blob: cbad192d3b3d4088a448fcedbfb3a8861bc84239 [file] [log] [blame]
Thomas Graf7e1e7762014-08-02 11:47:44 +02001/*
2 * Resizable, Scalable, Concurrent Hash Table
3 *
4 * Copyright (c) 2014 Thomas Graf <tgraf@suug.ch>
5 * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
6 *
7 * Based on the following paper:
8 * https://www.usenix.org/legacy/event/atc11/tech/final_files/Triplett.pdf
9 *
10 * Code partially derived from nft_hash
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
17#include <linux/kernel.h>
18#include <linux/init.h>
19#include <linux/log2.h>
20#include <linux/slab.h>
21#include <linux/vmalloc.h>
22#include <linux/mm.h>
Daniel Borkmann87545892014-12-10 16:33:11 +010023#include <linux/jhash.h>
Thomas Graf7e1e7762014-08-02 11:47:44 +020024#include <linux/random.h>
25#include <linux/rhashtable.h>
Thomas Graf7e1e7762014-08-02 11:47:44 +020026
27#define HASH_DEFAULT_SIZE 64UL
28#define HASH_MIN_SIZE 4UL
Thomas Graf97defe12015-01-02 23:00:20 +010029#define BUCKET_LOCKS_PER_CPU 128UL
30
Thomas Graff89bd6f2015-01-02 23:00:21 +010031/* Base bits plus 1 bit for nulls marker */
32#define HASH_RESERVED_SPACE (RHT_BASE_BITS + 1)
33
Thomas Graf97defe12015-01-02 23:00:20 +010034enum {
35 RHT_LOCK_NORMAL,
36 RHT_LOCK_NESTED,
37 RHT_LOCK_NESTED2,
38};
39
40/* The bucket lock is selected based on the hash and protects mutations
41 * on a group of hash buckets.
42 *
43 * IMPORTANT: When holding the bucket lock of both the old and new table
44 * during expansions and shrinking, the old bucket lock must always be
45 * acquired first.
46 */
47static spinlock_t *bucket_lock(const struct bucket_table *tbl, u32 hash)
48{
49 return &tbl->locks[hash & tbl->locks_mask];
50}
Thomas Graf7e1e7762014-08-02 11:47:44 +020051
52#define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT))
Thomas Graf97defe12015-01-02 23:00:20 +010053#define ASSERT_BUCKET_LOCK(TBL, HASH) \
54 BUG_ON(!lockdep_rht_bucket_is_held(TBL, HASH))
Thomas Graf7e1e7762014-08-02 11:47:44 +020055
56#ifdef CONFIG_PROVE_LOCKING
Thomas Graf97defe12015-01-02 23:00:20 +010057int lockdep_rht_mutex_is_held(struct rhashtable *ht)
Thomas Graf7e1e7762014-08-02 11:47:44 +020058{
Thomas Graf97defe12015-01-02 23:00:20 +010059 return (debug_locks) ? lockdep_is_held(&ht->mutex) : 1;
Thomas Graf7e1e7762014-08-02 11:47:44 +020060}
61EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held);
Thomas Graf88d6ed12015-01-02 23:00:16 +010062
63int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash)
64{
Thomas Graf97defe12015-01-02 23:00:20 +010065 spinlock_t *lock = bucket_lock(tbl, hash);
66
67 return (debug_locks) ? lockdep_is_held(lock) : 1;
Thomas Graf88d6ed12015-01-02 23:00:16 +010068}
69EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held);
Thomas Graf7e1e7762014-08-02 11:47:44 +020070#endif
71
Thomas Grafc91eee52014-08-13 16:38:30 +020072static void *rht_obj(const struct rhashtable *ht, const struct rhash_head *he)
Thomas Graf7e1e7762014-08-02 11:47:44 +020073{
74 return (void *) he - ht->p.head_offset;
75}
Thomas Graf7e1e7762014-08-02 11:47:44 +020076
Thomas Graf8d24c0b2015-01-02 23:00:14 +010077static u32 rht_bucket_index(const struct bucket_table *tbl, u32 hash)
Thomas Graf7e1e7762014-08-02 11:47:44 +020078{
Thomas Graf8d24c0b2015-01-02 23:00:14 +010079 return hash & (tbl->size - 1);
Thomas Graf7e1e7762014-08-02 11:47:44 +020080}
81
Thomas Graf8d24c0b2015-01-02 23:00:14 +010082static u32 obj_raw_hashfn(const struct rhashtable *ht, const void *ptr)
83{
84 u32 hash;
85
86 if (unlikely(!ht->p.key_len))
