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Commit | Line | Data |
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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> |
7e1e7763 TG |
22 | #include <linux/slab.h> |
23 | #include <linux/vmalloc.h> | |
24 | #include <linux/mm.h> | |
87545899 | 25 | #include <linux/jhash.h> |
7e1e7763 TG |
26 | #include <linux/random.h> |
27 | #include <linux/rhashtable.h> | |
61d7b097 | 28 | #include <linux/err.h> |
6d795413 | 29 | #include <linux/export.h> |
7e1e7763 TG |
30 | |
31 | #define HASH_DEFAULT_SIZE 64UL | |
c2e213cf | 32 | #define HASH_MIN_SIZE 4U |
4cf0b354 | 33 | #define BUCKET_LOCKS_PER_CPU 32UL |
97defe1e | 34 | |
da20420f HX |
35 | union nested_table { |
36 | union nested_table __rcu *table; | |
37 | struct rhash_head __rcu *bucket; | |
38 | }; | |
39 | ||
988dfbd7 | 40 | static u32 head_hashfn(struct rhashtable *ht, |
8d24c0b4 TG |
41 | const struct bucket_table *tbl, |
42 | const struct rhash_head *he) | |
7e1e7763 | 43 | { |
02fd97c3 | 44 | return rht_head_hashfn(ht, tbl, he, ht->p); |
7e1e7763 TG |
45 | } |
46 | ||
a03eaec0 | 47 | #ifdef CONFIG_PROVE_LOCKING |
a03eaec0 | 48 | #define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT)) |
a03eaec0 TG |
49 | |
50 | int lockdep_rht_mutex_is_held(struct rhashtable *ht) | |
51 | { | |
52 | return (debug_locks) ? lockdep_is_held(&ht->mutex) : 1; | |
53 | } | |
54 | EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held); | |
55 | ||
56 | int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash) | |
57 | { | |
02fd97c3 | 58 | spinlock_t *lock = rht_bucket_lock(tbl, hash); |
a03eaec0 TG |
59 | |
60 | return (debug_locks) ? lockdep_is_held(lock) : 1; | |
61 | } | |
62 | EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held); | |
63 | #else | |
64 | #define ASSERT_RHT_MUTEX(HT) | |
a03eaec0 TG |
65 | #endif |
66 | ||
67 | ||
b9ecfdaa HX |
68 | static int alloc_bucket_locks(struct rhashtable *ht, struct bucket_table *tbl, |
69 | gfp_t gfp) | |
97defe1e TG |
70 | { |
71 | unsigned int i, size; | |
72 | #if defined(CONFIG_PROVE_LOCKING) | |
73 | unsigned int nr_pcpus = 2; | |
74 | #else | |
75 | unsigned int nr_pcpus = num_possible_cpus(); | |
76 | #endif | |
77 | ||
4cf0b354 | 78 | nr_pcpus = min_t(unsigned int, nr_pcpus, 64UL); |
97defe1e TG |
79 | size = roundup_pow_of_two(nr_pcpus * ht->p.locks_mul); |
80 | ||
a5ec68e3 TG |
81 | /* Never allocate more than 0.5 locks per bucket */ |
82 | size = min_t(unsigned int, size, tbl->size >> 1); | |
97defe1e | 83 | |
da20420f HX |
84 | if (tbl->nest) |
85 | size = min(size, 1U << tbl->nest); | |
86 | ||
97defe1e | 87 | if (sizeof(spinlock_t) != 0) { |
9dbeea7f | 88 | tbl->locks = NULL; |
97defe1e | 89 | #ifdef CONFIG_NUMA |
b9ecfdaa HX |
90 | if (size * sizeof(spinlock_t) > PAGE_SIZE && |
91 | gfp == GFP_KERNEL) | |
97defe1e | 92 | tbl->locks = vmalloc(size * sizeof(spinlock_t)); |
97defe1e | 93 | #endif |
4cf0b354 FW |
94 | if (gfp != GFP_KERNEL) |
95 | gfp |= __GFP_NOWARN | __GFP_NORETRY; | |
96 | ||
9dbeea7f ED |
97 | if (!tbl->locks) |
98 | tbl->locks = kmalloc_array(size, sizeof(spinlock_t), | |
99 | gfp); | |
97defe1e TG |
100 | if (!tbl->locks) |
101 | return -ENOMEM; | |
102 | for (i = 0; i < size; i++) | |
103 | spin_lock_init(&tbl->locks[i]); | |
104 | } | |
105 | tbl->locks_mask = size - 1; | |
106 | ||
107 | return 0; | |
108 | } | |
109 | ||
da20420f HX |
110 | static void nested_table_free(union nested_table *ntbl, unsigned int size) |
111 | { | |
112 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
113 | const unsigned int len = 1 << shift; | |
114 | unsigned int i; | |
115 | ||
116 | ntbl = rcu_dereference_raw(ntbl->table); | |
117 | if (!ntbl) | |
118 | return; | |
119 | ||
120 | if (size > len) { | |
121 | size >>= shift; | |
122 | for (i = 0; i < len; i++) | |
123 | nested_table_free(ntbl + i, size); | |
124 | } | |
125 | ||
126 | kfree(ntbl); | |
127 | } | |
128 | ||
129 | static void nested_bucket_table_free(const struct bucket_table *tbl) | |
130 | { | |
131 | unsigned int size = tbl->size >> tbl->nest; | |
132 | unsigned int len = 1 << tbl->nest; | |
133 | union nested_table *ntbl; | |
134 | unsigned int i; | |
135 | ||
136 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
137 | ||
138 | for (i = 0; i < len; i++) | |
139 | nested_table_free(ntbl + i, size); | |
140 | ||
141 | kfree(ntbl); | |
142 | } | |
143 | ||
97defe1e TG |
144 | static void bucket_table_free(const struct bucket_table *tbl) |
145 | { | |
da20420f HX |
146 | if (tbl->nest) |
147 | nested_bucket_table_free(tbl); | |
148 | ||
ca435407 | 149 | kvfree(tbl->locks); |
97defe1e TG |
150 | kvfree(tbl); |
151 | } | |
152 | ||
9d901bc0 HX |
153 | static void bucket_table_free_rcu(struct rcu_head *head) |
154 | { | |
155 | bucket_table_free(container_of(head, struct bucket_table, rcu)); | |
156 | } | |
157 | ||
da20420f HX |
158 | static union nested_table *nested_table_alloc(struct rhashtable *ht, |
159 | union nested_table __rcu **prev, | |
160 | unsigned int shifted, | |
161 | unsigned int nhash) | |
162 | { | |
163 | union nested_table *ntbl; | |
164 | int i; | |
165 | ||
166 | ntbl = rcu_dereference(*prev); | |
