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rhashtable: allow rht_bucket_var to return NULL.
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CommitLineData
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
36union nested_table {
37 union nested_table __rcu *table;
38 struct rhash_head __rcu *bucket;
39};
40
988dfbd7 41static 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
51int lockdep_rht_mutex_is_held(struct rhashtable *ht)
52{
53 return (debug_locks) ? lockdep_is_held(&ht->mutex) : 1;
54}
55EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held);
56
57int 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}
63EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held);
64#else
65#define ASSERT_RHT_MUTEX(HT)
a03eaec0
TG
66#endif
67
da20420f
HX
68static 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
87static 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
102static 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
111static 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
116static union nested_table *nested_table_alloc(struct rhashtable *ht,
117 union nested_table __rcu **prev,
5af68ef7 118 bool leaf)
da20420f
HX
119{
120 union nested_table *ntbl;
121 int i;
122
123 ntbl = rcu_dereference(*prev);
124 if (ntbl)
125 return ntbl;
126
127 ntbl = kzalloc(PAGE_SIZE, GFP_ATOMIC);
128
5af68ef7
N
129 if (ntbl && leaf) {
130 for (i = 0; i < PAGE_SIZE / sizeof(ntbl[0]); i++)
9b4f64a2 131 INIT_RHT_NULLS_HEAD(ntbl[i].bucket);
da20420f
HX
132 }
133
7a41c294
N
134 if (cmpxchg(prev, NULL, ntbl) == NULL)
135 return ntbl;
136 /* Raced with another thread. */
137 kfree(ntbl);
138 return rcu_dereference(*prev);
da20420f
HX
139}
140
141static 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,
5af68ef7 159 false)) {
da20420f
HX
160 kfree(tbl);
161 return NULL;
162 }
163
164 tbl->nest = (ilog2(nbuckets) - 1) % shift + 1;
165
166 return tbl;
167}
168
97defe1e 169static 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]);
93f976b5 178 tbl = kvzalloc(size, gfp);
da20420f
HX
179
180 size = nbuckets;
181
2d22ecf6 182 if (tbl == NULL && (gfp & ~__GFP_NOFAIL) != GFP_KERNEL) {
da20420f
HX
183 tbl = nested_bucket_table_alloc(ht, nbuckets, gfp);
184 nbuckets = 0;
185 }
2d22ecf6 186
7e1e7763
TG
187 if (tbl == NULL)
188 return NULL;
189
da20420f 190 tbl->size = size;
7e1e7763 191
64e0cd0d
TH
192 max_locks = size >> 1;
193 if (tbl->nest)
194 max_locks = min_t(size_t, max_locks, 1U << tbl->nest);
195
196 if (alloc_bucket_spinlocks(&tbl->locks, &tbl->locks_mask, max_locks,
197 ht->p.locks_mul, gfp) < 0) {
97defe1e
TG
198 bucket_table_free(tbl);
199 return NULL;
200 }
7e1e7763 201
4feb7c7a 202 rcu_head_init(&tbl->rcu);
eddee5ba
HX
203 INIT_LIST_HEAD(&tbl->walkers);
204
d48ad080 205 tbl->hash_rnd = get_random_u32();
5269b53d 206
f89bd6f8 207 for (i = 0; i < nbuckets; i++)
9b4f64a2 208 INIT_RHT_NULLS_HEAD(tbl->buckets[i]);
f89bd6f8 209
97defe1e 210 return tbl;
7e1e7763
TG
211}
212
b824478b
HX
213static struct bucket_table *rhashtable_last_table(struct rhashtable *ht,
214 struct bucket_table *tbl)
215{
216 struct bucket_table *new_tbl;
217
218 do {
219 new_tbl = tbl;
220 tbl = rht_dereference_rcu(tbl->future_tbl, ht);
221 } while (tbl);
222
223 return new_tbl;
224}
225
299e5c32 226static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash)
a5ec68e3 227{
aa34a6cb 228 struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
c0690016 229 struct bucket_table *new_tbl = rhashtable_last_table(ht, old_tbl);
da20420f
HX
230 struct rhash_head __rcu **pprev = rht_bucket_var(old_tbl, old_hash);
231 int err = -EAGAIN;
aa34a6cb
HX
232 struct rhash_head *head, *next, *entry;
233 spinlock_t *new_bucket_lock;
299e5c32 234 unsigned int new_hash;
aa34a6cb 235
da20420f
HX
236 if (new_tbl->nest)
237 goto out;
238
239 err = -ENOENT;
ff302db9
N
240 if (!pprev)
241 goto out;
da20420f 242
ff302db9 243 rht_for_each_from(entry, *pprev, old_tbl, old_hash) {
aa34a6cb
HX
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
271out:
272 return err;
273}
97defe1e 274
da20420f 275static 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 287
4feb7c7a 288 if (err == -ENOENT)
da20420f 289 err = 0;
4feb7c7a 290
aa34a6cb 291 spin_unlock_bh(old_bucket_lock);
da20420f
HX
292
293 return err;
97defe1e
TG
294}
295
b824478b
HX
296static int rhashtable_rehash_attach(struct rhashtable *ht,
297 struct bucket_table *old_tbl,
298 struct bucket_table *new_tbl)
97defe1e 299{
aa34a6cb
HX
300 /* Make insertions go into the new, empty table right away. Deletions
301 * and lookups will be attempted in both tables until we synchronize.
