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, | |
118 | unsigned int shifted, | |
119 | unsigned int nhash) | |
120 | { | |
121 | union nested_table *ntbl; | |
122 | int i; | |
123 | ||
124 | ntbl = rcu_dereference(*prev); | |
125 | if (ntbl) | |
126 | return ntbl; | |
127 | ||
128 | ntbl = kzalloc(PAGE_SIZE, GFP_ATOMIC); | |
129 | ||
130 | if (ntbl && shifted) { | |
131 | for (i = 0; i < PAGE_SIZE / sizeof(ntbl[0].bucket); i++) | |
132 | INIT_RHT_NULLS_HEAD(ntbl[i].bucket, ht, | |
133 | (i << shifted) | nhash); | |
134 | } | |
135 | ||
136 | rcu_assign_pointer(*prev, ntbl); | |
137 | ||
138 | return ntbl; | |
139 | } | |
140 | ||
141 | static struct bucket_table *nested_bucket_table_alloc(struct rhashtable *ht, | |
142 | size_t nbuckets, | |
143 | gfp_t gfp) | |
144 | { | |
145 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
146 | struct bucket_table *tbl; | |
147 | size_t size; | |
148 | ||
149 | if (nbuckets < (1 << (shift + 1))) | |
150 | return NULL; | |
151 | ||
152 | size = sizeof(*tbl) + sizeof(tbl->buckets[0]); | |
153 | ||
154 | tbl = kzalloc(size, gfp); | |
155 | if (!tbl) | |
156 | return NULL; | |
157 | ||
158 | if (!nested_table_alloc(ht, (union nested_table __rcu **)tbl->buckets, | |
159 | 0, 0)) { | |
160 | kfree(tbl); | |
161 | return NULL; | |
162 | } | |
163 | ||
164 | tbl->nest = (ilog2(nbuckets) - 1) % shift + 1; | |
165 | ||
166 | return tbl; | |
167 | } | |
168 | ||
97defe1e | 169 | static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, |
b9ecfdaa HX |
170 | size_t nbuckets, |
171 | gfp_t gfp) | |
7e1e7763 | 172 | { |
eb6d1abf | 173 | struct bucket_table *tbl = NULL; |
64e0cd0d | 174 | size_t size, max_locks; |
f89bd6f8 | 175 | int i; |
7e1e7763 TG |
176 | |
177 | size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]); | |
12e8fd6f | 178 | if (gfp != GFP_KERNEL) |
b9ecfdaa | 179 | tbl = kzalloc(size, gfp | __GFP_NOWARN | __GFP_NORETRY); |
12e8fd6f MH |
180 | else |
181 | tbl = kvzalloc(size, gfp); | |
da20420f HX |
182 | |
183 | size = nbuckets; | |
184 | ||
185 | if (tbl == NULL && gfp != GFP_KERNEL) { | |
186 | tbl = nested_bucket_table_alloc(ht, nbuckets, gfp); | |
187 | nbuckets = 0; | |
188 | } | |
7e1e7763 TG |
189 | if (tbl == NULL) |
190 | return NULL; | |
191 | ||
da20420f | 192 | tbl->size = size; |
7e1e7763 | 193 | |
64e0cd0d TH |
194 | max_locks = size >> 1; |
195 | if (tbl->nest) | |
196 | max_locks = min_t(size_t, max_locks, 1U << tbl->nest); | |
197 | ||
198 | if (alloc_bucket_spinlocks(&tbl->locks, &tbl->locks_mask, max_locks, | |
199 | ht->p.locks_mul, gfp) < 0) { | |
97defe1e TG |
200 | bucket_table_free(tbl); |
201 | return NULL; | |
202 | } | |
7e1e7763 | 203 | |
eddee5ba HX |
204 | INIT_LIST_HEAD(&tbl->walkers); |
205 | ||
d48ad080 | 206 | tbl->hash_rnd = get_random_u32(); |
5269b53d | 207 | |
f89bd6f8 TG |
208 | for (i = 0; i < nbuckets; i++) |
209 | INIT_RHT_NULLS_HEAD(tbl->buckets[i], ht, i); | |
210 | ||
97defe1e | 211 | return tbl; |
7e1e7763 TG |
212 | } |
213 | ||
b824478b HX |
214 | static struct bucket_table *rhashtable_last_table(struct rhashtable *ht, |
215 | struct bucket_table *tbl) | |
216 | { | |
217 | struct bucket_table *new_tbl; | |
218 | ||
219 | do { | |
220 | new_tbl = tbl; | |
221 | tbl = rht_dereference_rcu(tbl->future_tbl, ht); | |
222 | } while (tbl); | |
223 | ||
224 | return new_tbl; | |
225 | } | |
226 | ||
299e5c32 | 227 | static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash) |
a5ec68e3 | 228 | { |
aa34a6cb | 229 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
b824478b HX |
230 | struct bucket_table *new_tbl = rhashtable_last_table(ht, |
231 | rht_dereference_rcu(old_tbl->future_tbl, ht)); | |
da20420f HX |
232 | struct rhash_head __rcu **pprev = rht_bucket_var(old_tbl, old_hash); |
233 | int err = -EAGAIN; | |
aa34a6cb HX |
234 | struct rhash_head *head, *next, *entry; |
235 | spinlock_t *new_bucket_lock; | |
299e5c32 | 236 | unsigned int new_hash; |
aa34a6cb | 237 | |
da20420f HX |
238 | if (new_tbl->nest) |
239 | goto out; | |
240 | ||
241 | err = -ENOENT; | |
242 | ||
aa34a6cb HX |
243 | rht_for_each(entry, old_tbl, old_hash) { |
244 | err = 0; | |
245 | next = rht_dereference_bucket(entry->next, old_tbl, old_hash); | |
246 | ||
247 | if (rht_is_a_nulls(next)) | |
248 | break; | |
a5ec68e3 | 249 | |
aa34a6cb HX |
250 | pprev = &entry->next; |
251 | } | |
a5ec68e3 | 252 | |
aa34a6cb HX |
253 | if (err) |
254 | goto out; | |
97defe1e | 255 | |
aa34a6cb | 256 | new_hash = head_hashfn(ht, new_tbl, entry); |
7e1e7763 | 257 | |
02fd97c3 | 258 | new_bucket_lock = rht_bucket_lock(new_tbl, new_hash); |
7e1e7763 | 259 | |
8f2484bd | 260 | spin_lock_nested(new_bucket_lock, SINGLE_DEPTH_NESTING); |
aa34a6cb HX |
261 | head = rht_dereference_bucket(new_tbl->buckets[new_hash], |
262 | new_tbl, new_hash); | |
97defe1e | 263 | |
7def0f95 | 264 | RCU_INIT_POINTER(entry->next, head); |
a5ec68e3 | 265 | |
