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Commit | Line | Data |
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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
7e1e7763 TG |
2 | /* |
3 | * Resizable, Scalable, Concurrent Hash Table | |
4 | * | |
02fd97c3 | 5 | * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> |
a5ec68e3 | 6 | * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch> |
7e1e7763 TG |
7 | * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net> |
8 | * | |
7e1e7763 | 9 | * Code partially derived from nft_hash |
02fd97c3 HX |
10 | * Rewritten with rehash code from br_multicast plus single list |
11 | * pointer as suggested by Josh Triplett | |
7e1e7763 TG |
12 | */ |
13 | ||
07ee0722 | 14 | #include <linux/atomic.h> |
7e1e7763 TG |
15 | #include <linux/kernel.h> |
16 | #include <linux/init.h> | |
17 | #include <linux/log2.h> | |
5beb5c90 | 18 | #include <linux/sched.h> |
b2d09103 | 19 | #include <linux/rculist.h> |
7e1e7763 TG |
20 | #include <linux/slab.h> |
21 | #include <linux/vmalloc.h> | |
22 | #include <linux/mm.h> | |
87545899 | 23 | #include <linux/jhash.h> |
7e1e7763 TG |
24 | #include <linux/random.h> |
25 | #include <linux/rhashtable.h> | |
61d7b097 | 26 | #include <linux/err.h> |
6d795413 | 27 | #include <linux/export.h> |
7e1e7763 TG |
28 | |
29 | #define HASH_DEFAULT_SIZE 64UL | |
c2e213cf | 30 | #define HASH_MIN_SIZE 4U |
97defe1e | 31 | |
da20420f HX |
32 | union nested_table { |
33 | union nested_table __rcu *table; | |
ba6306e3 | 34 | struct rhash_lock_head *bucket; |
da20420f HX |
35 | }; |
36 | ||
988dfbd7 | 37 | static u32 head_hashfn(struct rhashtable *ht, |
8d24c0b4 TG |
38 | const struct bucket_table *tbl, |
39 | const struct rhash_head *he) | |
7e1e7763 | 40 | { |
02fd97c3 | 41 | return rht_head_hashfn(ht, tbl, he, ht->p); |
7e1e7763 TG |
42 | } |
43 | ||
a03eaec0 | 44 | #ifdef CONFIG_PROVE_LOCKING |
a03eaec0 | 45 | #define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT)) |
a03eaec0 TG |
46 | |
47 | int lockdep_rht_mutex_is_held(struct rhashtable *ht) | |
48 | { | |
49 | return (debug_locks) ? lockdep_is_held(&ht->mutex) : 1; | |
50 | } | |
51 | EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held); | |
52 | ||
53 | int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash) | |
54 | { | |
8f0db018 N |
55 | if (!debug_locks) |
56 | return 1; | |
57 | if (unlikely(tbl->nest)) | |
58 | return 1; | |
ca0b709d | 59 | return bit_spin_is_locked(0, (unsigned long *)&tbl->buckets[hash]); |
a03eaec0 TG |
60 | } |
61 | EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held); | |
62 | #else | |
63 | #define ASSERT_RHT_MUTEX(HT) | |
a03eaec0 TG |
64 | #endif |
65 | ||
da20420f HX |
66 | static void nested_table_free(union nested_table *ntbl, unsigned int size) |
67 | { | |
68 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
69 | const unsigned int len = 1 << shift; | |
70 | unsigned int i; | |
71 | ||
72 | ntbl = rcu_dereference_raw(ntbl->table); | |
73 | if (!ntbl) | |
74 | return; | |
75 | ||
76 | if (size > len) { | |
77 | size >>= shift; | |
78 | for (i = 0; i < len; i++) | |
79 | nested_table_free(ntbl + i, size); | |
80 | } | |
81 | ||
82 | kfree(ntbl); | |
83 | } | |
84 | ||
85 | static void nested_bucket_table_free(const struct bucket_table *tbl) | |
86 | { | |
87 | unsigned int size = tbl->size >> tbl->nest; | |
88 | unsigned int len = 1 << tbl->nest; | |
89 | union nested_table *ntbl; | |
90 | unsigned int i; | |
91 | ||
92 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
93 | ||
94 | for (i = 0; i < len; i++) | |
95 | nested_table_free(ntbl + i, size); | |
96 | ||
97 | kfree(ntbl); | |
98 | } | |
99 | ||
97defe1e TG |
100 | static void bucket_table_free(const struct bucket_table *tbl) |
101 | { | |
da20420f HX |
102 | if (tbl->nest) |
103 | nested_bucket_table_free(tbl); | |
104 | ||
97defe1e TG |
105 | kvfree(tbl); |
106 | } | |
107 | ||
9d901bc0 HX |
108 | static void bucket_table_free_rcu(struct rcu_head *head) |
109 | { | |
110 | bucket_table_free(container_of(head, struct bucket_table, rcu)); | |
111 | } | |
112 | ||
da20420f HX |
113 | static union nested_table *nested_table_alloc(struct rhashtable *ht, |
114 | union nested_table __rcu **prev, | |
5af68ef7 | 115 | bool leaf) |
da20420f HX |
116 | { |
117 | union nested_table *ntbl; | |
118 | int i; | |
119 | ||
120 | ntbl = rcu_dereference(*prev); | |
121 | if (ntbl) | |
122 | return ntbl; | |
123 | ||
124 | ntbl = kzalloc(PAGE_SIZE, GFP_ATOMIC); | |
125 | ||
5af68ef7 N |
126 | if (ntbl && leaf) { |
127 | for (i = 0; i < PAGE_SIZE / sizeof(ntbl[0]); i++) | |
9b4f64a2 | 128 | INIT_RHT_NULLS_HEAD(ntbl[i].bucket); |
da20420f HX |
129 | } |
130 | ||
e9458a4e | 131 | if (cmpxchg((union nested_table **)prev, NULL, ntbl) == NULL) |
7a41c294 N |
132 | return ntbl; |
133 | /* Raced with another thread. */ | |
134 | kfree(ntbl); | |
135 | return rcu_dereference(*prev); | |
da20420f HX |
136 | } |
137 | ||
138 | static struct bucket_table *nested_bucket_table_alloc(struct rhashtable *ht, | |
139 | size_t nbuckets, | |
140 | gfp_t gfp) | |
141 | { | |
142 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
143 | struct bucket_table *tbl; | |
144 | size_t size; | |
145 | ||
146 | if (nbuckets < (1 << (shift + 1))) | |
147 | return NULL; | |
148 | ||
149 | size = sizeof(*tbl) + sizeof(tbl->buckets[0]); | |
150 | ||
151 | tbl = kzalloc(size, gfp); | |
152 | if (!tbl) | |
153 | return NULL; | |
154 | ||
155 | if (!nested_table_alloc(ht, (union nested_table __rcu **)tbl->buckets, | |
5af68ef7 | 156 | false)) { |
da20420f HX |
157 | kfree(tbl); |
158 | return NULL; | |
159 | } | |
160 | ||