0ad66449
N
302 * As cmpxchg() provides strong barriers, we do not need
303 * rcu_assign_pointer().
aa34a6cb 304 */
aa34a6cb 305
0ad66449
N
306 if (cmpxchg(&old_tbl->future_tbl, NULL, new_tbl) != NULL)
307 return -EEXIST;
b824478b
HX
308
309 return 0;
310}
311
312static int rhashtable_rehash_table(struct rhashtable *ht)
313{
314 struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
315 struct bucket_table *new_tbl;
316 struct rhashtable_walker *walker;
299e5c32 317 unsigned int old_hash;
da20420f 318 int err;
b824478b
HX
319
320 new_tbl = rht_dereference(old_tbl->future_tbl, ht);
321 if (!new_tbl)
322 return 0;
323
da20420f
HX
324 for (old_hash = 0; old_hash < old_tbl->size; old_hash++) {
325 err = rhashtable_rehash_chain(ht, old_hash);
326 if (err)
327 return err;
ae6da1f5 328 cond_resched();
da20420f 329 }
aa34a6cb
HX
330
331 /* Publish the new table pointer. */
332 rcu_assign_pointer(ht->tbl, new_tbl);
333
ba7c95ea 334 spin_lock(&ht->lock);
eddee5ba
HX
335 list_for_each_entry(walker, &old_tbl->walkers, list)
336 walker->tbl = NULL;
337
aa34a6cb
HX
338 /* Wait for readers. All new readers will see the new
339 * table, and thus no references to the old table will
340 * remain.
4feb7c7a
N
341 * We do this inside the locked region so that
342 * rhashtable_walk_stop() can use rcu_head_after_call_rcu()
343 * to check if it should not re-link the table.
aa34a6cb 344 */
9d901bc0 345 call_rcu(&old_tbl->rcu, bucket_table_free_rcu);
4feb7c7a 346 spin_unlock(&ht->lock);
b824478b
HX
347
348 return rht_dereference(new_tbl->future_tbl, ht) ? -EAGAIN : 0;
7e1e7763
TG
349}
350
da20420f
HX
351static int rhashtable_rehash_alloc(struct rhashtable *ht,
352 struct bucket_table *old_tbl,
353 unsigned int size)
7e1e7763 354{
da20420f 355 struct bucket_table *new_tbl;
b824478b 356 int err;
7e1e7763
TG
357
358 ASSERT_RHT_MUTEX(ht);
359
da20420f 360 new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL);
7e1e7763
TG
361 if (new_tbl == NULL)
362 return -ENOMEM;
363
b824478b
HX
364 err = rhashtable_rehash_attach(ht, old_tbl, new_tbl);
365 if (err)
366 bucket_table_free(new_tbl);
367
368 return err;
7e1e7763 369}
7e1e7763
TG
370
371/**
372 * rhashtable_shrink - Shrink hash table while allowing concurrent lookups
373 * @ht: the hash table to shrink
7e1e7763 374 *
18093d1c
HX
375 * This function shrinks the hash table to fit, i.e., the smallest
376 * size would not cause it to expand right away automatically.
7e1e7763 377 *
97defe1e
TG
378 * The caller must ensure that no concurrent resizing occurs by holding
379 * ht->mutex.
380 *
7e1e7763
TG
381 * The caller must ensure that no concurrent table mutations take place.
382 * It is however valid to have concurrent lookups if they are RCU protected.
97defe1e
TG
383 *
384 * It is valid to have concurrent insertions and deletions protected by per
385 * bucket locks or concurrent RCU protected lookups and traversals.
