2 * Resizable, Scalable, Concurrent Hash Table
4 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
5 * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
6 * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
8 * Code partially derived from nft_hash
9 * Rewritten with rehash code from br_multicast plus single list
10 * pointer as suggested by Josh Triplett
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.
17 #include <linux/atomic.h>
18 #include <linux/kernel.h>
19 #include <linux/init.h>
20 #include <linux/log2.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 #include <linux/vmalloc.h>
25 #include <linux/jhash.h>
26 #include <linux/random.h>
27 #include <linux/rhashtable.h>
28 #include <linux/err.h>
29 #include <linux/export.h>
31 #define HASH_DEFAULT_SIZE 64UL
32 #define HASH_MIN_SIZE 4U
33 #define BUCKET_LOCKS_PER_CPU 32UL
35 static u32
head_hashfn(struct rhashtable
*ht
,
36 const struct bucket_table
*tbl
,
37 const struct rhash_head
*he
)
39 return rht_head_hashfn(ht
, tbl
, he
, ht
->p
);
42 #ifdef CONFIG_PROVE_LOCKING
43 #define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT))
45 int lockdep_rht_mutex_is_held(struct rhashtable
*ht
)
47 return (debug_locks
) ? lockdep_is_held(&ht
->mutex
) : 1;
49 EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held
);
51 int lockdep_rht_bucket_is_held(const struct bucket_table
*tbl
, u32 hash
)
53 spinlock_t
*lock
= rht_bucket_lock(tbl
, hash
);
55 return (debug_locks
) ? lockdep_is_held(lock
) : 1;
57 EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held
);
59 #define ASSERT_RHT_MUTEX(HT)
63 static int alloc_bucket_locks(struct rhashtable
*ht
, struct bucket_table
*tbl
,
67 #if defined(CONFIG_PROVE_LOCKING)
68 unsigned int nr_pcpus
= 2;
70 unsigned int nr_pcpus
= num_possible_cpus();
73 nr_pcpus
= min_t(unsigned int, nr_pcpus
, 64UL);
74 size
= roundup_pow_of_two(nr_pcpus
* ht
->p
.locks_mul
);
76 /* Never allocate more than 0.5 locks per bucket */
77 size
= min_t(unsigned int, size
, tbl
->size
>> 1);
79 if (sizeof(spinlock_t
) != 0) {
81 if (size
* sizeof(spinlock_t
) > PAGE_SIZE
&&
83 tbl
->locks
= vmalloc(size
* sizeof(spinlock_t
));
86 if (gfp
!= GFP_KERNEL
)
87 gfp
|= __GFP_NOWARN
| __GFP_NORETRY
;
89 tbl
->locks
= kmalloc_array(size
, sizeof(spinlock_t
),
93 for (i
= 0; i
< size
; i
++)
94 spin_lock_init(&tbl
->locks
[i
]);
96 tbl
->locks_mask
= size
- 1;
101 static void bucket_table_free(const struct bucket_table
*tbl
)
109 static void bucket_table_free_rcu(struct rcu_head
*head
)
111 bucket_table_free(container_of(head
, struct bucket_table
, rcu
));
114 static struct bucket_table
*bucket_table_alloc(struct rhashtable
*ht
,
118 struct bucket_table
*tbl
= NULL
;
122 size
= sizeof(*tbl
) + nbuckets
* sizeof(tbl
->buckets
[0]);
123 if (size
<= (PAGE_SIZE
<< PAGE_ALLOC_COSTLY_ORDER
) ||
125 tbl
= kzalloc(size
, gfp
| __GFP_NOWARN
| __GFP_NORETRY
);
126 if (tbl
== NULL
&& gfp
== GFP_KERNEL
)
131 tbl
->size
= nbuckets
;
133 if (alloc_bucket_locks(ht
, tbl
, gfp
) < 0) {
134 bucket_table_free(tbl
);
138 INIT_LIST_HEAD(&tbl
->walkers
);
140 get_random_bytes(&tbl
->hash_rnd
, sizeof(tbl
->hash_rnd
));
142 for (i
= 0; i
< nbuckets
; i
++)
143 INIT_RHT_NULLS_HEAD(tbl
->buckets
[i
], ht
, i
);
148 static struct bucket_table