aa34a6cb HX |
266 | rcu_assign_pointer(new_tbl->buckets[new_hash], entry); |
267 | spin_unlock(new_bucket_lock); | |
97defe1e | 268 | |
aa34a6cb | 269 | rcu_assign_pointer(*pprev, next); |
7e1e7763 | 270 | |
aa34a6cb HX |
271 | out: |
272 | return err; | |
273 | } | |
97defe1e | 274 | |
da20420f | 275 | static int rhashtable_rehash_chain(struct rhashtable *ht, |
299e5c32 | 276 | unsigned int old_hash) |
aa34a6cb HX |
277 | { |
278 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); | |
279 | spinlock_t *old_bucket_lock; | |
da20420f | 280 | int err; |
aa34a6cb | 281 | |
02fd97c3 | 282 | old_bucket_lock = rht_bucket_lock(old_tbl, old_hash); |
a5ec68e3 | 283 | |
aa34a6cb | 284 | spin_lock_bh(old_bucket_lock); |
da20420f | 285 | while (!(err = rhashtable_rehash_one(ht, old_hash))) |
aa34a6cb | 286 | ; |
da20420f HX |
287 | |
288 | if (err == -ENOENT) { | |
289 | old_tbl->rehash++; | |
290 | err = 0; | |
291 | } | |
aa34a6cb | 292 | spin_unlock_bh(old_bucket_lock); |
da20420f HX |
293 | |
294 | return err; | |
97defe1e TG |
295 | } |
296 | ||
b824478b HX |
297 | static int rhashtable_rehash_attach(struct rhashtable *ht, |
298 | struct bucket_table *old_tbl, | |
299 | struct bucket_table *new_tbl) | |
97defe1e | 300 | { |
b824478b HX |
301 | /* Protect future_tbl using the first bucket lock. */ |
302 | spin_lock_bh(old_tbl->locks); | |
303 | ||
304 | /* Did somebody beat us to it? */ | |
305 | if (rcu_access_pointer(old_tbl->future_tbl)) { | |
306 | spin_unlock_bh(old_tbl->locks); | |
307 | return -EEXIST; | |
308 | } | |
7cd10db8 | 309 | |
aa34a6cb HX |
310 | /* Make insertions go into the new, empty table right away. Deletions |
311 | * and lookups will be attempted in both tables until we synchronize. | |
aa34a6cb | 312 | */ |
c4db8848 | 313 | rcu_assign_pointer(old_tbl->future_tbl, new_tbl); |
aa34a6cb | 314 | |
b824478b HX |
315 | spin_unlock_bh(old_tbl->locks); |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
320 | static int rhashtable_rehash_table(struct rhashtable *ht) | |
321 | { | |
322 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); | |
323 | struct bucket_table *new_tbl; | |
324 | struct rhashtable_walker *walker; | |
299e5c32 | 325 | unsigned int old_hash; |
da20420f | 326 | int err; |
b824478b HX |
327 | |
328 | new_tbl = rht_dereference(old_tbl->future_tbl, ht); | |
329 | if (!new_tbl) | |
330 | return 0; | |
331 | ||
da20420f HX |
332 | for (old_hash = 0; old_hash < old_tbl->size; old_hash++) { |
333 | err = rhashtable_rehash_chain(ht, old_hash); | |
334 | if (err) | |
335 | return err; | |
336 | } | |
aa34a6cb HX |
337 | |
338 | /* Publish the new table pointer. */ | |
339 | rcu_assign_pointer(ht->tbl, new_tbl); | |
340 | ||
ba7c95ea | 341 | spin_lock(&ht->lock); |
eddee5ba HX |
342 | list_for_each_entry(walker, &old_tbl->walkers, list) |
343 | walker->tbl = NULL; | |
ba7c95ea | 344 | spin_unlock(&ht->lock); |
eddee5ba | 345 | |
aa34a6cb HX |
346 | /* Wait for readers. All new readers will see the new |
347 | * table, and thus no references to the old table will | |
348 | * remain. | |
349 | */ | |
9d901bc0 | 350 | call_rcu(&old_tbl->rcu, bucket_table_free_rcu); |
b824478b HX |
351 | |
352 | return rht_dereference(new_tbl->future_tbl, ht) ? -EAGAIN : 0; | |
7e1e7763 TG |
353 | } |
354 | ||
da20420f HX |
355 | static int rhashtable_rehash_alloc(struct rhashtable *ht, |
356 | struct bucket_table *old_tbl, | |
357 | unsigned int size) | |
7e1e7763 | 358 | { |
da20420f | 359 | struct bucket_table *new_tbl; |
b824478b | 360 | int err; |
7e1e7763 TG |
361 | |
362 | ASSERT_RHT_MUTEX(ht); | |
363 | ||
da20420f | 364 | new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL); |
7e1e7763 TG |
365 | if (new_tbl == NULL) |
366 | return -ENOMEM; | |
367 | ||
b824478b HX |
368 | err = rhashtable_rehash_attach(ht, old_tbl, new_tbl); |
369 | if (err) | |
370 | bucket_table_free(new_tbl); | |
371 | ||
372 | return err; | |
7e1e7763 | 373 | } |
7e1e7763 TG |
374 | |
375 | /** | |
376 | * rhashtable_shrink - Shrink hash table while allowing concurrent lookups | |
377 | * @ht: the hash table to shrink | |
7e1e7763 | 378 | * |
18093d1c HX |
379 | * This function shrinks the hash table to fit, i.e., the smallest |
380 | * size would not cause it to expand right away automatically. | |
7e1e7763 | 381 | * |
97defe1e TG |
382 | * The caller must ensure that no concurrent resizing occurs by holding |
383 | * ht->mutex. | |
384 | * | |
7e1e7763 TG |
385 | * The caller must ensure that no concurrent table mutations take place. |
386 | * It is however valid to have concurrent lookups if they are RCU protected. | |
97defe1e TG |
387 | * |
388 | * It is valid to have concurrent insertions and deletions protected by per | |
389 | * bucket locks or concurrent RCU protected lookups and traversals. | |
7e1e7763 | 390 | */ |
b824478b | 391 | static int rhashtable_shrink(struct rhashtable *ht) |