161 | tbl->nest = (ilog2(nbuckets) - 1) % shift + 1; | |
162 | ||
163 | return tbl; | |
164 | } | |
165 | ||
97defe1e | 166 | static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, |
b9ecfdaa HX |
167 | size_t nbuckets, |
168 | gfp_t gfp) | |
7e1e7763 | 169 | { |
eb6d1abf | 170 | struct bucket_table *tbl = NULL; |
8f0db018 | 171 | size_t size; |
f89bd6f8 | 172 | int i; |
149212f0 | 173 | static struct lock_class_key __key; |
7e1e7763 | 174 | |
c252aa3e | 175 | tbl = kvzalloc(struct_size(tbl, buckets, nbuckets), gfp); |
da20420f HX |
176 | |
177 | size = nbuckets; | |
178 | ||
2d22ecf6 | 179 | if (tbl == NULL && (gfp & ~__GFP_NOFAIL) != GFP_KERNEL) { |
da20420f HX |
180 | tbl = nested_bucket_table_alloc(ht, nbuckets, gfp); |
181 | nbuckets = 0; | |
182 | } | |
2d22ecf6 | 183 | |
7e1e7763 TG |
184 | if (tbl == NULL) |
185 | return NULL; | |
186 | ||
149212f0 N |
187 | lockdep_init_map(&tbl->dep_map, "rhashtable_bucket", &__key, 0); |
188 | ||
da20420f | 189 | tbl->size = size; |
7e1e7763 | 190 | |
4feb7c7a | 191 | rcu_head_init(&tbl->rcu); |
eddee5ba HX |
192 | INIT_LIST_HEAD(&tbl->walkers); |
193 | ||
d48ad080 | 194 | tbl->hash_rnd = get_random_u32(); |
5269b53d | 195 | |
f89bd6f8 | 196 | for (i = 0; i < nbuckets; i++) |
9b4f64a2 | 197 | INIT_RHT_NULLS_HEAD(tbl->buckets[i]); |
f89bd6f8 | 198 | |
97defe1e | 199 | return tbl; |
7e1e7763 TG |
200 | } |
201 | ||
b824478b HX |
202 | static struct bucket_table *rhashtable_last_table(struct rhashtable *ht, |
203 | struct bucket_table *tbl) | |
204 | { | |
205 | struct bucket_table *new_tbl; | |
206 | ||
207 | do { | |
208 | new_tbl = tbl; | |
209 | tbl = rht_dereference_rcu(tbl->future_tbl, ht); | |
210 | } while (tbl); | |
211 | ||
212 | return new_tbl; | |
213 | } | |
214 | ||
8f0db018 | 215 | static int rhashtable_rehash_one(struct rhashtable *ht, |
ba6306e3 | 216 | struct rhash_lock_head **bkt, |
8f0db018 | 217 | unsigned int old_hash) |
a5ec68e3 | 218 | { |
aa34a6cb | 219 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
c0690016 | 220 | struct bucket_table *new_tbl = rhashtable_last_table(ht, old_tbl); |
da20420f | 221 | int err = -EAGAIN; |
aa34a6cb | 222 | struct rhash_head *head, *next, *entry; |
e4edbe3c | 223 | struct rhash_head __rcu **pprev = NULL; |
299e5c32 | 224 | unsigned int new_hash; |
aa34a6cb | 225 | |
da20420f HX |
226 | if (new_tbl->nest) |
227 | goto out; | |
228 | ||
229 | err = -ENOENT; | |
230 | ||
adc6a3ab N |
231 | rht_for_each_from(entry, rht_ptr(bkt, old_tbl, old_hash), |
232 | old_tbl, old_hash) { | |
aa34a6cb HX |
233 | err = 0; |
234 | next = rht_dereference_bucket(entry->next, old_tbl, old_hash); | |
235 | ||
236 | if (rht_is_a_nulls(next)) | |
237 | break; | |
a5ec68e3 | 238 | |
aa34a6cb HX |
239 | pprev = &entry->next; |
240 | } | |
a5ec68e3 | 241 | |
aa34a6cb HX |
242 | if (err) |
243 | goto out; | |
97defe1e | 244 | |
aa34a6cb | 245 | new_hash = head_hashfn(ht, new_tbl, entry); |
7e1e7763 | 246 | |
149212f0 | 247 | rht_lock_nested(new_tbl, &new_tbl->buckets[new_hash], SINGLE_DEPTH_NESTING); |
7e1e7763 | 248 | |
adc6a3ab | 249 | head = rht_ptr(new_tbl->buckets + new_hash, new_tbl, new_hash); |
97defe1e | 250 | |
7def0f95 | 251 | RCU_INIT_POINTER(entry->next, head); |
a5ec68e3 | 252 | |
149212f0 | 253 | rht_assign_unlock(new_tbl, &new_tbl->buckets[new_hash], entry); |
97defe1e | 254 | |
8f0db018 N |
255 | if (pprev) |
256 | rcu_assign_pointer(*pprev, next); | |
257 | else | |
258 | /* Need to preserved the bit lock. */ | |
f4712b46 | 259 | rht_assign_locked(bkt, next); |
7e1e7763 | 260 | |
aa34a6cb HX |
261 | out: |
262 | return err; | |
263 | } | |
97defe1e | 264 | |
da20420f | 265 | static int rhashtable_rehash_chain(struct rhashtable *ht, |
299e5c32 | 266 | unsigned int old_hash) |
aa34a6cb HX |
267 | { |
268 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); | |
ba6306e3 | 269 | struct rhash_lock_head **bkt = rht_bucket_var(old_tbl, old_hash); |
da20420f | 270 | int err; |
aa34a6cb | 271 | |
8f0db018 N |
272 | if (!bkt) |
273 | return 0; | |
149212f0 | 274 | rht_lock(old_tbl, bkt); |
a5ec68e3 | 275 | |
8f0db018 | 276 | while (!(err = rhashtable_rehash_one(ht, bkt, old_hash))) |
aa34a6cb | 277 | ; |
da20420f | 278 | |
4feb7c7a | 279 | if (err == -ENOENT) |
da20420f | 280 | err = 0; |
149212f0 | 281 | rht_unlock(old_tbl, bkt); |
da20420f HX |
282 | |
283 | return err; | |
97defe1e TG |
284 | } |
285 | ||
b824478b HX |
286 | static int rhashtable_rehash_attach(struct rhashtable *ht, |
287 | struct bucket_table *old_tbl, | |
288 | struct bucket_table *new_tbl) | |
97defe1e | 289 | { |
aa34a6cb HX |
290 | /* Make insertions go into the new, empty table right away. Deletions |
291 | * and lookups will be attempted in both tables until we synchronize. | |
0ad66449 N |
292 | * As cmpxchg() provides strong barriers, we do not need |
293 | * rcu_assign_pointer(). | |
aa34a6cb | 294 | */ |
aa34a6cb | 295 | |
e9458a4e HX |
296 | if (cmpxchg((struct bucket_table **)&old_tbl->future_tbl, NULL, |
297 | new_tbl) != NULL) | |
0ad66449 | 298 | return -EEXIST; |
b824478b HX |
299 | |
300 | return 0; | |
301 | } | |
302 | ||
303 | static int rhashtable_rehash_table(struct rhashtable *ht) | |
304 | { | |
305 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); | |
306 | struct bucket_table *new_tbl; | |
307 | struct rhashtable_walker *walker; | |
299e5c32 | 308 | unsigned int old_hash; |
da20420f | 309 | int err; |
b824478b HX |
310 | |
311 | new_tbl = rht_dereference(old_tbl->future_tbl, ht); | |
312 | if (!new_tbl) | |
313 | return 0; | |
314 | ||
da20420f HX |
315 | for (old_hash = 0; old_hash < old_tbl->size; old_hash++) { |
316 | err = rhashtable_rehash_chain(ht, old_hash); | |
317 | if (err) | |
