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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Resizable, Scalable, Concurrent Hash Table
4 *
5 * Copyright (c) 2015-2016 Herbert Xu <herbert@gondor.apana.org.au>
6 * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
7 * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
8 *
9 * Code partially derived from nft_hash
10 * Rewritten with rehash code from br_multicast plus single list
11 * pointer as suggested by Josh Triplett
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
16 */
17
18#ifndef _LINUX_RHASHTABLE_H
19#define _LINUX_RHASHTABLE_H
20
21#include <linux/err.h>
22#include <linux/errno.h>
23#include <linux/jhash.h>
24#include <linux/list_nulls.h>
25#include <linux/workqueue.h>
26#include <linux/rculist.h>
27#include <linux/bit_spinlock.h>
28
29#include <linux/rhashtable-types.h>
30/*
31 * Objects in an rhashtable have an embedded struct rhash_head
32 * which is linked into as hash chain from the hash table - or one
33 * of two or more hash tables when the rhashtable is being resized.
34 * The end of the chain is marked with a special nulls marks which has
35 * the least significant bit set but otherwise stores the address of
36 * the hash bucket. This allows us to be sure we've found the end
37 * of the right list.
38 * The value stored in the hash bucket has BIT(0) used as a lock bit.
39 * This bit must be atomically set before any changes are made to
40 * the chain. To avoid dereferencing this pointer without clearing
41 * the bit first, we use an opaque 'struct rhash_lock_head *' for the
42 * pointer stored in the bucket. This struct needs to be defined so
43 * that rcu_dereference() works on it, but it has no content so a
44 * cast is needed for it to be useful. This ensures it isn't
45 * used by mistake with clearing the lock bit first.
46 */
47struct rhash_lock_head {};
48
49/* Maximum chain length before rehash
50 *
51 * The maximum (not average) chain length grows with the size of the hash
52 * table, at a rate of (log N)/(log log N).
53 *
54 * The value of 16 is selected so that even if the hash table grew to
55 * 2^32 you would not expect the maximum chain length to exceed it
56 * unless we are under attack (or extremely unlucky).
57 *
58 * As this limit is only to detect attacks, we don't need to set it to a
59 * lower value as you'd need the chain length to vastly exceed 16 to have
60 * any real effect on the system.
61 */
62#define RHT_ELASTICITY 16u
63
64/**
65 * struct bucket_table - Table of hash buckets
66 * @size: Number of hash buckets
67 * @nest: Number of bits of first-level nested table.
68 * @rehash: Current bucket being rehashed
69 * @hash_rnd: Random seed to fold into hash
70 * @walkers: List of active walkers
71 * @rcu: RCU structure for freeing the table
72 * @future_tbl: Table under construction during rehashing
73 * @ntbl: Nested table used when out of memory.
74 * @buckets: size * hash buckets
75 */
76struct bucket_table {
77 unsigned int size;
78 unsigned int nest;
79 u32 hash_rnd;
80 struct list_head walkers;
81 struct rcu_head rcu;
82
83 struct bucket_table __rcu *future_tbl;
84
85 struct lockdep_map dep_map;
86
87 struct rhash_lock_head __rcu *buckets[] ____cacheline_aligned_in_smp;
88};
89
90/*
91 * NULLS_MARKER() expects a hash value with the low
92 * bits mostly likely to be significant, and it discards
93 * the msb.
94 * We give it an address, in which the bottom bit is
95 * always 0, and the msb might be significant.
96 * So we shift the address down one bit to align with
97 * expectations and avoid losing a significant bit.
98 *
99 * We never store the NULLS_MARKER in the hash table
100 * itself as we need the lsb for locking.
101 * Instead we store a NULL
102 */
103#define RHT_NULLS_MARKER(ptr) \
104 ((void *)NULLS_MARKER(((unsigned long) (ptr)) >> 1))
105#define INIT_RHT_NULLS_HEAD(ptr) \
106 ((ptr) = NULL)
107
108static inline bool rht_is_a_nulls(const struct rhash_head *ptr)
109{
110 return ((unsigned long) ptr & 1);
111}
112
113static inline void *rht_obj(const struct rhashtable *ht,
114 const struct rhash_head *he)
115{
116 return (char *)he - ht->p.head_offset;
117}
118
119static inline unsigned int rht_bucket_index(const struct bucket_table *tbl,
120 unsigned int hash)
121{
122 return hash & (tbl->size - 1);
123}
124
125static __always_inline unsigned int rht_key_get_hash(struct rhashtable *ht,
126 const void *key, const struct rhashtable_params params,
127 unsigned int hash_rnd)
128{
129 unsigned int hash;
130
131 /* params must be equal to ht->p if it isn't constant. */
132 if (!__builtin_constant_p(params.key_len))
133 hash = ht->p.hashfn(key, ht->key_len, hash_rnd);
134 else if (params.key_len) {
135 unsigned int key_len = params.key_len;
136
137 if (params.hashfn)
138 hash = params.hashfn(key, key_len, hash_rnd);
139 else if (key_len & (sizeof(u32) - 1))
140 hash = jhash(key, length: key_len, initval: hash_rnd);
141 else
142 hash = jhash2(k: key, length: key_len / sizeof(u32), initval: hash_rnd);
143 } else {
144 unsigned int key_len = ht->p.key_len;
145
146 if (params.hashfn)
147 hash = params.hashfn(key, key_len, hash_rnd);
148 else
149 hash = jhash(key, length: key_len, initval: hash_rnd);
150 }
151
152 return hash;
153}
154
155static __always_inline unsigned int rht_key_hashfn(
156 struct rhashtable *ht, const struct bucket_table *tbl,
157 const void *key, const struct rhashtable_params params)
158{
159 unsigned int hash = rht_key_get_hash(ht, key, params, hash_rnd: tbl->hash_rnd);
160
161 return rht_bucket_index(tbl, hash);
162}
163
164static __always_inline unsigned int rht_head_hashfn(
165 struct rhashtable *ht, const struct bucket_table *tbl,
166 const struct rhash_head *he, const struct rhashtable_params params)
167{
168 const char *ptr = rht_obj(ht, he);
169
170 return likely(params.obj_hashfn) ?