7e1e7763 | 392 | { |
da20420f | 393 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
12311959 VN |
394 | unsigned int nelems = atomic_read(&ht->nelems); |
395 | unsigned int size = 0; | |
7e1e7763 | 396 | |
12311959 VN |
397 | if (nelems) |
398 | size = roundup_pow_of_two(nelems * 3 / 2); | |
18093d1c HX |
399 | if (size < ht->p.min_size) |
400 | size = ht->p.min_size; | |
401 | ||
402 | if (old_tbl->size <= size) | |
403 | return 0; | |
404 | ||
b824478b HX |
405 | if (rht_dereference(old_tbl->future_tbl, ht)) |
406 | return -EEXIST; | |
407 | ||
da20420f | 408 | return rhashtable_rehash_alloc(ht, old_tbl, size); |
7e1e7763 | 409 | } |
7e1e7763 | 410 | |
97defe1e TG |
411 | static void rht_deferred_worker(struct work_struct *work) |
412 | { | |
413 | struct rhashtable *ht; | |
414 | struct bucket_table *tbl; | |
b824478b | 415 | int err = 0; |
97defe1e | 416 | |
57699a40 | 417 | ht = container_of(work, struct rhashtable, run_work); |
97defe1e | 418 | mutex_lock(&ht->mutex); |
28134a53 | 419 | |
97defe1e | 420 | tbl = rht_dereference(ht->tbl, ht); |
b824478b | 421 | tbl = rhashtable_last_table(ht, tbl); |
97defe1e | 422 | |
a5b6846f | 423 | if (rht_grow_above_75(ht, tbl)) |
da20420f | 424 | err = rhashtable_rehash_alloc(ht, tbl, tbl->size * 2); |
b5e2c150 | 425 | else if (ht->p.automatic_shrinking && rht_shrink_below_30(ht, tbl)) |
da20420f HX |
426 | err = rhashtable_shrink(ht); |
427 | else if (tbl->nest) | |
428 | err = rhashtable_rehash_alloc(ht, tbl, tbl->size); | |
b824478b | 429 | |
da20420f HX |
430 | if (!err) |
431 | err = rhashtable_rehash_table(ht); | |
b824478b | 432 | |
97defe1e | 433 | mutex_unlock(&ht->mutex); |
b824478b HX |
434 | |
435 | if (err) | |
436 | schedule_work(&ht->run_work); | |
97defe1e TG |
437 | } |
438 | ||
ca26893f HX |
439 | static int rhashtable_insert_rehash(struct rhashtable *ht, |
440 | struct bucket_table *tbl) | |
ccd57b1b HX |
441 | { |
442 | struct bucket_table *old_tbl; | |
443 | struct bucket_table *new_tbl; | |
ccd57b1b HX |
444 | unsigned int size; |
445 | int err; | |
446 | ||
447 | old_tbl = rht_dereference_rcu(ht->tbl, ht); | |
ccd57b1b HX |
448 | |
449 | size = tbl->size; | |
450 | ||
3cf92222 HX |
451 | err = -EBUSY; |
452 | ||
ccd57b1b HX |
453 | if (rht_grow_above_75(ht, tbl)) |
454 | size *= 2; | |
a87b9ebf TG |
455 | /* Do not schedule more than one rehash */ |
456 | else if (old_tbl != tbl) | |
3cf92222 HX |
457 | goto fail; |
458 | ||
459 | err = -ENOMEM; | |
ccd57b1b HX |
460 | |
461 | new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC); | |
3cf92222 HX |
462 | if (new_tbl == NULL) |
463 | goto fail; | |
ccd57b1b HX |
464 | |
465 | err = rhashtable_rehash_attach(ht, tbl, new_tbl); | |
466 | if (err) { | |
467 | bucket_table_free(new_tbl); | |
468 | if (err == -EEXIST) | |
469 | err = 0; | |
470 | } else | |
471 | schedule_work(&ht->run_work); | |
472 | ||
473 | return err; | |
3cf92222 HX |
474 | |
475 | fail: | |
476 | /* Do not fail the insert if someone else did a rehash. */ | |
477 | if (likely(rcu_dereference_raw(tbl->future_tbl))) | |
478 | return 0; | |
479 | ||
480 | /* Schedule async rehash to retry allocation in process context. */ | |
481 | if (err == -ENOMEM) | |
482 | schedule_work(&ht->run_work); | |
483 | ||
484 | return err; | |
ccd57b1b | 485 | } |
ccd57b1b | 486 | |
ca26893f HX |
487 | static void *rhashtable_lookup_one(struct rhashtable *ht, |
488 | struct bucket_table *tbl, unsigned int hash, | |
489 | const void *key, struct rhash_head *obj) | |
02fd97c3 | 490 | { |
ca26893f HX |
491 | struct rhashtable_compare_arg arg = { |
492 | .ht = ht, | |
493 | .key = key, | |
494 | }; | |
495 | struct rhash_head __rcu **pprev; | |
02fd97c3 | 496 | struct rhash_head *head; |
ca26893f | 497 | int elasticity; |
02fd97c3 | 498 | |
5f8ddeab | 499 | elasticity = RHT_ELASTICITY; |
da20420f HX |
500 | pprev = rht_bucket_var(tbl, hash); |
501 | rht_for_each_continue(head, *pprev, tbl, hash) { | |
ca26893f HX |
502 | struct rhlist_head *list; |
503 | struct rhlist_head *plist; | |
504 | ||
505 | elasticity--; | |
506 | if (!key || | |
507 | (ht->p.obj_cmpfn ? | |
508 | ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) : | |
509 | rhashtable_compare(&arg, rht_obj(ht, head)))) | |
510 | continue; | |
511 | ||
512 | if (!ht->rhlist) | |
513 | return rht_obj(ht, head); | |
514 | ||
515 | list = container_of(obj, struct rhlist_head, rhead); | |
516 | plist = container_of(head, struct rhlist_head, rhead); | |
517 | ||
518 | RCU_INIT_POINTER(list->next, plist); | |
519 | head = rht_dereference_bucket(head->next, tbl, hash); | |
520 | RCU_INIT_POINTER(list->rhead.next, head); | |
521 | rcu_assign_pointer(*pprev, obj); | |
522 | ||
523 | return NULL; | |
5ca8cc5b | 524 | } |
02fd97c3 | 525 | |
ca26893f HX |
526 | if (elasticity <= 0) |
527 | return ERR_PTR(-EAGAIN); | |
528 | ||
529 | return ERR_PTR(-ENOENT); | |
530 | } | |