167 | if (ntbl) | |
168 | return ntbl; | |
169 | ||
170 | ntbl = kzalloc(PAGE_SIZE, GFP_ATOMIC); | |
171 | ||
172 | if (ntbl && shifted) { | |
173 | for (i = 0; i < PAGE_SIZE / sizeof(ntbl[0].bucket); i++) | |
174 | INIT_RHT_NULLS_HEAD(ntbl[i].bucket, ht, | |
175 | (i << shifted) | nhash); | |
176 | } | |
177 | ||
178 | rcu_assign_pointer(*prev, ntbl); | |
179 | ||
180 | return ntbl; | |
181 | } | |
182 | ||
183 | static struct bucket_table *nested_bucket_table_alloc(struct rhashtable *ht, | |
184 | size_t nbuckets, | |
185 | gfp_t gfp) | |
186 | { | |
187 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
188 | struct bucket_table *tbl; | |
189 | size_t size; | |
190 | ||
191 | if (nbuckets < (1 << (shift + 1))) | |
192 | return NULL; | |
193 | ||
194 | size = sizeof(*tbl) + sizeof(tbl->buckets[0]); | |
195 | ||
196 | tbl = kzalloc(size, gfp); | |
197 | if (!tbl) | |
198 | return NULL; | |
199 | ||
200 | if (!nested_table_alloc(ht, (union nested_table __rcu **)tbl->buckets, | |
201 | 0, 0)) { | |
202 | kfree(tbl); | |
203 | return NULL; | |
204 | } | |
205 | ||
206 | tbl->nest = (ilog2(nbuckets) - 1) % shift + 1; | |
207 | ||
208 | return tbl; | |
209 | } | |
210 | ||
97defe1e | 211 | static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, |
b9ecfdaa HX |
212 | size_t nbuckets, |
213 | gfp_t gfp) | |
7e1e7763 | 214 | { |
eb6d1abf | 215 | struct bucket_table *tbl = NULL; |
7e1e7763 | 216 | size_t size; |
f89bd6f8 | 217 | int i; |
7e1e7763 TG |
218 | |
219 | size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]); | |
b9ecfdaa HX |
220 | if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER) || |
221 | gfp != GFP_KERNEL) | |
222 | tbl = kzalloc(size, gfp | __GFP_NOWARN | __GFP_NORETRY); | |
223 | if (tbl == NULL && gfp == GFP_KERNEL) | |
7e1e7763 | 224 | tbl = vzalloc(size); |
da20420f HX |
225 | |
226 | size = nbuckets; | |
227 | ||
228 | if (tbl == NULL && gfp != GFP_KERNEL) { | |
229 | tbl = nested_bucket_table_alloc(ht, nbuckets, gfp); | |
230 | nbuckets = 0; | |
231 | } | |
7e1e7763 TG |
232 | if (tbl == NULL) |
233 | return NULL; | |
234 | ||
da20420f | 235 | tbl->size = size; |
7e1e7763 | 236 | |
b9ecfdaa | 237 | if (alloc_bucket_locks(ht, tbl, gfp) < 0) { |
97defe1e TG |
238 | bucket_table_free(tbl); |
239 | return NULL; | |
240 | } | |
7e1e7763 | 241 | |
eddee5ba HX |
242 | INIT_LIST_HEAD(&tbl->walkers); |
243 | ||
5269b53d HX |
244 | get_random_bytes(&tbl->hash_rnd, sizeof(tbl->hash_rnd)); |
245 | ||
f89bd6f8 TG |
246 | for (i = 0; i < nbuckets; i++) |
247 | INIT_RHT_NULLS_HEAD(tbl->buckets[i], ht, i); | |
248 | ||
97defe1e | 249 | return tbl; |
7e1e7763 TG |
250 | } |
251 | ||
b824478b HX |
252 | static struct bucket_table *rhashtable_last_table(struct rhashtable *ht, |
253 | struct bucket_table *tbl) | |
254 | { | |
255 | struct bucket_table *new_tbl; | |
256 | ||
257 | do { | |
258 | new_tbl = tbl; | |
259 | tbl = rht_dereference_rcu(tbl->future_tbl, ht); | |
260 | } while (tbl); | |
261 | ||
262 | return new_tbl; | |
263 | } | |
264 | ||
299e5c32 | 265 | static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash) |
a5ec68e3 | 266 | { |
aa34a6cb | 267 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
b824478b HX |
268 | struct bucket_table *new_tbl = rhashtable_last_table(ht, |
269 | rht_dereference_rcu(old_tbl->future_tbl, ht)); | |
da20420f HX |
270 | struct rhash_head __rcu **pprev = rht_bucket_var(old_tbl, old_hash); |
271 | int err = -EAGAIN; | |
aa34a6cb HX |
272 | struct rhash_head *head, *next, *entry; |
273 | spinlock_t *new_bucket_lock; | |
299e5c32 | 274 | unsigned int new_hash; |
aa34a6cb | 275 | |
da20420f HX |
276 | if (new_tbl->nest) |
277 | goto out; | |
278 | ||
279 | err = -ENOENT; | |
280 | ||
aa34a6cb HX |
281 | rht_for_each(entry, old_tbl, old_hash) { |
282 | err = 0; | |
283 | next = rht_dereference_bucket(entry->next, old_tbl, old_hash); | |
284 | ||
285 | if (rht_is_a_nulls(next)) | |
286 | break; | |
a5ec68e3 | 287 | |
aa34a6cb HX |
288 | pprev = &entry->next; |
289 | } | |
a5ec68e3 | 290 | |
aa34a6cb HX |
291 | if (err) |
292 | goto out; | |
97defe1e | 293 | |
aa34a6cb | 294 | new_hash = head_hashfn(ht, new_tbl, entry); |
7e1e7763 | 295 | |
02fd97c3 | 296 | new_bucket_lock = rht_bucket_lock(new_tbl, new_hash); |
7e1e7763 | 297 | |
8f2484bd | 298 | spin_lock_nested(new_bucket_lock, SINGLE_DEPTH_NESTING); |
aa34a6cb HX |
299 | head = rht_dereference_bucket(new_tbl->buckets[new_hash], |
300 | new_tbl, new_hash); | |
97defe1e | 301 | |
7def0f95 | 302 | RCU_INIT_POINTER(entry->next, head); |
a5ec68e3 | 303 | |
aa34a6cb HX |
304 | rcu_assign_pointer(new_tbl->buckets[new_hash], entry); |
305 | spin_unlock(new_bucket_lock); | |
97defe1e | 306 | |
aa34a6cb | 307 | rcu_assign_pointer(*pprev, next); |
7e1e7763 | 308 | |
aa34a6cb HX |
309 | out: |
310 | return err; | |
311 | } | |
97defe1e | 312 | |
da20420f | 313 | static int rhashtable_rehash_chain(struct rhashtable *ht, |
299e5c32 | 314 | unsigned int old_hash) |
aa34a6cb HX |
315 | { |
316 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); | |
317 | spinlock_t *old_bucket_lock; | |
da20420f | 318 | int err; |
aa34a6cb | 319 | |
02fd97c3 | 320 | old_bucket_lock = rht_bucket_lock(old_tbl, old_hash); |