87 hash = ht->p.obj_hashfn(ptr, ht->p.hash_rnd);
88 else
89 hash = ht->p.hashfn(ptr + ht->p.key_offset, ht->p.key_len,
90 ht->p.hash_rnd);
91
Thomas Graff89bd6f2015-01-02 23:00:21 +010092 return hash >> HASH_RESERVED_SPACE;
Thomas Graf8d24c0b2015-01-02 23:00:14 +010093}
94
Thomas Graf97defe12015-01-02 23:00:20 +010095static u32 key_hashfn(struct rhashtable *ht, const void *key, u32 len)
Thomas Graf7e1e7762014-08-02 11:47:44 +020096{
97 struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
Thomas Graf8d24c0b2015-01-02 23:00:14 +010098 u32 hash;
Thomas Graf7e1e7762014-08-02 11:47:44 +020099
Thomas Graf8d24c0b2015-01-02 23:00:14 +0100100 hash = ht->p.hashfn(key, len, ht->p.hash_rnd);
Thomas Graff89bd6f2015-01-02 23:00:21 +0100101 hash >>= HASH_RESERVED_SPACE;
Thomas Graf8d24c0b2015-01-02 23:00:14 +0100102
103 return rht_bucket_index(tbl, hash);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200104}
Thomas Graf7e1e7762014-08-02 11:47:44 +0200105
106static u32 head_hashfn(const struct rhashtable *ht,
Thomas Graf8d24c0b2015-01-02 23:00:14 +0100107 const struct bucket_table *tbl,
108 const struct rhash_head *he)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200109{
Thomas Graf8d24c0b2015-01-02 23:00:14 +0100110 return rht_bucket_index(tbl, obj_raw_hashfn(ht, rht_obj(ht, he)));
Thomas Graf7e1e7762014-08-02 11:47:44 +0200111}
112
Thomas Grafb8e19432015-01-02 23:00:17 +0100113static struct rhash_head __rcu **bucket_tail(struct bucket_table *tbl, u32 n)
114{
115 struct rhash_head __rcu **pprev;
116
117 for (pprev = &tbl->buckets[n];
Thomas Graff89bd6f2015-01-02 23:00:21 +0100118 !rht_is_a_nulls(rht_dereference_bucket(*pprev, tbl, n));
Thomas Grafb8e19432015-01-02 23:00:17 +0100119 pprev = &rht_dereference_bucket(*pprev, tbl, n)->next)
120 ;
121
122 return pprev;
123}
124
Thomas Graf97defe12015-01-02 23:00:20 +0100125static int alloc_bucket_locks(struct rhashtable *ht, struct bucket_table *tbl)
126{
127 unsigned int i, size;
128#if defined(CONFIG_PROVE_LOCKING)
129 unsigned int nr_pcpus = 2;
130#else
131 unsigned int nr_pcpus = num_possible_cpus();
132#endif
133
134 nr_pcpus = min_t(unsigned int, nr_pcpus, 32UL);
135 size = roundup_pow_of_two(nr_pcpus * ht->p.locks_mul);
136
137 /* Never allocate more than one lock per bucket */
138 size = min_t(unsigned int, size, tbl->size);
139
140 if (sizeof(spinlock_t) != 0) {
141#ifdef CONFIG_NUMA
142 if (size * sizeof(spinlock_t) > PAGE_SIZE)
143 tbl->locks = vmalloc(size * sizeof(spinlock_t));
144 else
145#endif
146 tbl->locks = kmalloc_array(size, sizeof(spinlock_t),
147 GFP_KERNEL);
148 if (!tbl->locks)
149 return -ENOMEM;
150 for (i = 0; i < size; i++)
151 spin_lock_init(&tbl->locks[i]);
152 }
153 tbl->locks_mask = size - 1;
154
155 return 0;
156}
157
158static void bucket_table_free(const struct bucket_table *tbl)
159{
160 if (tbl)
161 kvfree(tbl->locks);
162
163 kvfree(tbl);
164}
165
166static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
167 size_t nbuckets)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200168{
169 struct bucket_table *tbl;
170 size_t size;
Thomas Graff89bd6f2015-01-02 23:00:21 +0100171 int i;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200172
173 size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
Thomas Graf6eba8222014-11-13 13:45:46 +0100174 tbl = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200175 if (tbl == NULL)
176 tbl = vzalloc(size);
177
178 if (tbl == NULL)
179 return NULL;
180
181 tbl->size = nbuckets;
182