318 | return err; | |
ae6da1f5 | 319 | cond_resched(); |
da20420f | 320 | } |
aa34a6cb HX |
321 | |
322 | /* Publish the new table pointer. */ | |
323 | rcu_assign_pointer(ht->tbl, new_tbl); | |
324 | ||
ba7c95ea | 325 | spin_lock(&ht->lock); |
eddee5ba HX |
326 | list_for_each_entry(walker, &old_tbl->walkers, list) |
327 | walker->tbl = NULL; | |
328 | ||
aa34a6cb HX |
329 | /* Wait for readers. All new readers will see the new |
330 | * table, and thus no references to the old table will | |
331 | * remain. | |
4feb7c7a N |
332 | * We do this inside the locked region so that |
333 | * rhashtable_walk_stop() can use rcu_head_after_call_rcu() | |
334 | * to check if it should not re-link the table. | |
aa34a6cb | 335 | */ |
9d901bc0 | 336 | call_rcu(&old_tbl->rcu, bucket_table_free_rcu); |
4feb7c7a | 337 | spin_unlock(&ht->lock); |
b824478b HX |
338 | |
339 | return rht_dereference(new_tbl->future_tbl, ht) ? -EAGAIN : 0; | |
7e1e7763 TG |
340 | } |
341 | ||
da20420f HX |
342 | static int rhashtable_rehash_alloc(struct rhashtable *ht, |
343 | struct bucket_table *old_tbl, | |
344 | unsigned int size) | |
7e1e7763 | 345 | { |
da20420f | 346 | struct bucket_table *new_tbl; |
b824478b | 347 | int err; |
7e1e7763 TG |
348 | |
349 | ASSERT_RHT_MUTEX(ht); | |
350 | ||
da20420f | 351 | new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL); |
7e1e7763 TG |
352 | if (new_tbl == NULL) |
353 | return -ENOMEM; | |
354 | ||
b824478b HX |
355 | err = rhashtable_rehash_attach(ht, old_tbl, new_tbl); |
356 | if (err) | |
357 | bucket_table_free(new_tbl); | |
358 | ||
359 | return err; | |
7e1e7763 | 360 | } |
7e1e7763 TG |
361 | |
362 | /** | |
363 | * rhashtable_shrink - Shrink hash table while allowing concurrent lookups | |
364 | * @ht: the hash table to shrink | |
7e1e7763 | 365 | * |
18093d1c HX |
366 | * This function shrinks the hash table to fit, i.e., the smallest |
367 | * size would not cause it to expand right away automatically. | |
7e1e7763 | 368 | * |
97defe1e TG |
369 | * The caller must ensure that no concurrent resizing occurs by holding |
370 | * ht->mutex. | |
371 | * | |
7e1e7763 TG |
372 | * The caller must ensure that no concurrent table mutations take place. |
373 | * It is however valid to have concurrent lookups if they are RCU protected. | |
97defe1e TG |
374 | * |
375 | * It is valid to have concurrent insertions and deletions protected by per | |
376 | * bucket locks or concurrent RCU protected lookups and traversals. | |
7e1e7763 | 377 | */ |
b824478b | 378 | static int rhashtable_shrink(struct rhashtable *ht) |
7e1e7763 | 379 | { |
da20420f | 380 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
12311959 VN |
381 | unsigned int nelems = atomic_read(&ht->nelems); |
382 | unsigned int size = 0; | |
7e1e7763 | 383 | |
12311959 VN |
384 | if (nelems) |
385 | size = roundup_pow_of_two(nelems * 3 / 2); | |
18093d1c HX |
386 | if (size < ht->p.min_size) |
387 | size = ht->p.min_size; | |
388 | ||
389 | if (old_tbl->size <= size) | |
390 | return 0; | |
391 | ||
b824478b HX |
392 | if (rht_dereference(old_tbl->future_tbl, ht)) |
393 | return -EEXIST; | |
394 | ||
da20420f | 395 | return rhashtable_rehash_alloc(ht, old_tbl, size); |
7e1e7763 | 396 | } |
7e1e7763 | 397 | |
97defe1e TG |
398 | static void rht_deferred_worker(struct work_struct *work) |
399 | { | |
400 | struct rhashtable *ht; | |
401 | struct bucket_table *tbl; | |
b824478b | 402 | int err = 0; |
97defe1e | 403 | |
57699a40 | 404 | ht = container_of(work, struct rhashtable, run_work); |
97defe1e | 405 | mutex_lock(&ht->mutex); |
28134a53 | 406 | |
97defe1e | 407 | tbl = rht_dereference(ht->tbl, ht); |
b824478b | 408 | tbl = rhashtable_last_table(ht, tbl); |
97defe1e | 409 | |
a5b6846f | 410 | if (rht_grow_above_75(ht, tbl)) |
da20420f | 411 | err = rhashtable_rehash_alloc(ht, tbl, tbl->size * 2); |
b5e2c150 | 412 | else if (ht->p.automatic_shrinking && rht_shrink_below_30(ht, tbl)) |
da20420f HX |
413 | err = rhashtable_shrink(ht); |
414 | else if (tbl->nest) | |
415 | err = rhashtable_rehash_alloc(ht, tbl, tbl->size); | |
b824478b | 416 | |
408f13ef HX |
417 | if (!err || err == -EEXIST) { |
418 | int nerr; | |
419 | ||
420 | nerr = rhashtable_rehash_table(ht); | |
421 | err = err ?: nerr; | |
422 | } | |
b824478b | 423 | |
97defe1e | 424 | mutex_unlock(&ht->mutex); |
b824478b HX |
425 | |
426 | if (err) | |
427 | schedule_work(&ht->run_work); | |
97defe1e TG |
428 | } |
429 | ||
ca26893f HX |
430 | static int rhashtable_insert_rehash(struct rhashtable *ht, |
431 | struct bucket_table *tbl) | |
ccd57b1b HX |
432 | { |
433 | struct bucket_table *old_tbl; | |
434 | struct bucket_table *new_tbl; | |
ccd57b1b HX |
435 | unsigned int size; |
436 | int err; | |
437 | ||
438 | old_tbl = rht_dereference_rcu(ht->tbl, ht); | |
ccd57b1b HX |
439 | |
440 | size = tbl->size; | |
441 | ||
3cf92222 HX |
442 | err = -EBUSY; |
443 | ||
ccd57b1b HX |
444 | if (rht_grow_above_75(ht, tbl)) |
445 | size *= 2; | |
a87b9ebf TG |
446 | /* Do not schedule more than one rehash */ |
447 | else if (old_tbl != tbl) | |
3cf92222 HX |
448 | goto fail; |
449 | ||
450 | err = -ENOMEM; | |
ccd57b1b | 451 | |
93f976b5 | 452 | new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC | __GFP_NOWARN); |
3cf92222 HX |
453 | if (new_tbl == NULL) |
454 | goto fail; | |
ccd57b1b HX |
455 | |
456 | err = rhashtable_rehash_attach(ht, tbl, new_tbl); | |
457 | if (err) { | |
458 | bucket_table_free(new_tbl); | |
459 | if (err == -EEXIST) | |
460 | err = 0; | |
461 | } else | |
462 | schedule_work(&ht->run_work); | |
463 | ||
464 | return err; | |
3cf92222 HX |
465 | |
466 | fail: | |