*rhashtable_last_table(struct rhashtable
*ht
,
149 struct bucket_table
*tbl
)
151 struct bucket_table
*new_tbl
;
155 tbl
= rht_dereference_rcu(tbl
->future_tbl
, ht
);
161 static int rhashtable_rehash_one(struct rhashtable
*ht
, unsigned int old_hash
)
163 struct bucket_table
*old_tbl
= rht_dereference(ht
->tbl
, ht
);
164 struct bucket_table
*new_tbl
= rhashtable_last_table(ht
,
165 rht_dereference_rcu(old_tbl
->future_tbl
, ht
));
166 struct rhash_head __rcu
**pprev
= &old_tbl
->buckets
[old_hash
];
168 struct rhash_head
*head
, *next
, *entry
;
169 spinlock_t
*new_bucket_lock
;
170 unsigned int new_hash
;
172 rht_for_each(entry
, old_tbl
, old_hash
) {
174 next
= rht_dereference_bucket(entry
->next
, old_tbl
, old_hash
);
176 if (rht_is_a_nulls(next
))
179 pprev
= &entry
->next
;
185 new_hash
= head_hashfn(ht
, new_tbl
, entry
);
187 new_bucket_lock
= rht_bucket_lock(new_tbl
, new_hash
);
189 spin_lock_nested(new_bucket_lock
, SINGLE_DEPTH_NESTING
);
190 head
= rht_dereference_bucket(new_tbl
->buckets
[new_hash
],
193 RCU_INIT_POINTER(entry
->next
, head
);
195 rcu_assign_pointer(new_tbl
->buckets
[new_hash
], entry
);
196 spin_unlock(new_bucket_lock
);
198 rcu_assign_pointer(*pprev
, next
);
204 static void rhashtable_rehash_chain(struct rhashtable
*ht
,
205 unsigned int old_hash
)
207 struct bucket_table
*old_tbl
= rht_dereference(ht
->tbl
, ht
);
208 spinlock_t
*old_bucket_lock
;
210 old_bucket_lock
= rht_bucket_lock(old_tbl
, old_hash
);
212 spin_lock_bh(old_bucket_lock
);
213 while (!rhashtable_rehash_one(ht
, old_hash
))
216 spin_unlock_bh(old_bucket_lock
);
219 static int rhashtable_rehash_attach(struct rhashtable
*ht
,
220 struct bucket_table
*old_tbl
,
221 struct bucket_table
*new_tbl
)
223 /* Protect future_tbl using the first bucket lock. */
224 spin_lock_bh(old_tbl
->locks
);
226 /* Did somebody beat us to it? */
227 if (rcu_access_pointer(old_tbl
->future_tbl
)) {
228 spin_unlock_bh(old_tbl
->locks
);
232 /* Make insertions go into the new, empty table right away. Deletions
233 * and lookups will be attempted in both tables until we synchronize.
235 rcu_assign_pointer(old_tbl
->future_tbl
, new_tbl
);
237 spin_unlock_bh(old_tbl
->locks
);
242 static int rhashtable_rehash_table(struct rhashtable
*ht
)
244 struct bucket_table
*old_tbl
= rht_dereference(ht
->tbl
, ht
);
245 struct bucket_table
*new_tbl
;
246 struct rhashtable_walker
*walker
;
247 unsigned int old_hash
;
249 new_tbl
= rht_dereference(old_tbl
->future_tbl
, ht
);
253 for (old_hash
= 0; old_hash
< old_tbl
->size
; old_hash
++)
254 rhashtable_rehash_chain(ht
, old_hash
);
256 /* Publish the new table pointer. */
257 rcu_assign_pointer(ht
->tbl
, new_tbl
);
259 spin_lock(&ht
->lock
);
260 list_for_each_entry(walker
, &old_tbl
->walkers
, list
)
262 spin_unlock(&ht
->lock
);
264 /* Wait for readers. All new readers will see the new
265 * table, and thus no references to the old table will
268 call_rcu(&old_tbl
->rcu
, bucket_table_free_rcu
);
270 return rht_dereference(new_tbl
->future_tbl
, ht
) ? -EAGAIN
: 0;
274 * rhashtable_expand - Expand hash table while allowing concurrent lookups
275 * @ht: the hash table to expand
277 * A secondary bucket array is allocated and the hash entries are migrated.