a5ec68e3 | 321 | |
aa34a6cb | 322 | spin_lock_bh(old_bucket_lock); |
da20420f | 323 | while (!(err = rhashtable_rehash_one(ht, old_hash))) |
aa34a6cb | 324 | ; |
da20420f HX |
325 | |
326 | if (err == -ENOENT) { | |
327 | old_tbl->rehash++; | |
328 | err = 0; | |
329 | } | |
aa34a6cb | 330 | spin_unlock_bh(old_bucket_lock); |
da20420f HX |
331 | |
332 | return err; | |
97defe1e TG |
333 | } |
334 | ||
b824478b HX |
335 | static int rhashtable_rehash_attach(struct rhashtable *ht, |
336 | struct bucket_table *old_tbl, | |
337 | struct bucket_table *new_tbl) | |
97defe1e | 338 | { |
b824478b HX |
339 | /* Protect future_tbl using the first bucket lock. */ |
340 | spin_lock_bh(old_tbl->locks); | |
341 | ||
342 | /* Did somebody beat us to it? */ | |
343 | if (rcu_access_pointer(old_tbl->future_tbl)) { | |
344 | spin_unlock_bh(old_tbl->locks); | |
345 | return -EEXIST; | |
346 | } | |
7cd10db8 | 347 | |
aa34a6cb HX |
348 | /* Make insertions go into the new, empty table right away. Deletions |
349 | * and lookups will be attempted in both tables until we synchronize. | |
aa34a6cb | 350 | */ |
c4db8848 | 351 | rcu_assign_pointer(old_tbl->future_tbl, new_tbl); |
aa34a6cb | 352 | |
b824478b HX |
353 | spin_unlock_bh(old_tbl->locks); |
354 | ||
355 | return 0; | |
356 | } | |
357 | ||
358 | static int rhashtable_rehash_table(struct rhashtable *ht) | |
359 | { | |
360 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); | |
361 | struct bucket_table *new_tbl; | |
362 | struct rhashtable_walker *walker; | |
299e5c32 | 363 | unsigned int old_hash; |
da20420f | 364 | int err; |
b824478b HX |
365 | |
366 | new_tbl = rht_dereference(old_tbl->future_tbl, ht); | |
367 | if (!new_tbl) | |
368 | return 0; | |
369 | ||
da20420f HX |
370 | for (old_hash = 0; old_hash < old_tbl->size; old_hash++) { |
371 | err = rhashtable_rehash_chain(ht, old_hash); | |
372 | if (err) | |
373 | return err; | |
374 | } | |
aa34a6cb HX |
375 | |
376 | /* Publish the new table pointer. */ | |
377 | rcu_assign_pointer(ht->tbl, new_tbl); | |
378 | ||
ba7c95ea | 379 | spin_lock(&ht->lock); |
eddee5ba HX |
380 | list_for_each_entry(walker, &old_tbl->walkers, list) |
381 | walker->tbl = NULL; | |
ba7c95ea | 382 | spin_unlock(&ht->lock); |
eddee5ba | 383 | |
aa34a6cb HX |
384 | /* Wait for readers. All new readers will see the new |
385 | * table, and thus no references to the old table will | |
386 | * remain. | |
387 | */ | |
9d901bc0 | 388 | call_rcu(&old_tbl->rcu, bucket_table_free_rcu); |
b824478b HX |
389 | |
390 | return rht_dereference(new_tbl->future_tbl, ht) ? -EAGAIN : 0; | |
7e1e7763 TG |
391 | } |
392 | ||
da20420f HX |
393 | static int rhashtable_rehash_alloc(struct rhashtable *ht, |
394 | struct bucket_table *old_tbl, | |
395 | unsigned int size) | |
7e1e7763 | 396 | { |
da20420f | 397 | struct bucket_table *new_tbl; |
b824478b | 398 | int err; |
7e1e7763 TG |
399 | |
400 | ASSERT_RHT_MUTEX(ht); | |
401 | ||
da20420f | 402 | new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL); |
7e1e7763 TG |
403 | if (new_tbl == NULL) |
404 | return -ENOMEM; | |
405 | ||
b824478b HX |
406 | err = rhashtable_rehash_attach(ht, old_tbl, new_tbl); |
407 | if (err) | |
408 | bucket_table_free(new_tbl); | |
409 | ||
410 | return err; | |
7e1e7763 | 411 | } |
7e1e7763 TG |
412 | |
413 | /** | |
414 | * rhashtable_shrink - Shrink hash table while allowing concurrent lookups | |
415 | * @ht: the hash table to shrink | |
7e1e7763 | 416 | * |
18093d1c HX |
417 | * This function shrinks the hash table to fit, i.e., the smallest |
418 | * size would not cause it to expand right away automatically. | |
7e1e7763 | 419 | * |
97defe1e TG |
420 | * The caller must ensure that no concurrent resizing occurs by holding |
421 | * ht->mutex. | |
422 | * | |
7e1e7763 TG |
423 | * The caller must ensure that no concurrent table mutations take place. |
424 | * It is however valid to have concurrent lookups if they are RCU protected. | |
97defe1e TG |
425 | * |
426 | * It is valid to have concurrent insertions and deletions protected by per | |
427 | * bucket locks or concurrent RCU protected lookups and traversals. | |
7e1e7763 | 428 | */ |
b824478b | 429 | static int rhashtable_shrink(struct rhashtable *ht) |
7e1e7763 | 430 | { |
da20420f | 431 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
12311959 VN |
432 | unsigned int nelems = atomic_read(&ht->nelems); |
433 | unsigned int size = 0; | |
7e1e7763 | 434 | |
12311959 VN |
435 | if (nelems) |
436 | size = roundup_pow_of_two(nelems * 3 / 2); | |
18093d1c HX |
437 | if (size < ht->p.min_size) |
438 | size = ht->p.min_size; | |
439 | ||
440 | if (old_tbl->size <= size) | |
441 | return 0; | |
442 | ||
b824478b HX |
443 | if (rht_dereference(old_tbl->future_tbl, ht)) |
444 | return -EEXIST; | |
445 | ||
da20420f | 446 | return rhashtable_rehash_alloc(ht, old_tbl, size); |
7e1e7763 | 447 | } |
7e1e7763 | 448 | |
97defe1e TG |
449 | static void rht_deferred_worker(struct work_struct *work) |
450 | { | |
451 | struct rhashtable *ht; | |
452 | struct bucket_table *tbl; | |
b824478b | 453 | int err = 0; |
97defe1e | 454 | |
57699a40 | 455 | ht = container_of(work, struct rhashtable, run_work); |