467 | /* Do not fail the insert if someone else did a rehash. */ | |
c0690016 | 468 | if (likely(rcu_access_pointer(tbl->future_tbl))) |
3cf92222 HX |
469 | return 0; |
470 | ||
471 | /* Schedule async rehash to retry allocation in process context. */ | |
472 | if (err == -ENOMEM) | |
473 | schedule_work(&ht->run_work); | |
474 | ||
475 | return err; | |
ccd57b1b | 476 | } |
ccd57b1b | 477 | |
ca26893f | 478 | static void *rhashtable_lookup_one(struct rhashtable *ht, |
ba6306e3 | 479 | struct rhash_lock_head **bkt, |
ca26893f HX |
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 | }; | |
e4edbe3c | 487 | struct rhash_head __rcu **pprev = NULL; |
02fd97c3 | 488 | struct rhash_head *head; |
ca26893f | 489 | int elasticity; |
02fd97c3 | 490 | |
5f8ddeab | 491 | elasticity = RHT_ELASTICITY; |
adc6a3ab | 492 | rht_for_each_from(head, rht_ptr(bkt, tbl, hash), tbl, hash) { |
ca26893f HX |
493 | struct rhlist_head *list; |
494 | struct rhlist_head *plist; | |
495 | ||
496 | elasticity--; | |
497 | if (!key || | |
498 | (ht->p.obj_cmpfn ? | |
499 | ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) : | |
d3dcf8eb PB |
500 | rhashtable_compare(&arg, rht_obj(ht, head)))) { |
501 | pprev = &head->next; | |
ca26893f | 502 | continue; |
d3dcf8eb | 503 | } |
ca26893f HX |
504 | |
505 | if (!ht->rhlist) | |
506 | return rht_obj(ht, head); | |
507 | ||
508 | list = container_of(obj, struct rhlist_head, rhead); | |
509 | plist = container_of(head, struct rhlist_head, rhead); | |
510 | ||
511 | RCU_INIT_POINTER(list->next, plist); | |
512 | head = rht_dereference_bucket(head->next, tbl, hash); | |
513 | RCU_INIT_POINTER(list->rhead.next, head); | |
8f0db018 N |
514 | if (pprev) |
515 | rcu_assign_pointer(*pprev, obj); | |
516 | else | |
517 | /* Need to preserve the bit lock */ | |
f4712b46 | 518 | rht_assign_locked(bkt, obj); |
ca26893f HX |
519 | |
520 | return NULL; | |
5ca8cc5b | 521 | } |
02fd97c3 | 522 | |
ca26893f HX |
523 | if (elasticity <= 0) |
524 | return ERR_PTR(-EAGAIN); | |
525 | ||
526 | return ERR_PTR(-ENOENT); | |
527 | } | |
528 | ||
529 | static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht, | |
ba6306e3 | 530 | struct rhash_lock_head **bkt, |
ca26893f HX |
531 | struct bucket_table *tbl, |
532 | unsigned int hash, | |
533 | struct rhash_head *obj, | |
534 | void *data) | |
535 | { | |
536 | struct bucket_table *new_tbl; | |
537 | struct rhash_head *head; | |
538 | ||
539 | if (!IS_ERR_OR_NULL(data)) | |
540 | return ERR_PTR(-EEXIST); | |
07ee0722 | 541 | |
ca26893f HX |
542 | if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT) |
543 | return ERR_CAST(data); | |
ccd57b1b | 544 | |
c0690016 | 545 | new_tbl = rht_dereference_rcu(tbl->future_tbl, ht); |
ca26893f HX |
546 | if (new_tbl) |
547 | return new_tbl; | |
548 | ||
549 | if (PTR_ERR(data) != -ENOENT) | |
550 | return ERR_CAST(data); | |
551 | ||
552 | if (unlikely(rht_grow_above_max(ht, tbl))) | |
553 | return ERR_PTR(-E2BIG); | |
554 | ||
555 | if (unlikely(rht_grow_above_100(ht, tbl))) | |
556 | return ERR_PTR(-EAGAIN); | |
02fd97c3 | 557 | |
adc6a3ab | 558 | head = rht_ptr(bkt, tbl, hash); |
02fd97c3 HX |
559 | |
560 | RCU_INIT_POINTER(obj->next, head); | |
ca26893f HX |
561 | if (ht->rhlist) { |
562 | struct rhlist_head *list; | |
563 | ||
564 | list = container_of(obj, struct rhlist_head, rhead); | |
565 | RCU_INIT_POINTER(list->next, NULL); | |
566 | } | |
02fd97c3 | 567 | |
8f0db018 N |
568 | /* bkt is always the head of the list, so it holds |
569 | * the lock, which we need to preserve | |
570 | */ | |
f4712b46 | 571 | rht_assign_locked(bkt, obj); |
02fd97c3 HX |
572 | |
573 | atomic_inc(&ht->nelems); | |
ca26893f HX |
574 | if (rht_grow_above_75(ht, tbl)) |
575 | schedule_work(&ht->run_work); | |
02fd97c3 | 576 | |
ca26893f HX |
577 | return NULL; |
578 | } | |
02fd97c3 | 579 | |
ca26893f HX |
580 | static void *rhashtable_try_insert(struct rhashtable *ht, const void *key, |
581 | struct rhash_head *obj) | |
582 | { | |
583 | struct bucket_table *new_tbl; | |
584 | struct bucket_table *tbl; | |
ba6306e3 | 585 | struct rhash_lock_head **bkt; |
ca26893f | 586 | unsigned int hash; |
ca26893f HX |
587 | void *data; |
588 | ||
4feb7c7a | 589 | new_tbl = rcu_dereference(ht->tbl); |
ca26893f | 590 | |
4feb7c7a | 591 | do { |
ca26893f HX |
592 | tbl = new_tbl; |
593 | hash = rht_head_hashfn(ht, tbl, obj, ht->p); | |
8f0db018 N |
594 | if (rcu_access_pointer(tbl->future_tbl)) |
595 | /* Failure is OK */ | |
596 | bkt = rht_bucket_var(tbl, hash); | |
597 | else | |
598 | bkt = rht_bucket_insert(ht, tbl, hash); | |
599 | if (bkt == NULL) { | |
600 | new_tbl = rht_dereference_rcu(tbl->future_tbl, ht); | |
601 | data = ERR_PTR(-EAGAIN); | |
602 | } else { | |
149212f0 | 603 | rht_lock(tbl, bkt); |
8f0db018 N |
604 | data = rhashtable_lookup_one(ht, bkt, tbl, |
605 | hash, key, obj); | |
606 | new_tbl = rhashtable_insert_one(ht, bkt, tbl, | |
607 | hash, obj, data); | |
608 | if (PTR_ERR(new_tbl) != -EEXIST) | |
609 | data = ERR_CAST(new_tbl); | |
610 | ||
149212f0 | 611 | rht_unlock(tbl, bkt); |
8f0db018 | 612 | } |
4feb7c7a | 613 | } while (!IS_ERR_OR_NULL(new_tbl)); |
ca26893f HX |
614 | |
615 | if (PTR_ERR(data) == -EAGAIN) | |
616 | data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?: | |
617 | -EAGAIN); | |
618 | ||
619 | return data; | |
620 | } | |
621 | ||
622 | void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, | |
623 | struct rhash_head *obj) | |
624 | { | |
625 | void *data; | |
626 | ||
627 | do { | |
628 | rcu_read_lock(); | |
629 | data = rhashtable_try_insert(ht, key, obj); | |
630 | rcu_read_unlock(); | |
631 | } while (PTR_ERR(data) == -EAGAIN); | |
632 | ||
