Commit | Line | Data |
---|---|---|
7e1e7763 TG |
1 | /* |
2 | * Resizable, Scalable, Concurrent Hash Table | |
3 | * | |
02fd97c3 | 4 | * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> |
a5ec68e3 | 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 |
02fd97c3 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 | ||
07ee0722 | 17 | #include <linux/atomic.h> |
7e1e7763 TG |
18 | #include <linux/kernel.h> |
19 | #include <linux/init.h> | |
20 | #include <linux/log2.h> | |
5beb5c90 | 21 | #include <linux/sched.h> |
b2d09103 | 22 | #include <linux/rculist.h> |
7e1e7763 TG |
23 | #include <linux/slab.h> |
24 | #include <linux/vmalloc.h> | |
25 | #include <linux/mm.h> | |
87545899 | 26 | #include <linux/jhash.h> |
7e1e7763 TG |
27 | #include <linux/random.h> |
28 | #include <linux/rhashtable.h> | |
61d7b097 | 29 | #include <linux/err.h> |
6d795413 | 30 | #include <linux/export.h> |
7e1e7763 TG |
31 | |
32 | #define HASH_DEFAULT_SIZE 64UL | |
c2e213cf | 33 | #define HASH_MIN_SIZE 4U |
4cf0b354 | 34 | #define BUCKET_LOCKS_PER_CPU 32UL |
97defe1e | 35 | |
da20420f HX |
36 | union nested_table { |
37 | union nested_table __rcu *table; | |
38 | struct rhash_head __rcu *bucket; | |
39 | }; | |
40 | ||
988dfbd7 | 41 | static u32 head_hashfn(struct rhashtable *ht, |
8d24c0b4 TG |
42 | const struct bucket_table *tbl, |
43 | const struct rhash_head *he) | |
7e1e7763 | 44 | { |
02fd97c3 | 45 | return rht_head_hashfn(ht, tbl, he, ht->p); |
7e1e7763 TG |
46 | } |
47 | ||
a03eaec0 | 48 | #ifdef CONFIG_PROVE_LOCKING |
a03eaec0 | 49 | #define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT)) |
a03eaec0 TG |
50 | |
51 | int lockdep_rht_mutex_is_held(struct rhashtable *ht) | |
52 | { | |
53 | return (debug_locks) ? lockdep_is_held(&ht->mutex) : 1; | |
54 | } | |
55 | EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held); | |
56 | ||
57 | int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash) | |
58 | { | |
02fd97c3 | 59 | spinlock_t *lock = rht_bucket_lock(tbl, hash); |
a03eaec0 TG |
60 | |
61 | return (debug_locks) ? lockdep_is_held(lock) : 1; | |
62 | } | |
63 | EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held); | |
64 | #else | |
65 | #define ASSERT_RHT_MUTEX(HT) | |
a03eaec0 TG |
66 | #endif |
67 | ||
da20420f HX |
68 | static void nested_table_free(union nested_table *ntbl, unsigned int size) |
69 | { | |
70 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
71 | const unsigned int len = 1 << shift; | |
72 | unsigned int i; | |
73 | ||
74 | ntbl = rcu_dereference_raw(ntbl->table); | |
75 | if (!ntbl) | |
76 | return; | |
77 | ||
78 | if (size > len) { | |
79 | size >>= shift; | |
80 | for (i = 0; i < len; i++) | |
81 | nested_table_free(ntbl + i, size); | |
82 | } | |
83 | ||
84 | kfree(ntbl); | |
85 | } | |
86 | ||
87 | static void nested_bucket_table_free(const struct bucket_table *tbl) | |
88 | { | |
89 | unsigned int size = tbl->size >> tbl->nest; | |
90 | unsigned int len = 1 << tbl->nest; | |
91 | union nested_table *ntbl; | |
92 | unsigned int i; | |
93 | ||
94 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
95 | ||
96 | for (i = 0; i < len; i++) | |
97 | nested_table_free(ntbl + i, size); | |
98 | ||
99 | kfree(ntbl); | |
100 | } | |
101 | ||
97defe1e TG |
102 | static void bucket_table_free(const struct bucket_table *tbl) |
103 | { | |
da20420f HX |
104 | if (tbl->nest) |
105 | nested_bucket_table_free(tbl); | |
106 | ||
64e0cd0d | 107 | free_bucket_spinlocks(tbl->locks); |
97defe1e TG |
108 | kvfree(tbl); |
109 | } | |
110 | ||
9d901bc0 HX |
111 | static void bucket_table_free_rcu(struct rcu_head *head) |
112 | { | |
113 | bucket_table_free(container_of(head, struct bucket_table, rcu)); | |
114 | } | |
115 | ||
da20420f HX |
116 | static union nested_table *nested_table_alloc(struct rhashtable *ht, |
117 | union nested_table __rcu **prev, | |
5af68ef7 | 118 | bool leaf) |
da20420f HX |
119 | { |
120 | union nested_table *ntbl; | |
121 | int i; | |
122 | ||
123 | ntbl = rcu_dereference(*prev); | |
124 | if (ntbl) | |
125 | return ntbl; | |
126 | ||
127 | ntbl = kzalloc(PAGE_SIZE, GFP_ATOMIC); | |
128 | ||
5af68ef7 N |
129 | if (ntbl && leaf) { |
130 | for (i = 0; i < PAGE_SIZE / sizeof(ntbl[0]); i++) | |
9b4f64a2 | 131 | INIT_RHT_NULLS_HEAD(ntbl[i].bucket); |
da20420f HX |
132 | } |
133 | ||
134 | rcu_assign_pointer(*prev, ntbl); | |
135 | ||
136 | return ntbl; | |
137 | } | |
138 | ||
139 | static struct bucket_table *nested_bucket_table_alloc(struct rhashtable *ht, | |
140 | size_t nbuckets, | |
141 | gfp_t gfp) | |
142 | { | |
143 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
144 | struct bucket_table *tbl; | |
145 | size_t size; | |
146 | ||
147 | if (nbuckets < (1 << (shift + 1))) | |
148 | return NULL; | |
149 | ||
150 | size = sizeof(*tbl) + sizeof(tbl->buckets[0]); | |
151 | ||
152 | tbl = kzalloc(size, gfp); | |
153 | if (!tbl) | |
154 | return NULL; | |
155 | ||
156 | if (!nested_table_alloc(ht, (union nested_table __rcu **)tbl->buckets, | |
5af68ef7 | 157 | false)) { |
da20420f HX |
158 | kfree(tbl); |
159 | return NULL; | |
160 | } | |
161 | ||
162 | tbl->nest = (ilog2(nbuckets) - 1) % shift + 1; | |
163 | ||
164 | return tbl; | |
165 | } | |
166 | ||
97defe1e | 167 | static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, |
b9ecfdaa HX |
168 | size_t nbuckets, |
169 | gfp_t gfp) | |
7e1e7763 | 170 | { |
eb6d1abf | 171 | struct bucket_table *tbl = NULL; |
64e0cd0d | 172 | size_t size, max_locks; |
f89bd6f8 | 173 | int i; |
7e1e7763 TG |
174 | |