97defe1e | 456 | mutex_lock(&ht->mutex); |
28134a53 | 457 | |
97defe1e | 458 | tbl = rht_dereference(ht->tbl, ht); |
b824478b | 459 | tbl = rhashtable_last_table(ht, tbl); |
97defe1e | 460 | |
a5b6846f | 461 | if (rht_grow_above_75(ht, tbl)) |
da20420f | 462 | err = rhashtable_rehash_alloc(ht, tbl, tbl->size * 2); |
b5e2c150 | 463 | else if (ht->p.automatic_shrinking && rht_shrink_below_30(ht, tbl)) |
da20420f HX |
464 | err = rhashtable_shrink(ht); |
465 | else if (tbl->nest) | |
466 | err = rhashtable_rehash_alloc(ht, tbl, tbl->size); | |
b824478b | 467 | |
da20420f HX |
468 | if (!err) |
469 | err = rhashtable_rehash_table(ht); | |
b824478b | 470 | |
97defe1e | 471 | mutex_unlock(&ht->mutex); |
b824478b HX |
472 | |
473 | if (err) | |
474 | schedule_work(&ht->run_work); | |
97defe1e TG |
475 | } |
476 | ||
ca26893f HX |
477 | static int rhashtable_insert_rehash(struct rhashtable *ht, |
478 | struct bucket_table *tbl) | |
ccd57b1b HX |
479 | { |
480 | struct bucket_table *old_tbl; | |
481 | struct bucket_table *new_tbl; | |
ccd57b1b HX |
482 | unsigned int size; |
483 | int err; | |
484 | ||
485 | old_tbl = rht_dereference_rcu(ht->tbl, ht); | |
ccd57b1b HX |
486 | |
487 | size = tbl->size; | |
488 | ||
3cf92222 HX |
489 | err = -EBUSY; |
490 | ||
ccd57b1b HX |
491 | if (rht_grow_above_75(ht, tbl)) |
492 | size *= 2; | |
a87b9ebf TG |
493 | /* Do not schedule more than one rehash */ |
494 | else if (old_tbl != tbl) | |
3cf92222 HX |
495 | goto fail; |
496 | ||
497 | err = -ENOMEM; | |
ccd57b1b HX |
498 | |
499 | new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC); | |
3cf92222 HX |
500 | if (new_tbl == NULL) |
501 | goto fail; | |
ccd57b1b HX |
502 | |
503 | err = rhashtable_rehash_attach(ht, tbl, new_tbl); | |
504 | if (err) { | |
505 | bucket_table_free(new_tbl); | |
506 | if (err == -EEXIST) | |
507 | err = 0; | |
508 | } else | |
509 | schedule_work(&ht->run_work); | |
510 | ||
511 | return err; | |
3cf92222 HX |
512 | |
513 | fail: | |
514 | /* Do not fail the insert if someone else did a rehash. */ | |
515 | if (likely(rcu_dereference_raw(tbl->future_tbl))) | |
516 | return 0; | |
517 | ||
518 | /* Schedule async rehash to retry allocation in process context. */ | |
519 | if (err == -ENOMEM) | |
520 | schedule_work(&ht->run_work); | |
521 | ||
522 | return err; | |
ccd57b1b | 523 | } |
ccd57b1b | 524 | |
ca26893f HX |
525 | static void *rhashtable_lookup_one(struct rhashtable *ht, |
526 | struct bucket_table *tbl, unsigned int hash, | |
527 | const void *key, struct rhash_head *obj) | |
02fd97c3 | 528 | { |
ca26893f HX |
529 | struct rhashtable_compare_arg arg = { |
530 | .ht = ht, | |
531 | .key = key, | |
532 | }; | |
533 | struct rhash_head __rcu **pprev; | |
02fd97c3 | 534 | struct rhash_head *head; |
ca26893f | 535 | int elasticity; |
02fd97c3 | 536 | |
ca26893f | 537 | elasticity = ht->elasticity; |
da20420f HX |
538 | pprev = rht_bucket_var(tbl, hash); |
539 | rht_for_each_continue(head, *pprev, tbl, hash) { | |
ca26893f HX |
540 | struct rhlist_head *list; |
541 | struct rhlist_head *plist; | |
542 | ||
543 | elasticity--; | |
544 | if (!key || | |
545 | (ht->p.obj_cmpfn ? | |
546 | ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) : | |
547 | rhashtable_compare(&arg, rht_obj(ht, head)))) | |
548 | continue; | |
549 | ||
550 | if (!ht->rhlist) | |
551 | return rht_obj(ht, head); | |
552 | ||
553 | list = container_of(obj, struct rhlist_head, rhead); | |
554 | plist = container_of(head, struct rhlist_head, rhead); | |
555 | ||
556 | RCU_INIT_POINTER(list->next, plist); | |
557 | head = rht_dereference_bucket(head->next, tbl, hash); | |
558 | RCU_INIT_POINTER(list->rhead.next, head); | |
559 | rcu_assign_pointer(*pprev, obj); | |
560 | ||
561 | return NULL; | |
5ca8cc5b | 562 | } |
02fd97c3 | 563 | |
ca26893f HX |
564 | if (elasticity <= 0) |
565 | return ERR_PTR(-EAGAIN); | |
566 | ||
567 | return ERR_PTR(-ENOENT); | |
568 | } | |
569 | ||
570 | static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht, | |
571 | struct bucket_table *tbl, | |
572 | unsigned int hash, | |
573 | struct rhash_head *obj, | |
574 | void *data) | |
575 | { | |
da20420f | 576 | struct rhash_head __rcu **pprev; |
ca26893f HX |
577 | struct bucket_table *new_tbl; |
578 | struct rhash_head *head; | |
579 | ||
580 | if (!IS_ERR_OR_NULL(data)) | |
581 | return ERR_PTR(-EEXIST); | |
07ee0722 | 582 | |
ca26893f HX |
583 | if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT) |
584 | return ERR_CAST(data); | |
ccd57b1b | 585 | |
ca26893f HX |
586 | new_tbl = rcu_dereference(tbl->future_tbl); |
587 | if (new_tbl) | |
588 | return new_tbl; | |
589 | ||
590 | if (PTR_ERR(data) != -ENOENT) | |
591 | return ERR_CAST(data); | |
592 | ||
593 | if (unlikely(rht_grow_above_max(ht, tbl))) | |
594 | return ERR_PTR(-E2BIG); | |
595 | ||
596 | if (unlikely(rht_grow_above_100(ht, tbl))) | |
597 | return ERR_PTR(-EAGAIN); | |
02fd97c3 | 598 | |
da20420f HX |
599 | pprev = rht_bucket_insert(ht, tbl, hash); |
600 | if (!pprev) | |
601 | return ERR_PTR(-ENOMEM); | |
602 | ||
603 | head = rht_dereference_bucket(*pprev, tbl, hash); | |
02fd97c3 HX |
604 | |