279 * This function may only be called in a context where it is safe to call
280 * synchronize_rcu(), e.g. not within a rcu_read_lock() section.
282 * The caller must ensure that no concurrent resizing occurs by holding
285 * It is valid to have concurrent insertions and deletions protected by per
286 * bucket locks or concurrent RCU protected lookups and traversals.
288 static int rhashtable_expand(struct rhashtable
*ht
)
290 struct bucket_table
*new_tbl
, *old_tbl
= rht_dereference(ht
->tbl
, ht
);
293 ASSERT_RHT_MUTEX(ht
);
295 old_tbl
= rhashtable_last_table(ht
, old_tbl
);
297 new_tbl
= bucket_table_alloc(ht
, old_tbl
->size
* 2, GFP_KERNEL
);
301 err
= rhashtable_rehash_attach(ht
, old_tbl
, new_tbl
);
303 bucket_table_free(new_tbl
);
309 * rhashtable_shrink - Shrink hash table while allowing concurrent lookups
310 * @ht: the hash table to shrink
312 * This function shrinks the hash table to fit, i.e., the smallest
313 * size would not cause it to expand right away automatically.
315 * The caller must ensure that no concurrent resizing occurs by holding
318 * The caller must ensure that no concurrent table mutations take place.
319 * It is however valid to have concurrent lookups if they are RCU protected.
321 * It is valid to have concurrent insertions and deletions protected by per
322 * bucket locks or concurrent RCU protected lookups and traversals.
324 static int rhashtable_shrink(struct rhashtable
*ht
)
326 struct bucket_table
*new_tbl
, *old_tbl
= rht_dereference(ht
->tbl
, ht
);
327 unsigned int nelems
= atomic_read(&ht
->nelems
);
328 unsigned int size
= 0;
331 ASSERT_RHT_MUTEX(ht
);
334 size
= roundup_pow_of_two(nelems
* 3 / 2);
335 if (size
< ht
->p
.min_size
)
336 size
= ht
->p
.min_size
;
338 if (old_tbl
->size
<= size
)
341 if (rht_dereference(old_tbl
->future_tbl
, ht
))
344 new_tbl
= bucket_table_alloc(ht
, size
, GFP_KERNEL
);
348 err
= rhashtable_rehash_attach(ht
, old_tbl
, new_tbl
);
350 bucket_table_free(new_tbl
);
355 static void rht_deferred_worker(struct work_struct
*work
)
357 struct rhashtable
*ht
;
358 struct bucket_table
*tbl
;
361 ht
= container_of(work
, struct rhashtable
, run_work
);
362 mutex_lock(&ht
->mutex
);
364 tbl
= rht_dereference(ht
->tbl
, ht
);
365 tbl
= rhashtable_last_table(ht
, tbl
);
367 if (rht_grow_above_75(ht
, tbl
))
368 rhashtable_expand(ht
);
369 else if (ht
->p
.automatic_shrinking
&& rht_shrink_below_30(ht
, tbl
))
370 rhashtable_shrink(ht
);
372 err
= rhashtable_rehash_table(ht
);
374 mutex_unlock(&ht
->mutex
);
377 schedule_work(&ht
->run_work
);
380 static bool rhashtable_check_elasticity(struct rhashtable
*ht
,
381 struct bucket_table
*tbl
,
384 unsigned int elasticity
= ht
->elasticity
;
385 struct rhash_head
*head
;
387 rht_for_each(head
, tbl
, hash
)
394 int rhashtable_insert_rehash(struct rhashtable
*ht
,
395 struct bucket_table
*tbl
)
397 struct bucket_table
*old_tbl
;
398 struct bucket_table
*new_tbl
;
402 old_tbl
= rht_dereference_rcu(ht
->tbl
, ht
);
408 if (rht_grow_above_75(ht
, tbl
))
410 /* Do not schedule more than one rehash */
411 else if (old_tbl
!= tbl
)
416 new_tbl
= bucket_table_alloc(ht
, size
, GFP_ATOMIC
);
420 err
= rhashtable_rehash_attach(ht
, tbl