633 | return data; | |
02fd97c3 HX |
634 | } |
635 | EXPORT_SYMBOL_GPL(rhashtable_insert_slow); | |
636 | ||
f2dba9c6 | 637 | /** |
246779dd | 638 | * rhashtable_walk_enter - Initialise an iterator |
f2dba9c6 HX |
639 | * @ht: Table to walk over |
640 | * @iter: Hash table Iterator | |
641 | * | |
642 | * This function prepares a hash table walk. | |
643 | * | |
644 | * Note that if you restart a walk after rhashtable_walk_stop you | |
645 | * may see the same object twice. Also, you may miss objects if | |
646 | * there are removals in between rhashtable_walk_stop and the next | |
647 | * call to rhashtable_walk_start. | |
648 | * | |
649 | * For a completely stable walk you should construct your own data | |
650 | * structure outside the hash table. | |
651 | * | |
82266e98 N |
652 | * This function may be called from any process context, including |
653 | * non-preemptable context, but cannot be called from softirq or | |
654 | * hardirq context. | |
f2dba9c6 | 655 | * |
246779dd | 656 | * You must call rhashtable_walk_exit after this function returns. |
f2dba9c6 | 657 | */ |
246779dd | 658 | void rhashtable_walk_enter(struct rhashtable *ht, struct rhashtable_iter *iter) |
f2dba9c6 HX |
659 | { |
660 | iter->ht = ht; | |
661 | iter->p = NULL; | |
662 | iter->slot = 0; | |
663 | iter->skip = 0; | |
2db54b47 | 664 | iter->end_of_table = 0; |
f2dba9c6 | 665 | |
c6ff5268 | 666 | spin_lock(&ht->lock); |
246779dd | 667 | iter->walker.tbl = |
179ccc0a | 668 | rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock)); |
246779dd | 669 | list_add(&iter->walker.list, &iter->walker.tbl->walkers); |
c6ff5268 | 670 | spin_unlock(&ht->lock); |
f2dba9c6 | 671 | } |
246779dd | 672 | EXPORT_SYMBOL_GPL(rhashtable_walk_enter); |
f2dba9c6 HX |
673 | |
674 | /** | |
675 | * rhashtable_walk_exit - Free an iterator | |
676 | * @iter: Hash table Iterator | |
677 | * | |
6c4128f6 | 678 | * This function frees resources allocated by rhashtable_walk_enter. |
f2dba9c6 HX |
679 | */ |
680 | void rhashtable_walk_exit(struct rhashtable_iter *iter) | |
681 | { | |
c6ff5268 | 682 | spin_lock(&iter->ht->lock); |
246779dd HX |
683 | if (iter->walker.tbl) |
684 | list_del(&iter->walker.list); | |
c6ff5268 | 685 | spin_unlock(&iter->ht->lock); |
f2dba9c6 HX |
686 | } |
687 | EXPORT_SYMBOL_GPL(rhashtable_walk_exit); | |
688 | ||
689 | /** | |
97a6ec4a | 690 | * rhashtable_walk_start_check - Start a hash table walk |
f2dba9c6 HX |
691 | * @iter: Hash table iterator |
692 | * | |
0647169c AG |
693 | * Start a hash table walk at the current iterator position. Note that we take |
694 | * the RCU lock in all cases including when we return an error. So you must | |
695 | * always call rhashtable_walk_stop to clean up. | |
f2dba9c6 HX |
696 | * |
697 | * Returns zero if successful. | |
698 | * | |
699 | * Returns -EAGAIN if resize event occured. Note that the iterator | |
700 | * will rewind back to the beginning and you may use it immediately | |
701 | * by calling rhashtable_walk_next. | |
97a6ec4a TH |
702 | * |
703 | * rhashtable_walk_start is defined as an inline variant that returns | |
704 | * void. This is preferred in cases where the caller would ignore | |
705 | * resize events and always continue. | |
f2dba9c6 | 706 | */ |
97a6ec4a | 707 | int rhashtable_walk_start_check(struct rhashtable_iter *iter) |
db4374f4 | 708 | __acquires(RCU) |
f2dba9c6 | 709 | { |
eddee5ba | 710 | struct rhashtable *ht = iter->ht; |
5d240a89 | 711 | bool rhlist = ht->rhlist; |
eddee5ba | 712 | |
c6ff5268 | 713 | rcu_read_lock(); |
eddee5ba | 714 | |
c6ff5268 | 715 | spin_lock(&ht->lock); |
246779dd HX |
716 | if (iter->walker.tbl) |
717 | list_del(&iter->walker.list); | |
c6ff5268 | 718 | spin_unlock(&ht->lock); |
eddee5ba | 719 | |
5d240a89 N |
720 | if (iter->end_of_table) |
721 | return 0; | |
722 | if (!iter->walker.tbl) { | |
246779dd | 723 | iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht); |
b41cc04b N |
724 | iter->slot = 0; |
725 | iter->skip = 0; | |
f2dba9c6 HX |
726 | return -EAGAIN; |
727 | } | |
728 | ||
5d240a89 N |
729 | if (iter->p && !rhlist) { |
730 | /* | |
731 | * We need to validate that 'p' is still in the table, and | |
732 | * if so, update 'skip' | |
733 | */ | |
734 | struct rhash_head *p; | |
735 | int skip = 0; | |
736 | rht_for_each_rcu(p, iter->walker.tbl, iter->slot) { | |
737 | skip++; | |
738 | if (p == iter->p) { | |
739 | iter->skip = skip; | |
740 | goto found; | |
741 | } | |
742 | } | |
743 | iter->p = NULL; | |
744 | } else if (iter->p && rhlist) { | |
745 | /* Need to validate that 'list' is still in the table, and | |
746 | * if so, update 'skip' and 'p'. | |
747 | */ | |
748 | struct rhash_head *p; | |
749 | struct rhlist_head *list; | |
750 | int skip = 0; | |
751 | rht_for_each_rcu(p, iter->walker.tbl, iter->slot) { | |
752 | for (list = container_of(p, struct rhlist_head, rhead); | |
753 | list; | |
754 | list = rcu_dereference(list->next)) { | |
755 | skip++; | |
756 | if (list == iter->list) { | |
757 | iter->p = p; | |
c643ecf3 | 758 | iter->skip = skip; |
5d240a89 N |
759 | goto found; |
760 | } | |
761 | } | |
762 | } | |
763 | iter->p = NULL; | |
764 | } | |
765 | found: | |
f2dba9c6 HX |
766 | return 0; |
767 | } | |
97a6ec4a | 768 | EXPORT_SYMBOL_GPL(rhashtable_walk_start_check); |
f2dba9c6 HX |
769 | |
770 | /** | |
2db54b47 TH |
771 | * __rhashtable_walk_find_next - Find the next element in a table (or the first |
772 | * one in case of a new walk). | |
773 | * | |
f2dba9c6 HX |
774 | * @iter: Hash table iterator |
775 | * | |
2db54b47 | 776 | * Returns the found object or NULL when the end of the table is reached. |
f2dba9c6 | 777 | * |