171 rht_bucket_index(tbl, hash: params.obj_hashfn(ptr, params.key_len ?:
172 ht->p.key_len,
173 tbl->hash_rnd)) :
174 rht_key_hashfn(ht, tbl, key: ptr + params.key_offset, params);
175}
176
177/**
178 * rht_grow_above_75 - returns true if nelems > 0.75 * table-size
179 * @ht: hash table
180 * @tbl: current table
181 */
182static inline bool rht_grow_above_75(const struct rhashtable *ht,
183 const struct bucket_table *tbl)
184{
185 /* Expand table when exceeding 75% load */
186 return atomic_read(v: &ht->nelems) > (tbl->size / 4 * 3) &&
187 (!ht->p.max_size || tbl->size < ht->p.max_size);
188}
189
190/**
191 * rht_shrink_below_30 - returns true if nelems < 0.3 * table-size
192 * @ht: hash table
193 * @tbl: current table
194 */
195static inline bool rht_shrink_below_30(const struct rhashtable *ht,
196 const struct bucket_table *tbl)
197{
198 /* Shrink table beneath 30% load */
199 return atomic_read(v: &ht->nelems) < (tbl->size * 3 / 10) &&
200 tbl->size > ht->p.min_size;
201}
202
203/**
204 * rht_grow_above_100 - returns true if nelems > table-size
205 * @ht: hash table
206 * @tbl: current table
207 */
208static inline bool rht_grow_above_100(const struct rhashtable *ht,
209 const struct bucket_table *tbl)
210{
211 return atomic_read(v: &ht->nelems) > tbl->size &&
212 (!ht->p.max_size || tbl->size < ht->p.max_size);
213}
214
215/**
216 * rht_grow_above_max - returns true if table is above maximum
217 * @ht: hash table
218 * @tbl: current table
219 */
220static inline bool rht_grow_above_max(const struct rhashtable *ht,
221 const struct bucket_table *tbl)
222{
223 return atomic_read(v: &ht->nelems) >= ht->max_elems;
224}
225
226#ifdef CONFIG_PROVE_LOCKING
227int lockdep_rht_mutex_is_held(struct rhashtable *ht);
228int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash);
229#else
230static inline int lockdep_rht_mutex_is_held(struct rhashtable *ht)
231{
232 return 1;
233}
234
235static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl,
236 u32 hash)
237{
238 return 1;
239}
240#endif /* CONFIG_PROVE_LOCKING */
241
242void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
243 struct rhash_head *obj);
244
245void rhashtable_walk_enter(struct rhashtable *ht,
246 struct rhashtable_iter *iter);
247void rhashtable_walk_exit(struct rhashtable_iter *iter);
248int rhashtable_walk_start_check(struct rhashtable_iter *iter) __acquires(RCU);
249
250static inline void rhashtable_walk_start(struct rhashtable_iter *iter)
251{
252 (void)rhashtable_walk_start_check(iter);
253}
254
255void *rhashtable_walk_next(struct rhashtable_iter *iter);
256void *rhashtable_walk_peek(struct rhashtable_iter *iter);
257void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases(RCU);
258
259void rhashtable_free_and_destroy(struct rhashtable *ht,
260 void (*free_fn)(void *ptr, void *arg),
261 void *arg);
262void rhashtable_destroy(struct rhashtable *ht);
263
264struct rhash_lock_head __rcu **rht_bucket_nested(
265 const struct bucket_table *tbl, unsigned int hash);
266struct rhash_lock_head __rcu **__rht_bucket_nested(
267 const struct bucket_table *tbl, unsigned int hash);
268struct rhash_lock_head __rcu **rht_bucket_nested_insert(
269 struct rhashtable *ht, struct bucket_table *tbl, unsigned int hash);
270
271#define rht_dereference(p, ht) \
272 rcu_dereference_protected(p, lockdep_rht_mutex_is_held(ht))
273
274#define rht_dereference_rcu(p, ht) \
275 rcu_dereference_all_check(p, lockdep_rht_mutex_is_held(ht))
276
277#define rht_dereference_bucket(p, tbl, hash) \
278 rcu_dereference_protected(p, lockdep_rht_bucket_is_held(tbl, hash))
279
280#define rht_dereference_bucket_rcu(p, tbl, hash) \
281 rcu_dereference_all_check(p, lockdep_rht_bucket_is_held(tbl, hash))
282
283#define rht_entry(tpos, pos, member) \
284 ({ tpos = container_of(pos, typeof(*tpos), member); 1; })
285
286static inline struct rhash_lock_head __rcu *const *rht_bucket(
287 const struct bucket_table *tbl, unsigned int hash)
288{
289 return unlikely(tbl->nest) ? rht_bucket_nested(tbl, hash) :
290 &tbl->buckets[hash];
291}
292
293static inline struct rhash_lock_head __rcu **rht_bucket_var(
294 struct bucket_table *tbl, unsigned int hash)
295{
296 return unlikely(tbl->nest) ? __rht_bucket_nested(tbl, hash) :
297 &tbl->buckets[hash];
298}
299
300static inline struct rhash_lock_head __rcu **rht_bucket_insert(
301 struct rhashtable *ht, struct bucket_table *tbl, unsigned int hash)
302{
303 return unlikely(tbl->nest) ? rht_bucket_nested_insert(ht, tbl, hash) :
304 &tbl->buckets[hash];
305}
306
307/*
308 * We lock a bucket by setting BIT(0) in the pointer - this is always
309 * zero in real pointers. The NULLS mark is never stored in the bucket,
310 * rather we store NULL if the bucket is empty.
311 * bit_spin_locks do not handle contention well, but the whole point
312 * of the hashtable design is to achieve minimum per-bucket contention.
313 * A nested hash table might not have a bucket pointer. In that case
314 * we cannot get a lock. For remove and replace the bucket cannot be
315 * interesting and doesn't need locking.
316 * For insert we allocate the bucket if this is the last bucket_table,
317 * and then take the lock.
318 * Sometimes we unlock a bucket by writing a new pointer there. In that
319 * case we don't need to unlock, but we do need to reset state such as
320 * local_bh. For that we have rht_assign_unlock(). As rcu_assign_pointer()
321 * provides the same release semantics that bit_spin_unlock() provides,
322 * this is safe.
323 * When we write to a bucket without unlocking, we use rht_assign_locked().