Thomas Graf97defe12015-01-02 23:00:20 +0100183 if (alloc_bucket_locks(ht, tbl) < 0) {
184 bucket_table_free(tbl);
185 return NULL;
186 }
Thomas Graf7e1e7762014-08-02 11:47:44 +0200187
Thomas Graff89bd6f2015-01-02 23:00:21 +0100188 for (i = 0; i < nbuckets; i++)
189 INIT_RHT_NULLS_HEAD(tbl->buckets[i], ht, i);
190
Thomas Graf97defe12015-01-02 23:00:20 +0100191 return tbl;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200192}
193
194/**
195 * rht_grow_above_75 - returns true if nelems > 0.75 * table-size
196 * @ht: hash table
197 * @new_size: new table size
198 */
199bool rht_grow_above_75(const struct rhashtable *ht, size_t new_size)
200{
201 /* Expand table when exceeding 75% load */
Thomas Graf97defe12015-01-02 23:00:20 +0100202 return atomic_read(&ht->nelems) > (new_size / 4 * 3);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200203}
204EXPORT_SYMBOL_GPL(rht_grow_above_75);
205
206/**
207 * rht_shrink_below_30 - returns true if nelems < 0.3 * table-size
208 * @ht: hash table
209 * @new_size: new table size
210 */
211bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size)
212{
213 /* Shrink table beneath 30% load */
Thomas Graf97defe12015-01-02 23:00:20 +0100214 return atomic_read(&ht->nelems) < (new_size * 3 / 10);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200215}
216EXPORT_SYMBOL_GPL(rht_shrink_below_30);
217
218static void hashtable_chain_unzip(const struct rhashtable *ht,
219 const struct bucket_table *new_tbl,
Thomas Graf97defe12015-01-02 23:00:20 +0100220 struct bucket_table *old_tbl,
221 size_t old_hash)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200222{
223 struct rhash_head *he, *p, *next;
Thomas Graf97defe12015-01-02 23:00:20 +0100224 spinlock_t *new_bucket_lock, *new_bucket_lock2 = NULL;
225 unsigned int new_hash, new_hash2;
226
227 ASSERT_BUCKET_LOCK(old_tbl, old_hash);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200228
229 /* Old bucket empty, no work needed. */
Thomas Graf97defe12015-01-02 23:00:20 +0100230 p = rht_dereference_bucket(old_tbl->buckets[old_hash], old_tbl,
231 old_hash);
Thomas Graff89bd6f2015-01-02 23:00:21 +0100232 if (rht_is_a_nulls(p))
Thomas Graf7e1e7762014-08-02 11:47:44 +0200233 return;
234
Thomas Graf97defe12015-01-02 23:00:20 +0100235 new_hash = new_hash2 = head_hashfn(ht, new_tbl, p);
236 new_bucket_lock = bucket_lock(new_tbl, new_hash);
237
Thomas Graf7e1e7762014-08-02 11:47:44 +0200238 /* Advance the old bucket pointer one or more times until it
239 * reaches a node that doesn't hash to the same bucket as the
240 * previous node p. Call the previous node p;
241 */
Thomas Graf97defe12015-01-02 23:00:20 +0100242 rht_for_each_continue(he, p->next, old_tbl, old_hash) {
243 new_hash2 = head_hashfn(ht, new_tbl, he);
244 if (new_hash != new_hash2)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200245 break;
246 p = he;
247 }
Thomas Graf97defe12015-01-02 23:00:20 +0100248 rcu_assign_pointer(old_tbl->buckets[old_hash], p->next);
249
250 spin_lock_bh_nested(new_bucket_lock, RHT_LOCK_NESTED);
251
252 /* If we have encountered an entry that maps to a different bucket in
253 * the new table, lock down that bucket as well as we might cut off
254 * the end of the chain.
255 */
256 new_bucket_lock2 = bucket_lock(new_tbl, new_hash);
257 if (new_bucket_lock != new_bucket_lock2)
258 spin_lock_bh_nested(new_bucket_lock2, RHT_LOCK_NESTED2);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200259
260 /* Find the subsequent node which does hash to the same
261 * bucket as node P, or NULL if no such node exists.