7e1e7763 386 */
b824478b 387static int rhashtable_shrink(struct rhashtable *ht)
7e1e7763 388{
da20420f 389 struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
12311959
VN
390 unsigned int nelems = atomic_read(&ht->nelems);
391 unsigned int size = 0;
7e1e7763 392
12311959
VN
393 if (nelems)
394 size = roundup_pow_of_two(nelems * 3 / 2);
18093d1c
HX
395 if (size < ht->p.min_size)
396 size = ht->p.min_size;
397
398 if (old_tbl->size <= size)
399 return 0;
400
b824478b
HX
401 if (rht_dereference(old_tbl->future_tbl, ht))
402 return -EEXIST;
403
da20420f 404 return rhashtable_rehash_alloc(ht, old_tbl, size);
7e1e7763 405}
7e1e7763 406
97defe1e
TG
407static void rht_deferred_worker(struct work_struct *work)
408{
409 struct rhashtable *ht;
410 struct bucket_table *tbl;
b824478b 411 int err = 0;
97defe1e 412
57699a40 413 ht = container_of(work, struct rhashtable, run_work);
97defe1e 414 mutex_lock(&ht->mutex);
28134a53 415
97defe1e 416 tbl = rht_dereference(ht->tbl, ht);
b824478b 417 tbl = rhashtable_last_table(ht, tbl);
97defe1e 418
a5b6846f 419 if (rht_grow_above_75(ht, tbl))
da20420f 420 err = rhashtable_rehash_alloc(ht, tbl, tbl->size * 2);
b5e2c150 421 else if (ht->p.automatic_shrinking && rht_shrink_below_30(ht, tbl))
da20420f
HX
422 err = rhashtable_shrink(ht);
423 else if (tbl->nest)
424 err = rhashtable_rehash_alloc(ht, tbl, tbl->size);
b824478b 425
408f13ef
HX
426 if (!err || err == -EEXIST) {
427 int nerr;
428
429 nerr = rhashtable_rehash_table(ht);
430 err = err ?: nerr;
431 }
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
439static 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 460
93f976b5 461 new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC | __GFP_NOWARN);
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
475fail:
476 /* Do not fail the insert if someone else did a rehash. */
c0690016 477 if (likely(rcu_access_pointer(tbl->future_tbl)))
3cf92222
HX
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
487static 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 500 pprev = rht_bucket_var(tbl, hash);
ff302db9
N
501 if (!pprev)
502 return ERR_PTR(-ENOENT);
f7ad68bf 503 rht_for_each_from(head, *pprev, tbl, hash) {
ca26893f
HX
504 struct rhlist_head *list;
505 struct rhlist_head *plist;
506
507 elasticity--;
508 if (!key ||
509 (ht->p.obj_cmpfn ?
510 ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) :
d3dcf8eb
PB
511 rhashtable_compare(&arg, rht_obj(ht, head)))) {
512 pprev = &head->next;
ca26893f 513 continue;
d3dcf8eb 514 }
ca26893f
HX
515
516 if (!ht->rhlist)
517 return rht_obj(ht, head);
518
519 list = container_of(obj, struct rhlist_head, rhead);
520 plist = container_of(head, struct rhlist_head, rhead);
521
522 RCU_INIT_POINTER(list->next, plist);
523 head = rht_dereference_bucket(head->next, tbl, hash);
524 RCU_INIT_POINTER(list->rhead.next, head);
525 rcu_assign_pointer(*pprev, obj);
526
527 return NULL;
5ca8cc5b 528 }
02fd97c3 529
ca26893f
HX
530 if (elasticity <= 0)
531 return ERR_PTR(-EAGAIN);
532
533 return ERR_PTR(-ENOENT);
534}
535
536static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
537 struct bucket_table *tbl,
538 unsigned int hash,
539 struct rhash_head *obj,
540 void *data)
541{
da20420f 542 struct rhash_head __rcu **pprev;
ca26893f
HX
543 struct bucket_table *new_tbl;
544 struct rhash_head *head;
545
546 if (!IS_ERR_OR_NULL(data))
547 return ERR_PTR(-EEXIST);
07ee0722 548
ca26893f
HX
549 if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT)
550 return ERR_CAST(data);
ccd57b1b 551
c0690016 552 new_tbl = rht_dereference_rcu(tbl->future_tbl, ht);
ca26893f
HX
553 if (new_tbl)
554 return new_tbl;
555
556 if (PTR_ERR(data) != -ENOENT)
557 return ERR_CAST(data);
558
559 if (unlikely(rht_grow_above_max(ht, tbl)))
560 return ERR_PTR(-E2BIG);
561
562 if (unlikely(rht_grow_above_100(ht, tbl)))
563 return ERR_PTR(-EAGAIN);
02fd97c3 564
da20420f
HX
565 pprev = rht_bucket_insert(ht, tbl, hash);
566 if (!pprev)
567 return ERR_PTR(-ENOMEM);
568
569 head = rht_dereference_bucket(*pprev, tbl, hash);
02fd97c3
HX
570
571 RCU_INIT_POINTER(obj->next, head);
ca26893f
HX
572 if (ht->rhlist) {
573 struct rhlist_head *list;
574
575 list = container_of(obj, struct rhlist_head, rhead);
576 RCU_INIT_POINTER(list->next, NULL);
577 }
02fd97c3 578
da20420f 579 rcu_assign_pointer(*pprev, obj);
02fd97c3
HX
580
581 atomic_inc(&ht->nelems);
ca26893f
HX
582 if (rht_grow_above_75(ht, tbl))
583 schedule_work(&ht->run_work);
02fd97c3 584
ca26893f
HX
585 return NULL;
586}
02fd97c3 587
ca26893f
HX
588static void *rhashtable_try_insert(struct rhashtable *ht, const void *key,
589 struct rhash_head *obj)
590{
591 struct bucket_table *new_tbl;
592 struct bucket_table *tbl;
593 unsigned int hash;
ca26893f
HX
594 void *data;
595
4feb7c7a 596 new_tbl = rcu_dereference(ht->tbl);
ca26893f 597
4feb7c7a 598 do {
ca26893f
HX
599 tbl = new_tbl;
600 hash = rht_head_hashfn(ht, tbl, obj, ht->p);
4feb7c7a 601 spin_lock_bh(rht_bucket_lock(tbl, hash));
ca26893f
HX
602
603 data = rhashtable_lookup_one(ht, tbl, hash, key, obj);
604 new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data);
605 if (PTR_ERR(new_tbl) != -EEXIST)
606 data = ERR_CAST(new_tbl);
607
4feb7c7a
N
608 spin_unlock_bh(rht_bucket_lock(tbl, hash));
609 } while (!IS_ERR_OR_NULL(new_tbl));
ca26893f
HX
610
611 if (PTR_ERR(data) == -EAGAIN)
612 data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?:
613 -EAGAIN);
614
615 return data;
616}
617
618void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
619 struct rhash_head *obj)
620{
621 void *data;
622
623 do {
624 rcu_read_lock();
625 data = rhashtable_try_insert(ht, key, obj);
626 rcu_read_unlock();
627 } while (PTR_ERR(data) == -EAGAIN);
628
629 return data;
02fd97c3
HX
630}
631EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
632
f2dba9c6 633/**
246779dd 634 * rhashtable_walk_enter - Initialise an iterator
f2dba9c6
HX
635 * @ht: Table to walk over
636 * @iter: Hash table Iterator
637 *
638 * This function prepares a hash table walk.