2db54b47 | 778 | * Returns -EAGAIN if resize event occurred. |
f2dba9c6 | 779 | */ |
2db54b47 | 780 | static void *__rhashtable_walk_find_next(struct rhashtable_iter *iter) |
f2dba9c6 | 781 | { |
246779dd | 782 | struct bucket_table *tbl = iter->walker.tbl; |
ca26893f | 783 | struct rhlist_head *list = iter->list; |
f2dba9c6 HX |
784 | struct rhashtable *ht = iter->ht; |
785 | struct rhash_head *p = iter->p; | |
ca26893f | 786 | bool rhlist = ht->rhlist; |
f2dba9c6 | 787 | |
2db54b47 TH |
788 | if (!tbl) |
789 | return NULL; | |
f2dba9c6 HX |
790 | |
791 | for (; iter->slot < tbl->size; iter->slot++) { | |
792 | int skip = iter->skip; | |
793 | ||
794 | rht_for_each_rcu(p, tbl, iter->slot) { | |
ca26893f HX |
795 | if (rhlist) { |
796 | list = container_of(p, struct rhlist_head, | |
797 | rhead); | |
798 | do { | |
799 | if (!skip) | |
800 | goto next; | |
801 | skip--; | |
802 | list = rcu_dereference(list->next); | |
803 | } while (list); | |
804 | ||
805 | continue; | |
806 | } | |
f2dba9c6 HX |
807 | if (!skip) |
808 | break; | |
809 | skip--; | |
810 | } | |
811 | ||
812 | next: | |
813 | if (!rht_is_a_nulls(p)) { | |
814 | iter->skip++; | |
815 | iter->p = p; | |
ca26893f HX |
816 | iter->list = list; |
817 | return rht_obj(ht, rhlist ? &list->rhead : p); | |
f2dba9c6 HX |
818 | } |
819 | ||
820 | iter->skip = 0; | |
821 | } | |
822 | ||
142b942a PS |
823 | iter->p = NULL; |
824 | ||
d88252f9 HX |
825 | /* Ensure we see any new tables. */ |
826 | smp_rmb(); | |
827 | ||
246779dd HX |
828 | iter->walker.tbl = rht_dereference_rcu(tbl->future_tbl, ht); |
829 | if (iter->walker.tbl) { | |
f2dba9c6 HX |
830 | iter->slot = 0; |
831 | iter->skip = 0; | |
f2dba9c6 | 832 | return ERR_PTR(-EAGAIN); |
2db54b47 TH |
833 | } else { |
834 | iter->end_of_table = true; | |
f2dba9c6 HX |
835 | } |
836 | ||
c936a79f | 837 | return NULL; |
f2dba9c6 | 838 | } |
2db54b47 TH |
839 | |
840 | /** | |
841 | * rhashtable_walk_next - Return the next object and advance the iterator | |
842 | * @iter: Hash table iterator | |
843 | * | |
844 | * Note that you must call rhashtable_walk_stop when you are finished | |
845 | * with the walk. | |
846 | * | |
847 | * Returns the next object or NULL when the end of the table is reached. | |
848 | * | |
849 | * Returns -EAGAIN if resize event occurred. Note that the iterator | |
850 | * will rewind back to the beginning and you may continue to use it. | |
851 | */ | |
852 | void *rhashtable_walk_next(struct rhashtable_iter *iter) | |
853 | { | |
854 | struct rhlist_head *list = iter->list; | |
855 | struct rhashtable *ht = iter->ht; | |
856 | struct rhash_head *p = iter->p; | |
857 | bool rhlist = ht->rhlist; | |
858 | ||
859 | if (p) { | |
860 | if (!rhlist || !(list = rcu_dereference(list->next))) { | |
861 | p = rcu_dereference(p->next); | |
862 | list = container_of(p, struct rhlist_head, rhead); | |
863 | } | |
864 | if (!rht_is_a_nulls(p)) { | |
865 | iter->skip++; | |
866 | iter->p = p; | |
867 | iter->list = list; | |
868 | return rht_obj(ht, rhlist ? &list->rhead : p); | |
869 | } | |
870 | ||
871 | /* At the end of this slot, switch to next one and then find | |
872 | * next entry from that point. | |
873 | */ | |
874 | iter->skip = 0; | |
875 | iter->slot++; | |
876 | } | |
877 | ||
878 | return __rhashtable_walk_find_next(iter); | |
879 | } | |
f2dba9c6 HX |
880 | EXPORT_SYMBOL_GPL(rhashtable_walk_next); |
881 | ||
2db54b47 TH |
882 | /** |
883 | * rhashtable_walk_peek - Return the next object but don't advance the iterator | |
884 | * @iter: Hash table iterator | |
885 | * | |
886 | * Returns the next object or NULL when the end of the table is reached. | |
887 | * | |
888 | * Returns -EAGAIN if resize event occurred. Note that the iterator | |
889 | * will rewind back to the beginning and you may continue to use it. | |
890 | */ | |
891 | void *rhashtable_walk_peek(struct rhashtable_iter *iter) | |
892 | { | |
893 | struct rhlist_head *list = iter->list; | |
894 | struct rhashtable *ht = iter->ht; | |
895 | struct rhash_head *p = iter->p; | |
896 | ||
897 | if (p) | |
898 | return rht_obj(ht, ht->rhlist ? &list->rhead : p); | |
899 | ||
900 | /* No object found in current iter, find next one in the table. */ | |
901 | ||
902 | if (iter->skip) { | |
903 | /* A nonzero skip value points to the next entry in the table | |
904 | * beyond that last one that was found. Decrement skip so | |
905 | * we find the current value. __rhashtable_walk_find_next | |
906 | * will restore the original value of skip assuming that | |
907 | * the table hasn't changed. | |
908 | */ | |
909 | iter->skip--; | |
910 | } | |
911 | ||
912 | return __rhashtable_walk_find_next(iter); | |
913 | } | |
914 | EXPORT_SYMBOL_GPL(rhashtable_walk_peek); | |
915 | ||
f2dba9c6 HX |
916 | /** |
917 | * rhashtable_walk_stop - Finish a hash table walk | |
918 | * @iter: Hash table iterator | |
919 | * | |
0647169c AG |
920 | * Finish a hash table walk. Does not reset the iterator to the start of the |
921 | * hash table. | |
f2dba9c6 HX |
922 | */ |
923 | void rhashtable_walk_stop(struct rhashtable_iter *iter) | |
db4374f4 | 924 | __releases(RCU) |
f2dba9c6 | 925 | { |
eddee5ba | 926 | struct rhashtable *ht; |
246779dd | 927 | struct bucket_table *tbl = iter->walker.tbl; |
eddee5ba | 928 | |
eddee5ba | 929 | if (!tbl) |
963ecbd4 | 930 | goto out; |
eddee5ba HX |
931 | |
932 | ht = iter->ht; | |
933 | ||
ba7c95ea | 934 | spin_lock(&ht->lock); |
4feb7c7a N |
935 | if (rcu_head_after_call_rcu(&tbl->rcu, bucket_table_free_rcu)) |
936 | /* This bucket table is being freed, don't re-link it. */ | |
246779dd | 937 | iter->walker.tbl = NULL; |
4feb7c7a N |
938 | else |
