_constant_p(params.key_len)) | |
2b860931 | 251 | hash = ht->p.hashfn(key, ht->key_len, hash_rnd); |
31ccde2d | 252 | else if (params.key_len) { |
299e5c32 | 253 | unsigned int key_len = params.key_len; |
31ccde2d HX |
254 | |
255 | if (params.hashfn) | |
2b860931 | 256 | hash = params.hashfn(key, key_len, hash_rnd); |
31ccde2d | 257 | else if (key_len & (sizeof(u32) - 1)) |
2b860931 | 258 | hash = jhash(key, key_len, hash_rnd); |
31ccde2d | 259 | else |
2b860931 | 260 | hash = jhash2(key, key_len / sizeof(u32), hash_rnd); |
31ccde2d | 261 | } else { |
299e5c32 | 262 | unsigned int key_len = ht->p.key_len; |
31ccde2d HX |
263 | |
264 | if (params.hashfn) | |
2b860931 | 265 | hash = params.hashfn(key, key_len, hash_rnd); |
31ccde2d | 266 | else |
2b860931 | 267 | hash = jhash(key, key_len, hash_rnd); |
31ccde2d HX |
268 | } |
269 | ||
2b860931 TH |
270 | return hash; |
271 | } | |
272 | ||
273 | static inline unsigned int rht_key_hashfn( | |
274 | struct rhashtable *ht, const struct bucket_table *tbl, | |
275 | const void *key, const struct rhashtable_params params) | |
276 | { | |
277 | unsigned int hash = rht_key_get_hash(ht, key, params, tbl->hash_rnd); | |
278 | ||
31ccde2d | 279 | return rht_bucket_index(tbl, hash); |
02fd97c3 HX |
280 | } |
281 | ||
282 | static inline unsigned int rht_head_hashfn( | |
283 | struct rhashtable *ht, const struct bucket_table *tbl, | |
284 | const struct rhash_head *he, const struct rhashtable_params params) | |
285 | { | |
286 | const char *ptr = rht_obj(ht, he); | |
287 | ||
288 | return likely(params.obj_hashfn) ? | |
49f7b33e PM |
289 | rht_bucket_index(tbl, params.obj_hashfn(ptr, params.key_len ?: |
290 | ht->p.key_len, | |
291 | tbl->hash_rnd)) : | |
02fd97c3 HX |
292 | rht_key_hashfn(ht, tbl, ptr + params.key_offset, params); |
293 | } | |
294 | ||
295 | /** | |
296 | * rht_grow_above_75 - returns true if nelems > 0.75 * table-size | |
297 | * @ht: hash table | |
298 | * @tbl: current table | |
299 | */ | |
300 | static inline bool rht_grow_above_75(const struct rhashtable *ht, | |
301 | const struct bucket_table *tbl) | |
302 | { | |
303 | /* Expand table when exceeding 75% load */ | |
304 | return atomic_read(&ht->nelems) > (tbl->size / 4 * 3) && | |
305 | (!ht->p.max_size || tbl->size < ht->p.max_size); | |
306 | } | |
307 | ||
308 | /** | |
309 | * rht_shrink_below_30 - returns true if nelems < 0.3 * table-size | |
310 | * @ht: hash table | |
311 | * @tbl: current table | |
312 | */ | |
313 | static inline bool rht_shrink_below_30(const struct rhashtable *ht, | |
314 | const struct bucket_table *tbl) | |
315 | { | |
316 | /* Shrink table beneath 30% load */ | |
317 | return atomic_read(&ht->nelems) < (tbl->size * 3 / 10) && | |
318 | tbl->size > ht->p.min_size; | |
319 | } | |
320 | ||
ccd57b1b HX |
321 | /** |
322 | * rht_grow_above_100 - returns true if nelems > table-size | |
323 | * @ht: hash table | |
324 | * @tbl: current table | |
325 | */ | |
326 | static inline bool rht_grow_above_100(const struct rhashtable *ht, | |
327 | const struct bucket_table *tbl) | |
328 | { | |
1d8dc3d3 JB |
329 | return atomic_read(&ht->nelems) > tbl->size && |
330 | (!ht->p.max_size || tbl->size < ht->p.max_size); | |
ccd57b1b HX |
331 | } |
332 | ||
07ee0722 HX |
333 | /** |
334 | * rht_grow_above_max - returns true if table is above maximum | |
335 | * @ht: hash table | |
336 | * @tbl: current table | |
337 | */ | |
338 | static inline bool rht_grow_above_max(const struct rhashtable *ht, | |
339 | const struct bucket_table *tbl) | |
340 | { | |
6d684e54 | 341 | return atomic_read(&ht->nelems) >= ht->max_elems; |
07ee0722 HX |
342 | } |
343 | ||
02fd97c3 HX |
344 | /* The bucket lock is selected based on the hash and protects mutations |
345 | * on a group of hash buckets. | |
346 | * | |
347 | * A maximum of tbl->size/2 bucket locks is allocated. This ensures that | |
348 | * a single lock always covers both buckets which may both contains | |
349 | * entries which link to the same bucket of the old table during resizing. | |
350 | * This allows to simplify the locking as locking the bucket in both | |
351 | * tables during resize always guarantee protection. | |
352 | * | |
353 | * IMPORTANT: When holding the bucket lock of both the old and new table | |
354 | * during expansions and shrinking, the old bucket lock must always be | |
355 | * acquired first. | |
356 | */ | |
357 | static inline spinlock_t *rht_bucket_lock(const struct bucket_table *tbl, | |
358 | unsigned int hash) | |
359 | { | |
360 | return &tbl->locks[hash & tbl->locks_mask]; | |
361 | } | |
362 | ||
7e1e7763 | 363 | #ifdef CONFIG_PROVE_LOCKING |
97defe1e | 364 | int lockdep_rht_mutex_is_held(struct rhashtable *ht); |
88d6ed15 | 365 | int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash); |
7e1e7763 | 366 | #else |
97defe1e | 367 | static inline int lockdep_rht_mutex_is_held(struct rhashtable *ht) |
7e1e7763 TG |
368 | { |
369 | return 1; | |
370 | } | |
88d6ed15 TG |
371 | |
372 | static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, | |
373 | u32 hash) | |
374 | { | |
375 | return 1; | |
376 | } | |
7e1e7763 TG |
377 | #endif /* CONFIG_PROVE_LOCKING */ |
378 | ||
488fb86e HX |
379 | int rhashtable_init(struct rhashtable *ht, |
380 | const struct rhashtable_params *params); | |
ca26893f HX |
381 | int rhltable_init(struct rhltable *hlt, |
382 | const struct rhashtable_params *params); | |
7e1e7763 | 383 | |
ca26893f HX |