324 */
325
326static inline unsigned long rht_lock(struct bucket_table *tbl,
327 struct rhash_lock_head __rcu **bkt)
328{
329 unsigned long flags;
330
331 local_irq_save(flags);
332 bit_spin_lock(bitnum: 0, addr: (unsigned long *)bkt);
333 lock_map_acquire(&tbl->dep_map);
334 return flags;
335}
336
337static inline unsigned long rht_lock_nested(struct bucket_table *tbl,
338 struct rhash_lock_head __rcu **bucket,
339 unsigned int subclass)
340{
341 unsigned long flags;
342
343 local_irq_save(flags);
344 bit_spin_lock(bitnum: 0, addr: (unsigned long *)bucket);
345 lock_acquire_exclusive(&tbl->dep_map, subclass, 0, NULL, _THIS_IP_);
346 return flags;
347}
348
349static inline void rht_unlock(struct bucket_table *tbl,
350 struct rhash_lock_head __rcu **bkt,
351 unsigned long flags)
352{
353 lock_map_release(&tbl->dep_map);
354 bit_spin_unlock(bitnum: 0, addr: (unsigned long *)bkt);
355 local_irq_restore(flags);
356}
357
358enum rht_lookup_freq {
359 RHT_LOOKUP_NORMAL,
360 RHT_LOOKUP_LIKELY,
361};
362
363static __always_inline struct rhash_head *__rht_ptr(
364 struct rhash_lock_head *p, struct rhash_lock_head __rcu *const *bkt,
365 const enum rht_lookup_freq freq)
366{
367 unsigned long p_val = (unsigned long)p & ~BIT(0);
368
369 BUILD_BUG_ON(!__builtin_constant_p(freq));
370
371 if (freq == RHT_LOOKUP_LIKELY)
372 return (struct rhash_head *)
373 (likely(p_val) ? p_val : (unsigned long)RHT_NULLS_MARKER(bkt));
374 else
375 return (struct rhash_head *)
376 (p_val ?: (unsigned long)RHT_NULLS_MARKER(bkt));
377}
378
379/*
380 * Where 'bkt' is a bucket and might be locked:
381 * rht_ptr_rcu() dereferences that pointer and clears the lock bit.
382 * rht_ptr() dereferences in a context where the bucket is locked.
383 * rht_ptr_exclusive() dereferences in a context where exclusive
384 * access is guaranteed, such as when destroying the table.
385 */
386static __always_inline struct rhash_head *__rht_ptr_rcu(
387 struct rhash_lock_head __rcu *const *bkt,
388 const enum rht_lookup_freq freq)
389{
390 return __rht_ptr(rcu_dereference_all(*bkt), bkt, freq);
391}
392
393static inline struct rhash_head *rht_ptr_rcu(
394 struct rhash_lock_head __rcu *const *bkt)
395{
396 return __rht_ptr_rcu(bkt, freq: RHT_LOOKUP_NORMAL);
397}
398
399static inline struct rhash_head *rht_ptr(
400 struct rhash_lock_head __rcu *const *bkt,
401 struct bucket_table *tbl,
402 unsigned int hash)
403{
404 return __rht_ptr(rht_dereference_bucket(*bkt, tbl, hash), bkt,
405 freq: RHT_LOOKUP_NORMAL);
406}
407
408static inline struct rhash_head *rht_ptr_exclusive(
409 struct rhash_lock_head __rcu *const *bkt)
410{
411 return __rht_ptr(rcu_dereference_protected(*bkt, 1), bkt,
412 freq: RHT_LOOKUP_NORMAL);
413}
414
415static inline void rht_assign_locked(struct rhash_lock_head __rcu **bkt,
416 struct rhash_head *obj)
417{
418 if (rht_is_a_nulls(ptr: obj))
419 obj = NULL;
420 rcu_assign_pointer(*bkt, (void *)((unsigned long)obj | BIT(0)));
421}
422
423static inline void rht_assign_unlock(struct bucket_table *tbl,
424 struct rhash_lock_head __rcu **bkt,
425 struct rhash_head *obj,
426 unsigned long flags)
427{
428 if (rht_is_a_nulls(ptr: obj))
429 obj = NULL;
430 lock_map_release(&tbl->dep_map);
431 rcu_assign_pointer(*bkt, (void *)obj);
432 preempt_enable();
433 __release(bitlock);
434 local_irq_restore(flags);
435}
436
437/**
438 * rht_for_each_from - iterate over hash chain from given head
439 * @pos: the &struct rhash_head to use as a loop cursor.
440 * @head: the &struct rhash_head to start from
441 * @tbl: the &struct bucket_table
442 * @hash: the hash value / bucket index
443 */
444#define rht_for_each_from(pos, head, tbl, hash) \
445 for (pos = head; \
446 !rht_is_a_nulls(pos); \
447 pos = rht_dereference_bucket((pos)->next, tbl, hash))
448
449/**
450 * rht_for_each - iterate over hash chain
451 * @pos: the &struct rhash_head to use as a loop cursor.
452 * @tbl: the &struct bucket_table
453 * @hash: the hash value / bucket index
454 */
455#define rht_for_each(pos, tbl, hash) \
456 rht_for_each_from(pos, rht_ptr(rht_bucket(tbl, hash), tbl, hash), \
457 tbl, hash)
458
459/**
460 * rht_for_each_entry_from - iterate over hash chain from given head
461 * @tpos: the type * to use as a loop cursor.
462 * @pos: the &struct rhash_head to use as a loop cursor.
463 * @head: the &struct rhash_head to start from
464 * @tbl: the &struct bucket_table
465 * @hash: the hash value / bucket index
466 * @member: name of the &struct rhash_head within the hashable struct.
467 */
468#define rht_for_each_entry_from(tpos, pos, head, tbl, hash, member) \
469 for (pos = head; \
470 (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \
471 pos = rht_dereference_bucket((pos)->next, tbl, hash))
472
473/**
474 * rht_for_each_entry - iterate over hash chain of given type
475 * @tpos: the type * to use as a loop cursor.
476 * @pos: the &struct rhash_head to use as a loop cursor.
477 * @tbl: the &struct bucket_table
478 * @hash: the hash value / bucket index
479 * @member: name of the &struct rhash_head within the hashable struct.