531 | ||
532 | static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht, | |
533 | struct bucket_table *tbl, | |
534 | unsigned int hash, | |
535 | struct rhash_head *obj, | |
536 | void *data) | |
537 | { | |
da20420f | 538 | struct rhash_head __rcu **pprev; |
ca26893f HX |
539 | struct bucket_table *new_tbl; |
540 | struct rhash_head *head; | |
541 | ||
542 | if (!IS_ERR_OR_NULL(data)) | |
543 | return ERR_PTR(-EEXIST); | |
07ee0722 | 544 | |
ca26893f HX |
545 | if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT) |
546 | return ERR_CAST(data); | |
ccd57b1b | 547 | |
ca26893f HX |
548 | new_tbl = rcu_dereference(tbl->future_tbl); |
549 | if (new_tbl) | |
550 | return new_tbl; | |
551 | ||
552 | if (PTR_ERR(data) != -ENOENT) | |
553 | return ERR_CAST(data); | |
554 | ||
555 | if (unlikely(rht_grow_above_max(ht, tbl))) | |
556 | return ERR_PTR(-E2BIG); | |
557 | ||
558 | if (unlikely(rht_grow_above_100(ht, tbl))) | |
559 | return ERR_PTR(-EAGAIN); | |
02fd97c3 | 560 | |
da20420f HX |
561 | pprev = rht_bucket_insert(ht, tbl, hash); |
562 | if (!pprev) | |
563 | return ERR_PTR(-ENOMEM); | |
564 | ||
565 | head = rht_dereference_bucket(*pprev, tbl, hash); | |
02fd97c3 HX |
566 | |
567 | RCU_INIT_POINTER(obj->next, head); | |
ca26893f HX |
568 | if (ht->rhlist) { |
569 | struct rhlist_head *list; | |
570 | ||
571 | list = container_of(obj, struct rhlist_head, rhead); | |
572 | RCU_INIT_POINTER(list->next, NULL); | |
573 | } | |
02fd97c3 | 574 | |
da20420f | 575 | rcu_assign_pointer(*pprev, obj); |
02fd97c3 HX |
576 | |
577 | atomic_inc(&ht->nelems); | |
ca26893f HX |
578 | if (rht_grow_above_75(ht, tbl)) |
579 | schedule_work(&ht->run_work); | |
02fd97c3 | 580 | |
ca26893f HX |
581 | return NULL; |
582 | } | |
02fd97c3 | 583 | |
ca26893f HX |
584 | static void *rhashtable_try_insert(struct rhashtable *ht, const void *key, |
585 | struct rhash_head *obj) | |
586 | { | |
587 | struct bucket_table *new_tbl; | |
588 | struct bucket_table *tbl; | |
589 | unsigned int hash; | |
590 | spinlock_t *lock; | |
591 | void *data; | |
592 | ||
593 | tbl = rcu_dereference(ht->tbl); | |
594 | ||
595 | /* All insertions must grab the oldest table containing | |
596 | * the hashed bucket that is yet to be rehashed. | |
597 | */ | |
598 | for (;;) { | |
599 | hash = rht_head_hashfn(ht, tbl, obj, ht->p); | |
600 | lock = rht_bucket_lock(tbl, hash); | |
601 | spin_lock_bh(lock); | |
602 | ||
603 | if (tbl->rehash <= hash) | |
604 | break; | |
605 | ||
606 | spin_unlock_bh(lock); | |
607 | tbl = rcu_dereference(tbl->future_tbl); | |
608 | } | |
609 | ||
610 | data = rhashtable_lookup_one(ht, tbl, hash, key, obj); | |
611 | new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data); | |
612 | if (PTR_ERR(new_tbl) != -EEXIST) | |
613 | data = ERR_CAST(new_tbl); | |
614 | ||
615 | while (!IS_ERR_OR_NULL(new_tbl)) { | |
616 | tbl = new_tbl; | |
617 | hash = rht_head_hashfn(ht, tbl, obj, ht->p); | |
618 | spin_lock_nested(rht_bucket_lock(tbl, hash), | |
619 | SINGLE_DEPTH_NESTING); | |
620 | ||
621 | data = rhashtable_lookup_one(ht, tbl, hash, key, obj); | |
622 | new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data); | |
623 | if (PTR_ERR(new_tbl) != -EEXIST) | |
624 | data = ERR_CAST(new_tbl); | |
625 | ||
626 | spin_unlock(rht_bucket_lock(tbl, hash)); | |
627 | } | |
628 | ||
629 | spin_unlock_bh(lock); | |
630 | ||
631 | if (PTR_ERR(data) == -EAGAIN) | |
632 | data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?: | |
633 | -EAGAIN); | |
634 | ||
635 | return data; | |
636 | } | |
637 | ||
638 | void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, | |
639 | struct rhash_head *obj) | |
640 | { | |
641 | void *data; | |
642 | ||
643 | do { | |
644 | rcu_read_lock(); | |
645 | data = rhashtable_try_insert(ht, key, obj); | |
646 | rcu_read_unlock(); | |
647 | } while (PTR_ERR(data) == -EAGAIN); | |
648 | ||
649 | return data; | |
02fd97c3 HX |
650 | } |
651 | EXPORT_SYMBOL_GPL(rhashtable_insert_slow); | |
652 | ||
f2dba9c6 | 653 | /** |
246779dd | 654 | * rhashtable_walk_enter - Initialise an iterator |
f2dba9c6 HX |
655 | * @ht: Table to walk over |
656 | * @iter: Hash table Iterator | |
657 | * | |
658 | * This function prepares a hash table walk. | |
659 | * | |
660 | * Note that if you restart a walk after rhashtable_walk_stop you | |
661 | * may see the same object twice. Also, you may miss objects if | |
662 | * there are removals in between rhashtable_walk_stop and the next | |
663 | * call to rhashtable_walk_start. | |
664 | * | |
665 | * For a completely stable walk you should construct your own data | |
666 | * structure outside the hash table. | |
667 | * | |
668 | * This function may sleep so you must not call it from interrupt | |
669 | * context or with spin locks held. | |
670 | * | |
246779dd | 671 | * You must call rhashtable_walk_exit after this function returns. |
f2dba9c6 | 672 | */ |