384 | void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, |
385 | struct rhash_head *obj); | |
7e1e7763 | 386 | |
246779dd HX |
387 | void rhashtable_walk_enter(struct rhashtable *ht, |
388 | struct rhashtable_iter *iter); | |
f2dba9c6 | 389 | void rhashtable_walk_exit(struct rhashtable_iter *iter); |
97a6ec4a TH |
390 | int rhashtable_walk_start_check(struct rhashtable_iter *iter) __acquires(RCU); |
391 | ||
392 | static inline void rhashtable_walk_start(struct rhashtable_iter *iter) | |
393 | { | |
394 | (void)rhashtable_walk_start_check(iter); | |
395 | } | |
396 | ||
f2dba9c6 | 397 | void *rhashtable_walk_next(struct rhashtable_iter *iter); |
2db54b47 | 398 | void *rhashtable_walk_peek(struct rhashtable_iter *iter); |
f2dba9c6 HX |
399 | void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases(RCU); |
400 | ||
6b6f302c TG |
401 | void rhashtable_free_and_destroy(struct rhashtable *ht, |
402 | void (*free_fn)(void *ptr, void *arg), | |
403 | void *arg); | |
97defe1e | 404 | void rhashtable_destroy(struct rhashtable *ht); |
7e1e7763 | 405 | |
da20420f HX |
406 | struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl, |
407 | unsigned int hash); | |
408 | struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht, | |
409 | struct bucket_table *tbl, | |
410 | unsigned int hash); | |
411 | ||
7e1e7763 TG |
412 | #define rht_dereference(p, ht) \ |
413 | rcu_dereference_protected(p, lockdep_rht_mutex_is_held(ht)) | |
414 | ||
415 | #define rht_dereference_rcu(p, ht) \ | |
416 | rcu_dereference_check(p, lockdep_rht_mutex_is_held(ht)) | |
417 | ||
88d6ed15 TG |
418 | #define rht_dereference_bucket(p, tbl, hash) \ |
419 | rcu_dereference_protected(p, lockdep_rht_bucket_is_held(tbl, hash)) | |
7e1e7763 | 420 | |
88d6ed15 TG |
421 | #define rht_dereference_bucket_rcu(p, tbl, hash) \ |
422 | rcu_dereference_check(p, lockdep_rht_bucket_is_held(tbl, hash)) | |
423 | ||
424 | #define rht_entry(tpos, pos, member) \ | |
425 | ({ tpos = container_of(pos, typeof(*tpos), member); 1; }) | |
7e1e7763 | 426 | |
da20420f HX |
427 | static inline struct rhash_head __rcu *const *rht_bucket( |
428 | const struct bucket_table *tbl, unsigned int hash) | |
429 | { | |
430 | return unlikely(tbl->nest) ? rht_bucket_nested(tbl, hash) : | |
431 | &tbl->buckets[hash]; | |
432 | } | |
433 | ||
434 | static inline struct rhash_head __rcu **rht_bucket_var( | |
435 | struct bucket_table *tbl, unsigned int hash) | |
436 | { | |
437 | return unlikely(tbl->nest) ? rht_bucket_nested(tbl, hash) : | |
438 | &tbl->buckets[hash]; | |
439 | } | |
440 | ||
441 | static inline struct rhash_head __rcu **rht_bucket_insert( | |
442 | struct rhashtable *ht, struct bucket_table *tbl, unsigned int hash) | |
443 | { | |
444 | return unlikely(tbl->nest) ? rht_bucket_nested_insert(ht, tbl, hash) : | |
445 | &tbl->buckets[hash]; | |
446 | } | |
447 | ||
7e1e7763 | 448 | /** |
88d6ed15 TG |
449 | * rht_for_each_continue - continue iterating over hash chain |
450 | * @pos: the &struct rhash_head to use as a loop cursor. | |
451 | * @head: the previous &struct rhash_head to continue from | |
452 | * @tbl: the &struct bucket_table | |
453 | * @hash: the hash value / bucket index | |
7e1e7763 | 454 | */ |
88d6ed15 TG |
455 | #define rht_for_each_continue(pos, head, tbl, hash) \ |
456 | for (pos = rht_dereference_bucket(head, tbl, hash); \ | |
f89bd6f8 | 457 | !rht_is_a_nulls(pos); \ |
88d6ed15 TG |
458 | pos = rht_dereference_bucket((pos)->next, tbl, hash)) |
459 | ||
460 | /** | |
461 | * rht_for_each - iterate over hash chain | |
462 | * @pos: the &struct rhash_head to use as a loop cursor. | |
463 | * @tbl: the &struct bucket_table | |
464 | * @hash: the hash value / bucket index | |
465 | */ | |
466 | #define rht_for_each(pos, tbl, hash) \ | |
da20420f | 467 | rht_for_each_continue(pos, *rht_bucket(tbl, hash), tbl, hash) |
88d6ed15 TG |
468 | |
469 | /** | |
470 | * rht_for_each_entry_continue - continue iterating over hash chain | |
471 | * @tpos: the type * to use as a loop cursor. | |
472 | * @pos: the &struct rhash_head to use as a loop cursor. | |
473 | * @head: the previous &struct rhash_head to continue from | |
474 | * @tbl: the &struct bucket_table | |
475 | * @hash: the hash value / bucket index | |
476 | * @member: name of the &struct rhash_head within the hashable struct. | |
477 | */ | |
478 | #define rht_for_each_entry_continue(tpos, pos, head, tbl, hash, member) \ | |
479 | for (pos = rht_dereference_bucket(head, tbl, hash); \ | |
f89bd6f8 | 480 | (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \ |
88d6ed15 | 481 | pos = rht_dereference_bucket((pos)->next, tbl, hash)) |
7e1e7763 TG |
482 | |
483 | /** | |
484 | * rht_for_each_entry - iterate over hash chain of given type | |
88d6ed15 TG |
485 | * @tpos: the type * to use as a loop cursor. |
486 | * @pos: the &struct rhash_head to use as a loop cursor. | |
487 | * @tbl: the &struct bucket_table | |
488 | * @hash: the hash value / bucket index | |
489 | * @member: name of the &struct rhash_head within the hashable struct. | |
7e1e7763 | 490 | */ |
88d6ed15 | 491 | #define rht_for_each_entry(tpos, pos, tbl, hash, member) \ |
da20420f | 492 | rht_for_each_entry_continue(tpos, pos, *rht_bucket(tbl, hash), \ |
88d6ed15 | 493 | tbl, hash, member) |
7e1e7763 TG |
494 | |
495 | /** | |
496 | * rht_for_each_entry_safe - safely iterate over hash chain of given type | |
88d6ed15 TG |
497 | * @tpos: the type * to use as a loop cursor. |