639 *
640 * Note that if you restart a walk after rhashtable_walk_stop you
641 * may see the same object twice. Also, you may miss objects if
642 * there are removals in between rhashtable_walk_stop and the next
643 * call to rhashtable_walk_start.
644 *
645 * For a completely stable walk you should construct your own data
646 * structure outside the hash table.
647 *
82266e98
N
648 * This function may be called from any process context, including
649 * non-preemptable context, but cannot be called from softirq or
650 * hardirq context.
f2dba9c6 651 *
246779dd 652 * You must call rhashtable_walk_exit after this function returns.
f2dba9c6 653 */
246779dd 654void rhashtable_walk_enter(struct rhashtable *ht, struct rhashtable_iter *iter)
f2dba9c6
HX
655{
656 iter->ht = ht;
657 iter->p = NULL;
658 iter->slot = 0;
659 iter->skip = 0;
2db54b47 660 iter->end_of_table = 0;
f2dba9c6 661
c6ff5268 662 spin_lock(&ht->lock);
246779dd 663 iter->walker.tbl =
179ccc0a 664 rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock));
246779dd 665 list_add(&iter->walker.list, &iter->walker.tbl->walkers);
c6ff5268 666 spin_unlock(&ht->lock);
f2dba9c6 667}
246779dd 668EXPORT_SYMBOL_GPL(rhashtable_walk_enter);
f2dba9c6
HX
669
670/**
671 * rhashtable_walk_exit - Free an iterator
672 * @iter: Hash table Iterator
673 *
6c4128f6 674 * This function frees resources allocated by rhashtable_walk_enter.
f2dba9c6
HX
675 */
676void rhashtable_walk_exit(struct rhashtable_iter *iter)
677{
c6ff5268 678 spin_lock(&iter->ht->lock);
246779dd
HX
679 if (iter->walker.tbl)
680 list_del(&iter->walker.list);
c6ff5268 681 spin_unlock(&iter->ht->lock);
f2dba9c6
HX
682}
683EXPORT_SYMBOL_GPL(rhashtable_walk_exit);
684
685/**
97a6ec4a 686 * rhashtable_walk_start_check - Start a hash table walk
f2dba9c6
HX
687 * @iter: Hash table iterator
688 *
0647169c
AG
689 * Start a hash table walk at the current iterator position. Note that we take
690 * the RCU lock in all cases including when we return an error. So you must
691 * always call rhashtable_walk_stop to clean up.
f2dba9c6
HX
692 *
693 * Returns zero if successful.
694 *
695 * Returns -EAGAIN if resize event occured. Note that the iterator
696 * will rewind back to the beginning and you may use it immediately
697 * by calling rhashtable_walk_next.
97a6ec4a
TH
698 *
699 * rhashtable_walk_start is defined as an inline variant that returns
700 * void. This is preferred in cases where the caller would ignore
701 * resize events and always continue.