480 */
481#define rht_for_each_entry(tpos, pos, tbl, hash, member) \
482 rht_for_each_entry_from(tpos, pos, \
483 rht_ptr(rht_bucket(tbl, hash), tbl, hash), \
484 tbl, hash, member)
485
486/**
487 * rht_for_each_entry_safe - safely iterate over hash chain of given type
488 * @tpos: the type * to use as a loop cursor.
489 * @pos: the &struct rhash_head to use as a loop cursor.
490 * @next: the &struct rhash_head to use as next in loop cursor.
491 * @tbl: the &struct bucket_table
492 * @hash: the hash value / bucket index
493 * @member: name of the &struct rhash_head within the hashable struct.
494 *
495 * This hash chain list-traversal primitive allows for the looped code to
496 * remove the loop cursor from the list.
497 */
498#define rht_for_each_entry_safe(tpos, pos, next, tbl, hash, member) \
499 for (pos = rht_ptr(rht_bucket(tbl, hash), tbl, hash), \
500 next = !rht_is_a_nulls(pos) ? \
501 rht_dereference_bucket(pos->next, tbl, hash) : NULL; \
502 (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \
503 pos = next, \
504 next = !rht_is_a_nulls(pos) ? \
505 rht_dereference_bucket(pos->next, tbl, hash) : NULL)
506
507/**
508 * rht_for_each_rcu_from - iterate over rcu hash chain from given head
509 * @pos: the &struct rhash_head to use as a loop cursor.
510 * @head: the &struct rhash_head to start from
511 * @tbl: the &struct bucket_table
512 * @hash: the hash value / bucket index
513 *
514 * This hash chain list-traversal primitive may safely run concurrently with
515 * the _rcu mutation primitives such as rhashtable_insert() as long as the
516 * traversal is guarded by rcu_read_lock().
517 */
518#define rht_for_each_rcu_from(pos, head, tbl, hash) \
519 for (({barrier(); }), \
520 pos = head; \
521 !rht_is_a_nulls(pos); \
522 pos = rcu_dereference_all(pos->next))
523
524/**
525 * rht_for_each_rcu - iterate over rcu hash chain
526 * @pos: the &struct rhash_head to use as a loop cursor.
527 * @tbl: the &struct bucket_table
528 * @hash: the hash value / bucket index
529 *
530 * This hash chain list-traversal primitive may safely run concurrently with
531 * the _rcu mutation primitives such as rhashtable_insert() as long as the
532 * traversal is guarded by rcu_read_lock().
533 */
534#define rht_for_each_rcu(pos, tbl, hash) \
535 for (({barrier(); }), \
536 pos = rht_ptr_rcu(rht_bucket(tbl, hash)); \
537 !rht_is_a_nulls(pos); \
538 pos = rcu_dereference_all(pos->next))
539
540/**
541 * rht_for_each_entry_rcu_from - iterated over rcu hash chain from given head
542 * @tpos: the type * to use as a loop cursor.
543 * @pos: the &struct rhash_head to use as a loop cursor.
544 * @head: the &struct rhash_head to start from
545 * @tbl: the &struct bucket_table
546 * @hash: the hash value / bucket index
547 * @member: name of the &struct rhash_head within the hashable struct.
548 *
549 * This hash chain list-traversal primitive may safely run concurrently with
550 * the _rcu mutation primitives such as rhashtable_insert() as long as the
551 * traversal is guarded by rcu_read_lock().
552 */
553#define rht_for_each_entry_rcu_from(tpos, pos, head, tbl, hash, member) \
554 for (({barrier(); }), \
555 pos = head; \
556 (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member); \
557 pos = rht_dereference_bucket_rcu(pos->next, tbl, hash))
558
559/**
560 * rht_for_each_entry_rcu - iterate over rcu hash chain of given type
561 * @tpos: the type * to use as a loop cursor.
562 * @pos: the &struct rhash_head to use as a loop cursor.
563 * @tbl: the &struct bucket_table
564 * @hash: the hash value / bucket index
565 * @member: name of the &struct rhash_head within the hashable struct.
566 *
567 * This hash chain list-traversal primitive may safely run concurrently with
568 * the _rcu mutation primitives such as rhashtable_insert() as long as the
569 * traversal is guarded by rcu_read_lock().
570 */
571#define rht_for_each_entry_rcu(tpos, pos, tbl, hash, member) \
572 rht_for_each_entry_rcu_from(tpos, pos, \
573 rht_ptr_rcu(rht_bucket(tbl, hash)), \
574 tbl, hash, member)
575
576/**
577 * rhl_for_each_rcu - iterate over rcu hash table list
578 * @pos: the &struct rlist_head to use as a loop cursor.
579 * @list: the head of the list
580 *
581 * This hash chain list-traversal primitive should be used on the
582 * list returned by rhltable_lookup.
583 */
584#define rhl_for_each_rcu(pos, list) \
585 for (pos = list; pos; pos = rcu_dereference_all(pos->next))
586
587/**
588 * rhl_for_each_entry_rcu - iterate over rcu hash table list of given type
589 * @tpos: the type * to use as a loop cursor.
590 * @pos: the &struct rlist_head to use as a loop cursor.
591 * @list: the head of the list
592 * @member: name of the &struct rlist_head within the hashable struct.
593 *
594 * This hash chain list-traversal primitive should be used on the
595 * list returned by rhltable_lookup.
596 */
597#define rhl_for_each_entry_rcu(tpos, pos, list, member) \
598 for (pos = list; pos && rht_entry(tpos, pos, member); \
599 pos = rcu_dereference_all(pos->next))
600
601static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
602 const void *obj)
603{
604 struct rhashtable *ht = arg->ht;
605 const char *ptr = obj;
606
607 return memcmp(p: ptr + ht->p.key_offset, q: arg->key, size: ht->p.key_len);
608}
609
610/* Internal function, do not use. */
611static __always_inline struct rhash_head *__rhashtable_lookup(
612 struct rhashtable *ht, const void *key,
613 const struct rhashtable_params params,
614 const enum rht_lookup_freq freq)
615{
616 struct rhashtable_compare_arg arg = {
617 .ht = ht,
618 .key = key,
619 };
620 struct rhash_lock_head __rcu *const *bkt;
621 struct bucket_table *tbl;
622 struct rhash_head *he;
623 unsigned int hash;
624
625 BUILD_BUG_ON(!__builtin_constant_p(freq));
626 tbl = rht_dereference_rcu(ht->tbl, ht);
627restart:
628 hash = rht_key_hashfn(ht, tbl, key, params);
629 bkt = rht_bucket(tbl, hash);
630 do {
631 rht_for_each_rcu_from(he, __rht_ptr_rcu(bkt, freq), tbl, hash) {
632 if (params.obj_cmpfn ?