498 | * @pos: the &struct rhash_head to use as a loop cursor. | |
499 | * @next: the &struct rhash_head to use as next in loop cursor. | |
500 | * @tbl: the &struct bucket_table | |
501 | * @hash: the hash value / bucket index | |
502 | * @member: name of the &struct rhash_head within the hashable struct. | |
7e1e7763 TG |
503 | * |
504 | * This hash chain list-traversal primitive allows for the looped code to | |
505 | * remove the loop cursor from the list. | |
506 | */ | |
da20420f HX |
507 | #define rht_for_each_entry_safe(tpos, pos, next, tbl, hash, member) \ |
508 | for (pos = rht_dereference_bucket(*rht_bucket(tbl, hash), tbl, hash), \ | |
509 | next = !rht_is_a_nulls(pos) ? \ | |
510 | rht_dereference_bucket(pos->next, tbl, hash) : NULL; \ | |
511 | (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \ | |
512 | pos = next, \ | |
513 | next = !rht_is_a_nulls(pos) ? \ | |
607954b0 | 514 | rht_dereference_bucket(pos->next, tbl, hash) : NULL) |
88d6ed15 TG |
515 | |
516 | /** | |
517 | * rht_for_each_rcu_continue - continue iterating over rcu hash chain | |
518 | * @pos: the &struct rhash_head to use as a loop cursor. | |
519 | * @head: the previous &struct rhash_head to continue from | |
520 | * @tbl: the &struct bucket_table | |
521 | * @hash: the hash value / bucket index | |
522 | * | |
523 | * This hash chain list-traversal primitive may safely run concurrently with | |
524 | * the _rcu mutation primitives such as rhashtable_insert() as long as the | |
525 | * traversal is guarded by rcu_read_lock(). | |
526 | */ | |
527 | #define rht_for_each_rcu_continue(pos, head, tbl, hash) \ | |
528 | for (({barrier(); }), \ | |
529 | pos = rht_dereference_bucket_rcu(head, tbl, hash); \ | |
f89bd6f8 | 530 | !rht_is_a_nulls(pos); \ |
88d6ed15 | 531 | pos = rcu_dereference_raw(pos->next)) |
7e1e7763 TG |
532 | |
533 | /** | |
534 | * rht_for_each_rcu - iterate over rcu hash chain | |
88d6ed15 TG |
535 | * @pos: the &struct rhash_head to use as a loop cursor. |
536 | * @tbl: the &struct bucket_table | |
537 | * @hash: the hash value / bucket index | |
7e1e7763 TG |
538 | * |
539 | * This hash chain list-traversal primitive may safely run concurrently with | |
88d6ed15 | 540 | * the _rcu mutation primitives such as rhashtable_insert() as long as the |
7e1e7763 TG |
541 | * traversal is guarded by rcu_read_lock(). |
542 | */ | |
88d6ed15 | 543 | #define rht_for_each_rcu(pos, tbl, hash) \ |
da20420f | 544 | rht_for_each_rcu_continue(pos, *rht_bucket(tbl, hash), tbl, hash) |
88d6ed15 TG |
545 | |
546 | /** | |
547 | * rht_for_each_entry_rcu_continue - continue iterating over rcu hash chain | |
548 | * @tpos: the type * to use as a loop cursor. | |
549 | * @pos: the &struct rhash_head to use as a loop cursor. | |
550 | * @head: the previous &struct rhash_head to continue from | |
551 | * @tbl: the &struct bucket_table | |
552 | * @hash: the hash value / bucket index | |
553 | * @member: name of the &struct rhash_head within the hashable struct. | |
554 | * | |
555 | * This hash chain list-traversal primitive may safely run concurrently with | |
556 | * the _rcu mutation primitives such as rhashtable_insert() as long as the | |
557 | * traversal is guarded by rcu_read_lock(). | |
558 | */ | |
559 | #define rht_for_each_entry_rcu_continue(tpos, pos, head, tbl, hash, member) \ | |
560 | for (({barrier(); }), \ | |
561 | pos = rht_dereference_bucket_rcu(head, tbl, hash); \ | |
f89bd6f8 | 562 | (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \ |
88d6ed15 | 563 | pos = rht_dereference_bucket_rcu(pos->next, tbl, hash)) |
7e1e7763 TG |
564 | |
565 | /** | |
566 | * rht_for_each_entry_rcu - iterate over rcu hash chain of given type | |
88d6ed15 TG |
567 | * @tpos: the type * to use as a loop cursor. |
568 | * @pos: the &struct rhash_head to use as a loop cursor. | |
569 | * @tbl: the &struct bucket_table | |
570 | * @hash: the hash value / bucket index | |
571 | * @member: name of the &struct rhash_head within the hashable struct. | |
7e1e7763 TG |
572 | * |
573 | * This hash chain list-traversal primitive may safely run concurrently with | |
88d6ed15 | 574 | * the _rcu mutation primitives such as rhashtable_insert() as long as the |
7e1e7763 TG |
575 | * traversal is guarded by rcu_read_lock(). |
576 | */ | |
da20420f HX |
577 | #define rht_for_each_entry_rcu(tpos, pos, tbl, hash, member) \ |
578 | rht_for_each_entry_rcu_continue(tpos, pos, *rht_bucket(tbl, hash), \ | |
88d6ed15 | 579 | tbl, hash, member) |
7e1e7763 | 580 | |
ca26893f HX |
581 | /** |
582 | * rhl_for_each_rcu - iterate over rcu hash table list | |
583 | * @pos: the &struct rlist_head to use as a loop cursor. | |
584 | * @list: the head of the list | |
585 | * | |
586 | * This hash chain list-traversal primitive should be used on the | |
587 | * list returned by rhltable_lookup. | |
588 | */ | |
589 | #define rhl_for_each_rcu(pos, list) \ | |
590 | for (pos = list; pos; pos = rcu_dereference_raw(pos->next)) | |
591 | ||
592 | /** | |
593 | * rhl_for_each_entry_rcu - iterate over rcu hash table list of given type | |
594 | * @tpos: the type * to use as a loop cursor. | |
595 | * @pos: the &struct rlist_head to use as a loop cursor. | |
596 | * @list: the head of the list | |
597 | * @member: name of the &struct rlist_head within the hashable struct. | |
598 | * | |
599 | * This hash chain list-traversal primitive should be used on the | |
600 | * list returned by rhltable_lookup. | |