939 | list_add(&iter->walker.list, &tbl->walkers); | |
ba7c95ea | 940 | spin_unlock(&ht->lock); |
eddee5ba | 941 | |
963ecbd4 HX |
942 | out: |
943 | rcu_read_unlock(); | |
f2dba9c6 HX |
944 | } |
945 | EXPORT_SYMBOL_GPL(rhashtable_walk_stop); | |
946 | ||
488fb86e | 947 | static size_t rounded_hashtable_size(const struct rhashtable_params *params) |
7e1e7763 | 948 | { |
107d01f5 DB |
949 | size_t retsize; |
950 | ||
951 | if (params->nelem_hint) | |
952 | retsize = max(roundup_pow_of_two(params->nelem_hint * 4 / 3), | |
953 | (unsigned long)params->min_size); | |
954 | else | |
955 | retsize = max(HASH_DEFAULT_SIZE, | |
956 | (unsigned long)params->min_size); | |
957 | ||
958 | return retsize; | |
7e1e7763 TG |
959 | } |
960 | ||
31ccde2d HX |
961 | static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed) |
962 | { | |
963 | return jhash2(key, length, seed); | |
964 | } | |
965 | ||
7e1e7763 TG |
966 | /** |
967 | * rhashtable_init - initialize a new hash table | |
968 | * @ht: hash table to be initialized | |
969 | * @params: configuration parameters | |
970 | * | |
971 | * Initializes a new hash table based on the provided configuration | |
972 | * parameters. A table can be configured either with a variable or | |
973 | * fixed length key: | |
974 | * | |
975 | * Configuration Example 1: Fixed length keys | |
976 | * struct test_obj { | |
977 | * int key; | |
978 | * void * my_member; | |
979 | * struct rhash_head node; | |
980 | * }; | |
981 | * | |
982 | * struct rhashtable_params params = { | |
983 | * .head_offset = offsetof(struct test_obj, node), | |
984 | * .key_offset = offsetof(struct test_obj, key), | |
985 | * .key_len = sizeof(int), | |
87545899 | 986 | * .hashfn = jhash, |
7e1e7763 TG |
987 | * }; |
988 | * | |
989 | * Configuration Example 2: Variable length keys | |
990 | * struct test_obj { | |
991 | * [...] | |
992 | * struct rhash_head node; | |
993 | * }; | |
994 | * | |
49f7b33e | 995 | * u32 my_hash_fn(const void *data, u32 len, u32 seed) |
7e1e7763 TG |
996 | * { |
997 | * struct test_obj *obj = data; | |
998 | * | |
999 | * return [... hash ...]; | |
1000 | * } | |
1001 | * | |
1002 | * struct rhashtable_params params = { | |
1003 | * .head_offset = offsetof(struct test_obj, node), | |
87545899 | 1004 | * .hashfn = jhash, |
7e1e7763 | 1005 | * .obj_hashfn = my_hash_fn, |
7e1e7763 TG |
1006 | * }; |
1007 | */ | |
488fb86e HX |
1008 | int rhashtable_init(struct rhashtable *ht, |
1009 | const struct rhashtable_params *params) | |
7e1e7763 TG |
1010 | { |
1011 | struct bucket_table *tbl; | |
1012 | size_t size; | |
1013 | ||
31ccde2d | 1014 | if ((!params->key_len && !params->obj_hashfn) || |
02fd97c3 | 1015 | (params->obj_hashfn && !params->obj_cmpfn)) |
7e1e7763 TG |
1016 | return -EINVAL; |
1017 | ||
97defe1e TG |
1018 | memset(ht, 0, sizeof(*ht)); |
1019 | mutex_init(&ht->mutex); | |
ba7c95ea | 1020 | spin_lock_init(&ht->lock); |
97defe1e TG |
1021 | memcpy(&ht->p, params, sizeof(*params)); |
1022 | ||
a998f712 TG |
1023 | if (params->min_size) |
1024 | ht->p.min_size = roundup_pow_of_two(params->min_size); | |
1025 | ||
6d684e54 HX |
1026 | /* Cap total entries at 2^31 to avoid nelems overflow. */ |
1027 | ht->max_elems = 1u << 31; | |
2d2ab658 HX |
1028 | |
1029 | if (params->max_size) { | |
1030 | ht->p.max_size = rounddown_pow_of_two(params->max_size); | |
1031 | if (ht->p.max_size < ht->max_elems / 2) | |
1032 | ht->max_elems = ht->p.max_size * 2; | |
1033 | } | |
6d684e54 | 1034 | |
48e75b43 | 1035 | ht->p.min_size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE); |
a998f712 | 1036 | |
107d01f5 | 1037 | size = rounded_hashtable_size(&ht->p); |
3a324606 | 1038 | |
31ccde2d HX |
1039 | ht->key_len = ht->p.key_len; |
1040 | if (!params->hashfn) { | |
1041 | ht->p.hashfn = jhash; | |
1042 | ||
1043 | if (!(ht->key_len & (sizeof(u32) - 1))) { | |
1044 | ht->key_len /= sizeof(u32); | |
1045 | ht->p.hashfn = rhashtable_jhash2; | |
1046 | } | |
1047 | } | |
1048 | ||
2d22ecf6 DB |
1049 | /* |
1050 | * This is api initialization and thus we need to guarantee the | |
1051 | * initial rhashtable allocation. Upon failure, retry with the | |
1052 | * smallest possible size with __GFP_NOFAIL semantics. | |
1053 | */ | |
b9ecfdaa | 1054 | tbl = bucket_table_alloc(ht, size, GFP_KERNEL); |
2d22ecf6 DB |
1055 | if (unlikely(tbl == NULL)) { |
1056 | size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE); | |
1057 | tbl = bucket_table_alloc(ht, size, GFP_KERNEL | __GFP_NOFAIL); | |
1058 | } | |
7e1e7763 | 1059 | |
545a148e | 1060 | atomic_set(&ht->nelems, 0); |
a5b6846f | 1061 | |
7e1e7763 TG |
1062 | RCU_INIT_POINTER(ht->tbl, tbl); |
1063 | ||
4c4b52d9 | 1064 | INIT_WORK(&ht->run_work, rht_deferred_worker); |
97defe1e | 1065 | |
7e1e7763 TG |
1066 | return 0; |
1067 | } | |
1068 | EXPORT_SYMBOL_GPL(rhashtable_init); | |
1069 | ||
ca26893f HX |
1070 | /** |
1071 | * rhltable_init - initialize a new hash list table | |
1072 | * @hlt: hash list table to be initialized | |
1073 | * @params: configuration parameters | |
1074 | * | |
1075 | * Initializes a new hash list table. | |
1076 | * | |
1077 | * See documentation for rhashtable_init. | |
1078 | */ | |
1079 | int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params) | |
1080 | { | |
1081 | int err; | |
1082 | ||
ca26893f HX |
1083 | err = rhashtable_init(&hlt->ht, params); |
1084 | hlt->ht.rhlist = true; | |
1085 | return err; | |
1086 | } | |
1087 | EXPORT_SYMBOL_GPL(rhltable_init); | |
1088 | ||
1089 | static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj, | |
1090 | void (*free_fn)(void *ptr, void *arg), | |
1091 | void *arg) | |
1092 | { | |