246779dd | 673 | void rhashtable_walk_enter(struct rhashtable *ht, struct rhashtable_iter *iter) |
f2dba9c6 HX |
674 | { |
675 | iter->ht = ht; | |
676 | iter->p = NULL; | |
677 | iter->slot = 0; | |
678 | iter->skip = 0; | |
2db54b47 | 679 | iter->end_of_table = 0; |
f2dba9c6 | 680 | |
c6ff5268 | 681 | spin_lock(&ht->lock); |
246779dd | 682 | iter->walker.tbl = |
179ccc0a | 683 | rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock)); |
246779dd | 684 | list_add(&iter->walker.list, &iter->walker.tbl->walkers); |
c6ff5268 | 685 | spin_unlock(&ht->lock); |
f2dba9c6 | 686 | } |
246779dd | 687 | EXPORT_SYMBOL_GPL(rhashtable_walk_enter); |
f2dba9c6 HX |
688 | |
689 | /** | |
690 | * rhashtable_walk_exit - Free an iterator | |
691 | * @iter: Hash table Iterator | |
692 | * | |
693 | * This function frees resources allocated by rhashtable_walk_init. | |
694 | */ | |
695 | void rhashtable_walk_exit(struct rhashtable_iter *iter) | |
696 | { | |
c6ff5268 | 697 | spin_lock(&iter->ht->lock); |
246779dd HX |
698 | if (iter->walker.tbl) |
699 | list_del(&iter->walker.list); | |
c6ff5268 | 700 | spin_unlock(&iter->ht->lock); |
f2dba9c6 HX |
701 | } |
702 | EXPORT_SYMBOL_GPL(rhashtable_walk_exit); | |
703 | ||
704 | /** | |
97a6ec4a | 705 | * rhashtable_walk_start_check - Start a hash table walk |
f2dba9c6 HX |
706 | * @iter: Hash table iterator |
707 | * | |
0647169c AG |
708 | * Start a hash table walk at the current iterator position. Note that we take |
709 | * the RCU lock in all cases including when we return an error. So you must | |
710 | * always call rhashtable_walk_stop to clean up. | |
f2dba9c6 HX |
711 | * |
712 | * Returns zero if successful. | |
713 | * | |
714 | * Returns -EAGAIN if resize event occured. Note that the iterator | |
715 | * will rewind back to the beginning and you may use it immediately | |
716 | * by calling rhashtable_walk_next. | |
97a6ec4a TH |
717 | * |
718 | * rhashtable_walk_start is defined as an inline variant that returns | |
719 | * void. This is preferred in cases where the caller would ignore | |
720 | * resize events and always continue. | |
f2dba9c6 | 721 | */ |
97a6ec4a | 722 | int rhashtable_walk_start_check(struct rhashtable_iter *iter) |
db4374f4 | 723 | __acquires(RCU) |
f2dba9c6 | 724 | { |
eddee5ba HX |
725 | struct rhashtable *ht = iter->ht; |
726 | ||
c6ff5268 | 727 | rcu_read_lock(); |
eddee5ba | 728 | |
c6ff5268 | 729 | spin_lock(&ht->lock); |
246779dd HX |
730 | if (iter->walker.tbl) |
731 | list_del(&iter->walker.list); | |
c6ff5268 | 732 | spin_unlock(&ht->lock); |
eddee5ba | 733 | |
2db54b47 | 734 | if (!iter->walker.tbl && !iter->end_of_table) { |
246779dd | 735 | iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht); |
f2dba9c6 HX |
736 | return -EAGAIN; |
737 | } | |
738 | ||
739 | return 0; | |
740 | } | |
97a6ec4a | 741 | EXPORT_SYMBOL_GPL(rhashtable_walk_start_check); |
f2dba9c6 HX |
742 | |
743 | /** | |
2db54b47 TH |
744 | * __rhashtable_walk_find_next - Find the next element in a table (or the first |
745 | * one in case of a new walk). | |
746 | * | |
f2dba9c6 HX |
747 | * @iter: Hash table iterator |
748 | * | |
2db54b47 | 749 | * Returns the found object or NULL when the end of the table is reached. |
f2dba9c6 | 750 | * |
2db54b47 | 751 | * Returns -EAGAIN if resize event occurred. |
f2dba9c6 | 752 | */ |
2db54b47 | 753 | static void *__rhashtable_walk_find_next(struct rhashtable_iter *iter) |
f2dba9c6 | 754 | { |
246779dd | 755 | struct bucket_table *tbl = iter->walker.tbl; |
ca26893f | 756 | struct rhlist_head *list = iter->list; |
f2dba9c6 HX |
757 | struct rhashtable *ht = iter->ht; |
758 | struct rhash_head *p = iter->p; | |
ca26893f | 759 | bool rhlist = ht->rhlist; |
f2dba9c6 | 760 | |
2db54b47 TH |
761 | if (!tbl) |
762 | return NULL; | |
f2dba9c6 HX |
763 | |
764 | for (; iter->slot < tbl->size; iter->slot++) { | |
765 | int skip = iter->skip; | |
766 | ||
767 | rht_for_each_rcu(p, tbl, iter->slot) { | |
ca26893f HX |
768 | if (rhlist) { |
769 | list = container_of(p, struct rhlist_head, | |
770 | rhead); | |
771 | do { | |
772 | if (!skip) | |
773 | goto next; | |
774 | skip--; | |
775 | list = rcu_dereference(list->next); | |
776 | } while (list); | |
777 | ||
778 | continue; | |
779 | } | |
f2dba9c6 HX |
780 | if (!skip) |
781 | break; | |
782 | skip--; | |
783 | } | |
784 | ||
785 | next: | |
786 | if (!rht_is_a_nulls(p)) { | |
787 | iter->skip++; | |
788 | iter->p = p; | |
ca26893f HX |
789 | iter->list = list; |
790 | return rht_obj(ht, rhlist ? &list->rhead : p); | |
f2dba9c6 HX |
791 | } |
792 | ||
793 | iter->skip = 0; | |
794 | } | |
795 | ||
142b942a PS |
796 | iter->p = NULL; |
797 | ||
d88252f9 HX |
798 | /* Ensure we see any new tables. */ |
799 | smp_rmb(); | |
800 | ||
246779dd HX |
801 | iter->walker.tbl = rht_dereference_rcu(tbl->future_tbl, ht); |
802 | if (iter->walker.tbl) { | |
f2dba9c6 HX |