175 | size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]); | |
93f976b5 | 176 | tbl = kvzalloc(size, gfp); |
da20420f HX |
177 | |
178 | size = nbuckets; | |
179 | ||
2d22ecf6 | 180 | if (tbl == NULL && (gfp & ~__GFP_NOFAIL) != GFP_KERNEL) { |
da20420f HX |
181 | tbl = nested_bucket_table_alloc(ht, nbuckets, gfp); |
182 | nbuckets = 0; | |
183 | } | |
2d22ecf6 | 184 | |
7e1e7763 TG |
185 | if (tbl == NULL) |
186 | return NULL; | |
187 | ||
da20420f | 188 | tbl->size = size; |
7e1e7763 | 189 | |
64e0cd0d TH |
190 | max_locks = size >> 1; |
191 | if (tbl->nest) | |
192 | max_locks = min_t(size_t, max_locks, 1U << tbl->nest); | |
193 | ||
194 | if (alloc_bucket_spinlocks(&tbl->locks, &tbl->locks_mask, max_locks, | |
195 | ht->p.locks_mul, gfp) < 0) { | |
97defe1e TG |
196 | bucket_table_free(tbl); |
197 | return NULL; | |
198 | } | |
7e1e7763 | 199 | |
4feb7c7a | 200 | rcu_head_init(&tbl->rcu); |
eddee5ba HX |
201 | INIT_LIST_HEAD(&tbl->walkers); |
202 | ||
d48ad080 | 203 | tbl->hash_rnd = get_random_u32(); |
5269b53d | 204 | |
f89bd6f8 | 205 | for (i = 0; i < nbuckets; i++) |
9b4f64a2 | 206 | INIT_RHT_NULLS_HEAD(tbl->buckets[i]); |
f89bd6f8 | 207 | |
97defe1e | 208 | return tbl; |
7e1e7763 TG |
209 | } |
210 | ||
b824478b HX |
211 | static struct bucket_table *rhashtable_last_table(struct rhashtable *ht, |
212 | struct bucket_table *tbl) | |
213 | { | |
214 | struct bucket_table *new_tbl; | |
215 | ||
216 | do { | |
217 | new_tbl = tbl; | |
218 | tbl = rht_dereference_rcu(tbl->future_tbl, ht); | |
219 | } while (tbl); | |
220 | ||
221 | return new_tbl; | |
222 | } | |
223 | ||
299e5c32 | 224 | static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash) |
a5ec68e3 | 225 | { |
aa34a6cb | 226 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
c0690016 | 227 | struct bucket_table *new_tbl = rhashtable_last_table(ht, old_tbl); |
da20420f HX |
228 | struct rhash_head __rcu **pprev = rht_bucket_var(old_tbl, old_hash); |
229 | int err = -EAGAIN; | |
aa34a6cb HX |
230 | struct rhash_head *head, *next, *entry; |
231 | spinlock_t *new_bucket_lock; | |
299e5c32 | 232 | unsigned int new_hash; |
aa34a6cb | 233 | |
da20420f HX |
234 | if (new_tbl->nest) |
235 | goto out; | |
236 | ||
237 | err = -ENOENT; | |
238 | ||
aa34a6cb HX |
239 | rht_for_each(entry, old_tbl, old_hash) { |
240 | err = 0; | |
241 | next = rht_dereference_bucket(entry->next, old_tbl, old_hash); | |
242 | ||
243 | if (rht_is_a_nulls(next)) | |
244 | break; | |
a5ec68e3 | 245 | |
aa34a6cb HX |
246 | pprev = &entry->next; |
247 | } | |
a5ec68e3 | 248 | |
aa34a6cb HX |
249 | if (err) |
250 | goto out; | |
97defe1e | 251 | |
aa34a6cb | 252 | new_hash = head_hashfn(ht, new_tbl, entry); |
7e1e7763 | 253 | |
02fd97c3 | 254 | new_bucket_lock = rht_bucket_lock(new_tbl, new_hash); |
7e1e7763 | 255 | |
8f2484bd | 256 | spin_lock_nested(new_bucket_lock, SINGLE_DEPTH_NESTING); |
aa34a6cb HX |
257 | head = rht_dereference_bucket(new_tbl->buckets[new_hash], |
258 | new_tbl, new_hash); | |
97defe1e | 259 | |
7def0f95 | 260 | RCU_INIT_POINTER(entry->next, head); |
a5ec68e3 | 261 | |
aa34a6cb HX |
262 | rcu_assign_pointer(new_tbl->buckets[new_hash], entry); |
263 | spin_unlock(new_bucket_lock); | |
97defe1e | 264 | |
aa34a6cb | 265 | rcu_assign_pointer(*pprev, next); |
7e1e7763 | 266 | |
aa34a6cb HX |
267 | out: |
268 | return err; | |
269 | } | |
97defe1e | 270 | |
da20420f | 271 | static int rhashtable_rehash_chain(struct rhashtable *ht, |
299e5c32 | 272 | unsigned int old_hash) |
aa34a6cb HX |
273 | { |
274 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); | |
275 | spinlock_t *old_bucket_lock; | |
da20420f | 276 | int err; |
aa34a6cb | 277 | |
02fd97c3 | 278 | old_bucket_lock = rht_bucket_lock(old_tbl, old_hash); |
a5ec68e3 | 279 | |
aa34a6cb | 280 | spin_lock_bh(old_bucket_lock); |
da20420f | 281 | while (!(err = rhashtable_rehash_one(ht, old_hash))) |
aa34a6cb | 282 | ; |
da20420f | 283 | |
4feb7c7a | 284 | if (err == -ENOENT) |
da20420f | 285 | err = 0; |
4feb7c7a | 286 | |
aa34a6cb | 287 | spin_unlock_bh(old_bucket_lock); |
da20420f HX |
288 | |
289 | return err; | |
97defe1e TG |
290 | } |
291 | ||
b824478b HX |
292 | static int rhashtable_rehash_attach(struct rhashtable *ht, |
293 | struct bucket_table *old_tbl, | |
294 | struct bucket_table *new_tbl) | |
97defe1e | 295 | { |
aa34a6cb HX |
296 | /* Make insertions go into the new, empty table right away. Deletions |
297 | * and lookups will be attempted in both tables until we synchronize. | |
0ad66449 N |
298 | * As cmpxchg() provides strong barriers, we do not need |
299 | * rcu_assign_pointer(). | |
aa34a6cb | 300 | */ |
aa34a6cb | 301 | |
0ad66449 N |
302 | if (cmpxchg(&old_tbl->future_tbl, NULL, new_tbl) != NULL) |
303 | return -EEXIST; | |
b824478b HX |
304 | |
305 | return 0; | |
306 | } | |
307 | ||
308 | static int rhashtable_rehash_table(struct rhashtable *ht) | |
309 | { | |
310 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); | |
311 | struct bucket_table *new_tbl; | |
312 | struct rhashtable_walker *walker; | |
299e5c32 | 313 | unsigned int old_hash; |
da20420f | 314 | int err; |
b824478b HX |
315 | |
316 | new_tbl = rht_dereference(old_tbl->future_tbl, ht); | |
317 | if (!new_tbl) | |
318 | return 0; | |
319 | ||
da20420f HX |
320 | for (old_hash = 0; old_hash < old_tbl->size; old_hash++) { |
321 | err = rhashtable_rehash_chain(ht, old_hash); | |
322 | if (err) | |
323 | return err; | |
ae6da1f5 | 324 | cond_resched(); |
da20420f | 325 | } |
aa34a6cb HX |
326 | |
327 | /* Publish the new table pointer. */ | |