605 | RCU_INIT_POINTER(obj->next, head); | |
ca26893f HX |
606 | if (ht->rhlist) { |
607 | struct rhlist_head *list; | |
608 | ||
609 | list = container_of(obj, struct rhlist_head, rhead); | |
610 | RCU_INIT_POINTER(list->next, NULL); | |
611 | } | |
02fd97c3 | 612 | |
da20420f | 613 | rcu_assign_pointer(*pprev, obj); |
02fd97c3 HX |
614 | |
615 | atomic_inc(&ht->nelems); | |
ca26893f HX |
616 | if (rht_grow_above_75(ht, tbl)) |
617 | schedule_work(&ht->run_work); | |
02fd97c3 | 618 | |
ca26893f HX |
619 | return NULL; |
620 | } | |
02fd97c3 | 621 | |
ca26893f HX |
622 | static void *rhashtable_try_insert(struct rhashtable *ht, const void *key, |
623 | struct rhash_head *obj) | |
624 | { | |
625 | struct bucket_table *new_tbl; | |
626 | struct bucket_table *tbl; | |
627 | unsigned int hash; | |
628 | spinlock_t *lock; | |
629 | void *data; | |
630 | ||
631 | tbl = rcu_dereference(ht->tbl); | |
632 | ||
633 | /* All insertions must grab the oldest table containing | |
634 | * the hashed bucket that is yet to be rehashed. | |
635 | */ | |
636 | for (;;) { | |
637 | hash = rht_head_hashfn(ht, tbl, obj, ht->p); | |
638 | lock = rht_bucket_lock(tbl, hash); | |
639 | spin_lock_bh(lock); | |
640 | ||
641 | if (tbl->rehash <= hash) | |
642 | break; | |
643 | ||
644 | spin_unlock_bh(lock); | |
645 | tbl = rcu_dereference(tbl->future_tbl); | |
646 | } | |
647 | ||
648 | data = rhashtable_lookup_one(ht, tbl, hash, key, obj); | |
649 | new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data); | |
650 | if (PTR_ERR(new_tbl) != -EEXIST) | |
651 | data = ERR_CAST(new_tbl); | |
652 | ||
653 | while (!IS_ERR_OR_NULL(new_tbl)) { | |
654 | tbl = new_tbl; | |
655 | hash = rht_head_hashfn(ht, tbl, obj, ht->p); | |
656 | spin_lock_nested(rht_bucket_lock(tbl, hash), | |
657 | SINGLE_DEPTH_NESTING); | |
658 | ||
659 | data = rhashtable_lookup_one(ht, tbl, hash, key, obj); | |
660 | new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data); | |
661 | if (PTR_ERR(new_tbl) != -EEXIST) | |
662 | data = ERR_CAST(new_tbl); | |
663 | ||
664 | spin_unlock(rht_bucket_lock(tbl, hash)); | |
665 | } | |
666 | ||
667 | spin_unlock_bh(lock); | |
668 | ||
669 | if (PTR_ERR(data) == -EAGAIN) | |
670 | data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?: | |
671 | -EAGAIN); | |
672 | ||
673 | return data; | |
674 | } | |
675 | ||
676 | void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, | |
677 | struct rhash_head *obj) | |
678 | { | |
679 | void *data; | |
680 | ||
681 | do { | |
682 | rcu_read_lock(); | |
683 | data = rhashtable_try_insert(ht, key, obj); | |
684 | rcu_read_unlock(); | |
685 | } while (PTR_ERR(data) == -EAGAIN); | |
686 | ||
687 | return data; | |
02fd97c3 HX |
688 | } |
689 | EXPORT_SYMBOL_GPL(rhashtable_insert_slow); | |
690 | ||
f2dba9c6 | 691 | /** |
246779dd | 692 | * rhashtable_walk_enter - Initialise an iterator |
f2dba9c6 HX |
693 | * @ht: Table to walk over |
694 | * @iter: Hash table Iterator | |
695 | * | |
696 | * This function prepares a hash table walk. | |
697 | * | |
698 | * Note that if you restart a walk after rhashtable_walk_stop you | |
699 | * may see the same object twice. Also, you may miss objects if | |
700 | * there are removals in between rhashtable_walk_stop and the next | |
701 | * call to rhashtable_walk_start. | |
702 | * | |
703 | * For a completely stable walk you should construct your own data | |
704 | * structure outside the hash table. | |
705 | * | |
706 | * This function may sleep so you must not call it from interrupt | |
707 | * context or with spin locks held. | |
708 | * | |
246779dd | 709 | * You must call rhashtable_walk_exit after this function returns. |
f2dba9c6 | 710 | */ |
246779dd | 711 | void rhashtable_walk_enter(struct rhashtable *ht, struct rhashtable_iter *iter) |
f2dba9c6 HX |
712 | { |
713 | iter->ht = ht; | |
714 | iter->p = NULL; | |
715 | iter->slot = 0; | |
716 | iter->skip = 0; | |
717 | ||
c6ff5268 | 718 | spin_lock(&ht->lock); |
246779dd | 719 | iter->walker.tbl = |
179ccc0a | 720 | rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock)); |
246779dd | 721 | list_add(&iter->walker.list, &iter->walker.tbl->walkers); |
c6ff5268 | 722 | spin_unlock(&ht->lock); |
f2dba9c6 | 723 | } |
246779dd | 724 | EXPORT_SYMBOL_GPL(rhashtable_walk_enter); |
f2dba9c6 HX |
725 | |
726 | /** | |
727 | * rhashtable_walk_exit - Free an iterator | |
728 | * @iter: Hash table Iterator | |
729 | * | |
730 | * This function frees resources allocated by rhashtable_walk_init. | |
731 | */ | |
732 | void rhashtable_walk_exit(struct rhashtable_iter *iter) | |
733 | { | |
c6ff5268 | 734 | spin_lock(&iter->ht->lock); |
246779dd HX |
735 | if (iter->walker.tbl) |
736 | list_del(&iter->walker.list); | |
c6ff5268 | 737 | spin_unlock(&iter->ht->lock); |
f2dba9c6 HX |
738 | } |
739 | EXPORT_SYMBOL_GPL(rhashtable_walk_exit); | |
740 | ||
741 | /** | |
742 | * rhashtable_walk_start - Start a hash table walk | |
743 | * @iter: Hash table iterator | |
744 | * | |
745 | * Start a hash table walk. Note that we take the RCU lock in all | |
746 | * cases including when we return an error. So you must always call | |
747 | * rhashtable_walk_stop to clean up. | |
748 | * | |