633 params.obj_cmpfn(&arg, rht_obj(ht, he)) :
634 rhashtable_compare(arg: &arg, obj: rht_obj(ht, he)))
635 continue;
636 return he;
637 }
638 /* An object might have been moved to a different hash chain,
639 * while we walk along it - better check and retry.
640 */
641 } while (he != RHT_NULLS_MARKER(bkt));
642
643 /* Ensure we see any new tables. */
644 smp_rmb();
645
646 tbl = rht_dereference_rcu(tbl->future_tbl, ht);
647 if (unlikely(tbl))
648 goto restart;
649
650 return NULL;
651}
652
653/**
654 * rhashtable_lookup - search hash table
655 * @ht: hash table
656 * @key: the pointer to the key
657 * @params: hash table parameters
658 *
659 * Computes the hash value for the key and traverses the bucket chain looking
660 * for an entry with an identical key. The first matching entry is returned.
661 *
662 * This must only be called under the RCU read lock.
663 *
664 * Returns the first entry on which the compare function returned true.
665 */
666static __always_inline void *rhashtable_lookup(
667 struct rhashtable *ht, const void *key,
668 const struct rhashtable_params params)
669{
670 struct rhash_head *he = __rhashtable_lookup(ht, key, params,
671 freq: RHT_LOOKUP_NORMAL);
672
673 return he ? rht_obj(ht, he) : NULL;
674}
675
676static __always_inline void *rhashtable_lookup_likely(
677 struct rhashtable *ht, const void *key,
678 const struct rhashtable_params params)
679{
680 struct rhash_head *he = __rhashtable_lookup(ht, key, params,
681 freq: RHT_LOOKUP_LIKELY);
682
683 return likely(he) ? rht_obj(ht, he) : NULL;
684}
685
686/**
687 * rhashtable_lookup_fast - search hash table, without RCU read lock
688 * @ht: hash table
689 * @key: the pointer to the key
690 * @params: hash table parameters
691 *
692 * Computes the hash value for the key and traverses the bucket chain looking
693 * for an entry with an identical key. The first matching entry is returned.
694 *
695 * Only use this function when you have other mechanisms guaranteeing
696 * that the object won't go away after the RCU read lock is released.
697 *
698 * Returns the first entry on which the compare function returned true.
699 */
700static __always_inline void *rhashtable_lookup_fast(
701 struct rhashtable *ht, const void *key,
702 const struct rhashtable_params params)
703{
704 void *obj;
705
706 rcu_read_lock();
707 obj = rhashtable_lookup(ht, key, params);
708 rcu_read_unlock();
709
710 return obj;
711}
712
713/**
714 * rhltable_lookup - search hash list table
715 * @hlt: hash table
716 * @key: the pointer to the key
717 * @params: hash table parameters
718 *
719 * Computes the hash value for the key and traverses the bucket chain looking
720 * for an entry with an identical key. All matching entries are returned
721 * in a list.
722 *
723 * This must only be called under the RCU read lock.
724 *
725 * Returns the list of entries that match the given key.
726 */
727static __always_inline struct rhlist_head *rhltable_lookup(
728 struct rhltable *hlt, const void *key,
729 const struct rhashtable_params params)
730{
731 struct rhash_head *he = __rhashtable_lookup(ht: &hlt->ht, key, params,
732 freq: RHT_LOOKUP_NORMAL);
733
734 return he ? container_of(he, struct rhlist_head, rhead) : NULL;
735}
736
737static __always_inline struct rhlist_head *rhltable_lookup_likely(
738 struct rhltable *hlt, const void *key,
739 const struct rhashtable_params params)
740{
741 struct rhash_head *he = __rhashtable_lookup(ht: &hlt->ht, key, params,
742 freq: RHT_LOOKUP_LIKELY);
743
744 return likely(he) ? container_of(he, struct rhlist_head, rhead) : NULL;
745}
746
747/* Internal function, please use rhashtable_insert_fast() instead. This
748 * function returns the existing element already in hashes if there is a clash,
749 * otherwise it returns an error via ERR_PTR().
750 */
751static __always_inline void *__rhashtable_insert_fast(
752 struct rhashtable *ht, const void *key, struct rhash_head *obj,
753 const struct rhashtable_params params, bool rhlist)
754{
755 struct rhashtable_compare_arg arg = {
756 .ht = ht,
757 .key = key,
758 };
759 struct rhash_lock_head __rcu **bkt;
760 struct rhash_head __rcu **pprev;
761 struct bucket_table *tbl;
762 struct rhash_head *head;
763 unsigned long flags;
764 unsigned int hash;
765 int elasticity;
766 void *data;
767
768 rcu_read_lock();
769
770 tbl = rht_dereference_rcu(ht->tbl, ht);
771 hash = rht_head_hashfn(ht, tbl, he: obj, params);
772 elasticity = RHT_ELASTICITY;
773 bkt = rht_bucket_insert(ht, tbl, hash);
774 data = ERR_PTR(error: -ENOMEM);
775 if (!bkt)
776 goto out;
777 pprev = NULL;
778 flags = rht_lock(tbl, bkt);
779
780 if (unlikely(rcu_access_pointer(tbl->future_tbl))) {
781slow_path:
782 rht_unlock(tbl, bkt, flags);
783 rcu_read_unlock();
784 return rhashtable_insert_slow(ht, key, obj);
785 }
786
787 rht_for_each_from(head, rht_ptr(bkt, tbl, hash), tbl, hash) {
788 struct rhlist_head *plist;
789 struct rhlist_head *list;
790
791 elasticity--;
792 if (!key ||
793 (params.obj_cmpfn ?