328 | rcu_assign_pointer(ht->tbl, new_tbl); | |
329 | ||
ba7c95ea | 330 | spin_lock(&ht->lock); |
eddee5ba HX |
331 | list_for_each_entry(walker, &old_tbl->walkers, list) |
332 | walker->tbl = NULL; | |
333 | ||
aa34a6cb HX |
334 | /* Wait for readers. All new readers will see the new |
335 | * table, and thus no references to the old table will | |
336 | * remain. | |
4feb7c7a N |
337 | * We do this inside the locked region so that |
338 | * rhashtable_walk_stop() can use rcu_head_after_call_rcu() | |
339 | * to check if it should not re-link the table. | |
aa34a6cb | 340 | */ |
9d901bc0 | 341 | call_rcu(&old_tbl->rcu, bucket_table_free_rcu); |
4feb7c7a | 342 | spin_unlock(&ht->lock); |
b824478b HX |
343 | |
344 | return rht_dereference(new_tbl->future_tbl, ht) ? -EAGAIN : 0; | |
7e1e7763 TG |
345 | } |
346 | ||
da20420f HX |
347 | static int rhashtable_rehash_alloc(struct rhashtable *ht, |
348 | struct bucket_table *old_tbl, | |
349 | unsigned int size) | |
7e1e7763 | 350 | { |
da20420f | 351 | struct bucket_table *new_tbl; |
b824478b | 352 | int err; |
7e1e7763 TG |
353 | |
354 | ASSERT_RHT_MUTEX(ht); | |
355 | ||
da20420f | 356 | new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL); |
7e1e7763 TG |
357 | if (new_tbl == NULL) |
358 | return -ENOMEM; | |
359 | ||
b824478b HX |
360 | err = rhashtable_rehash_attach(ht, old_tbl, new_tbl); |
361 | if (err) | |
362 | bucket_table_free(new_tbl); | |
363 | ||
364 | return err; | |
7e1e7763 | 365 | } |
7e1e7763 TG |
366 | |
367 | /** | |
368 | * rhashtable_shrink - Shrink hash table while allowing concurrent lookups | |
369 | * @ht: the hash table to shrink | |
7e1e7763 | 370 | * |
18093d1c HX |
371 | * This function shrinks the hash table to fit, i.e., the smallest |
372 | * size would not cause it to expand right away automatically. | |
7e1e7763 | 373 | * |
97defe1e TG |
374 | * The caller must ensure that no concurrent resizing occurs by holding |
375 | * ht->mutex. | |
376 | * | |
7e1e7763 TG |
377 | * The caller must ensure that no concurrent table mutations take place. |
378 | * It is however valid to have concurrent lookups if they are RCU protected. | |
97defe1e TG |
379 | * |
380 | * It is valid to have concurrent insertions and deletions protected by per | |
381 | * bucket locks or concurrent RCU protected lookups and traversals. | |
7e1e7763 | 382 | */ |
b824478b | 383 | static int rhashtable_shrink(struct rhashtable *ht) |
7e1e7763 | 384 | { |
da20420f | 385 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
12311959 VN |
386 | unsigned int nelems = atomic_read(&ht->nelems); |
387 | unsigned int size = 0; | |
7e1e7763 | 388 | |
12311959 VN |
389 | if (nelems) |
390 | size = roundup_pow_of_two(nelems * 3 / 2); | |
18093d1c HX |
391 | if (size < ht->p.min_size) |
392 | size = ht->p.min_size; | |
393 | ||
394 | if (old_tbl->size <= size) | |
395 | return 0; | |
396 | ||
b824478b HX |
397 | if (rht_dereference(old_tbl->future_tbl, ht)) |
398 | return -EEXIST; | |
399 | ||
da20420f | 400 | return rhashtable_rehash_alloc(ht, old_tbl, size); |
7e1e7763 | 401 | } |
7e1e7763 | 402 | |
97defe1e TG |
403 | static void rht_deferred_worker(struct work_struct *work) |
404 | { | |
405 | struct rhashtable *ht; | |
406 | struct bucket_table *tbl; | |
b824478b | 407 | int err = 0; |
97defe1e | 408 | |
57699a40 | 409 | ht = container_of(work, struct rhashtable, run_work); |
97defe1e | 410 | mutex_lock(&ht->mutex); |
28134a53 | 411 | |
97defe1e | 412 | tbl = rht_dereference(ht->tbl, ht); |
b824478b | 413 | tbl = rhashtable_last_table(ht, tbl); |
97defe1e | 414 | |
a5b6846f | 415 | if (rht_grow_above_75(ht, tbl)) |
da20420f | 416 | err = rhashtable_rehash_alloc(ht, tbl, tbl->size * 2); |
b5e2c150 | 417 | else if (ht->p.automatic_shrinking && rht_shrink_below_30(ht, tbl)) |
da20420f HX |
418 | err = rhashtable_shrink(ht); |
419 | else if (tbl->nest) | |
420 | err = rhashtable_rehash_alloc(ht, tbl, tbl->size); | |
b824478b | 421 | |
da20420f HX |
422 | if (!err) |
423 | err = rhashtable_rehash_table(ht); | |
b824478b | 424 | |
97defe1e | 425 | mutex_unlock(&ht->mutex); |
b824478b HX |
426 | |
427 | if (err) | |
428 | schedule_work(&ht->run_work); | |
97defe1e TG |
429 | } |
430 | ||
ca26893f HX |
431 | static int rhashtable_insert_rehash(struct rhashtable *ht, |
432 | struct bucket_table *tbl) | |
ccd57b1b HX |
433 | { |
434 | struct bucket_table *old_tbl; | |
435 | struct bucket_table *new_tbl; | |
ccd57b1b HX |
436 | unsigned int size; |
437 | int err; | |
438 | ||
439 | old_tbl = rht_dereference_rcu(ht->tbl, ht); | |
ccd57b1b HX |
440 | |
441 | size = tbl->size; | |
442 | ||
3cf92222 HX |
443 | err = -EBUSY; |
444 | ||
ccd57b1b HX |
445 | if (rht_grow_above_75(ht, tbl)) |
446 | size *= 2; | |
a87b9ebf TG |
447 | /* Do not schedule more than one rehash */ |
448 | else if (old_tbl != tbl) | |
3cf92222 HX |
449 | goto fail; |
450 | ||
451 | err = -ENOMEM; | |
ccd57b1b | 452 | |
93f976b5 | 453 | new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC | __GFP_NOWARN); |
3cf92222 HX |
454 | if (new_tbl == NULL) |
455 | goto fail; | |
ccd57b1b HX |
456 | |
457 | err = rhashtable_rehash_attach(ht, tbl, new_tbl); | |
458 | if (err) { | |
459 | bucket_table_free(new_tbl); | |
460 | if (err == -EEXIST) | |
461 | err = 0; | |
462 | } else | |
463 | schedule_work(&ht->run_work); | |
464 | ||
465 | return err; | |
3cf92222 HX |
466 | |
467 | fail: | |
468 | /* Do not fail the insert if someone else did a rehash. */ | |
c0690016 | 469 | if (likely(rcu_access_pointer(tbl->future_tbl))) |