601 | */ | |
602 | #define rhl_for_each_entry_rcu(tpos, pos, list, member) \ | |
603 | for (pos = list; pos && rht_entry(tpos, pos, member); \ | |
604 | pos = rcu_dereference_raw(pos->next)) | |
605 | ||
02fd97c3 HX |
606 | static inline int rhashtable_compare(struct rhashtable_compare_arg *arg, |
607 | const void *obj) | |
608 | { | |
609 | struct rhashtable *ht = arg->ht; | |
610 | const char *ptr = obj; | |
611 | ||
612 | return memcmp(ptr + ht->p.key_offset, arg->key, ht->p.key_len); | |
613 | } | |
614 | ||
ca26893f HX |
615 | /* Internal function, do not use. */ |
616 | static inline struct rhash_head *__rhashtable_lookup( | |
02fd97c3 HX |
617 | struct rhashtable *ht, const void *key, |
618 | const struct rhashtable_params params) | |
619 | { | |
620 | struct rhashtable_compare_arg arg = { | |
621 | .ht = ht, | |
622 | .key = key, | |
623 | }; | |
da20420f | 624 | struct bucket_table *tbl; |
02fd97c3 | 625 | struct rhash_head *he; |
299e5c32 | 626 | unsigned int hash; |
02fd97c3 | 627 | |
02fd97c3 HX |
628 | tbl = rht_dereference_rcu(ht->tbl, ht); |
629 | restart: | |
630 | hash = rht_key_hashfn(ht, tbl, key, params); | |
631 | rht_for_each_rcu(he, tbl, hash) { | |
632 | if (params.obj_cmpfn ? | |
633 | params.obj_cmpfn(&arg, rht_obj(ht, he)) : | |
634 | rhashtable_compare(&arg, rht_obj(ht, he))) | |
635 | continue; | |
ca26893f | 636 | return he; |
02fd97c3 HX |
637 | } |
638 | ||
639 | /* Ensure we see any new tables. */ | |
640 | smp_rmb(); | |
641 | ||
642 | tbl = rht_dereference_rcu(tbl->future_tbl, ht); | |
643 | if (unlikely(tbl)) | |
644 | goto restart; | |
02fd97c3 HX |
645 | |
646 | return NULL; | |
647 | } | |
648 | ||
ca26893f HX |
649 | /** |
650 | * rhashtable_lookup - search hash table | |
651 | * @ht: hash table | |
652 | * @key: the pointer to the key | |
653 | * @params: hash table parameters | |
654 | * | |
655 | * Computes the hash value for the key and traverses the bucket chain looking | |
656 | * for a entry with an identical key. The first matching entry is returned. | |
657 | * | |
658 | * This must only be called under the RCU read lock. | |
659 | * | |
660 | * Returns the first entry on which the compare function returned true. | |
661 | */ | |
662 | static inline void *rhashtable_lookup( | |
663 | struct rhashtable *ht, const void *key, | |
664 | const struct rhashtable_params params) | |
665 | { | |
666 | struct rhash_head *he = __rhashtable_lookup(ht, key, params); | |
667 | ||
668 | return he ? rht_obj(ht, he) : NULL; | |
669 | } | |
670 | ||
671 | /** | |
672 | * rhashtable_lookup_fast - search hash table, without RCU read lock | |
673 | * @ht: hash table | |
674 | * @key: the pointer to the key | |
675 | * @params: hash table parameters | |
676 | * | |
677 | * Computes the hash value for the key and traverses the bucket chain looking | |
678 | * for a entry with an identical key. The first matching entry is returned. | |
679 | * | |
680 | * Only use this function when you have other mechanisms guaranteeing | |
681 | * that the object won't go away after the RCU read lock is released. | |
682 | * | |
683 | * Returns the first entry on which the compare function returned true. | |
684 | */ | |
685 | static inline void *rhashtable_lookup_fast( | |
686 | struct rhashtable *ht, const void *key, | |
687 | const struct rhashtable_params params) | |
688 | { | |
689 | void *obj; | |
690 | ||
691 | rcu_read_lock(); | |
692 | obj = rhashtable_lookup(ht, key, params); | |
693 | rcu_read_unlock(); | |
694 | ||
695 | return obj; | |
696 | } | |
697 | ||
698 | /** | |
699 | * rhltable_lookup - search hash list table | |
700 | * @hlt: hash table | |
701 | * @key: the pointer to the key | |
702 | * @params: hash table parameters | |
703 | * | |
704 | * Computes the hash value for the key and traverses the bucket chain looking | |
705 | * for a entry with an identical key. All matching entries are returned | |
706 | * in a list. | |
707 | * | |
708 | * This must only be called under the RCU read lock. | |
709 | * | |
710 | * Returns the list of entries that match the given key. | |
711 | */ | |
712 | static inline struct rhlist_head *rhltable_lookup( | |
713 | struct rhltable *hlt, const void *key, | |
714 | const struct rhashtable_params params) | |
715 | { | |
716 | struct rhash_head *he = __rhashtable_lookup(&hlt->ht, key, params); | |
717 | ||
718 | return he ? container_of(he, struct rhlist_head, rhead) : NULL; | |
719 | } | |
720 | ||
5ca8cc5b PNA |
721 | /* Internal function, please use rhashtable_insert_fast() instead. This |
722 | * function returns the existing element already in hashes in there is a clash, | |
723 | * otherwise it returns an error via ERR_PTR(). | |
724 | */ | |
725 | static inline void *__rhashtable_insert_fast( | |
02fd97c3 | 726 | struct rhashtable *ht, const void *key, struct rhash_head *obj, |
ca26893f | 727 | const struct rhashtable_params params, bool rhlist) |
02fd97c3 HX |
728 | { |
729 | struct rhashtable_compare_arg arg = { | |
730 | .ht = ht, | |
731 | .key = key, | |
732 | }; | |
ca26893f HX |
733 | struct rhash_head __rcu **pprev; |
734 | struct bucket_table *tbl; | |
02fd97c3 HX |
735 | struct rhash_head *head; |
736 | spinlock_t *lock; | |
299e5c32 | 737 | unsigned int hash; |
ca26893f HX |
738 | int elasticity; |
739 | void *data; | |
02fd97c3 HX |
740 | |
741 | rcu_read_lock(); | |
742 | ||
743 | tbl = rht_dereference_rcu(ht->tbl, ht); | |
ca26893f HX |