794 params.obj_cmpfn(&arg, rht_obj(ht, he: head)) :
795 rhashtable_compare(arg: &arg, obj: rht_obj(ht, he: head)))) {
796 pprev = &head->next;
797 continue;
798 }
799
800 data = rht_obj(ht, he: head);
801
802 if (!rhlist)
803 goto out_unlock;
804
805
806 list = container_of(obj, struct rhlist_head, rhead);
807 plist = container_of(head, struct rhlist_head, rhead);
808
809 RCU_INIT_POINTER(list->next, plist);
810 head = rht_dereference_bucket(head->next, tbl, hash);
811 RCU_INIT_POINTER(list->rhead.next, head);
812 if (pprev) {
813 rcu_assign_pointer(*pprev, obj);
814 rht_unlock(tbl, bkt, flags);
815 } else
816 rht_assign_unlock(tbl, bkt, obj, flags);
817 data = NULL;
818 goto out;
819 }
820
821 if (elasticity <= 0)
822 goto slow_path;
823
824 data = ERR_PTR(error: -E2BIG);
825 if (unlikely(rht_grow_above_max(ht, tbl)))
826 goto out_unlock;
827
828 if (unlikely(rht_grow_above_100(ht, tbl)))
829 goto slow_path;
830
831 /* Inserting at head of list makes unlocking free. */
832 head = rht_ptr(bkt, tbl, hash);
833
834 RCU_INIT_POINTER(obj->next, head);
835 if (rhlist) {
836 struct rhlist_head *list;
837
838 list = container_of(obj, struct rhlist_head, rhead);
839 RCU_INIT_POINTER(list->next, NULL);
840 }
841
842 atomic_inc(v: &ht->nelems);
843 rht_assign_unlock(tbl, bkt, obj, flags);
844
845 if (rht_grow_above_75(ht, tbl))
846 schedule_work(work: &ht->run_work);
847
848 data = NULL;
849out:
850 rcu_read_unlock();
851
852 return data;
853
854out_unlock:
855 rht_unlock(tbl, bkt, flags);
856 goto out;
857}
858
859/**
860 * rhashtable_insert_fast - insert object into hash table
861 * @ht: hash table
862 * @obj: pointer to hash head inside object
863 * @params: hash table parameters
864 *
865 * Will take the per bucket bitlock to protect against mutual mutations
866 * on the same bucket. Multiple insertions may occur in parallel unless
867 * they map to the same bucket.
868 *
869 * It is safe to call this function from atomic context.
870 *
871 * Will trigger an automatic deferred table resizing if residency in the
872 * table grows beyond 70%.
873 */
874static __always_inline int rhashtable_insert_fast(
875 struct rhashtable *ht, struct rhash_head *obj,
876 const struct rhashtable_params params)
877{
878 void *ret;
879
880 ret = __rhashtable_insert_fast(ht, NULL, obj, params, rhlist: false);
881 if (IS_ERR(ptr: ret))
882 return PTR_ERR(ptr: ret);
883
884 return ret == NULL ? 0 : -EEXIST;
885}
886
887/**
888 * rhltable_insert_key - insert object into hash list table
889 * @hlt: hash list table
890 * @key: the pointer to the key
891 * @list: pointer to hash list head inside object
892 * @params: hash table parameters
893 *
894 * Will take the per bucket bitlock to protect against mutual mutations
895 * on the same bucket. Multiple insertions may occur in parallel unless
896 * they map to the same bucket.
897 *
898 * It is safe to call this function from atomic context.
899 *
900 * Will trigger an automatic deferred table resizing if residency in the
901 * table grows beyond 70%.
902 */
903static __always_inline int rhltable_insert_key(
904 struct rhltable *hlt, const void *key, struct rhlist_head *list,
905 const struct rhashtable_params params)
906{
907 return PTR_ERR(ptr: __rhashtable_insert_fast(ht: &hlt->ht, key, obj: &list->rhead,
908 params, rhlist: true));
909}
910
911/**
912 * rhltable_insert - insert object into hash list table
913 * @hlt: hash list table
914 * @list: pointer to hash list head inside object
915 * @params: hash table parameters
916 *
917 * Will take the per bucket bitlock to protect against mutual mutations
918 * on the same bucket. Multiple insertions may occur in parallel unless
919 * they map to the same bucket.
920 *
921 * It is safe to call this function from atomic context.
922 *
923 * Will trigger an automatic deferred table resizing if residency in the
924 * table grows beyond 70%.
925 */
926static __always_inline int rhltable_insert(
927 struct rhltable *hlt, struct rhlist_head *list,
928 const struct rhashtable_params params)
929{
930 const char *key = rht_obj(ht: &hlt->ht, he: &list->rhead);
931
932 key += params.key_offset;
933
934 return rhltable_insert_key(hlt, key, list, params);
935}
936
937/**
938 * rhashtable_lookup_insert_fast - lookup and insert object into hash table
939 * @ht: hash table
940 * @obj: pointer to hash head inside object
941 * @params: hash table parameters
942 *
943 * This lookup function may only be used for fixed key hash table (key_len
944 * parameter set). It will BUG() if used inappropriately.
945 *
946 * It is safe to call this function from atomic context.
947 *
948 * Will trigger an automatic deferred table resizing if residency in the
949 * table grows beyond 70%.
950 */
951static __always_inline int rhashtable_lookup_insert_fast(
952 struct rhashtable *ht, struct rhash_head *obj,
953 const struct rhashtable_params params)
954{
955 const char *key = rht_obj(ht, he: obj);
956 void *ret;
957
958 BUG_ON(ht->p.obj_hashfn);
959
960 ret = __rhashtable_insert_fast(ht, key: key + ht->p.key_offset, obj, params,
961 rhlist: false);
962 if (IS_ERR(ptr: ret))
963 return PTR_ERR(ptr: ret);
964
965 return ret == NULL ? 0 : -EEXIST;
966}
967
968/**
969 * rhashtable_lookup_get_insert_fast - lookup and insert object into hash table
970 * @ht: hash table
971 * @obj: pointer to hash head inside object
972 * @params: hash table parameters
973 *
974 * Just like rhashtable_lookup_insert_fast(), but this function returns the
975 * object if it exists, NULL if it did not and the insertion was successful,
976 * and an ERR_PTR otherwise.