1093 | struct rhlist_head *list; | |
1094 | ||
1095 | if (!ht->rhlist) { | |
1096 | free_fn(rht_obj(ht, obj), arg); | |
1097 | return; | |
1098 | } | |
1099 | ||
1100 | list = container_of(obj, struct rhlist_head, rhead); | |
1101 | do { | |
1102 | obj = &list->rhead; | |
1103 | list = rht_dereference(list->next, ht); | |
1104 | free_fn(rht_obj(ht, obj), arg); | |
1105 | } while (list); | |
1106 | } | |
1107 | ||
7e1e7763 | 1108 | /** |
6b6f302c | 1109 | * rhashtable_free_and_destroy - free elements and destroy hash table |
7e1e7763 | 1110 | * @ht: the hash table to destroy |
6b6f302c TG |
1111 | * @free_fn: callback to release resources of element |
1112 | * @arg: pointer passed to free_fn | |
7e1e7763 | 1113 | * |
6b6f302c TG |
1114 | * Stops an eventual async resize. If defined, invokes free_fn for each |
1115 | * element to releasal resources. Please note that RCU protected | |
1116 | * readers may still be accessing the elements. Releasing of resources | |
1117 | * must occur in a compatible manner. Then frees the bucket array. | |
1118 | * | |
1119 | * This function will eventually sleep to wait for an async resize | |
1120 | * to complete. The caller is responsible that no further write operations | |
1121 | * occurs in parallel. | |
7e1e7763 | 1122 | */ |
6b6f302c TG |
1123 | void rhashtable_free_and_destroy(struct rhashtable *ht, |
1124 | void (*free_fn)(void *ptr, void *arg), | |
1125 | void *arg) | |
7e1e7763 | 1126 | { |
0026129c | 1127 | struct bucket_table *tbl, *next_tbl; |
6b6f302c | 1128 | unsigned int i; |
97defe1e | 1129 | |
4c4b52d9 | 1130 | cancel_work_sync(&ht->run_work); |
97defe1e | 1131 | |
57699a40 | 1132 | mutex_lock(&ht->mutex); |
6b6f302c | 1133 | tbl = rht_dereference(ht->tbl, ht); |
0026129c | 1134 | restart: |
6b6f302c TG |
1135 | if (free_fn) { |
1136 | for (i = 0; i < tbl->size; i++) { | |
1137 | struct rhash_head *pos, *next; | |
1138 | ||
ae6da1f5 | 1139 | cond_resched(); |
adc6a3ab | 1140 | for (pos = rht_ptr_exclusive(rht_bucket(tbl, i)), |
6b6f302c TG |
1141 | next = !rht_is_a_nulls(pos) ? |
1142 | rht_dereference(pos->next, ht) : NULL; | |
1143 | !rht_is_a_nulls(pos); | |
1144 | pos = next, | |
1145 | next = !rht_is_a_nulls(pos) ? | |
1146 | rht_dereference(pos->next, ht) : NULL) | |
ca26893f | 1147 | rhashtable_free_one(ht, pos, free_fn, arg); |
6b6f302c TG |
1148 | } |
1149 | } | |
1150 | ||
0026129c | 1151 | next_tbl = rht_dereference(tbl->future_tbl, ht); |
6b6f302c | 1152 | bucket_table_free(tbl); |
0026129c TY |
1153 | if (next_tbl) { |
1154 | tbl = next_tbl; | |
1155 | goto restart; | |
1156 | } | |
97defe1e | 1157 | mutex_unlock(&ht->mutex); |
7e1e7763 | 1158 | } |
6b6f302c TG |
1159 | EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy); |
1160 | ||
1161 | void rhashtable_destroy(struct rhashtable *ht) | |
1162 | { | |
1163 | return rhashtable_free_and_destroy(ht, NULL, NULL); | |
1164 | } | |
7e1e7763 | 1165 | EXPORT_SYMBOL_GPL(rhashtable_destroy); |
da20420f | 1166 | |
ba6306e3 HX |
1167 | struct rhash_lock_head **__rht_bucket_nested(const struct bucket_table *tbl, |
1168 | unsigned int hash) | |
da20420f HX |
1169 | { |
1170 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
da20420f HX |
1171 | unsigned int index = hash & ((1 << tbl->nest) - 1); |
1172 | unsigned int size = tbl->size >> tbl->nest; | |
1173 | unsigned int subhash = hash; | |
1174 | union nested_table *ntbl; | |
1175 | ||
1176 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
c4d2603d | 1177 | ntbl = rht_dereference_bucket_rcu(ntbl[index].table, tbl, hash); |
da20420f HX |
1178 | subhash >>= tbl->nest; |
1179 | ||
1180 | while (ntbl && size > (1 << shift)) { | |
1181 | index = subhash & ((1 << shift) - 1); | |
c4d2603d HX |
1182 | ntbl = rht_dereference_bucket_rcu(ntbl[index].table, |
1183 | tbl, hash); | |
da20420f HX |
1184 | size >>= shift; |
1185 | subhash >>= shift; | |
1186 | } | |
1187 | ||
ff302db9 N |
1188 | if (!ntbl) |
1189 | return NULL; | |
da20420f HX |
1190 | |
1191 | return &ntbl[subhash].bucket; | |
1192 | ||
1193 | } | |
ff302db9 N |
1194 | EXPORT_SYMBOL_GPL(__rht_bucket_nested); |
1195 | ||
ba6306e3 HX |
1196 | struct rhash_lock_head **rht_bucket_nested(const struct bucket_table *tbl, |
1197 | unsigned int hash) | |
ff302db9 | 1198 | { |
ba6306e3 | 1199 | static struct rhash_lock_head *rhnull; |
ff302db9 N |
1200 | |
1201 | if (!rhnull) | |
1202 | INIT_RHT_NULLS_HEAD(rhnull); | |
1203 | return __rht_bucket_nested(tbl, hash) ?: &rhnull; | |
1204 | } | |
da20420f HX |
1205 | EXPORT_SYMBOL_GPL(rht_bucket_nested); |
1206 | ||
ba6306e3 HX |
1207 | struct rhash_lock_head **rht_bucket_nested_insert(struct rhashtable *ht, |
1208 | struct bucket_table *tbl, | |
1209 | unsigned int hash) | |
da20420f HX |
1210 | { |
1211 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
1212 | unsigned int index = hash & ((1 << tbl->nest) - 1); | |
1213 | unsigned int size = tbl->size >> tbl->nest; | |
1214 | union nested_table *ntbl; | |
da20420f HX |
1215 | |
1216 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
1217 | hash >>= tbl->nest; | |
da20420f | 1218 | ntbl = nested_table_alloc(ht, &ntbl[index].table, |
5af68ef7 | 1219 | size <= (1 << shift)); |
da20420f HX |
1220 | |
1221 | while (ntbl && size > (1 << shift)) { | |
1222 | index = hash & ((1 << shift) - 1); | |
1223 | size >>= shift; | |
1224 | hash >>= shift; | |
da20420f | 1225 | ntbl = nested_table_alloc(ht, &ntbl[index].table, |
5af68ef7 | 1226 | size <= (1 << shift)); |
da20420f HX |
1227 | } |
1228 | ||
1229 | if (!ntbl) | |
1230 | return NULL; | |
1231 | ||
1232 | return &ntbl[hash].bucket; | |
1233 | ||
1234 | } | |
1235 | EXPORT_SYMBOL_GPL(rht_bucket_nested_insert); |