3cf92222 HX |
470 | return 0; |
471 | ||
472 | /* Schedule async rehash to retry allocation in process context. */ | |
473 | if (err == -ENOMEM) | |
474 | schedule_work(&ht->run_work); | |
475 | ||
476 | return err; | |
ccd57b1b | 477 | } |
ccd57b1b | 478 | |
ca26893f HX |
479 | static void *rhashtable_lookup_one(struct rhashtable *ht, |
480 | struct bucket_table *tbl, unsigned int hash, | |
481 | const void *key, struct rhash_head *obj) | |
02fd97c3 | 482 | { |
ca26893f HX |
483 | struct rhashtable_compare_arg arg = { |
484 | .ht = ht, | |
485 | .key = key, | |
486 | }; | |
487 | struct rhash_head __rcu **pprev; | |
02fd97c3 | 488 | struct rhash_head *head; |
ca26893f | 489 | int elasticity; |
02fd97c3 | 490 | |
5f8ddeab | 491 | elasticity = RHT_ELASTICITY; |
da20420f | 492 | pprev = rht_bucket_var(tbl, hash); |
f7ad68bf | 493 | rht_for_each_from(head, *pprev, tbl, hash) { |
ca26893f HX |
494 | struct rhlist_head *list; |
495 | struct rhlist_head *plist; | |
496 | ||
497 | elasticity--; | |
498 | if (!key || | |
499 | (ht->p.obj_cmpfn ? | |
500 | ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) : | |
d3dcf8eb PB |
501 | rhashtable_compare(&arg, rht_obj(ht, head)))) { |
502 | pprev = &head->next; | |
ca26893f | 503 | continue; |
d3dcf8eb | 504 | } |
ca26893f HX |
505 | |
506 | if (!ht->rhlist) | |
507 | return rht_obj(ht, head); | |
508 | ||
509 | list = container_of(obj, struct rhlist_head, rhead); | |
510 | plist = container_of(head, struct rhlist_head, rhead); | |
511 | ||
512 | RCU_INIT_POINTER(list->next, plist); | |
513 | head = rht_dereference_bucket(head->next, tbl, hash); | |
514 | RCU_INIT_POINTER(list->rhead.next, head); | |
515 | rcu_assign_pointer(*pprev, obj); | |
516 | ||
517 | return NULL; | |
5ca8cc5b | 518 | } |
02fd97c3 | 519 | |
ca26893f HX |
520 | if (elasticity <= 0) |
521 | return ERR_PTR(-EAGAIN); | |
522 | ||
523 | return ERR_PTR(-ENOENT); | |
524 | } | |
525 | ||
526 | static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht, | |
527 | struct bucket_table *tbl, | |
528 | unsigned int hash, | |
529 | struct rhash_head *obj, | |
530 | void *data) | |
531 | { | |
da20420f | 532 | struct rhash_head __rcu **pprev; |
ca26893f HX |
533 | struct bucket_table *new_tbl; |
534 | struct rhash_head *head; | |
535 | ||
536 | if (!IS_ERR_OR_NULL(data)) | |
537 | return ERR_PTR(-EEXIST); | |
07ee0722 | 538 | |
ca26893f HX |
539 | if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT) |
540 | return ERR_CAST(data); | |
ccd57b1b | 541 | |
c0690016 | 542 | new_tbl = rht_dereference_rcu(tbl->future_tbl, ht); |
ca26893f HX |
543 | if (new_tbl) |
544 | return new_tbl; | |
545 | ||
546 | if (PTR_ERR(data) != -ENOENT) | |
547 | return ERR_CAST(data); | |
548 | ||
549 | if (unlikely(rht_grow_above_max(ht, tbl))) | |
550 | return ERR_PTR(-E2BIG); | |
551 | ||
552 | if (unlikely(rht_grow_above_100(ht, tbl))) | |
553 | return ERR_PTR(-EAGAIN); | |
02fd97c3 | 554 | |
da20420f HX |
555 | pprev = rht_bucket_insert(ht, tbl, hash); |
556 | if (!pprev) | |
557 | return ERR_PTR(-ENOMEM); | |
558 | ||
559 | head = rht_dereference_bucket(*pprev, tbl, hash); | |
02fd97c3 HX |
560 | |
561 | RCU_INIT_POINTER(obj->next, head); | |
ca26893f HX |
562 | if (ht->rhlist) { |
563 | struct rhlist_head *list; | |
564 | ||
565 | list = container_of(obj, struct rhlist_head, rhead); | |
566 | RCU_INIT_POINTER(list->next, NULL); | |
567 | } | |
02fd97c3 | 568 | |
da20420f | 569 | rcu_assign_pointer(*pprev, obj); |
02fd97c3 HX |
570 | |
571 | atomic_inc(&ht->nelems); | |
ca26893f HX |
572 | if (rht_grow_above_75(ht, tbl)) |
573 | schedule_work(&ht->run_work); | |
02fd97c3 | 574 | |
ca26893f HX |
575 | return NULL; |
576 | } | |
02fd97c3 | 577 | |
ca26893f HX |
578 | static void *rhashtable_try_insert(struct rhashtable *ht, const void *key, |
579 | struct rhash_head *obj) | |
580 | { | |
581 | struct bucket_table *new_tbl; | |
582 | struct bucket_table *tbl; | |
583 | unsigned int hash; | |
ca26893f HX |
584 | void *data; |
585 | ||
4feb7c7a | 586 | new_tbl = rcu_dereference(ht->tbl); |
ca26893f | 587 | |
4feb7c7a | 588 | do { |
ca26893f HX |
589 | tbl = new_tbl; |
590 | hash = rht_head_hashfn(ht, tbl, obj, ht->p); | |
4feb7c7a | 591 | spin_lock_bh(rht_bucket_lock(tbl, hash)); |
ca26893f HX |
592 | |
593 | data = rhashtable_lookup_one(ht, tbl, hash, key, obj); | |
594 | new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data); | |
595 | if (PTR_ERR(new_tbl) != -EEXIST) | |
596 | data = ERR_CAST(new_tbl); | |
597 | ||
4feb7c7a N |
598 | spin_unlock_bh(rht_bucket_lock(tbl, hash)); |
599 | } while (!IS_ERR_OR_NULL(new_tbl)); | |
ca26893f HX |
600 | |
601 | if (PTR_ERR(data) == -EAGAIN) | |
602 | data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?: | |
603 | -EAGAIN); | |
604 | ||
605 | return data; | |
606 | } | |
607 | ||
608 | void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, | |
609 | struct rhash_head *obj) | |
610 | { | |
611 | void *data; | |
612 | ||
613 | do { | |
614 | rcu_read_lock(); | |
615 | data = rhashtable_try_insert(ht, key, obj); | |
616 | rcu_read_unlock(); | |
617 | } while (PTR_ERR(data) == -EAGAIN); | |
618 | ||
619 | return data; | |
02fd97c3 HX |
620 | } |
621 | EXPORT_SYMBOL_GPL(rhashtable_insert_slow); | |
622 | ||
f2dba9c6 | 623 | /** |
246779dd | 624 | * rhashtable_walk_enter - Initialise an iterator |
f2dba9c6 HX |
625 | * @ht: Table to walk over |
626 | * @iter: Hash table Iterator | |
627 | * | |
628 | * This function prepares a hash table walk. | |
629 | * | |