749 | * Returns zero if successful. | |
750 | * | |
751 | * Returns -EAGAIN if resize event occured. Note that the iterator | |
752 | * will rewind back to the beginning and you may use it immediately | |
753 | * by calling rhashtable_walk_next. | |
754 | */ | |
755 | int rhashtable_walk_start(struct rhashtable_iter *iter) | |
db4374f4 | 756 | __acquires(RCU) |
f2dba9c6 | 757 | { |
eddee5ba HX |
758 | struct rhashtable *ht = iter->ht; |
759 | ||
c6ff5268 | 760 | rcu_read_lock(); |
eddee5ba | 761 | |
c6ff5268 | 762 | spin_lock(&ht->lock); |
246779dd HX |
763 | if (iter->walker.tbl) |
764 | list_del(&iter->walker.list); | |
c6ff5268 | 765 | spin_unlock(&ht->lock); |
eddee5ba | 766 | |
246779dd HX |
767 | if (!iter->walker.tbl) { |
768 | iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht); | |
f2dba9c6 HX |
769 | return -EAGAIN; |
770 | } | |
771 | ||
772 | return 0; | |
773 | } | |
774 | EXPORT_SYMBOL_GPL(rhashtable_walk_start); | |
775 | ||
776 | /** | |
777 | * rhashtable_walk_next - Return the next object and advance the iterator | |
778 | * @iter: Hash table iterator | |
779 | * | |
780 | * Note that you must call rhashtable_walk_stop when you are finished | |
781 | * with the walk. | |
782 | * | |
783 | * Returns the next object or NULL when the end of the table is reached. | |
784 | * | |
785 | * Returns -EAGAIN if resize event occured. Note that the iterator | |
786 | * will rewind back to the beginning and you may continue to use it. | |
787 | */ | |
788 | void *rhashtable_walk_next(struct rhashtable_iter *iter) | |
789 | { | |
246779dd | 790 | struct bucket_table *tbl = iter->walker.tbl; |
ca26893f | 791 | struct rhlist_head *list = iter->list; |
f2dba9c6 HX |
792 | struct rhashtable *ht = iter->ht; |
793 | struct rhash_head *p = iter->p; | |
ca26893f | 794 | bool rhlist = ht->rhlist; |
f2dba9c6 | 795 | |
f2dba9c6 | 796 | if (p) { |
ca26893f HX |
797 | if (!rhlist || !(list = rcu_dereference(list->next))) { |
798 | p = rcu_dereference(p->next); | |
799 | list = container_of(p, struct rhlist_head, rhead); | |
800 | } | |
f2dba9c6 HX |
801 | goto next; |
802 | } | |
803 | ||
804 | for (; iter->slot < tbl->size; iter->slot++) { | |
805 | int skip = iter->skip; | |
806 | ||
807 | rht_for_each_rcu(p, tbl, iter->slot) { | |
ca26893f HX |
808 | if (rhlist) { |
809 | list = container_of(p, struct rhlist_head, | |
810 | rhead); | |
811 | do { | |
812 | if (!skip) | |
813 | goto next; | |
814 | skip--; | |
815 | list = rcu_dereference(list->next); | |
816 | } while (list); | |
817 | ||
818 | continue; | |
819 | } | |
f2dba9c6 HX |
820 | if (!skip) |
821 | break; | |
822 | skip--; | |
823 | } | |
824 | ||
825 | next: | |
826 | if (!rht_is_a_nulls(p)) { | |
827 | iter->skip++; | |
828 | iter->p = p; | |
ca26893f HX |
829 | iter->list = list; |
830 | return rht_obj(ht, rhlist ? &list->rhead : p); | |
f2dba9c6 HX |
831 | } |
832 | ||
833 | iter->skip = 0; | |
834 | } | |
835 | ||
142b942a PS |
836 | iter->p = NULL; |
837 | ||
d88252f9 HX |
838 | /* Ensure we see any new tables. */ |
839 | smp_rmb(); | |
840 | ||
246779dd HX |
841 | iter->walker.tbl = rht_dereference_rcu(tbl->future_tbl, ht); |
842 | if (iter->walker.tbl) { | |
f2dba9c6 HX |
843 | iter->slot = 0; |
844 | iter->skip = 0; | |
f2dba9c6 HX |
845 | return ERR_PTR(-EAGAIN); |
846 | } | |
847 | ||
c936a79f | 848 | return NULL; |
f2dba9c6 HX |
849 | } |
850 | EXPORT_SYMBOL_GPL(rhashtable_walk_next); | |
851 | ||
852 | /** | |
853 | * rhashtable_walk_stop - Finish a hash table walk | |
854 | * @iter: Hash table iterator | |
855 | * | |
856 | * Finish a hash table walk. | |
857 | */ | |
858 | void rhashtable_walk_stop(struct rhashtable_iter *iter) | |
db4374f4 | 859 | __releases(RCU) |
f2dba9c6 | 860 | { |
eddee5ba | 861 | struct rhashtable *ht; |
246779dd | 862 | struct bucket_table *tbl = iter->walker.tbl; |
eddee5ba | 863 | |
eddee5ba | 864 | if (!tbl) |
963ecbd4 | 865 | goto out; |
eddee5ba HX |
866 | |
867 | ht = iter->ht; | |
868 | ||
ba7c95ea | 869 | spin_lock(&ht->lock); |
c4db8848 | 870 | if (tbl->rehash < tbl->size) |
246779dd | 871 | list_add(&iter->walker.list, &tbl->walkers); |
eddee5ba | 872 | else |
246779dd | 873 | iter->walker.tbl = NULL; |
ba7c95ea | 874 | spin_unlock(&ht->lock); |
eddee5ba | 875 | |
f2dba9c6 | 876 | iter->p = NULL; |
963ecbd4 HX |
877 | |
878 | out: | |
879 | rcu_read_unlock(); | |
f2dba9c6 HX |
880 | } |
881 | EXPORT_SYMBOL_GPL(rhashtable_walk_stop); | |
882 | ||
488fb86e | 883 | static size_t rounded_hashtable_size(const struct rhashtable_params *params) |
7e1e7763 | 884 | { |
94000176 | 885 | return max(roundup_pow_of_two(params->nelem_hint * 4 / 3), |
e2e21c1c | 886 | (unsigned long)params->min_size); |
7e1e7763 TG |
887 | } |
888 | ||
31ccde2d HX |
889 | static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed) |
890 | { | |
891 | return jhash2(key, length, seed); | |
892 | } | |
893 | ||
7e1e7763 TG |
894 | /** |
895 | * rhashtable_init - initialize a new hash table | |
896 | * @ht: hash table to be initialized | |
897 | * @params: configuration parameters | |
898 | * | |
899 | * Initializes a new hash table based on the provided configuration | |