803 | iter->slot = 0; |
804 | iter->skip = 0; | |
f2dba9c6 | 805 | return ERR_PTR(-EAGAIN); |
2db54b47 TH |
806 | } else { |
807 | iter->end_of_table = true; | |
f2dba9c6 HX |
808 | } |
809 | ||
c936a79f | 810 | return NULL; |
f2dba9c6 | 811 | } |
2db54b47 TH |
812 | |
813 | /** | |
814 | * rhashtable_walk_next - Return the next object and advance the iterator | |
815 | * @iter: Hash table iterator | |
816 | * | |
817 | * Note that you must call rhashtable_walk_stop when you are finished | |
818 | * with the walk. | |
819 | * | |
820 | * Returns the next object or NULL when the end of the table is reached. | |
821 | * | |
822 | * Returns -EAGAIN if resize event occurred. Note that the iterator | |
823 | * will rewind back to the beginning and you may continue to use it. | |
824 | */ | |
825 | void *rhashtable_walk_next(struct rhashtable_iter *iter) | |
826 | { | |
827 | struct rhlist_head *list = iter->list; | |
828 | struct rhashtable *ht = iter->ht; | |
829 | struct rhash_head *p = iter->p; | |
830 | bool rhlist = ht->rhlist; | |
831 | ||
832 | if (p) { | |
833 | if (!rhlist || !(list = rcu_dereference(list->next))) { | |
834 | p = rcu_dereference(p->next); | |
835 | list = container_of(p, struct rhlist_head, rhead); | |
836 | } | |
837 | if (!rht_is_a_nulls(p)) { | |
838 | iter->skip++; | |
839 | iter->p = p; | |
840 | iter->list = list; | |
841 | return rht_obj(ht, rhlist ? &list->rhead : p); | |
842 | } | |
843 | ||
844 | /* At the end of this slot, switch to next one and then find | |
845 | * next entry from that point. | |
846 | */ | |
847 | iter->skip = 0; | |
848 | iter->slot++; | |
849 | } | |
850 | ||
851 | return __rhashtable_walk_find_next(iter); | |
852 | } | |
f2dba9c6 HX |
853 | EXPORT_SYMBOL_GPL(rhashtable_walk_next); |
854 | ||
2db54b47 TH |
855 | /** |
856 | * rhashtable_walk_peek - Return the next object but don't advance the iterator | |
857 | * @iter: Hash table iterator | |
858 | * | |
859 | * Returns the next object or NULL when the end of the table is reached. | |
860 | * | |
861 | * Returns -EAGAIN if resize event occurred. Note that the iterator | |
862 | * will rewind back to the beginning and you may continue to use it. | |
863 | */ | |
864 | void *rhashtable_walk_peek(struct rhashtable_iter *iter) | |
865 | { | |
866 | struct rhlist_head *list = iter->list; | |
867 | struct rhashtable *ht = iter->ht; | |
868 | struct rhash_head *p = iter->p; | |
869 | ||
870 | if (p) | |
871 | return rht_obj(ht, ht->rhlist ? &list->rhead : p); | |
872 | ||
873 | /* No object found in current iter, find next one in the table. */ | |
874 | ||
875 | if (iter->skip) { | |
876 | /* A nonzero skip value points to the next entry in the table | |
877 | * beyond that last one that was found. Decrement skip so | |
878 | * we find the current value. __rhashtable_walk_find_next | |
879 | * will restore the original value of skip assuming that | |
880 | * the table hasn't changed. | |
881 | */ | |
882 | iter->skip--; | |
883 | } | |
884 | ||
885 | return __rhashtable_walk_find_next(iter); | |
886 | } | |
887 | EXPORT_SYMBOL_GPL(rhashtable_walk_peek); | |
888 | ||
f2dba9c6 HX |
889 | /** |
890 | * rhashtable_walk_stop - Finish a hash table walk | |
891 | * @iter: Hash table iterator | |
892 | * | |
0647169c AG |
893 | * Finish a hash table walk. Does not reset the iterator to the start of the |
894 | * hash table. | |
f2dba9c6 HX |
895 | */ |
896 | void rhashtable_walk_stop(struct rhashtable_iter *iter) | |
db4374f4 | 897 | __releases(RCU) |
f2dba9c6 | 898 | { |
eddee5ba | 899 | struct rhashtable *ht; |
246779dd | 900 | struct bucket_table *tbl = iter->walker.tbl; |
eddee5ba | 901 | |
eddee5ba | 902 | if (!tbl) |
963ecbd4 | 903 | goto out; |
eddee5ba HX |
904 | |
905 | ht = iter->ht; | |
906 | ||
ba7c95ea | 907 | spin_lock(&ht->lock); |
c4db8848 | 908 | if (tbl->rehash < tbl->size) |
246779dd | 909 | list_add(&iter->walker.list, &tbl->walkers); |
eddee5ba | 910 | else |
246779dd | 911 | iter->walker.tbl = NULL; |
ba7c95ea | 912 | spin_unlock(&ht->lock); |
eddee5ba | 913 | |
f2dba9c6 | 914 | iter->p = NULL; |
963ecbd4 HX |
915 | |
916 | out: | |
917 | rcu_read_unlock(); | |
f2dba9c6 HX |
918 | } |
919 | EXPORT_SYMBOL_GPL(rhashtable_walk_stop); | |
920 | ||
488fb86e | 921 | static size_t rounded_hashtable_size(const struct rhashtable_params *params) |
7e1e7763 | 922 | { |
94000176 | 923 | return max(roundup_pow_of_two(params->nelem_hint * 4 / 3), |
e2e21c1c | 924 | (unsigned long)params->min_size); |
7e1e7763 TG |
925 | } |
926 | ||
31ccde2d HX |
927 | static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed) |
928 | { | |
929 | return jhash2(key, length, seed); | |
930 | } | |
931 | ||
7e1e7763 TG |
932 | /** |
933 | * rhashtable_init - initialize a new hash table | |
934 | * @ht: hash table to be initialized | |
935 | * @params: configuration parameters | |
936 | * | |