630 | * Note that if you restart a walk after rhashtable_walk_stop you | |
631 | * may see the same object twice. Also, you may miss objects if | |
632 | * there are removals in between rhashtable_walk_stop and the next | |
633 | * call to rhashtable_walk_start. | |
634 | * | |
635 | * For a completely stable walk you should construct your own data | |
636 | * structure outside the hash table. | |
637 | * | |
82266e98 N |
638 | * This function may be called from any process context, including |
639 | * non-preemptable context, but cannot be called from softirq or | |
640 | * hardirq context. | |
f2dba9c6 | 641 | * |
246779dd | 642 | * You must call rhashtable_walk_exit after this function returns. |
f2dba9c6 | 643 | */ |
246779dd | 644 | void rhashtable_walk_enter(struct rhashtable *ht, struct rhashtable_iter *iter) |
f2dba9c6 HX |
645 | { |
646 | iter->ht = ht; | |
647 | iter->p = NULL; | |
648 | iter->slot = 0; | |
649 | iter->skip = 0; | |
2db54b47 | 650 | iter->end_of_table = 0; |
f2dba9c6 | 651 | |
c6ff5268 | 652 | spin_lock(&ht->lock); |
246779dd | 653 | iter->walker.tbl = |
179ccc0a | 654 | rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock)); |
246779dd | 655 | list_add(&iter->walker.list, &iter->walker.tbl->walkers); |
c6ff5268 | 656 | spin_unlock(&ht->lock); |
f2dba9c6 | 657 | } |
246779dd | 658 | EXPORT_SYMBOL_GPL(rhashtable_walk_enter); |
f2dba9c6 HX |
659 | |
660 | /** | |
661 | * rhashtable_walk_exit - Free an iterator | |
662 | * @iter: Hash table Iterator | |
663 | * | |
6c4128f6 | 664 | * This function frees resources allocated by rhashtable_walk_enter. |
f2dba9c6 HX |
665 | */ |
666 | void rhashtable_walk_exit(struct rhashtable_iter *iter) | |
667 | { | |
c6ff5268 | 668 | spin_lock(&iter->ht->lock); |
246779dd HX |
669 | if (iter->walker.tbl) |
670 | list_del(&iter->walker.list); | |
c6ff5268 | 671 | spin_unlock(&iter->ht->lock); |
f2dba9c6 HX |
672 | } |
673 | EXPORT_SYMBOL_GPL(rhashtable_walk_exit); | |
674 | ||
675 | /** | |
97a6ec4a | 676 | * rhashtable_walk_start_check - Start a hash table walk |
f2dba9c6 HX |
677 | * @iter: Hash table iterator |
678 | * | |
0647169c AG |
679 | * Start a hash table walk at the current iterator position. Note that we take |
680 | * the RCU lock in all cases including when we return an error. So you must | |
681 | * always call rhashtable_walk_stop to clean up. | |
f2dba9c6 HX |
682 | * |
683 | * Returns zero if successful. | |
684 | * | |
685 | * Returns -EAGAIN if resize event occured. Note that the iterator | |
686 | * will rewind back to the beginning and you may use it immediately | |
687 | * by calling rhashtable_walk_next. | |
97a6ec4a TH |
688 | * |
689 | * rhashtable_walk_start is defined as an inline variant that returns | |
690 | * void. This is preferred in cases where the caller would ignore | |
691 | * resize events and always continue. | |
f2dba9c6 | 692 | */ |
97a6ec4a | 693 | int rhashtable_walk_start_check(struct rhashtable_iter *iter) |
db4374f4 | 694 | __acquires(RCU) |
f2dba9c6 | 695 | { |
eddee5ba | 696 | struct rhashtable *ht = iter->ht; |
5d240a89 | 697 | bool rhlist = ht->rhlist; |
eddee5ba | 698 | |
c6ff5268 | 699 | rcu_read_lock(); |
eddee5ba | 700 | |
c6ff5268 | 701 | spin_lock(&ht->lock); |
246779dd HX |
702 | if (iter->walker.tbl) |
703 | list_del(&iter->walker.list); | |
c6ff5268 | 704 | spin_unlock(&ht->lock); |
eddee5ba | 705 | |
5d240a89 N |
706 | if (iter->end_of_table) |
707 | return 0; | |
708 | if (!iter->walker.tbl) { | |
246779dd | 709 | iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht); |
b41cc04b N |
710 | iter->slot = 0; |
711 | iter->skip = 0; | |
f2dba9c6 HX |
712 | return -EAGAIN; |
713 | } | |
714 | ||
5d240a89 N |
715 | if (iter->p && !rhlist) { |
716 | /* | |
717 | * We need to validate that 'p' is still in the table, and | |
718 | * if so, update 'skip' | |
719 | */ | |
720 | struct rhash_head *p; | |
721 | int skip = 0; | |
722 | rht_for_each_rcu(p, iter->walker.tbl, iter->slot) { | |
723 | skip++; | |
724 | if (p == iter->p) { | |
725 | iter->skip = skip; | |
726 | goto found; | |
727 | } | |
728 | } | |
729 | iter->p = NULL; | |
730 | } else if (iter->p && rhlist) { | |
731 | /* Need to validate that 'list' is still in the table, and | |
732 | * if so, update 'skip' and 'p'. | |
733 | */ | |
734 | struct rhash_head *p; | |
735 | struct rhlist_head *list; | |
736 | int skip = 0; | |
737 | rht_for_each_rcu(p, iter->walker.tbl, iter->slot) { | |
738 | for (list = container_of(p, struct rhlist_head, rhead); | |
739 | list; | |
740 | list = rcu_dereference(list->next)) { | |
741 | skip++; | |
742 | if (list == iter->list) { | |
743 | iter->p = p; | |
c643ecf3 | 744 | iter->skip = skip; |
5d240a89 N |
745 | goto found; |
746 | } | |
747 | } | |
748 | } | |
749 | iter->p = NULL; | |
750 | } | |
751 | found: | |
f2dba9c6 HX |
752 | return 0; |
753 | } | |
97a6ec4a | 754 | EXPORT_SYMBOL_GPL(rhashtable_walk_start_check); |
f2dba9c6 HX |
755 | |
756 | /** | |
2db54b47 TH |
757 | * __rhashtable_walk_find_next - Find the next element in a table (or the first |
758 | * one in case of a new walk). | |
759 | * | |
f2dba9c6 HX |
760 | * @iter: Hash table iterator |
761 | * | |
2db54b47 | 762 | * Returns the found object or NULL when the end of the table is reached. |
f2dba9c6 | 763 | * |
2db54b47 | 764 | * Returns -EAGAIN if resize event occurred. |
f2dba9c6 | 765 | */ |
2db54b47 | 766 | static void *__rhashtable_walk_find_next(struct rhashtable_iter *iter) |
f2dba9c6 | 767 | { |
246779dd | 768 | struct bucket_table *tbl = iter->walker.tbl; |