900 | * parameters. A table can be configured either with a variable or | |
901 | * fixed length key: | |
902 | * | |
903 | * Configuration Example 1: Fixed length keys | |
904 | * struct test_obj { | |
905 | * int key; | |
906 | * void * my_member; | |
907 | * struct rhash_head node; | |
908 | * }; | |
909 | * | |
910 | * struct rhashtable_params params = { | |
911 | * .head_offset = offsetof(struct test_obj, node), | |
912 | * .key_offset = offsetof(struct test_obj, key), | |
913 | * .key_len = sizeof(int), | |
87545899 | 914 | * .hashfn = jhash, |
f89bd6f8 | 915 | * .nulls_base = (1U << RHT_BASE_SHIFT), |
7e1e7763 TG |
916 | * }; |
917 | * | |
918 | * Configuration Example 2: Variable length keys | |
919 | * struct test_obj { | |
920 | * [...] | |
921 | * struct rhash_head node; | |
922 | * }; | |
923 | * | |
49f7b33e | 924 | * u32 my_hash_fn(const void *data, u32 len, u32 seed) |
7e1e7763 TG |
925 | * { |
926 | * struct test_obj *obj = data; | |
927 | * | |
928 | * return [... hash ...]; | |
929 | * } | |
930 | * | |
931 | * struct rhashtable_params params = { | |
932 | * .head_offset = offsetof(struct test_obj, node), | |
87545899 | 933 | * .hashfn = jhash, |
7e1e7763 | 934 | * .obj_hashfn = my_hash_fn, |
7e1e7763 TG |
935 | * }; |
936 | */ | |
488fb86e HX |
937 | int rhashtable_init(struct rhashtable *ht, |
938 | const struct rhashtable_params *params) | |
7e1e7763 TG |
939 | { |
940 | struct bucket_table *tbl; | |
941 | size_t size; | |
942 | ||
943 | size = HASH_DEFAULT_SIZE; | |
944 | ||
31ccde2d | 945 | if ((!params->key_len && !params->obj_hashfn) || |
02fd97c3 | 946 | (params->obj_hashfn && !params->obj_cmpfn)) |
7e1e7763 TG |
947 | return -EINVAL; |
948 | ||
f89bd6f8 TG |
949 | if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT)) |
950 | return -EINVAL; | |
951 | ||
97defe1e TG |
952 | memset(ht, 0, sizeof(*ht)); |
953 | mutex_init(&ht->mutex); | |
ba7c95ea | 954 | spin_lock_init(&ht->lock); |
97defe1e TG |
955 | memcpy(&ht->p, params, sizeof(*params)); |
956 | ||
a998f712 TG |
957 | if (params->min_size) |
958 | ht->p.min_size = roundup_pow_of_two(params->min_size); | |
959 | ||
960 | if (params->max_size) | |
961 | ht->p.max_size = rounddown_pow_of_two(params->max_size); | |
962 | ||
07ee0722 HX |
963 | if (params->insecure_max_entries) |
964 | ht->p.insecure_max_entries = | |
965 | rounddown_pow_of_two(params->insecure_max_entries); | |
966 | else | |
967 | ht->p.insecure_max_entries = ht->p.max_size * 2; | |
968 | ||
488fb86e | 969 | ht->p.min_size = max(ht->p.min_size, HASH_MIN_SIZE); |
a998f712 | 970 | |
3a324606 HX |
971 | if (params->nelem_hint) |
972 | size = rounded_hashtable_size(&ht->p); | |
973 | ||
27ed44a5 HX |
974 | /* The maximum (not average) chain length grows with the |
975 | * size of the hash table, at a rate of (log N)/(log log N). | |
976 | * The value of 16 is selected so that even if the hash | |
977 | * table grew to 2^32 you would not expect the maximum | |
978 | * chain length to exceed it unless we are under attack | |
979 | * (or extremely unlucky). | |
980 | * | |
981 | * As this limit is only to detect attacks, we don't need | |
982 | * to set it to a lower value as you'd need the chain | |
983 | * length to vastly exceed 16 to have any real effect | |
984 | * on the system. | |
985 | */ | |
ccd57b1b HX |
986 | if (!params->insecure_elasticity) |
987 | ht->elasticity = 16; | |
988 | ||
97defe1e TG |
989 | if (params->locks_mul) |
990 | ht->p.locks_mul = roundup_pow_of_two(params->locks_mul); | |
991 | else | |
992 | ht->p.locks_mul = BUCKET_LOCKS_PER_CPU; | |
993 | ||
31ccde2d HX |
994 | ht->key_len = ht->p.key_len; |
995 | if (!params->hashfn) { | |
996 | ht->p.hashfn = jhash; | |
997 | ||
998 | if (!(ht->key_len & (sizeof(u32) - 1))) { | |
999 | ht->key_len /= sizeof(u32); | |
1000 | ht->p.hashfn = rhashtable_jhash2; | |
1001 | } | |
1002 | } | |
1003 | ||
b9ecfdaa | 1004 | tbl = bucket_table_alloc(ht, size, GFP_KERNEL); |
7e1e7763 TG |
1005 | if (tbl == NULL) |
1006 | return -ENOMEM; | |
1007 | ||
545a148e | 1008 | atomic_set(&ht->nelems, 0); |
a5b6846f | 1009 | |
7e1e7763 TG |
1010 | RCU_INIT_POINTER(ht->tbl, tbl); |
1011 | ||
4c4b52d9 | 1012 | INIT_WORK(&ht->run_work, rht_deferred_worker); |
97defe1e | 1013 | |
7e1e7763 TG |
1014 | return 0; |
1015 | } | |
1016 | EXPORT_SYMBOL_GPL(rhashtable_init); | |
1017 | ||
ca26893f HX |
1018 | /** |
1019 | * rhltable_init - initialize a new hash list table | |
1020 | * @hlt: hash list table to be initialized | |
1021 | * @params: configuration parameters | |
1022 | * | |
1023 | * Initializes a new hash list table. | |
1024 | * | |
1025 | * See documentation for rhashtable_init. | |
1026 | */ | |
1027 | int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params) | |
1028 | { | |
1029 | int err; | |
1030 | ||
1031 | /* No rhlist NULLs marking for now. */ | |
1032 | if (params->nulls_base) | |
1033 | return -EINVAL; | |
1034 | ||
1035 | err = rhashtable_init(&hlt->ht, params); | |
1036 | hlt->ht.rhlist = true; | |
1037 | return err; | |
1038 | } | |
1039 | EXPORT_SYMBOL_GPL(rhltable_init); | |
1040 | ||
1041 | static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj, | |
1042 | void (*free_fn)(void *ptr, void *arg), | |