744 | hash = rht_head_hashfn(ht, tbl, obj, params); |
745 | lock = rht_bucket_lock(tbl, hash); | |
746 | spin_lock_bh(lock); | |
02fd97c3 | 747 | |
ca26893f HX |
748 | if (unlikely(rht_dereference_bucket(tbl->future_tbl, tbl, hash))) { |
749 | slow_path: | |
b824478b | 750 | spin_unlock_bh(lock); |
ca26893f HX |
751 | rcu_read_unlock(); |
752 | return rhashtable_insert_slow(ht, key, obj); | |
b824478b HX |
753 | } |
754 | ||
5f8ddeab | 755 | elasticity = RHT_ELASTICITY; |
da20420f HX |
756 | pprev = rht_bucket_insert(ht, tbl, hash); |
757 | data = ERR_PTR(-ENOMEM); | |
758 | if (!pprev) | |
759 | goto out; | |
760 | ||
761 | rht_for_each_continue(head, *pprev, tbl, hash) { | |
ca26893f HX |
762 | struct rhlist_head *plist; |
763 | struct rhlist_head *list; | |
764 | ||
765 | elasticity--; | |
766 | if (!key || | |
767 | (params.obj_cmpfn ? | |
768 | params.obj_cmpfn(&arg, rht_obj(ht, head)) : | |
769 | rhashtable_compare(&arg, rht_obj(ht, head)))) | |
770 | continue; | |
771 | ||
772 | data = rht_obj(ht, head); | |
3cf92222 | 773 | |
ca26893f HX |
774 | if (!rhlist) |
775 | goto out; | |
5ca8cc5b | 776 | |
02fd97c3 | 777 | |
ca26893f HX |
778 | list = container_of(obj, struct rhlist_head, rhead); |
779 | plist = container_of(head, struct rhlist_head, rhead); | |
07ee0722 | 780 | |
ca26893f HX |
781 | RCU_INIT_POINTER(list->next, plist); |
782 | head = rht_dereference_bucket(head->next, tbl, hash); | |
783 | RCU_INIT_POINTER(list->rhead.next, head); | |
784 | rcu_assign_pointer(*pprev, obj); | |
ccd57b1b | 785 | |
ca26893f | 786 | goto good; |
ccd57b1b | 787 | } |
02fd97c3 | 788 | |
ca26893f HX |
789 | if (elasticity <= 0) |
790 | goto slow_path; | |
791 | ||
792 | data = ERR_PTR(-E2BIG); | |
793 | if (unlikely(rht_grow_above_max(ht, tbl))) | |
794 | goto out; | |
795 | ||
796 | if (unlikely(rht_grow_above_100(ht, tbl))) | |
797 | goto slow_path; | |
02fd97c3 | 798 | |
da20420f | 799 | head = rht_dereference_bucket(*pprev, tbl, hash); |
02fd97c3 HX |
800 | |
801 | RCU_INIT_POINTER(obj->next, head); | |
ca26893f HX |
802 | if (rhlist) { |
803 | struct rhlist_head *list; | |
804 | ||
805 | list = container_of(obj, struct rhlist_head, rhead); | |
806 | RCU_INIT_POINTER(list->next, NULL); | |
807 | } | |
02fd97c3 | 808 | |
da20420f | 809 | rcu_assign_pointer(*pprev, obj); |
02fd97c3 HX |
810 | |
811 | atomic_inc(&ht->nelems); | |
812 | if (rht_grow_above_75(ht, tbl)) | |
813 | schedule_work(&ht->run_work); | |
814 | ||
ca26893f HX |
815 | good: |
816 | data = NULL; | |
817 | ||
02fd97c3 HX |
818 | out: |
819 | spin_unlock_bh(lock); | |
820 | rcu_read_unlock(); | |
821 | ||
ca26893f | 822 | return data; |
02fd97c3 HX |
823 | } |
824 | ||
825 | /** | |
826 | * rhashtable_insert_fast - insert object into hash table | |
827 | * @ht: hash table | |
828 | * @obj: pointer to hash head inside object | |
829 | * @params: hash table parameters | |
830 | * | |
831 | * Will take a per bucket spinlock to protect against mutual mutations | |
832 | * on the same bucket. Multiple insertions may occur in parallel unless | |
833 | * they map to the same bucket lock. | |
834 | * | |
835 | * It is safe to call this function from atomic context. | |
836 | * | |
837 | * Will trigger an automatic deferred table resizing if the size grows | |
838 | * beyond the watermark indicated by grow_decision() which can be passed | |
839 | * to rhashtable_init(). | |
840 | */ | |
841 | static inline int rhashtable_insert_fast( | |
842 | struct rhashtable *ht, struct rhash_head *obj, | |
843 | const struct rhashtable_params params) | |
844 | { | |
5ca8cc5b PNA |
845 | void *ret; |
846 | ||
ca26893f | 847 | ret = __rhashtable_insert_fast(ht, NULL, obj, params, false); |
5ca8cc5b PNA |
848 | if (IS_ERR(ret)) |
849 | return PTR_ERR(ret); | |
850 | ||
851 | return ret == NULL ? 0 : -EEXIST; | |
02fd97c3 HX |
852 | } |
853 | ||
ca26893f HX |
854 | /** |
855 | * rhltable_insert_key - insert object into hash list table | |
856 | * @hlt: hash list table | |
857 | * @key: the pointer to the key | |
858 | * @list: pointer to hash list head inside object | |
859 | * @params: hash table parameters | |
860 | * | |
861 | * Will take a per bucket spinlock to protect against mutual mutations | |
862 | * on the same bucket. Multiple insertions may occur in parallel unless | |
863 | * they map to the same bucket lock. | |
864 | * | |
865 | * It is safe to call this function from atomic context. | |
866 | * | |
867 | * Will trigger an automatic deferred table resizing if the size grows | |
868 | * beyond the watermark indicated by grow_decision() which can be passed | |
869 | * to rhashtable_init(). | |
870 | */ | |
871 | static inline int rhltable_insert_key( | |
872 | struct rhltable *hlt, const void *key, struct rhlist_head *list, | |
873 | const struct rhashtable_params params) | |
874 | { | |
875 | return PTR_ERR(__rhashtable_insert_fast(&hlt->ht, key, &list->rhead, | |
876 | params, true)); | |
877 | } | |
878 | ||
879 | /** | |
880 | * rhltable_insert - insert object into hash list table | |
881 | * @hlt: hash list table | |
882 | * @list: pointer to hash list head inside object | |
883 | * @params: hash table parameters | |
884 | * | |
885 | * Will take a per bucket spinlock to protect against mutual mutations | |
886 | * on the same bucket. Multiple insertions may occur in parallel unless | |
887 | * they map to the same bucket lock. | |
888 | * | |
889 | * It is safe to call this function from atomic context. | |