, new_tbl
);
422 bucket_table_free(new_tbl
);
426 schedule_work(&ht
->run_work
);
431 /* Do not fail the insert if someone else did a rehash. */
432 if (likely(rcu_dereference_raw(tbl
->future_tbl
)))
435 /* Schedule async rehash to retry allocation in process context. */
437 schedule_work(&ht
->run_work
);
441 EXPORT_SYMBOL_GPL(rhashtable_insert_rehash
);
443 struct bucket_table
*rhashtable_insert_slow(struct rhashtable
*ht
,
445 struct rhash_head
*obj
,
446 struct bucket_table
*tbl
)
448 struct rhash_head
*head
;
452 tbl
= rhashtable_last_table(ht
, tbl
);
453 hash
= head_hashfn(ht
, tbl
, obj
);
454 spin_lock_nested(rht_bucket_lock(tbl
, hash
), SINGLE_DEPTH_NESTING
);
457 if (key
&& rhashtable_lookup_fast(ht
, key
, ht
->p
))
461 if (unlikely(rht_grow_above_max(ht
, tbl
)))
465 if (rhashtable_check_elasticity(ht
, tbl
, hash
) ||
466 rht_grow_above_100(ht
, tbl
))
471 head
= rht_dereference_bucket(tbl
->buckets
[hash
], tbl
, hash
);
473 RCU_INIT_POINTER(obj
->next
, head
);
475 rcu_assign_pointer(tbl
->buckets
[hash
], obj
);
477 atomic_inc(&ht
->nelems
);
480 spin_unlock(rht_bucket_lock(tbl
, hash
));
484 else if (err
== -EAGAIN
)
489 EXPORT_SYMBOL_GPL(rhashtable_insert_slow
);
492 * rhashtable_walk_init - Initialise an iterator
493 * @ht: Table to walk over
494 * @iter: Hash table Iterator
495 * @gfp: GFP flags for allocations
497 * This function prepares a hash table walk.
499 * Note that if you restart a walk after rhashtable_walk_stop you
500 * may see the same object twice. Also, you may miss objects if
501 * there are removals in between rhashtable_walk_stop and the next
502 * call to rhashtable_walk_start.
504 * For a completely stable walk you should construct your own data
505 * structure outside the hash table.
507 * This function may sleep so you must not call it from interrupt
508 * context or with spin locks held.
510 * You must call rhashtable_walk_exit if this function returns
513 int rhashtable_walk_init(struct rhashtable
*ht
, struct rhashtable_iter
*iter
,
521 iter
->walker
= kmalloc(sizeof(*iter
->walker
), gfp
);
525 spin_lock(&ht
->lock
);
527 rcu_dereference_protected(ht
->tbl
, lockdep_is_held(&ht
->lock
));
528 list_add(&iter
->walker
->list
, &iter
->walker
->tbl
->walkers
);
529 spin_unlock(&ht
->lock
);
533 EXPORT_SYMBOL_GPL(rhashtable_walk_init
);
536 * rhashtable_walk_exit - Free an iterator
537 * @iter: Hash table Iterator
539 * This function frees resources allocated by rhashtable_walk_init.
541 void rhashtable_walk_exit(struct rhashtable_iter
*iter
)
543 spin_lock(&iter
->ht
->lock
);
544 if (iter
->walker
->tbl
)
545 list_del(&iter
->walker
->list
);
546 spin_unlock(&iter
->ht
->lock
);
549 EXPORT_SYMBOL_GPL(rhashtable_walk_exit
);
552 * rhashtable_walk_start - Start a hash table walk
553 * @iter: Hash table iterator
555 * Start a hash table walk. Note that we take the RCU lock in all
556 * cases including when we return an error. So you must always call
557 * rhashtable_walk_stop to clean up.
559 * Returns zero if successful.
561 * Returns -EAGAIN if resize event occured. Note that the iterator
562 * will rewind back to the beginning and you may use it immediately
563 * by calling rhashtable_walk_next.