1043 | void *arg) | |
1044 | { | |
1045 | struct rhlist_head *list; | |
1046 | ||
1047 | if (!ht->rhlist) { | |
1048 | free_fn(rht_obj(ht, obj), arg); | |
1049 | return; | |
1050 | } | |
1051 | ||
1052 | list = container_of(obj, struct rhlist_head, rhead); | |
1053 | do { | |
1054 | obj = &list->rhead; | |
1055 | list = rht_dereference(list->next, ht); | |
1056 | free_fn(rht_obj(ht, obj), arg); | |
1057 | } while (list); | |
1058 | } | |
1059 | ||
7e1e7763 | 1060 | /** |
6b6f302c | 1061 | * rhashtable_free_and_destroy - free elements and destroy hash table |
7e1e7763 | 1062 | * @ht: the hash table to destroy |
6b6f302c TG |
1063 | * @free_fn: callback to release resources of element |
1064 | * @arg: pointer passed to free_fn | |
7e1e7763 | 1065 | * |
6b6f302c TG |
1066 | * Stops an eventual async resize. If defined, invokes free_fn for each |
1067 | * element to releasal resources. Please note that RCU protected | |
1068 | * readers may still be accessing the elements. Releasing of resources | |
1069 | * must occur in a compatible manner. Then frees the bucket array. | |
1070 | * | |
1071 | * This function will eventually sleep to wait for an async resize | |
1072 | * to complete. The caller is responsible that no further write operations | |
1073 | * occurs in parallel. | |
7e1e7763 | 1074 | */ |
6b6f302c TG |
1075 | void rhashtable_free_and_destroy(struct rhashtable *ht, |
1076 | void (*free_fn)(void *ptr, void *arg), | |
1077 | void *arg) | |
7e1e7763 | 1078 | { |
da20420f | 1079 | struct bucket_table *tbl; |
6b6f302c | 1080 | unsigned int i; |
97defe1e | 1081 | |
4c4b52d9 | 1082 | cancel_work_sync(&ht->run_work); |
97defe1e | 1083 | |
57699a40 | 1084 | mutex_lock(&ht->mutex); |
6b6f302c TG |
1085 | tbl = rht_dereference(ht->tbl, ht); |
1086 | if (free_fn) { | |
1087 | for (i = 0; i < tbl->size; i++) { | |
1088 | struct rhash_head *pos, *next; | |
1089 | ||
da20420f | 1090 | for (pos = rht_dereference(*rht_bucket(tbl, i), ht), |
6b6f302c TG |
1091 | next = !rht_is_a_nulls(pos) ? |
1092 | rht_dereference(pos->next, ht) : NULL; | |
1093 | !rht_is_a_nulls(pos); | |
1094 | pos = next, | |
1095 | next = !rht_is_a_nulls(pos) ? | |
1096 | rht_dereference(pos->next, ht) : NULL) | |
ca26893f | 1097 | rhashtable_free_one(ht, pos, free_fn, arg); |
6b6f302c TG |
1098 | } |
1099 | } | |
1100 | ||
1101 | bucket_table_free(tbl); | |
97defe1e | 1102 | mutex_unlock(&ht->mutex); |
7e1e7763 | 1103 | } |
6b6f302c TG |
1104 | EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy); |
1105 | ||
1106 | void rhashtable_destroy(struct rhashtable *ht) | |
1107 | { | |
1108 | return rhashtable_free_and_destroy(ht, NULL, NULL); | |
1109 | } | |
7e1e7763 | 1110 | EXPORT_SYMBOL_GPL(rhashtable_destroy); |
da20420f HX |
1111 | |
1112 | struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl, | |
1113 | unsigned int hash) | |
1114 | { | |
1115 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
1116 | static struct rhash_head __rcu *rhnull = | |
1117 | (struct rhash_head __rcu *)NULLS_MARKER(0); | |
1118 | unsigned int index = hash & ((1 << tbl->nest) - 1); | |
1119 | unsigned int size = tbl->size >> tbl->nest; | |
1120 | unsigned int subhash = hash; | |
1121 | union nested_table *ntbl; | |
1122 | ||
1123 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
c4d2603d | 1124 | ntbl = rht_dereference_bucket_rcu(ntbl[index].table, tbl, hash); |
da20420f HX |
1125 | subhash >>= tbl->nest; |
1126 | ||
1127 | while (ntbl && size > (1 << shift)) { | |
1128 | index = subhash & ((1 << shift) - 1); | |
c4d2603d HX |
1129 | ntbl = rht_dereference_bucket_rcu(ntbl[index].table, |
1130 | tbl, hash); | |
da20420f HX |
1131 | size >>= shift; |
1132 | subhash >>= shift; | |
1133 | } | |
1134 | ||
1135 | if (!ntbl) | |
1136 | return &rhnull; | |
1137 | ||
1138 | return &ntbl[subhash].bucket; | |
1139 | ||
1140 | } | |
1141 | EXPORT_SYMBOL_GPL(rht_bucket_nested); | |
1142 | ||
1143 | struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht, | |
1144 | struct bucket_table *tbl, | |
1145 | unsigned int hash) | |
1146 | { | |
1147 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
1148 | unsigned int index = hash & ((1 << tbl->nest) - 1); | |
1149 | unsigned int size = tbl->size >> tbl->nest; | |
1150 | union nested_table *ntbl; | |
1151 | unsigned int shifted; | |
1152 | unsigned int nhash; | |
1153 | ||
1154 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
1155 | hash >>= tbl->nest; | |
1156 | nhash = index; | |
1157 | shifted = tbl->nest; | |
1158 | ntbl = nested_table_alloc(ht, &ntbl[index].table, | |
1159 | size <= (1 << shift) ? shifted : 0, nhash); | |
1160 | ||
1161 | while (ntbl && size > (1 << shift)) { | |
1162 | index = hash & ((1 << shift) - 1); | |
1163 | size >>= shift; | |
1164 | hash >>= shift; | |
1165 | nhash |= index << shifted; | |
1166 | shifted += shift; | |
1167 | ntbl = nested_table_alloc(ht, &ntbl[index].table, | |
1168 | size <= (1 << shift) ? shifted : 0, | |
1169 | nhash); | |
1170 | } | |
1171 | ||
1172 | if (!ntbl) | |
1173 | return NULL; | |
1174 | ||
1175 | return &ntbl[hash].bucket; | |
1176 | ||
1177 | } | |
1178 | EXPORT_SYMBOL_GPL(rht_bucket_nested_insert); |