ca26893f | 769 | struct rhlist_head *list = iter->list; |
f2dba9c6 HX |
770 | struct rhashtable *ht = iter->ht; |
771 | struct rhash_head *p = iter->p; | |
ca26893f | 772 | bool rhlist = ht->rhlist; |
f2dba9c6 | 773 | |
2db54b47 TH |
774 | if (!tbl) |
775 | return NULL; | |
f2dba9c6 HX |
776 | |
777 | for (; iter->slot < tbl->size; iter->slot++) { | |
778 | int skip = iter->skip; | |
779 | ||
780 | rht_for_each_rcu(p, tbl, iter->slot) { | |
ca26893f HX |
781 | if (rhlist) { |
782 | list = container_of(p, struct rhlist_head, | |
783 | rhead); | |
784 | do { | |
785 | if (!skip) | |
786 | goto next; | |
787 | skip--; | |
788 | list = rcu_dereference(list->next); | |
789 | } while (list); | |
790 | ||
791 | continue; | |
792 | } | |
f2dba9c6 HX |
793 | if (!skip) |
794 | break; | |
795 | skip--; | |
796 | } | |
797 | ||
798 | next: | |
799 | if (!rht_is_a_nulls(p)) { | |
800 | iter->skip++; | |
801 | iter->p = p; | |
ca26893f HX |
802 | iter->list = list; |
803 | return rht_obj(ht, rhlist ? &list->rhead : p); | |
f2dba9c6 HX |
804 | } |
805 | ||
806 | iter->skip = 0; | |
807 | } | |
808 | ||
142b942a PS |
809 | iter->p = NULL; |
810 | ||
d88252f9 HX |
811 | /* Ensure we see any new tables. */ |
812 | smp_rmb(); | |
813 | ||
246779dd HX |
814 | iter->walker.tbl = rht_dereference_rcu(tbl->future_tbl, ht); |
815 | if (iter->walker.tbl) { | |
f2dba9c6 HX |
816 | iter->slot = 0; |
817 | iter->skip = 0; | |
f2dba9c6 | 818 | return ERR_PTR(-EAGAIN); |
2db54b47 TH |
819 | } else { |
820 | iter->end_of_table = true; | |
f2dba9c6 HX |
821 | } |
822 | ||
c936a79f | 823 | return NULL; |
f2dba9c6 | 824 | } |
2db54b47 TH |
825 | |
826 | /** | |
827 | * rhashtable_walk_next - Return the next object and advance the iterator | |
828 | * @iter: Hash table iterator | |
829 | * | |
830 | * Note that you must call rhashtable_walk_stop when you are finished | |
831 | * with the walk. | |
832 | * | |
833 | * Returns the next object or NULL when the end of the table is reached. | |
834 | * | |
835 | * Returns -EAGAIN if resize event occurred. Note that the iterator | |
836 | * will rewind back to the beginning and you may continue to use it. | |
837 | */ | |
838 | void *rhashtable_walk_next(struct rhashtable_iter *iter) | |
839 | { | |
840 | struct rhlist_head *list = iter->list; | |
841 | struct rhashtable *ht = iter->ht; | |
842 | struct rhash_head *p = iter->p; | |
843 | bool rhlist = ht->rhlist; | |
844 | ||
845 | if (p) { | |
846 | if (!rhlist || !(list = rcu_dereference(list->next))) { | |
847 | p = rcu_dereference(p->next); | |
848 | list = container_of(p, struct rhlist_head, rhead); | |
849 | } | |
850 | if (!rht_is_a_nulls(p)) { | |
851 | iter->skip++; | |
852 | iter->p = p; | |
853 | iter->list = list; | |
854 | return rht_obj(ht, rhlist ? &list->rhead : p); | |
855 | } | |
856 | ||
857 | /* At the end of this slot, switch to next one and then find | |
858 | * next entry from that point. | |
859 | */ | |
860 | iter->skip = 0; | |
861 | iter->slot++; | |
862 | } | |
863 | ||
864 | return __rhashtable_walk_find_next(iter); | |
865 | } | |
f2dba9c6 HX |
866 | EXPORT_SYMBOL_GPL(rhashtable_walk_next); |
867 | ||
2db54b47 TH |
868 | /** |
869 | * rhashtable_walk_peek - Return the next object but don't advance the iterator | |
870 | * @iter: Hash table iterator | |
871 | * | |
872 | * Returns the next object or NULL when the end of the table is reached. | |
873 | * | |
874 | * Returns -EAGAIN if resize event occurred. Note that the iterator | |
875 | * will rewind back to the beginning and you may continue to use it. | |
876 | */ | |
877 | void *rhashtable_walk_peek(struct rhashtable_iter *iter) | |
878 | { | |
879 | struct rhlist_head *list = iter->list; | |
880 | struct rhashtable *ht = iter->ht; | |
881 | struct rhash_head *p = iter->p; | |
882 | ||
883 | if (p) | |
884 | return rht_obj(ht, ht->rhlist ? &list->rhead : p); | |
885 | ||
886 | /* No object found in current iter, find next one in the table. */ | |
887 | ||
888 | if (iter->skip) { | |
889 | /* A nonzero skip value points to the next entry in the table | |
890 | * beyond that last one that was found. Decrement skip so | |
891 | * we find the current value. __rhashtable_walk_find_next | |
892 | * will restore the original value of skip assuming that | |
893 | * the table hasn't changed. | |
894 | */ | |
895 | iter->skip--; | |
896 | } | |
897 | ||
898 | return __rhashtable_walk_find_next(iter); | |
899 | } | |
900 | EXPORT_SYMBOL_GPL(rhashtable_walk_peek); | |
901 | ||
f2dba9c6 HX |
902 | /** |
903 | * rhashtable_walk_stop - Finish a hash table walk | |
904 | * @iter: Hash table iterator | |
905 | * | |
0647169c AG |
906 | * Finish a hash table walk. Does not reset the iterator to the start of the |
907 | * hash table. | |
f2dba9c6 HX |
908 | */ |
909 | void rhashtable_walk_stop(struct rhashtable_iter *iter) | |
db4374f4 | 910 | __releases(RCU) |
f2dba9c6 | 911 | { |
eddee5ba | 912 | struct rhashtable *ht; |
246779dd | 913 | struct bucket_table *tbl = iter->walker.tbl; |
eddee5ba | 914 | |
eddee5ba | 915 | if (!tbl) |
963ecbd4 | 916 | goto out; |
eddee5ba HX |
917 | |
918 | ht = iter->ht; | |
919 | ||
ba7c95ea | 920 | spin_lock(&ht->lock); |
4feb7c7a N |
921 | if (rcu_head_after_call_rcu(&tbl->rcu, bucket_table_free_rcu)) |
922 | /* This bucket table is being freed, don't re-link it. */ | |
246779dd | 923 | iter->walker.tbl = NULL; |
4feb7c7a N |
924 | else |
925 | list_add(&iter->walker.list, &tbl->walkers); | |
ba7c95ea | 926 | spin_unlock(&ht->lock); |