565 int rhashtable_walk_start(struct rhashtable_iter
*iter
)
568 struct rhashtable
*ht
= iter
->ht
;
572 spin_lock(&ht
->lock
);
573 if (iter
->walker
->tbl
)
574 list_del(&iter
->walker
->list
);
575 spin_unlock(&ht
->lock
);
577 if (!iter
->walker
->tbl
) {
578 iter
->walker
->tbl
= rht_dereference_rcu(ht
->tbl
, ht
);
584 EXPORT_SYMBOL_GPL(rhashtable_walk_start
);
587 * rhashtable_walk_next - Return the next object and advance the iterator
588 * @iter: Hash table iterator
590 * Note that you must call rhashtable_walk_stop when you are finished
593 * Returns the next object or NULL when the end of the table is reached.
595 * Returns -EAGAIN if resize event occured. Note that the iterator
596 * will rewind back to the beginning and you may continue to use it.
598 void *rhashtable_walk_next(struct rhashtable_iter
*iter
)
600 struct bucket_table
*tbl
= iter
->walker
->tbl
;
601 struct rhashtable
*ht
= iter
->ht
;
602 struct rhash_head
*p
= iter
->p
;
605 p
= rht_dereference_bucket_rcu(p
->next
, tbl
, iter
->slot
);
609 for (; iter
->slot
< tbl
->size
; iter
->slot
++) {
610 int skip
= iter
->skip
;
612 rht_for_each_rcu(p
, tbl
, iter
->slot
) {
619 if (!rht_is_a_nulls(p
)) {
622 return rht_obj(ht
, p
);
630 /* Ensure we see any new tables. */
633 iter
->walker
->tbl
= rht_dereference_rcu(tbl
->future_tbl
, ht
);
634 if (iter
->walker
->tbl
) {
637 return ERR_PTR(-EAGAIN
);
642 EXPORT_SYMBOL_GPL(rhashtable_walk_next
);
645 * rhashtable_walk_stop - Finish a hash table walk
646 * @iter: Hash table iterator
648 * Finish a hash table walk.
650 void rhashtable_walk_stop(struct rhashtable_iter
*iter
)
653 struct rhashtable
*ht
;
654 struct bucket_table
*tbl
= iter
->walker
->tbl
;
661 spin_lock(&ht
->lock
);
662 if (tbl
->rehash
< tbl
->size
)
663 list_add(&iter
->walker
->list
, &tbl
->walkers
);
665 iter
->walker
->tbl
= NULL
;
666 spin_unlock(&ht
->lock
);
673 EXPORT_SYMBOL_GPL(rhashtable_walk_stop
);
675 static size_t rounded_hashtable_size(const struct rhashtable_params
*params
)
677 return max(roundup_pow_of_two(params
->nelem_hint
* 4 / 3),
678 (unsigned long)params
->min_size
);
681 static u32
rhashtable_jhash2(const void *key
, u32 length
, u32 seed
)
683 return jhash2(key
, length
, seed
);
687 * rhashtable_init - initialize a new hash table
688 * @ht: hash table to be initialized
689 * @params: configuration parameters
691 * Initializes a new hash table based on the provided configuration
692 * parameters. A table can be configured either with a variable or
695 * Configuration Example 1: Fixed length keys
699 * struct rhash_head node;
702 * struct rhashtable_params params = {
703 * .head_offset = offsetof(struct test_obj, node),
704 * .key_offset = offsetof(struct test_obj, key),
705 * .key_len = sizeof(int),
707 * .nulls_base = (1U << RHT_BASE_SHIFT),
710 * Configuration Example 2: Variable length keys
713 * struct rhash_head node;
716 * u32 my_hash_fn(const void *data, u32 len, u32 seed)
718 * struct test_obj *obj = data;
720 * return [... hash ...];
723 * struct rhashtable_params params = {
724 * .head_offset = offsetof(struct test_obj, node),
726 * .obj_hashfn = my_hash_fn,
729 int rhashtable_init(struct rhashtable
*ht
,
730 const struct rhashtable_params
*params
)
732 struct bucket_table
*tbl
;
735 size
= HASH_DEFAULT_SIZE
;
737 if ((!params
->key_len
&& !params
->obj_hashfn
) ||
738 (params
->obj_hashfn
&& !params
->obj_cmpfn
))
741 if (params
->nulls_base
&& params
->nulls_base
< (1U << RHT_BASE_SHIFT
))
744 memset(ht
, 0, sizeof(*ht
));
745 mutex_init(&ht
->mutex
);
746 spin_lock_init(&ht
->lock
);
747 memcpy(&ht
->p
, params
, sizeof(*params
));
749 if (params
->min_size
)
750 ht
->p
.min_size
= roundup_pow_of_two(params
->min_size
);
752 if (params
->max_size
)
753 ht
->p
.max_size
= rounddown_pow_of_two(params
->max_size
);
755 if (params
->insecure_max_entries
)
756 ht
->p
.insecure_max_entries
=
757 rounddown_pow_of_two(params
->insecure_max_entries
);
759 ht
->p
.insecure_max_entries
= ht
->p
.max_size
* 2;
761 ht
->p
.min_size
= max(ht
->p
.min_size
, HASH_MIN_SIZE
);
763 if (params
->nelem_hint
)
764 size
= rounded_hashtable_size(&ht
->p
);
766 /* The maximum (not average) chain length grows with the
767 * size of the hash table, at a rate of (log N)/(log log N).