890 | * | |
891 | * Will trigger an automatic deferred table resizing if the size grows | |
892 | * beyond the watermark indicated by grow_decision() which can be passed | |
893 | * to rhashtable_init(). | |
894 | */ | |
895 | static inline int rhltable_insert( | |
896 | struct rhltable *hlt, struct rhlist_head *list, | |
897 | const struct rhashtable_params params) | |
898 | { | |
899 | const char *key = rht_obj(&hlt->ht, &list->rhead); | |
900 | ||
901 | key += params.key_offset; | |
902 | ||
903 | return rhltable_insert_key(hlt, key, list, params); | |
904 | } | |
905 | ||
02fd97c3 HX |
906 | /** |
907 | * rhashtable_lookup_insert_fast - lookup and insert object into hash table | |
908 | * @ht: hash table | |
909 | * @obj: pointer to hash head inside object | |
910 | * @params: hash table parameters | |
911 | * | |
912 | * Locks down the bucket chain in both the old and new table if a resize | |
913 | * is in progress to ensure that writers can't remove from the old table | |
914 | * and can't insert to the new table during the atomic operation of search | |
915 | * and insertion. Searches for duplicates in both the old and new table if | |
916 | * a resize is in progress. | |
917 | * | |
918 | * This lookup function may only be used for fixed key hash table (key_len | |
919 | * parameter set). It will BUG() if used inappropriately. | |
920 | * | |
921 | * It is safe to call this function from atomic context. | |
922 | * | |
923 | * Will trigger an automatic deferred table resizing if the size grows | |
924 | * beyond the watermark indicated by grow_decision() which can be passed | |
925 | * to rhashtable_init(). | |
926 | */ | |
927 | static inline int rhashtable_lookup_insert_fast( | |
928 | struct rhashtable *ht, struct rhash_head *obj, | |
929 | const struct rhashtable_params params) | |
930 | { | |
931 | const char *key = rht_obj(ht, obj); | |
5ca8cc5b | 932 | void *ret; |
02fd97c3 HX |
933 | |
934 | BUG_ON(ht->p.obj_hashfn); | |
935 | ||
ca26893f HX |
936 | ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params, |
937 | false); | |
5ca8cc5b PNA |
938 | if (IS_ERR(ret)) |
939 | return PTR_ERR(ret); | |
940 | ||
941 | return ret == NULL ? 0 : -EEXIST; | |
02fd97c3 HX |
942 | } |
943 | ||
f9fe1c12 AG |
944 | /** |
945 | * rhashtable_lookup_get_insert_fast - lookup and insert object into hash table | |
946 | * @ht: hash table | |
947 | * @obj: pointer to hash head inside object | |
948 | * @params: hash table parameters | |
949 | * | |
950 | * Just like rhashtable_lookup_insert_fast(), but this function returns the | |
951 | * object if it exists, NULL if it did not and the insertion was successful, | |
952 | * and an ERR_PTR otherwise. | |
953 | */ | |
954 | static inline void *rhashtable_lookup_get_insert_fast( | |
955 | struct rhashtable *ht, struct rhash_head *obj, | |
956 | const struct rhashtable_params params) | |
957 | { | |
958 | const char *key = rht_obj(ht, obj); | |
959 | ||
960 | BUG_ON(ht->p.obj_hashfn); | |
961 | ||
962 | return __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params, | |
963 | false); | |
964 | } | |
965 | ||
02fd97c3 HX |
966 | /** |
967 | * rhashtable_lookup_insert_key - search and insert object to hash table | |
968 | * with explicit key | |
969 | * @ht: hash table | |
970 | * @key: key | |
971 | * @obj: pointer to hash head inside object | |
972 | * @params: hash table parameters | |
973 | * | |
974 | * Locks down the bucket chain in both the old and new table if a resize | |
975 | * is in progress to ensure that writers can't remove from the old table | |
976 | * and can't insert to the new table during the atomic operation of search | |
977 | * and insertion. Searches for duplicates in both the old and new table if | |
978 | * a resize is in progress. | |
979 | * | |
980 | * Lookups may occur in parallel with hashtable mutations and resizing. | |
981 | * | |
982 | * Will trigger an automatic deferred table resizing if the size grows | |
983 | * beyond the watermark indicated by grow_decision() which can be passed | |
984 | * to rhashtable_init(). | |
985 | * | |
986 | * Returns zero on success. | |
987 | */ | |
988 | static inline int rhashtable_lookup_insert_key( | |
989 | struct rhashtable *ht, const void *key, struct rhash_head *obj, | |
990 | const struct rhashtable_params params) | |
5ca8cc5b PNA |
991 | { |
992 | void *ret; | |
993 | ||
994 | BUG_ON(!ht->p.obj_hashfn || !key); | |
995 | ||
ca26893f | 996 | ret = __rhashtable_insert_fast(ht, key, obj, params, false); |
5ca8cc5b PNA |
997 | if (IS_ERR(ret)) |
998 | return PTR_ERR(ret); | |
999 | ||
1000 | return ret == NULL ? 0 : -EEXIST; | |
1001 | } | |
1002 | ||
1003 | /** | |
1004 | * rhashtable_lookup_get_insert_key - lookup and insert object into hash table | |
1005 | * @ht: hash table | |
1006 | * @obj: pointer to hash head inside object | |
1007 | * @params: hash table parameters | |
1008 | * @data: pointer to element data already in hashes | |
1009 | * | |
1010 | * Just like rhashtable_lookup_insert_key(), but this function returns the | |
1011 | * object if it exists, NULL if it does not and the insertion was successful, | |
1012 | * and an ERR_PTR otherwise. | |
1013 | */ | |
1014 | static inline void *rhashtable_lookup_get_insert_key( | |
1015 | struct rhashtable *ht, const void *key, struct rhash_head *obj, | |
1016 | const struct rhashtable_params params) | |
02fd97c3 HX |
1017 | { |
1018 | BUG_ON(!ht->p.obj_hashfn || !key); | |