977 */
978static __always_inline void *rhashtable_lookup_get_insert_fast(
979 struct rhashtable *ht, struct rhash_head *obj,
980 const struct rhashtable_params params)
981{
982 const char *key = rht_obj(ht, he: obj);
983
984 BUG_ON(ht->p.obj_hashfn);
985
986 return __rhashtable_insert_fast(ht, key: key + ht->p.key_offset, obj, params,
987 rhlist: false);
988}
989
990/**
991 * rhashtable_lookup_insert_key - search and insert object to hash table
992 * with explicit key
993 * @ht: hash table
994 * @key: key
995 * @obj: pointer to hash head inside object
996 * @params: hash table parameters
997 *
998 * Lookups may occur in parallel with hashtable mutations and resizing.
999 *
1000 * Will trigger an automatic deferred table resizing if residency in the
1001 * table grows beyond 70%.
1002 *
1003 * Returns zero on success.
1004 */
1005static __always_inline int rhashtable_lookup_insert_key(
1006 struct rhashtable *ht, const void *key, struct rhash_head *obj,
1007 const struct rhashtable_params params)
1008{
1009 void *ret;
1010
1011 BUG_ON(!ht->p.obj_hashfn || !key);
1012
1013 ret = __rhashtable_insert_fast(ht, key, obj, params, rhlist: false);
1014 if (IS_ERR(ptr: ret))
1015 return PTR_ERR(ptr: ret);
1016
1017 return ret == NULL ? 0 : -EEXIST;
1018}
1019
1020/**
1021 * rhashtable_lookup_get_insert_key - lookup and insert object into hash table
1022 * @ht: hash table
1023 * @key: key
1024 * @obj: pointer to hash head inside object
1025 * @params: hash table parameters
1026 *
1027 * Just like rhashtable_lookup_insert_key(), but this function returns the
1028 * object if it exists, NULL if it does not and the insertion was successful,
1029 * and an ERR_PTR otherwise.
1030 */
1031static __always_inline void *rhashtable_lookup_get_insert_key(
1032 struct rhashtable *ht, const void *key, struct rhash_head *obj,
1033 const struct rhashtable_params params)
1034{
1035 BUG_ON(!ht->p.obj_hashfn || !key);
1036
1037 return __rhashtable_insert_fast(ht, key, obj, params, rhlist: false);
1038}
1039
1040/* Internal function, please use rhashtable_remove_fast() instead */
1041static __always_inline int __rhashtable_remove_fast_one(
1042 struct rhashtable *ht, struct bucket_table *tbl,
1043 struct rhash_head *obj, const struct rhashtable_params params,
1044 bool rhlist)
1045{
1046 struct rhash_lock_head __rcu **bkt;
1047 struct rhash_head __rcu **pprev;
1048 struct rhash_head *he;
1049 unsigned long flags;
1050 unsigned int hash;
1051 int err = -ENOENT;
1052
1053 hash = rht_head_hashfn(ht, tbl, he: obj, params);
1054 bkt = rht_bucket_var(tbl, hash);
1055 if (!bkt)
1056 return -ENOENT;
1057 pprev = NULL;
1058 flags = rht_lock(tbl, bkt);
1059
1060 rht_for_each_from(he, rht_ptr(bkt, tbl, hash), tbl, hash) {
1061 struct rhlist_head *list;
1062
1063 list = container_of(he, struct rhlist_head, rhead);
1064
1065 if (he != obj) {
1066 struct rhlist_head __rcu **lpprev;
1067
1068 pprev = &he->next;
1069
1070 if (!rhlist)
1071 continue;
1072
1073 do {
1074 lpprev = &list->next;
1075 list = rht_dereference_bucket(list->next,
1076 tbl, hash);
1077 } while (list && obj != &list->rhead);
1078
1079 if (!list)
1080 continue;
1081
1082 list = rht_dereference_bucket(list->next, tbl, hash);
1083 RCU_INIT_POINTER(*lpprev, list);
1084 err = 0;
1085 break;
1086 }
1087
1088 obj = rht_dereference_bucket(obj->next, tbl, hash);
1089 err = 1;
1090
1091 if (rhlist) {
1092 list = rht_dereference_bucket(list->next, tbl, hash);
1093 if (list) {
1094 RCU_INIT_POINTER(list->rhead.next, obj);
1095 obj = &list->rhead;
1096 err = 0;
1097 }
1098 }
1099
1100 if (pprev) {
1101 rcu_assign_pointer(*pprev, obj);
1102 rht_unlock(tbl, bkt, flags);
1103 } else {
1104 rht_assign_unlock(tbl, bkt, obj, flags);
1105 }
1106 goto unlocked;
1107 }
1108
1109 rht_unlock(tbl, bkt, flags);
1110unlocked:
1111 if (err > 0) {
1112 atomic_dec(v: &ht->nelems);
1113 if (unlikely(ht->p.automatic_shrinking &&
1114 rht_shrink_below_30(ht, tbl)))
1115 schedule_work(work: &ht->run_work);
1116 err = 0;
1117 }
1118
1119 return err;
1120}
1121
1122/* Internal function, please use rhashtable_remove_fast() instead */
1123static __always_inline int __rhashtable_remove_fast(
1124 struct rhashtable *ht, struct rhash_head *obj,
1125 const struct rhashtable_params params, bool rhlist)
1126{
1127 struct bucket_table *tbl;
1128 int err;
1129
1130 rcu_read_lock();
1131
1132 tbl = rht_dereference_rcu(ht->tbl, ht);
1133
1134 /* Because we have already taken (and released) the bucket
1135 * lock in old_tbl, if we find that future_tbl is not yet
1136 * visible then that guarantees the entry to still be in
1137 * the old tbl if it exists.
1138 */
1139 while ((err = __rhashtable_remove_fast_one(ht, tbl, obj, params,
1140 rhlist)) &&
1141 (tbl = rht_dereference_rcu(tbl->future_tbl, ht)))
1142 ;
1143
1144 rcu_read_unlock();
1145
1146 return err;
1147}
1148
1149/**
1150 * rhashtable_remove_fast - remove object from hash table
1151 * @ht: hash table
1152 * @obj: pointer to hash head inside object
1153 * @params: hash table parameters
1154 *
1155 * Since the hash chain is single linked, the removal operation needs to
1156 * walk the bucket chain upon removal. The removal operation is thus
1157 * considerable slow if the hash table is not correctly sized.
1158 *
1159 * Will automatically shrink the table if permitted when residency drops
1160 * below 30%.
1161 *
1162 * Returns zero on success, -ENOENT if the entry could not be found.