937 | * Initializes a new hash table based on the provided configuration | |
938 | * parameters. A table can be configured either with a variable or | |
939 | * fixed length key: | |
940 | * | |
941 | * Configuration Example 1: Fixed length keys | |
942 | * struct test_obj { | |
943 | * int key; | |
944 | * void * my_member; | |
945 | * struct rhash_head node; | |
946 | * }; | |
947 | * | |
948 | * struct rhashtable_params params = { | |
949 | * .head_offset = offsetof(struct test_obj, node), | |
950 | * .key_offset = offsetof(struct test_obj, key), | |
951 | * .key_len = sizeof(int), | |
87545899 | 952 | * .hashfn = jhash, |
f89bd6f8 | 953 | * .nulls_base = (1U << RHT_BASE_SHIFT), |
7e1e7763 TG |
954 | * }; |
955 | * | |
956 | * Configuration Example 2: Variable length keys | |
957 | * struct test_obj { | |
958 | * [...] | |
959 | * struct rhash_head node; | |
960 | * }; | |
961 | * | |
49f7b33e | 962 | * u32 my_hash_fn(const void *data, u32 len, u32 seed) |
7e1e7763 TG |
963 | * { |
964 | * struct test_obj *obj = data; | |
965 | * | |
966 | * return [... hash ...]; | |
967 | * } | |
968 | * | |
969 | * struct rhashtable_params params = { | |
970 | * .head_offset = offsetof(struct test_obj, node), | |
87545899 | 971 | * .hashfn = jhash, |
7e1e7763 | 972 | * .obj_hashfn = my_hash_fn, |
7e1e7763 TG |
973 | * }; |
974 | */ | |
488fb86e HX |
975 | int rhashtable_init(struct rhashtable *ht, |
976 | const struct rhashtable_params *params) | |
7e1e7763 TG |
977 | { |
978 | struct bucket_table *tbl; | |
979 | size_t size; | |
980 | ||
981 | size = HASH_DEFAULT_SIZE; | |
982 | ||
31ccde2d | 983 | if ((!params->key_len && !params->obj_hashfn) || |
02fd97c3 | 984 | (params->obj_hashfn && !params->obj_cmpfn)) |
7e1e7763 TG |
985 | return -EINVAL; |
986 | ||
f89bd6f8 TG |
987 | if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT)) |
988 | return -EINVAL; | |
989 | ||
97defe1e TG |
990 | memset(ht, 0, sizeof(*ht)); |
991 | mutex_init(&ht->mutex); | |
ba7c95ea | 992 | spin_lock_init(&ht->lock); |
97defe1e TG |
993 | memcpy(&ht->p, params, sizeof(*params)); |
994 | ||
a998f712 TG |
995 | if (params->min_size) |
996 | ht->p.min_size = roundup_pow_of_two(params->min_size); | |
997 | ||
6d684e54 HX |
998 | /* Cap total entries at 2^31 to avoid nelems overflow. */ |
999 | ht->max_elems = 1u << 31; | |
2d2ab658 HX |
1000 | |
1001 | if (params->max_size) { | |
1002 | ht->p.max_size = rounddown_pow_of_two(params->max_size); | |
1003 | if (ht->p.max_size < ht->max_elems / 2) | |
1004 | ht->max_elems = ht->p.max_size * 2; | |
1005 | } | |
6d684e54 | 1006 | |
48e75b43 | 1007 | ht->p.min_size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE); |
a998f712 | 1008 | |
3a324606 HX |
1009 | if (params->nelem_hint) |
1010 | size = rounded_hashtable_size(&ht->p); | |
1011 | ||
97defe1e TG |
1012 | if (params->locks_mul) |
1013 | ht->p.locks_mul = roundup_pow_of_two(params->locks_mul); | |
1014 | else | |
1015 | ht->p.locks_mul = BUCKET_LOCKS_PER_CPU; | |
1016 | ||
31ccde2d HX |
1017 | ht->key_len = ht->p.key_len; |
1018 | if (!params->hashfn) { | |
1019 | ht->p.hashfn = jhash; | |
1020 | ||
1021 | if (!(ht->key_len & (sizeof(u32) - 1))) { | |
1022 | ht->key_len /= sizeof(u32); | |
1023 | ht->p.hashfn = rhashtable_jhash2; | |
1024 | } | |
1025 | } | |
1026 | ||
b9ecfdaa | 1027 | tbl = bucket_table_alloc(ht, size, GFP_KERNEL); |
7e1e7763 TG |
1028 | if (tbl == NULL) |
1029 | return -ENOMEM; | |
1030 | ||
545a148e | 1031 | atomic_set(&ht->nelems, 0); |
a5b6846f | 1032 | |
7e1e7763 TG |
1033 | RCU_INIT_POINTER(ht->tbl, tbl); |
1034 | ||
4c4b52d9 | 1035 | INIT_WORK(&ht->run_work, rht_deferred_worker); |
97defe1e | 1036 | |
7e1e7763 TG |
1037 | return 0; |
1038 | } | |
1039 | EXPORT_SYMBOL_GPL(rhashtable_init); | |
1040 | ||
ca26893f HX |
1041 | /** |
1042 | * rhltable_init - initialize a new hash list table | |
1043 | * @hlt: hash list table to be initialized | |
1044 | * @params: configuration parameters | |
1045 | * | |
1046 | * Initializes a new hash list table. | |
1047 | * | |
1048 | * See documentation for rhashtable_init. | |
1049 | */ | |
1050 | int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params) | |
1051 | { | |
1052 | int err; | |
1053 | ||
1054 | /* No rhlist NULLs marking for now. */ | |
1055 | if (params->nulls_base) | |
1056 | return -EINVAL; | |
1057 | ||
1058 | err = rhashtable_init(&hlt->ht, params); | |
1059 | hlt->ht.rhlist = true; | |
1060 | return err; | |
1061 | } | |
1062 | EXPORT_SYMBOL_GPL(rhltable_init); | |
1063 | ||
1064 | static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj, | |
1065 | void (*free_fn)(void *ptr, void *arg), | |
1066 | void *arg) | |
1067 | { | |
1068 | struct rhlist_head *list; | |
1069 | ||
1070 | if (!ht->rhlist) { | |
1071 | free_fn(rht_obj(ht, obj), arg); | |
1072 | return; | |
1073 | } | |
1074 | ||
1075 | list = container_of(obj, struct rhlist_head, rhead); | |
1076 | do { | |