f2dba9c6 702 */
97a6ec4a 703int rhashtable_walk_start_check(struct rhashtable_iter *iter)
db4374f4 704 __acquires(RCU)
f2dba9c6 705{
eddee5ba 706 struct rhashtable *ht = iter->ht;
5d240a89 707 bool rhlist = ht->rhlist;
eddee5ba 708
c6ff5268 709 rcu_read_lock();
eddee5ba 710
c6ff5268 711 spin_lock(&ht->lock);
246779dd
HX
712 if (iter->walker.tbl)
713 list_del(&iter->walker.list);
c6ff5268 714 spin_unlock(&ht->lock);
eddee5ba 715
5d240a89
N
716 if (iter->end_of_table)
717 return 0;
718 if (!iter->walker.tbl) {
246779dd 719 iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht);
b41cc04b
N
720 iter->slot = 0;
721 iter->skip = 0;
f2dba9c6
HX
722 return -EAGAIN;
723 }
724
5d240a89
N
725 if (iter->p && !rhlist) {
726 /*
727 * We need to validate that 'p' is still in the table, and
728 * if so, update 'skip'
729 */
730 struct rhash_head *p;
731 int skip = 0;
732 rht_for_each_rcu(p, iter->walker.tbl, iter->slot) {
733 skip++;
734 if (p == iter->p) {
735 iter->skip = skip;
736 goto found;
737 }
738 }
739 iter->p = NULL;
740 } else if (iter->p && rhlist) {
741 /* Need to validate that 'list' is still in the table, and
742 * if so, update 'skip' and 'p'.
743 */
744 struct rhash_head *p;
745 struct rhlist_head *list;
746 int skip = 0;
747 rht_for_each_rcu(p, iter->walker.tbl, iter->slot) {
748 for (list = container_of(p, struct rhlist_head, rhead);
749 list;
750 list = rcu_dereference(list->next)) {
751 skip++;
752 if (list == iter->list) {
753 iter->p = p;
c643ecf3 754 iter->skip = skip;
5d240a89
N
755 goto found;
756 }
757 }
758 }
759 iter->p = NULL;
760 }
761found:
f2dba9c6
HX
762 return 0;
763}
97a6ec4a 764EXPORT_SYMBOL_GPL(rhashtable_walk_start_check);
f2dba9c6
HX
765
766/**
2db54b47
TH
767 * __rhashtable_walk_find_next - Find the next element in a table (or the first
768 * one in case of a new walk).
769 *
f2dba9c6
HX
770 * @iter: Hash table iterator
771 *
2db54b47 772 * Returns the found object or NULL when the end of the table is reached.
f2dba9c6 773 *
2db54b47 774 * Returns -EAGAIN if resize event occurred.
f2dba9c6 775 */
2db54b47 776static void *__rhashtable_walk_find_next(struct rhashtable_iter *iter)
f2dba9c6 777{
246779dd 778 struct bucket_table *tbl = iter->walker.tbl;
ca26893f 779 struct rhlist_head *list = iter->list;
f2dba9c6
HX
780 struct rhashtable *ht = iter->ht;
781 struct rhash_head *p = iter->p;
ca26893f 782 bool rhlist = ht->rhlist;
f2dba9c6 783
2db54b47
TH
784 if (!tbl)
785 return NULL;
f2dba9c6
HX
786
787 for (; iter->slot < tbl->size; iter->slot++) {
788 int skip = iter->skip;
789
790 rht_for_each_rcu(p, tbl, iter->slot) {
ca26893f
HX
791 if (rhlist) {
792 list = container_of(p, struct rhlist_head,
793 rhead);
794 do {
795 if (!skip)
796 goto next;
797 skip--;
798 list = rcu_dereference(list->next);
799 } while (list);
800
801 continue;
802 }
f2dba9c6
HX
803 if (!skip)
804 break;
805 skip--;
806 }
807
808next:
809 if (!rht_is_a_nulls(p)) {
810 iter->skip++;
811 iter->p = p;
ca26893f
HX
812 iter->list = list;
813 return rht_obj(ht, rhlist ? &list->rhead : p);
f2dba9c6
HX
814 }
815
816 iter->skip = 0;
817 }
818
142b942a
PS
819 iter->p = NULL;
820
d88252f9
HX
821 /* Ensure we see any new tables. */
822 smp_rmb();
823
246779dd
HX
824 iter->walker.tbl = rht_dereference_rcu(tbl->future_tbl, ht);
825 if (iter->walker.tbl) {
f2dba9c6
HX
826 iter->slot = 0;
827 iter->skip = 0;
f2dba9c6 828 return ERR_PTR(-EAGAIN);
2db54b47
TH
829 } else {
830 iter->end_of_table = true;
f2dba9c6
HX
831 }
832
c936a79f 833 return NULL;
f2dba9c6 834}
2db54b47
TH
835
836/**
837 * rhashtable_walk_next - Return the next object and advance the iterator
838 * @iter: Hash table iterator
839 *
840 * Note that you must call rhashtable_walk_stop when you are finished
841 * with the walk.
842 *
843 * Returns the next object or NULL when the end of the table is reached.
844 *
845 * Returns -EAGAIN if resize event occurred. Note that the iterator
846 * will rewind back to the beginning and you may continue to use it.
847 */
848void *rhashtable_walk_next(struct rhashtable_iter *iter)
849{
850 struct rhlist_head *list = iter->list;
851 struct rhashtable *ht = iter->ht;
852 struct rhash_head *p = iter->p;
853 bool rhlist = ht->rhlist;
854
855 if (p) {
856 if (!rhlist || !(list = rcu_dereference(list->next))) {
857 p = rcu_dereference(p->next);
858 list = container_of(p, struct rhlist_head, rhead);
859 }
860 if (!rht_is_a_nulls(p)) {
861 iter->skip++;
862 iter->p = p;
863 iter->list = list;
864 return rht_obj(ht, rhlist ? &list->rhead : p);
865 }
866
867 /* At the end of this slot, switch to next one and then find
868 * next entry from that point.