eddee5ba | 927 | |
963ecbd4 HX |
928 | out: |
929 | rcu_read_unlock(); | |
f2dba9c6 HX |
930 | } |
931 | EXPORT_SYMBOL_GPL(rhashtable_walk_stop); | |
932 | ||
488fb86e | 933 | static size_t rounded_hashtable_size(const struct rhashtable_params *params) |
7e1e7763 | 934 | { |
107d01f5 DB |
935 | size_t retsize; |
936 | ||
937 | if (params->nelem_hint) | |
938 | retsize = max(roundup_pow_of_two(params->nelem_hint * 4 / 3), | |
939 | (unsigned long)params->min_size); | |
940 | else | |
941 | retsize = max(HASH_DEFAULT_SIZE, | |
942 | (unsigned long)params->min_size); | |
943 | ||
944 | return retsize; | |
7e1e7763 TG |
945 | } |
946 | ||
31ccde2d HX |
947 | static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed) |
948 | { | |
949 | return jhash2(key, length, seed); | |
950 | } | |
951 | ||
7e1e7763 TG |
952 | /** |
953 | * rhashtable_init - initialize a new hash table | |
954 | * @ht: hash table to be initialized | |
955 | * @params: configuration parameters | |
956 | * | |
957 | * Initializes a new hash table based on the provided configuration | |
958 | * parameters. A table can be configured either with a variable or | |
959 | * fixed length key: | |
960 | * | |
961 | * Configuration Example 1: Fixed length keys | |
962 | * struct test_obj { | |
963 | * int key; | |
964 | * void * my_member; | |
965 | * struct rhash_head node; | |
966 | * }; | |
967 | * | |
968 | * struct rhashtable_params params = { | |
969 | * .head_offset = offsetof(struct test_obj, node), | |
970 | * .key_offset = offsetof(struct test_obj, key), | |
971 | * .key_len = sizeof(int), | |
87545899 | 972 | * .hashfn = jhash, |
7e1e7763 TG |
973 | * }; |
974 | * | |
975 | * Configuration Example 2: Variable length keys | |
976 | * struct test_obj { | |
977 | * [...] | |
978 | * struct rhash_head node; | |
979 | * }; | |
980 | * | |
49f7b33e | 981 | * u32 my_hash_fn(const void *data, u32 len, u32 seed) |
7e1e7763 TG |
982 | * { |
983 | * struct test_obj *obj = data; | |
984 | * | |
985 | * return [... hash ...]; | |
986 | * } | |
987 | * | |
988 | * struct rhashtable_params params = { | |
989 | * .head_offset = offsetof(struct test_obj, node), | |
87545899 | 990 | * .hashfn = jhash, |
7e1e7763 | 991 | * .obj_hashfn = my_hash_fn, |
7e1e7763 TG |
992 | * }; |
993 | */ | |
488fb86e HX |
994 | int rhashtable_init(struct rhashtable *ht, |
995 | const struct rhashtable_params *params) | |
7e1e7763 TG |
996 | { |
997 | struct bucket_table *tbl; | |
998 | size_t size; | |
999 | ||
31ccde2d | 1000 | if ((!params->key_len && !params->obj_hashfn) || |
02fd97c3 | 1001 | (params->obj_hashfn && !params->obj_cmpfn)) |
7e1e7763 TG |
1002 | return -EINVAL; |
1003 | ||
97defe1e TG |
1004 | memset(ht, 0, sizeof(*ht)); |
1005 | mutex_init(&ht->mutex); | |
ba7c95ea | 1006 | spin_lock_init(&ht->lock); |
97defe1e TG |
1007 | memcpy(&ht->p, params, sizeof(*params)); |
1008 | ||
a998f712 TG |
1009 | if (params->min_size) |
1010 | ht->p.min_size = roundup_pow_of_two(params->min_size); | |
1011 | ||
6d684e54 HX |
1012 | /* Cap total entries at 2^31 to avoid nelems overflow. */ |
1013 | ht->max_elems = 1u << 31; | |
2d2ab658 HX |
1014 | |
1015 | if (params->max_size) { | |
1016 | ht->p.max_size = rounddown_pow_of_two(params->max_size); | |
1017 | if (ht->p.max_size < ht->max_elems / 2) | |
1018 | ht->max_elems = ht->p.max_size * 2; | |
1019 | } | |
6d684e54 | 1020 | |
48e75b43 | 1021 | ht->p.min_size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE); |
a998f712 | 1022 | |
107d01f5 | 1023 | size = rounded_hashtable_size(&ht->p); |
3a324606 | 1024 | |
97defe1e TG |
1025 | if (params->locks_mul) |
1026 | ht->p.locks_mul = roundup_pow_of_two(params->locks_mul); | |
1027 | else | |
1028 | ht->p.locks_mul = BUCKET_LOCKS_PER_CPU; | |
1029 | ||
31ccde2d HX |
1030 | ht->key_len = ht->p.key_len; |
1031 | if (!params->hashfn) { | |
1032 | ht->p.hashfn = jhash; | |
1033 | ||
1034 | if (!(ht->key_len & (sizeof(u32) - 1))) { | |
1035 | ht->key_len /= sizeof(u32); | |
1036 | ht->p.hashfn = rhashtable_jhash2; | |
1037 | } | |
1038 | } | |
1039 | ||
2d22ecf6 DB |
1040 | /* |
1041 | * This is api initialization and thus we need to guarantee the | |
1042 | * initial rhashtable allocation. Upon failure, retry with the | |
1043 | * smallest possible size with __GFP_NOFAIL semantics. | |
1044 | */ | |
b9ecfdaa | 1045 | tbl = bucket_table_alloc(ht, size, GFP_KERNEL); |
2d22ecf6 DB |
1046 | if (unlikely(tbl == NULL)) { |
1047 | size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE); | |
1048 | tbl = bucket_table_alloc(ht, size, GFP_KERNEL | __GFP_NOFAIL); | |
1049 | } | |
7e1e7763 | 1050 | |
545a148e | 1051 | atomic_set(&ht->nelems, 0); |
a5b6846f | 1052 | |
7e1e7763 TG |
1053 | RCU_INIT_POINTER(ht->tbl, tbl); |
1054 | ||
4c4b52d9 | 1055 | INIT_WORK(&ht->run_work, rht_deferred_worker); |
97defe1e | 1056 | |
7e1e7763 TG |
1057 | return 0; |
1058 | } | |
1059 | EXPORT_SYMBOL_GPL(rhashtable_init); | |
1060 | ||
ca26893f HX |
1061 | /** |
1062 | * rhltable_init - initialize a new hash list table | |
1063 | * @hlt: hash list table to be initialized | |
1064 | * @params: configuration parameters | |
1065 | * | |
1066 | * Initializes a new hash list table. | |
1067 | * | |
1068 | * See documentation for rhashtable_init. | |
1069 | */ | |
1070 | int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params) | |
1071 | { | |
1072 | int err; | |
1073 | ||
ca26893f HX |
1074 | err = rhashtable_init(&hlt->ht, params); |
1075 | hlt->ht.rhlist = true; | |
1076 | return err; | |
1077 | } | |