1019 | ||
ca26893f | 1020 | return __rhashtable_insert_fast(ht, key, obj, params, false); |
02fd97c3 HX |
1021 | } |
1022 | ||
ac833bdd | 1023 | /* Internal function, please use rhashtable_remove_fast() instead */ |
ca26893f | 1024 | static inline int __rhashtable_remove_fast_one( |
02fd97c3 | 1025 | struct rhashtable *ht, struct bucket_table *tbl, |
ca26893f HX |
1026 | struct rhash_head *obj, const struct rhashtable_params params, |
1027 | bool rhlist) | |
02fd97c3 HX |
1028 | { |
1029 | struct rhash_head __rcu **pprev; | |
1030 | struct rhash_head *he; | |
1031 | spinlock_t * lock; | |
299e5c32 | 1032 | unsigned int hash; |
02fd97c3 HX |
1033 | int err = -ENOENT; |
1034 | ||
1035 | hash = rht_head_hashfn(ht, tbl, obj, params); | |
1036 | lock = rht_bucket_lock(tbl, hash); | |
1037 | ||
1038 | spin_lock_bh(lock); | |
1039 | ||
da20420f HX |
1040 | pprev = rht_bucket_var(tbl, hash); |
1041 | rht_for_each_continue(he, *pprev, tbl, hash) { | |
ca26893f HX |
1042 | struct rhlist_head *list; |
1043 | ||
1044 | list = container_of(he, struct rhlist_head, rhead); | |
1045 | ||
02fd97c3 | 1046 | if (he != obj) { |
ca26893f HX |
1047 | struct rhlist_head __rcu **lpprev; |
1048 | ||
02fd97c3 | 1049 | pprev = &he->next; |
ca26893f HX |
1050 | |
1051 | if (!rhlist) | |
1052 | continue; | |
1053 | ||
1054 | do { | |
1055 | lpprev = &list->next; | |
1056 | list = rht_dereference_bucket(list->next, | |
1057 | tbl, hash); | |
1058 | } while (list && obj != &list->rhead); | |
1059 | ||
1060 | if (!list) | |
1061 | continue; | |
1062 | ||
1063 | list = rht_dereference_bucket(list->next, tbl, hash); | |
1064 | RCU_INIT_POINTER(*lpprev, list); | |
1065 | err = 0; | |
1066 | break; | |
02fd97c3 HX |
1067 | } |
1068 | ||
ca26893f HX |
1069 | obj = rht_dereference_bucket(obj->next, tbl, hash); |
1070 | err = 1; | |
1071 | ||
1072 | if (rhlist) { | |
1073 | list = rht_dereference_bucket(list->next, tbl, hash); | |
1074 | if (list) { | |
1075 | RCU_INIT_POINTER(list->rhead.next, obj); | |
1076 | obj = &list->rhead; | |
1077 | err = 0; | |
1078 | } | |
1079 | } | |
1080 | ||
1081 | rcu_assign_pointer(*pprev, obj); | |
02fd97c3 HX |
1082 | break; |
1083 | } | |
1084 | ||
1085 | spin_unlock_bh(lock); | |
1086 | ||
ca26893f HX |
1087 | if (err > 0) { |
1088 | atomic_dec(&ht->nelems); | |
1089 | if (unlikely(ht->p.automatic_shrinking && | |
1090 | rht_shrink_below_30(ht, tbl))) | |
1091 | schedule_work(&ht->run_work); | |
1092 | err = 0; | |
1093 | } | |
1094 | ||
02fd97c3 HX |
1095 | return err; |
1096 | } | |
1097 | ||
ca26893f HX |
1098 | /* Internal function, please use rhashtable_remove_fast() instead */ |
1099 | static inline int __rhashtable_remove_fast( | |
02fd97c3 | 1100 | struct rhashtable *ht, struct rhash_head *obj, |
ca26893f | 1101 | const struct rhashtable_params params, bool rhlist) |
02fd97c3 HX |
1102 | { |
1103 | struct bucket_table *tbl; | |
1104 | int err; | |
1105 | ||
1106 | rcu_read_lock(); | |
1107 | ||
1108 | tbl = rht_dereference_rcu(ht->tbl, ht); | |
1109 | ||
1110 | /* Because we have already taken (and released) the bucket | |
1111 | * lock in old_tbl, if we find that future_tbl is not yet | |
1112 | * visible then that guarantees the entry to still be in | |
1113 | * the old tbl if it exists. | |
1114 | */ | |
ca26893f HX |
1115 | while ((err = __rhashtable_remove_fast_one(ht, tbl, obj, params, |
1116 | rhlist)) && | |
02fd97c3 HX |
1117 | (tbl = rht_dereference_rcu(tbl->future_tbl, ht))) |
1118 | ; | |
1119 | ||
02fd97c3 HX |
1120 | rcu_read_unlock(); |
1121 | ||
1122 | return err; | |
1123 | } | |
1124 | ||
ca26893f HX |
1125 | /** |
1126 | * rhashtable_remove_fast - remove object from hash table | |
1127 | * @ht: hash table | |
1128 | * @obj: pointer to hash head inside object | |
1129 | * @params: hash table parameters | |
1130 | * | |
1131 | * Since the hash chain is single linked, the removal operation needs to | |
1132 | * walk the bucket chain upon removal. The removal operation is thus | |
1133 | * considerable slow if the hash table is not correctly sized. | |
1134 | * | |
1135 | * Will automatically shrink the table via rhashtable_expand() if the | |
1136 | * shrink_decision function specified at rhashtable_init() returns true. | |
1137 | * | |
1138 | * Returns zero on success, -ENOENT if the entry could not be found. | |
1139 | */ | |
1140 | static inline int rhashtable_remove_fast( | |
1141 | struct rhashtable *ht, struct rhash_head *obj, | |
1142 | const struct rhashtable_params params) | |
1143 | { | |
1144 | return __rhashtable_remove_fast(ht, obj, params, false); | |
1145 | } | |
1146 | ||
1147 | /** | |
1148 | * rhltable_remove - remove object from hash list table | |
1149 | * @hlt: hash list table | |
1150 | * @list: pointer to hash list head inside object | |
1151 | * @params: hash table parameters | |
1152 | * | |
1153 | * Since the hash chain is single linked, the removal operation needs to | |
1154 | * walk the bucket chain upon removal. The removal operation is thus | |
1155 | * considerable slow if the hash table is not correctly sized. | |
1156 | * | |
1157 | * Will automatically shrink the table via rhashtable_expand() if the | |
1158 | * shrink_decision function specified at rhashtable_init() returns true. | |
1159 | * | |
1160 | * Returns zero on success, -ENOENT if the entry could not be found. | |
1161 | */ | |
1162 | static inline int rhltable_remove( | |
1163 | struct rhltable *hlt, struct rhlist_head *list, | |