869 */
870 iter->skip = 0;
871 iter->slot++;
872 }
873
874 return __rhashtable_walk_find_next(iter);
875}
f2dba9c6
HX
876EXPORT_SYMBOL_GPL(rhashtable_walk_next);
877
2db54b47
TH
878/**
879 * rhashtable_walk_peek - Return the next object but don't advance the iterator
880 * @iter: Hash table iterator
881 *
882 * Returns the next object or NULL when the end of the table is reached.
883 *
884 * Returns -EAGAIN if resize event occurred. Note that the iterator
885 * will rewind back to the beginning and you may continue to use it.
886 */
887void *rhashtable_walk_peek(struct rhashtable_iter *iter)
888{
889 struct rhlist_head *list = iter->list;
890 struct rhashtable *ht = iter->ht;
891 struct rhash_head *p = iter->p;
892
893 if (p)
894 return rht_obj(ht, ht->rhlist ? &list->rhead : p);
895
896 /* No object found in current iter, find next one in the table. */
897
898 if (iter->skip) {
899 /* A nonzero skip value points to the next entry in the table
900 * beyond that last one that was found. Decrement skip so
901 * we find the current value. __rhashtable_walk_find_next
902 * will restore the original value of skip assuming that
903 * the table hasn't changed.
904 */
905 iter->skip--;
906 }
907
908 return __rhashtable_walk_find_next(iter);
909}
910EXPORT_SYMBOL_GPL(rhashtable_walk_peek);
911
f2dba9c6
HX
912/**
913 * rhashtable_walk_stop - Finish a hash table walk
914 * @iter: Hash table iterator
915 *
0647169c
AG
916 * Finish a hash table walk. Does not reset the iterator to the start of the
917 * hash table.
f2dba9c6
HX
918 */
919void rhashtable_walk_stop(struct rhashtable_iter *iter)
db4374f4 920 __releases(RCU)
f2dba9c6 921{
eddee5ba 922 struct rhashtable *ht;
246779dd 923 struct bucket_table *tbl = iter->walker.tbl;
eddee5ba 924
eddee5ba 925 if (!tbl)
963ecbd4 926 goto out;
eddee5ba
HX
927
928 ht = iter->ht;
929
ba7c95ea 930 spin_lock(&ht->lock);
4feb7c7a
N
931 if (rcu_head_after_call_rcu(&tbl->rcu, bucket_table_free_rcu))
932 /* This bucket table is being freed, don't re-link it. */
246779dd 933 iter->walker.tbl = NULL;
4feb7c7a
N
934 else
935 list_add(&iter->walker.list, &tbl->walkers);
ba7c95ea 936 spin_unlock(&ht->lock);
eddee5ba 937
963ecbd4
HX
938out:
939 rcu_read_unlock();
f2dba9c6
HX
940}
941EXPORT_SYMBOL_GPL(rhashtable_walk_stop);
942
488fb86e 943static size_t rounded_hashtable_size(const struct rhashtable_params *params)
7e1e7763 944{
107d01f5
DB
945 size_t retsize;
946
947 if (params->nelem_hint)
948 retsize = max(roundup_pow_of_two(params->nelem_hint * 4 / 3),
949 (unsigned long)params->min_size);
950 else
951 retsize = max(HASH_DEFAULT_SIZE,
952 (unsigned long)params->min_size);
953
954 return retsize;
7e1e7763
TG
955}
956
31ccde2d
HX
957static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed)
958{
959 return jhash2(key, length, seed);
960}
961
7e1e7763
TG
962/**
963 * rhashtable_init - initialize a new hash table
964 * @ht: hash table to be initialized
965 * @params: configuration parameters
966 *
967 * Initializes a new hash table based on the provided configuration
968 * parameters. A table can be configured either with a variable or
969 * fixed length key:
970 *
971 * Configuration Example 1: Fixed length keys
972 * struct test_obj {
973 * int key;
974 * void * my_member;
975 * struct rhash_head node;
976 * };
977 *
978 * struct rhashtable_params params = {
979 * .head_offset = offsetof(struct test_obj, node),
980 * .key_offset = offsetof(struct test_obj, key),
981 * .key_len = sizeof(int),
87545899 982 * .hashfn = jhash,
7e1e7763
TG
983 * };
984 *
985 * Configuration Example 2: Variable length keys
986 * struct test_obj {
987 * [...]