1078 | EXPORT_SYMBOL_GPL(rhltable_init); | |
1079 | ||
1080 | static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj, | |
1081 | void (*free_fn)(void *ptr, void *arg), | |
1082 | void *arg) | |
1083 | { | |
1084 | struct rhlist_head *list; | |
1085 | ||
1086 | if (!ht->rhlist) { | |
1087 | free_fn(rht_obj(ht, obj), arg); | |
1088 | return; | |
1089 | } | |
1090 | ||
1091 | list = container_of(obj, struct rhlist_head, rhead); | |
1092 | do { | |
1093 | obj = &list->rhead; | |
1094 | list = rht_dereference(list->next, ht); | |
1095 | free_fn(rht_obj(ht, obj), arg); | |
1096 | } while (list); | |
1097 | } | |
1098 | ||
7e1e7763 | 1099 | /** |
6b6f302c | 1100 | * rhashtable_free_and_destroy - free elements and destroy hash table |
7e1e7763 | 1101 | * @ht: the hash table to destroy |
6b6f302c TG |
1102 | * @free_fn: callback to release resources of element |
1103 | * @arg: pointer passed to free_fn | |
7e1e7763 | 1104 | * |
6b6f302c TG |
1105 | * Stops an eventual async resize. If defined, invokes free_fn for each |
1106 | * element to releasal resources. Please note that RCU protected | |
1107 | * readers may still be accessing the elements. Releasing of resources | |
1108 | * must occur in a compatible manner. Then frees the bucket array. | |
1109 | * | |
1110 | * This function will eventually sleep to wait for an async resize | |
1111 | * to complete. The caller is responsible that no further write operations | |
1112 | * occurs in parallel. | |
7e1e7763 | 1113 | */ |
6b6f302c TG |
1114 | void rhashtable_free_and_destroy(struct rhashtable *ht, |
1115 | void (*free_fn)(void *ptr, void *arg), | |
1116 | void *arg) | |
7e1e7763 | 1117 | { |
0026129c | 1118 | struct bucket_table *tbl, *next_tbl; |
6b6f302c | 1119 | unsigned int i; |
97defe1e | 1120 | |
4c4b52d9 | 1121 | cancel_work_sync(&ht->run_work); |
97defe1e | 1122 | |
57699a40 | 1123 | mutex_lock(&ht->mutex); |
6b6f302c | 1124 | tbl = rht_dereference(ht->tbl, ht); |
0026129c | 1125 | restart: |
6b6f302c TG |
1126 | if (free_fn) { |
1127 | for (i = 0; i < tbl->size; i++) { | |
1128 | struct rhash_head *pos, *next; | |
1129 | ||
ae6da1f5 | 1130 | cond_resched(); |
da20420f | 1131 | for (pos = rht_dereference(*rht_bucket(tbl, i), ht), |
6b6f302c TG |
1132 | next = !rht_is_a_nulls(pos) ? |
1133 | rht_dereference(pos->next, ht) : NULL; | |
1134 | !rht_is_a_nulls(pos); | |
1135 | pos = next, | |
1136 | next = !rht_is_a_nulls(pos) ? | |
1137 | rht_dereference(pos->next, ht) : NULL) | |
ca26893f | 1138 | rhashtable_free_one(ht, pos, free_fn, arg); |
6b6f302c TG |
1139 | } |
1140 | } | |
1141 | ||
0026129c | 1142 | next_tbl = rht_dereference(tbl->future_tbl, ht); |
6b6f302c | 1143 | bucket_table_free(tbl); |
0026129c TY |
1144 | if (next_tbl) { |
1145 | tbl = next_tbl; | |
1146 | goto restart; | |
1147 | } | |
97defe1e | 1148 | mutex_unlock(&ht->mutex); |
7e1e7763 | 1149 | } |
6b6f302c TG |
1150 | EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy); |
1151 | ||
1152 | void rhashtable_destroy(struct rhashtable *ht) | |
1153 | { | |
1154 | return rhashtable_free_and_destroy(ht, NULL, NULL); | |
1155 | } | |
7e1e7763 | 1156 | EXPORT_SYMBOL_GPL(rhashtable_destroy); |
da20420f HX |
1157 | |
1158 | struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl, | |
1159 | unsigned int hash) | |
1160 | { | |
1161 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
82208d0d | 1162 | static struct rhash_head __rcu *rhnull; |
da20420f HX |
1163 | unsigned int index = hash & ((1 << tbl->nest) - 1); |
1164 | unsigned int size = tbl->size >> tbl->nest; | |
1165 | unsigned int subhash = hash; | |
1166 | union nested_table *ntbl; | |
1167 | ||
1168 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
c4d2603d | 1169 | ntbl = rht_dereference_bucket_rcu(ntbl[index].table, tbl, hash); |
da20420f HX |
1170 | subhash >>= tbl->nest; |
1171 | ||
1172 | while (ntbl && size > (1 << shift)) { | |
1173 | index = subhash & ((1 << shift) - 1); | |
c4d2603d HX |
1174 | ntbl = rht_dereference_bucket_rcu(ntbl[index].table, |
1175 | tbl, hash); | |
da20420f HX |
1176 | size >>= shift; |
1177 | subhash >>= shift; | |
1178 | } | |
1179 | ||
82208d0d N |
1180 | if (!ntbl) { |
1181 | if (!rhnull) | |
1182 | INIT_RHT_NULLS_HEAD(rhnull); | |
da20420f | 1183 | return &rhnull; |
82208d0d | 1184 | } |
da20420f HX |
1185 | |
1186 | return &ntbl[subhash].bucket; | |
1187 | ||
1188 | } | |
1189 | EXPORT_SYMBOL_GPL(rht_bucket_nested); | |
1190 | ||
1191 | struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht, | |
1192 | struct bucket_table *tbl, | |
1193 | unsigned int hash) | |
1194 | { | |
1195 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
1196 | unsigned int index = hash & ((1 << tbl->nest) - 1); | |
1197 | unsigned int size = tbl->size >> tbl->nest; | |
1198 | union nested_table *ntbl; | |
da20420f HX |
1199 | |
1200 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
1201 | hash >>= tbl->nest; | |
da20420f | 1202 | ntbl = nested_table_alloc(ht, &ntbl[index].table, |
5af68ef7 | 1203 | size <= (1 << shift)); |
da20420f HX |
1204 | |
1205 | while (ntbl && size > (1 << shift)) { | |
1206 | index = hash & ((1 << shift) - 1); | |
1207 | size >>= shift; | |
1208 | hash >>= shift; | |
da20420f | 1209 | ntbl = nested_table_alloc(ht, &ntbl[index].table, |
5af68ef7 | 1210 | size <= (1 << shift)); |
da20420f HX |
1211 | } |
1212 | ||
1213 | if (!ntbl) | |
1214 | return NULL; | |
1215 | ||
1216 | return &ntbl[hash].bucket; | |
1217 | ||
1218 | } | |
1219 | EXPORT_SYMBOL_GPL(rht_bucket_nested_insert); |