1164 | const struct rhashtable_params params) | |
1165 | { | |
1166 | return __rhashtable_remove_fast(&hlt->ht, &list->rhead, params, true); | |
1167 | } | |
1168 | ||
3502cad7 TH |
1169 | /* Internal function, please use rhashtable_replace_fast() instead */ |
1170 | static inline int __rhashtable_replace_fast( | |
1171 | struct rhashtable *ht, struct bucket_table *tbl, | |
1172 | struct rhash_head *obj_old, struct rhash_head *obj_new, | |
1173 | const struct rhashtable_params params) | |
1174 | { | |
1175 | struct rhash_head __rcu **pprev; | |
1176 | struct rhash_head *he; | |
1177 | spinlock_t *lock; | |
1178 | unsigned int hash; | |
1179 | int err = -ENOENT; | |
1180 | ||
1181 | /* Minimally, the old and new objects must have same hash | |
1182 | * (which should mean identifiers are the same). | |
1183 | */ | |
1184 | hash = rht_head_hashfn(ht, tbl, obj_old, params); | |
1185 | if (hash != rht_head_hashfn(ht, tbl, obj_new, params)) | |
1186 | return -EINVAL; | |
1187 | ||
1188 | lock = rht_bucket_lock(tbl, hash); | |
1189 | ||
1190 | spin_lock_bh(lock); | |
1191 | ||
da20420f HX |
1192 | pprev = rht_bucket_var(tbl, hash); |
1193 | rht_for_each_continue(he, *pprev, tbl, hash) { | |
3502cad7 TH |
1194 | if (he != obj_old) { |
1195 | pprev = &he->next; | |
1196 | continue; | |
1197 | } | |
1198 | ||
1199 | rcu_assign_pointer(obj_new->next, obj_old->next); | |
1200 | rcu_assign_pointer(*pprev, obj_new); | |
1201 | err = 0; | |
1202 | break; | |
1203 | } | |
1204 | ||
1205 | spin_unlock_bh(lock); | |
1206 | ||
1207 | return err; | |
1208 | } | |
1209 | ||
1210 | /** | |
1211 | * rhashtable_replace_fast - replace an object in hash table | |
1212 | * @ht: hash table | |
1213 | * @obj_old: pointer to hash head inside object being replaced | |
1214 | * @obj_new: pointer to hash head inside object which is new | |
1215 | * @params: hash table parameters | |
1216 | * | |
1217 | * Replacing an object doesn't affect the number of elements in the hash table | |
1218 | * or bucket, so we don't need to worry about shrinking or expanding the | |
1219 | * table here. | |
1220 | * | |
1221 | * Returns zero on success, -ENOENT if the entry could not be found, | |
1222 | * -EINVAL if hash is not the same for the old and new objects. | |
1223 | */ | |
1224 | static inline int rhashtable_replace_fast( | |
1225 | struct rhashtable *ht, struct rhash_head *obj_old, | |
1226 | struct rhash_head *obj_new, | |
1227 | const struct rhashtable_params params) | |
1228 | { | |
1229 | struct bucket_table *tbl; | |
1230 | int err; | |
1231 | ||
1232 | rcu_read_lock(); | |
1233 | ||
1234 | tbl = rht_dereference_rcu(ht->tbl, ht); | |
1235 | ||
1236 | /* Because we have already taken (and released) the bucket | |
1237 | * lock in old_tbl, if we find that future_tbl is not yet | |
1238 | * visible then that guarantees the entry to still be in | |
1239 | * the old tbl if it exists. | |
1240 | */ | |
1241 | while ((err = __rhashtable_replace_fast(ht, tbl, obj_old, | |
1242 | obj_new, params)) && | |
1243 | (tbl = rht_dereference_rcu(tbl->future_tbl, ht))) | |
1244 | ; | |
1245 | ||
1246 | rcu_read_unlock(); | |
1247 | ||
1248 | return err; | |
1249 | } | |
1250 | ||
246779dd HX |
1251 | /* Obsolete function, do not use in new code. */ |
1252 | static inline int rhashtable_walk_init(struct rhashtable *ht, | |
1253 | struct rhashtable_iter *iter, gfp_t gfp) | |
1254 | { | |
1255 | rhashtable_walk_enter(ht, iter); | |
1256 | return 0; | |
1257 | } | |
1258 | ||
ca26893f HX |
1259 | /** |
1260 | * rhltable_walk_enter - Initialise an iterator | |
1261 | * @hlt: Table to walk over | |
1262 | * @iter: Hash table Iterator | |
1263 | * | |
1264 | * This function prepares a hash table walk. | |
1265 | * | |
1266 | * Note that if you restart a walk after rhashtable_walk_stop you | |
1267 | * may see the same object twice. Also, you may miss objects if | |
1268 | * there are removals in between rhashtable_walk_stop and the next | |
1269 | * call to rhashtable_walk_start. | |
1270 | * | |
1271 | * For a completely stable walk you should construct your own data | |
1272 | * structure outside the hash table. | |
1273 | * | |
1274 | * This function may sleep so you must not call it from interrupt | |
1275 | * context or with spin locks held. | |
1276 | * | |
1277 | * You must call rhashtable_walk_exit after this function returns. | |
1278 | */ | |
1279 | static inline void rhltable_walk_enter(struct rhltable *hlt, | |
1280 | struct rhashtable_iter *iter) | |
1281 | { | |
1282 | return rhashtable_walk_enter(&hlt->ht, iter); | |
1283 | } | |
1284 | ||
1285 | /** | |
1286 | * rhltable_free_and_destroy - free elements and destroy hash list table | |
1287 | * @hlt: the hash list table to destroy | |
1288 | * @free_fn: callback to release resources of element | |
1289 | * @arg: pointer passed to free_fn | |
1290 | * | |
1291 | * See documentation for rhashtable_free_and_destroy. | |
1292 | */ | |
1293 | static inline void rhltable_free_and_destroy(struct rhltable *hlt, | |
1294 | void (*free_fn)(void *ptr, | |
1295 | void *arg), | |
1296 | void *arg) | |
1297 | { | |
1298 | return rhashtable_free_and_destroy(&hlt->ht, free_fn, arg); | |
1299 | } | |
1300 | ||
1301 | static inline void rhltable_destroy(struct rhltable *hlt) | |
1302 | { | |
1303 | return rhltable_free_and_destroy(hlt, NULL, NULL); | |
1304 | } | |
1305 | ||
7e1e7763 | 1306 | #endif /* _LINUX_RHASHTABLE_H */ |