988 * struct rhash_head node;
989 * };
990 *
49f7b33e 991 * u32 my_hash_fn(const void *data, u32 len, u32 seed)
7e1e7763
TG
992 * {
993 * struct test_obj *obj = data;
994 *
995 * return [... hash ...];
996 * }
997 *
998 * struct rhashtable_params params = {
999 * .head_offset = offsetof(struct test_obj, node),
87545899 1000 * .hashfn = jhash,
7e1e7763 1001 * .obj_hashfn = my_hash_fn,
7e1e7763
TG
1002 * };
1003 */
488fb86e
HX
1004int rhashtable_init(struct rhashtable *ht,
1005 const struct rhashtable_params *params)
7e1e7763
TG
1006{
1007 struct bucket_table *tbl;
1008 size_t size;
1009
31ccde2d 1010 if ((!params->key_len && !params->obj_hashfn) ||
02fd97c3 1011 (params->obj_hashfn && !params->obj_cmpfn))
7e1e7763
TG
1012 return -EINVAL;
1013
97defe1e
TG
1014 memset(ht, 0, sizeof(*ht));
1015 mutex_init(&ht->mutex);
ba7c95ea 1016 spin_lock_init(&ht->lock);
97defe1e
TG
1017 memcpy(&ht->p, params, sizeof(*params));
1018
a998f712
TG
1019 if (params->min_size)
1020 ht->p.min_size = roundup_pow_of_two(params->min_size);
1021
6d684e54
HX
1022 /* Cap total entries at 2^31 to avoid nelems overflow. */
1023 ht->max_elems = 1u << 31;
2d2ab658
HX
1024
1025 if (params->max_size) {
1026 ht->p.max_size = rounddown_pow_of_two(params->max_size);
1027 if (ht->p.max_size < ht->max_elems / 2)
1028 ht->max_elems = ht->p.max_size * 2;
1029 }
6d684e54 1030
48e75b43 1031 ht->p.min_size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE);
a998f712 1032
107d01f5 1033 size = rounded_hashtable_size(&ht->p);
3a324606 1034
97defe1e
TG
1035 if (params->locks_mul)
1036 ht->p.locks_mul = roundup_pow_of_two(params->locks_mul);
1037 else
1038 ht->p.locks_mul = BUCKET_LOCKS_PER_CPU;
1039
31ccde2d
HX
1040 ht->key_len = ht->p.key_len;
1041 if (!params->hashfn) {
1042 ht->p.hashfn = jhash;
1043
1044 if (!(ht->key_len & (sizeof(u32) - 1))) {
1045 ht->key_len /= sizeof(u32);
1046 ht->p.hashfn = rhashtable_jhash2;
1047 }
1048 }
1049
2d22ecf6
DB
1050 /*
1051 * This is api initialization and thus we need to guarantee the
1052 * initial rhashtable allocation. Upon failure, retry with the
1053 * smallest possible size with __GFP_NOFAIL semantics.
1054 */
b9ecfdaa 1055 tbl = bucket_table_alloc(ht, size, GFP_KERNEL);
2d22ecf6
DB
1056 if (unlikely(tbl == NULL)) {
1057 size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE);
1058 tbl = bucket_table_alloc(ht, size, GFP_KERNEL | __GFP_NOFAIL);
1059 }
7e1e7763 1060
545a148e 1061 atomic_set(&ht->nelems, 0);
a5b6846f 1062
7e1e7763
TG
1063 RCU_INIT_POINTER(ht->tbl, tbl);
1064
4c4b52d9 1065 INIT_WORK(&ht->run_work, rht_deferred_worker);
97defe1e 1066
7e1e7763
TG
1067 return 0;
1068}
1069EXPORT_SYMBOL_GPL(rhashtable_init);
1070
ca26893f
HX
1071/**
1072 * rhltable_init - initialize a new hash list table
1073 * @hlt: hash list table to be initialized
1074 * @params: configuration parameters
1075 *
1076 * Initializes a new hash list table.
1077 *
1078 * See documentation for rhashtable_init.
1079 */
1080int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params)
1081{
1082 int err;
1083
ca26893f
HX
1084 err = rhashtable_init(&hlt->ht, params);
1085 hlt->ht.rhlist = true;
1086 return err;
1087}
1088EXPORT_SYMBOL_GPL(rhltable_init);
1089
1090static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj,
1091 void (*free_fn)(void *ptr, void *arg),
1092 void *arg)
1093{
1094 struct rhlist_head *list;
1095
1096 if (!ht->rhlist) {
1097 free_fn(rht_obj(ht, obj), arg);
1098 return;
1099 }
1100
1101 list = container_of(obj, struct rhlist_head, rhead);
1102 do {
1103 obj = &list->rhead;
1104 list = rht_dereference(list->next, ht);
1105 free_fn(rht_obj(ht, obj), arg);
1106 } while (list);
1107}
1108
7e1e7763 1109/**
6b6f302c 1110 * rhashtable_free_and_destroy - free elements and destroy hash table
7e1e7763 1111 * @ht: the hash table to destroy
6b6f302c
TG
1112 * @free_fn: callback to release resources of element
1113 * @arg: pointer passed to free_fn
7e1e7763 1114 *
6b6f302c
TG
1115 * Stops an eventual async resize. If defined, invokes free_fn for each
1116 * element to releasal resources. Please note that RCU protected
1117 * readers may still be accessing the elements. Releasing of resources
1118 * must occur in a compatible manner. Then frees the bucket array.