1163 */
1164static __always_inline int rhashtable_remove_fast(
1165 struct rhashtable *ht, struct rhash_head *obj,
1166 const struct rhashtable_params params)
1167{
1168 return __rhashtable_remove_fast(ht, obj, params, rhlist: false);
1169}
1170
1171/**
1172 * rhltable_remove - remove object from hash list table
1173 * @hlt: hash list table
1174 * @list: pointer to hash list head inside object
1175 * @params: hash table parameters
1176 *
1177 * Since the hash chain is single linked, the removal operation needs to
1178 * walk the bucket chain upon removal. The removal operation is thus
1179 * considerably slower if the hash table is not correctly sized.
1180 *
1181 * Will automatically shrink the table if permitted when residency drops
1182 * below 30%
1183 *
1184 * Returns zero on success, -ENOENT if the entry could not be found.
1185 */
1186static __always_inline int rhltable_remove(
1187 struct rhltable *hlt, struct rhlist_head *list,
1188 const struct rhashtable_params params)
1189{
1190 return __rhashtable_remove_fast(ht: &hlt->ht, obj: &list->rhead, params, rhlist: true);
1191}
1192
1193/* Internal function, please use rhashtable_replace_fast() instead */
1194static __always_inline int __rhashtable_replace_fast(
1195 struct rhashtable *ht, struct bucket_table *tbl,
1196 struct rhash_head *obj_old, struct rhash_head *obj_new,
1197 const struct rhashtable_params params)
1198{
1199 struct rhash_lock_head __rcu **bkt;
1200 struct rhash_head __rcu **pprev;
1201 struct rhash_head *he;
1202 unsigned long flags;
1203 unsigned int hash;
1204 int err = -ENOENT;
1205
1206 /* Minimally, the old and new objects must have same hash
1207 * (which should mean identifiers are the same).
1208 */
1209 hash = rht_head_hashfn(ht, tbl, he: obj_old, params);
1210 if (hash != rht_head_hashfn(ht, tbl, he: obj_new, params))
1211 return -EINVAL;
1212
1213 bkt = rht_bucket_var(tbl, hash);
1214 if (!bkt)
1215 return -ENOENT;
1216
1217 pprev = NULL;
1218 flags = rht_lock(tbl, bkt);
1219
1220 rht_for_each_from(he, rht_ptr(bkt, tbl, hash), tbl, hash) {
1221 if (he != obj_old) {
1222 pprev = &he->next;
1223 continue;
1224 }
1225
1226 rcu_assign_pointer(obj_new->next, obj_old->next);
1227 if (pprev) {
1228 rcu_assign_pointer(*pprev, obj_new);
1229 rht_unlock(tbl, bkt, flags);
1230 } else {
1231 rht_assign_unlock(tbl, bkt, obj: obj_new, flags);
1232 }
1233 err = 0;
1234 goto unlocked;
1235 }
1236
1237 rht_unlock(tbl, bkt, flags);
1238
1239unlocked:
1240 return err;
1241}
1242
1243/**
1244 * rhashtable_replace_fast - replace an object in hash table
1245 * @ht: hash table
1246 * @obj_old: pointer to hash head inside object being replaced
1247 * @obj_new: pointer to hash head inside object which is new
1248 * @params: hash table parameters
1249 *
1250 * Replacing an object doesn't affect the number of elements in the hash table
1251 * or bucket, so we don't need to worry about shrinking or expanding the
1252 * table here.
1253 *
1254 * Returns zero on success, -ENOENT if the entry could not be found,
1255 * -EINVAL if hash is not the same for the old and new objects.
1256 */
1257static __always_inline int rhashtable_replace_fast(
1258 struct rhashtable *ht, struct rhash_head *obj_old,
1259 struct rhash_head *obj_new,
1260 const struct rhashtable_params params)
1261{
1262 struct bucket_table *tbl;
1263 int err;
1264
1265 rcu_read_lock();
1266
1267 tbl = rht_dereference_rcu(ht->tbl, ht);
1268
1269 /* Because we have already taken (and released) the bucket
1270 * lock in old_tbl, if we find that future_tbl is not yet
1271 * visible then that guarantees the entry to still be in
1272 * the old tbl if it exists.
1273 */
1274 while ((err = __rhashtable_replace_fast(ht, tbl, obj_old,
1275 obj_new, params)) &&
1276 (tbl = rht_dereference_rcu(tbl->future_tbl, ht)))
1277 ;
1278
1279 rcu_read_unlock();
1280
1281 return err;
1282}
1283
1284/**
1285 * rhltable_walk_enter - Initialise an iterator
1286 * @hlt: Table to walk over
1287 * @iter: Hash table Iterator
1288 *
1289 * This function prepares a hash table walk.
1290 *
1291 * Note that if you restart a walk after rhashtable_walk_stop you
1292 * may see the same object twice. Also, you may miss objects if
1293 * there are removals in between rhashtable_walk_stop and the next
1294 * call to rhashtable_walk_start.
1295 *
1296 * For a completely stable walk you should construct your own data
1297 * structure outside the hash table.
1298 *
1299 * This function may be called from any process context, including
1300 * non-preemptable context, but cannot be called from softirq or
1301 * hardirq context.
1302 *
1303 * You must call rhashtable_walk_exit after this function returns.
1304 */
1305static inline void rhltable_walk_enter(struct rhltable *hlt,
1306 struct rhashtable_iter *iter)
1307{
1308 rhashtable_walk_enter(ht: &hlt->ht, iter);
1309}
1310
1311/**
1312 * rhltable_free_and_destroy - free elements and destroy hash list table
1313 * @hlt: the hash list table to destroy
1314 * @free_fn: callback to release resources of element
1315 * @arg: pointer passed to free_fn
1316 *
1317 * See documentation for rhashtable_free_and_destroy.
1318 */
1319static inline void rhltable_free_and_destroy(struct rhltable *hlt,
1320 void (*free_fn)(void *ptr,
1321 void *arg),
1322 void *arg)
1323{
1324 rhashtable_free_and_destroy(ht: &hlt->ht, free_fn, arg);
1325}
1326
1327static inline void rhltable_destroy(struct rhltable *hlt)
1328{
1329 rhltable_free_and_destroy(hlt, NULL, NULL);
1330}
1331
1332#endif /* _LINUX_RHASHTABLE_H */
1333

source code of linux/include/linux/rhashtable.h