768 * The value of 16 is selected so that even if the hash
769 * table grew to 2^32 you would not expect the maximum
770 * chain length to exceed it unless we are under attack
771 * (or extremely unlucky).
773 * As this limit is only to detect attacks, we don't need
774 * to set it to a lower value as you'd need the chain
775 * length to vastly exceed 16 to have any real effect
778 if (!params
->insecure_elasticity
)
781 if (params
->locks_mul
)
782 ht
->p
.locks_mul
= roundup_pow_of_two(params
->locks_mul
);
784 ht
->p
.locks_mul
= BUCKET_LOCKS_PER_CPU
;
786 ht
->key_len
= ht
->p
.key_len
;
787 if (!params
->hashfn
) {
788 ht
->p
.hashfn
= jhash
;
790 if (!(ht
->key_len
& (sizeof(u32
) - 1))) {
791 ht
->key_len
/= sizeof(u32
);
792 ht
->p
.hashfn
= rhashtable_jhash2
;
796 tbl
= bucket_table_alloc(ht
, size
, GFP_KERNEL
);
800 atomic_set(&ht
->nelems
, 0);
802 RCU_INIT_POINTER(ht
->tbl
, tbl
);
804 INIT_WORK(&ht
->run_work
, rht_deferred_worker
);
808 EXPORT_SYMBOL_GPL(rhashtable_init
);
811 * rhashtable_free_and_destroy - free elements and destroy hash table
812 * @ht: the hash table to destroy
813 * @free_fn: callback to release resources of element
814 * @arg: pointer passed to free_fn
816 * Stops an eventual async resize. If defined, invokes free_fn for each
817 * element to releasal resources. Please note that RCU protected
818 * readers may still be accessing the elements. Releasing of resources
819 * must occur in a compatible manner. Then frees the bucket array.
821 * This function will eventually sleep to wait for an async resize
822 * to complete. The caller is responsible that no further write operations
823 * occurs in parallel.
825 void rhashtable_free_and_destroy(struct rhashtable
*ht
,
826 void (*free_fn
)(void *ptr
, void *arg
),
829 const struct bucket_table
*tbl
;
832 cancel_work_sync(&ht
->run_work
);
834 mutex_lock(&ht
->mutex
);
835 tbl
= rht_dereference(ht
->tbl
, ht
);
837 for (i
= 0; i
< tbl
->size
; i
++) {
838 struct rhash_head
*pos
, *next
;
840 for (pos
= rht_dereference(tbl
->buckets
[i
], ht
),
841 next
= !rht_is_a_nulls(pos
) ?
842 rht_dereference(pos
->next
, ht
) : NULL
;
843 !rht_is_a_nulls(pos
);
845 next
= !rht_is_a_nulls(pos
) ?
846 rht_dereference(pos
->next
, ht
) : NULL
)
847 free_fn(rht_obj(ht
, pos
), arg
);
851 bucket_table_free(tbl
);
852 mutex_unlock(&ht
->mutex
);
854 EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy
);
856 void rhashtable_destroy(struct rhashtable
*ht
)
858 return rhashtable_free_and_destroy(ht
, NULL
, NULL
);
860 EXPORT_SYMBOL_GPL(rhashtable_destroy
);