1119 *
1120 * This function will eventually sleep to wait for an async resize
1121 * to complete. The caller is responsible that no further write operations
1122 * occurs in parallel.
7e1e7763 1123 */
6b6f302c
TG
1124void rhashtable_free_and_destroy(struct rhashtable *ht,
1125 void (*free_fn)(void *ptr, void *arg),
1126 void *arg)
7e1e7763 1127{
0026129c 1128 struct bucket_table *tbl, *next_tbl;
6b6f302c 1129 unsigned int i;
97defe1e 1130
4c4b52d9 1131 cancel_work_sync(&ht->run_work);
97defe1e 1132
57699a40 1133 mutex_lock(&ht->mutex);
6b6f302c 1134 tbl = rht_dereference(ht->tbl, ht);
0026129c 1135restart:
6b6f302c
TG
1136 if (free_fn) {
1137 for (i = 0; i < tbl->size; i++) {
1138 struct rhash_head *pos, *next;
1139
ae6da1f5 1140 cond_resched();
da20420f 1141 for (pos = rht_dereference(*rht_bucket(tbl, i), ht),
6b6f302c
TG
1142 next = !rht_is_a_nulls(pos) ?
1143 rht_dereference(pos->next, ht) : NULL;
1144 !rht_is_a_nulls(pos);
1145 pos = next,
1146 next = !rht_is_a_nulls(pos) ?
1147 rht_dereference(pos->next, ht) : NULL)
ca26893f 1148 rhashtable_free_one(ht, pos, free_fn, arg);
6b6f302c
TG
1149 }
1150 }
1151
0026129c 1152 next_tbl = rht_dereference(tbl->future_tbl, ht);
6b6f302c 1153 bucket_table_free(tbl);
0026129c
TY
1154 if (next_tbl) {
1155 tbl = next_tbl;
1156 goto restart;
1157 }
97defe1e 1158 mutex_unlock(&ht->mutex);
7e1e7763 1159}
6b6f302c
TG
1160EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy);
1161
1162void rhashtable_destroy(struct rhashtable *ht)
1163{
1164 return rhashtable_free_and_destroy(ht, NULL, NULL);
1165}
7e1e7763 1166EXPORT_SYMBOL_GPL(rhashtable_destroy);
da20420f 1167
ff302db9
N
1168struct rhash_head __rcu **__rht_bucket_nested(const struct bucket_table *tbl,
1169 unsigned int hash)
da20420f
HX
1170{
1171 const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
da20420f
HX
1172 unsigned int index = hash & ((1 << tbl->nest) - 1);
1173 unsigned int size = tbl->size >> tbl->nest;
1174 unsigned int subhash = hash;
1175 union nested_table *ntbl;
1176
1177 ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]);
c4d2603d 1178 ntbl = rht_dereference_bucket_rcu(ntbl[index].table, tbl, hash);
da20420f
HX
1179 subhash >>= tbl->nest;
1180
1181 while (ntbl && size > (1 << shift)) {
1182 index = subhash & ((1 << shift) - 1);
c4d2603d
HX
1183 ntbl = rht_dereference_bucket_rcu(ntbl[index].table,
1184 tbl, hash);
da20420f
HX
1185 size >>= shift;
1186 subhash >>= shift;
1187 }
1188
ff302db9
N
1189 if (!ntbl)
1190 return NULL;
da20420f
HX
1191
1192 return &ntbl[subhash].bucket;
1193
1194}
ff302db9
N
1195EXPORT_SYMBOL_GPL(__rht_bucket_nested);
1196
1197struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
1198 unsigned int hash)
1199{
1200 static struct rhash_head __rcu *rhnull;
1201
1202 if (!rhnull)
1203 INIT_RHT_NULLS_HEAD(rhnull);
1204 return __rht_bucket_nested(tbl, hash) ?: &rhnull;
1205}
da20420f
HX
1206EXPORT_SYMBOL_GPL(rht_bucket_nested);
1207
1208struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
1209 struct bucket_table *tbl,
1210 unsigned int hash)
1211{
1212 const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
1213 unsigned int index = hash & ((1 << tbl->nest) - 1);
1214 unsigned int size = tbl->size >> tbl->nest;
1215 union nested_table *ntbl;
da20420f
HX
1216
1217 ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]);
1218 hash >>= tbl->nest;
da20420f 1219 ntbl = nested_table_alloc(ht, &ntbl[index].table,
5af68ef7 1220 size <= (1 << shift));
da20420f
HX
1221
1222 while (ntbl && size > (1 << shift)) {
1223 index = hash & ((1 << shift) - 1);
1224 size >>= shift;
1225 hash >>= shift;
da20420f 1226 ntbl = nested_table_alloc(ht, &ntbl[index].table,
5af68ef7 1227 size <= (1 << shift));
da20420f
HX
1228 }
1229
1230 if (!ntbl)
1231 return NULL;
1232
1233 return &ntbl[hash].bucket;
1234
1235}
1236EXPORT_SYMBOL_GPL(rht_bucket_nested_insert);