1077 | obj = &list->rhead; | |
1078 | list = rht_dereference(list->next, ht); | |
1079 | free_fn(rht_obj(ht, obj), arg); | |
1080 | } while (list); | |
1081 | } | |
1082 | ||
7e1e7763 | 1083 | /** |
6b6f302c | 1084 | * rhashtable_free_and_destroy - free elements and destroy hash table |
7e1e7763 | 1085 | * @ht: the hash table to destroy |
6b6f302c TG |
1086 | * @free_fn: callback to release resources of element |
1087 | * @arg: pointer passed to free_fn | |
7e1e7763 | 1088 | * |
6b6f302c TG |
1089 | * Stops an eventual async resize. If defined, invokes free_fn for each |
1090 | * element to releasal resources. Please note that RCU protected | |
1091 | * readers may still be accessing the elements. Releasing of resources | |
1092 | * must occur in a compatible manner. Then frees the bucket array. | |
1093 | * | |
1094 | * This function will eventually sleep to wait for an async resize | |
1095 | * to complete. The caller is responsible that no further write operations | |
1096 | * occurs in parallel. | |
7e1e7763 | 1097 | */ |
6b6f302c TG |
1098 | void rhashtable_free_and_destroy(struct rhashtable *ht, |
1099 | void (*free_fn)(void *ptr, void *arg), | |
1100 | void *arg) | |
7e1e7763 | 1101 | { |
da20420f | 1102 | struct bucket_table *tbl; |
6b6f302c | 1103 | unsigned int i; |
97defe1e | 1104 | |
4c4b52d9 | 1105 | cancel_work_sync(&ht->run_work); |
97defe1e | 1106 | |
57699a40 | 1107 | mutex_lock(&ht->mutex); |
6b6f302c TG |
1108 | tbl = rht_dereference(ht->tbl, ht); |
1109 | if (free_fn) { | |
1110 | for (i = 0; i < tbl->size; i++) { | |
1111 | struct rhash_head *pos, *next; | |
1112 | ||
da20420f | 1113 | for (pos = rht_dereference(*rht_bucket(tbl, i), ht), |
6b6f302c TG |
1114 | next = !rht_is_a_nulls(pos) ? |
1115 | rht_dereference(pos->next, ht) : NULL; | |
1116 | !rht_is_a_nulls(pos); | |
1117 | pos = next, | |
1118 | next = !rht_is_a_nulls(pos) ? | |
1119 | rht_dereference(pos->next, ht) : NULL) | |
ca26893f | 1120 | rhashtable_free_one(ht, pos, free_fn, arg); |
6b6f302c TG |
1121 | } |
1122 | } | |
1123 | ||
1124 | bucket_table_free(tbl); | |
97defe1e | 1125 | mutex_unlock(&ht->mutex); |
7e1e7763 | 1126 | } |
6b6f302c TG |
1127 | EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy); |
1128 | ||
1129 | void rhashtable_destroy(struct rhashtable *ht) | |
1130 | { | |
1131 | return rhashtable_free_and_destroy(ht, NULL, NULL); | |
1132 | } | |
7e1e7763 | 1133 | EXPORT_SYMBOL_GPL(rhashtable_destroy); |
da20420f HX |
1134 | |
1135 | struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl, | |
1136 | unsigned int hash) | |
1137 | { | |
1138 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
1139 | static struct rhash_head __rcu *rhnull = | |
1140 | (struct rhash_head __rcu *)NULLS_MARKER(0); | |
1141 | unsigned int index = hash & ((1 << tbl->nest) - 1); | |
1142 | unsigned int size = tbl->size >> tbl->nest; | |
1143 | unsigned int subhash = hash; | |
1144 | union nested_table *ntbl; | |
1145 | ||
1146 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
c4d2603d | 1147 | ntbl = rht_dereference_bucket_rcu(ntbl[index].table, tbl, hash); |
da20420f HX |
1148 | subhash >>= tbl->nest; |
1149 | ||
1150 | while (ntbl && size > (1 << shift)) { | |
1151 | index = subhash & ((1 << shift) - 1); | |
c4d2603d HX |
1152 | ntbl = rht_dereference_bucket_rcu(ntbl[index].table, |
1153 | tbl, hash); | |
da20420f HX |
1154 | size >>= shift; |
1155 | subhash >>= shift; | |
1156 | } | |
1157 | ||
1158 | if (!ntbl) | |
1159 | return &rhnull; | |
1160 | ||
1161 | return &ntbl[subhash].bucket; | |
1162 | ||
1163 | } | |
1164 | EXPORT_SYMBOL_GPL(rht_bucket_nested); | |
1165 | ||
1166 | struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht, | |
1167 | struct bucket_table *tbl, | |
1168 | unsigned int hash) | |
1169 | { | |
1170 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); | |
1171 | unsigned int index = hash & ((1 << tbl->nest) - 1); | |
1172 | unsigned int size = tbl->size >> tbl->nest; | |
1173 | union nested_table *ntbl; | |
1174 | unsigned int shifted; | |
1175 | unsigned int nhash; | |
1176 | ||
1177 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); | |
1178 | hash >>= tbl->nest; | |
1179 | nhash = index; | |
1180 | shifted = tbl->nest; | |
1181 | ntbl = nested_table_alloc(ht, &ntbl[index].table, | |
1182 | size <= (1 << shift) ? shifted : 0, nhash); | |
1183 | ||
1184 | while (ntbl && size > (1 << shift)) { | |
1185 | index = hash & ((1 << shift) - 1); | |
1186 | size >>= shift; | |
1187 | hash >>= shift; | |
1188 | nhash |= index << shifted; | |
1189 | shifted += shift; | |
1190 | ntbl = nested_table_alloc(ht, &ntbl[index].table, | |
1191 | size <= (1 << shift) ? shifted : 0, | |
1192 | nhash); | |
1193 | } | |
1194 | ||
1195 | if (!ntbl) | |
1196 | return NULL; | |
1197 | ||
1198 | return &ntbl[hash].bucket; | |
1199 | ||
1200 | } | |
1201 | EXPORT_SYMBOL_GPL(rht_bucket_nested_insert); |