262 */
Thomas Graff89bd6f2015-01-02 23:00:21 +0100263 INIT_RHT_NULLS_HEAD(next, ht, old_hash);
264 if (!rht_is_a_nulls(he)) {
Thomas Graf97defe12015-01-02 23:00:20 +0100265 rht_for_each_continue(he, he->next, old_tbl, old_hash) {
266 if (head_hashfn(ht, new_tbl, he) == new_hash) {
Thomas Graf7e1e7762014-08-02 11:47:44 +0200267 next = he;
268 break;
269 }
270 }
271 }
272
273 /* Set p's next pointer to that subsequent node pointer,
274 * bypassing the nodes which do not hash to p's bucket
275 */
Thomas Graf97defe12015-01-02 23:00:20 +0100276 rcu_assign_pointer(p->next, next);
277
278 if (new_bucket_lock != new_bucket_lock2)
279 spin_unlock_bh(new_bucket_lock2);
280 spin_unlock_bh(new_bucket_lock);
281}
282
283static void link_old_to_new(struct bucket_table *new_tbl,
284 unsigned int new_hash, struct rhash_head *entry)
285{
286 spinlock_t *new_bucket_lock;
287
288 new_bucket_lock = bucket_lock(new_tbl, new_hash);
289
290 spin_lock_bh_nested(new_bucket_lock, RHT_LOCK_NESTED);
291 rcu_assign_pointer(*bucket_tail(new_tbl, new_hash), entry);
292 spin_unlock_bh(new_bucket_lock);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200293}
294
295/**
296 * rhashtable_expand - Expand hash table while allowing concurrent lookups
297 * @ht: the hash table to expand
Thomas Graf7e1e7762014-08-02 11:47:44 +0200298 *
299 * A secondary bucket array is allocated and the hash entries are migrated
300 * while keeping them on both lists until the end of the RCU grace period.
301 *
302 * This function may only be called in a context where it is safe to call
303 * synchronize_rcu(), e.g. not within a rcu_read_lock() section.
304 *
Thomas Graf97defe12015-01-02 23:00:20 +0100305 * The caller must ensure that no concurrent resizing occurs by holding
306 * ht->mutex.
307 *
308 * It is valid to have concurrent insertions and deletions protected by per
309 * bucket locks or concurrent RCU protected lookups and traversals.
Thomas Graf7e1e7762014-08-02 11:47:44 +0200310 */
Thomas Graf6eba8222014-11-13 13:45:46 +0100311int rhashtable_expand(struct rhashtable *ht)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200312{
313 struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);
314 struct rhash_head *he;
Thomas Graf97defe12015-01-02 23:00:20 +0100315 spinlock_t *old_bucket_lock;
316 unsigned int new_hash, old_hash;
317 bool complete = false;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200318
319 ASSERT_RHT_MUTEX(ht);
320
321 if (ht->p.max_shift && ht->shift >= ht->p.max_shift)
322 return 0;
323
Thomas Graf97defe12015-01-02 23:00:20 +0100324 new_tbl = bucket_table_alloc(ht, old_tbl->size * 2);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200325 if (new_tbl == NULL)
326 return -ENOMEM;
327
328 ht->shift++;
329
Thomas Graf97defe12015-01-02 23:00:20 +0100330 /* Make insertions go into the new, empty table right away. Deletions
331 * and lookups will be attempted in both tables until we synchronize.
332 * The synchronize_rcu() guarantees for the new table to be picked up
333 * so no new additions go into the old table while we relink.
Thomas Graf7e1e7762014-08-02 11:47:44 +0200334 */
Thomas Graf97defe12015-01-02 23:00:20 +0100335 rcu_assign_pointer(ht->future_tbl, new_tbl);
336 synchronize_rcu();
337
338 /* For each new bucket, search the corresponding old bucket for the
339 * first entry that hashes to the new bucket, and link the end of
340 * newly formed bucket chain (containing entries added to future
341 * table) to that entry. Since all the entries which will end up in
342 * the new bucket appear in the same old bucket, this constructs an
343 * entirely valid new hash table, but with multiple buckets
344 * "zipped" together into a single imprecise chain.
345 */
346 for (new_hash = 0; new_hash < new_tbl->size; new_hash++) {
347 old_hash = rht_bucket_index(old_tbl, new_hash);
348 old_bucket_lock = bucket_lock(old_tbl, old_hash);
349
350 spin_lock_bh(old_bucket_lock);
351 rht_for_each(he, old_tbl, old_hash) {
352 if (head_hashfn(ht, new_tbl, he) == new_hash) {
353 link_old_to_new(new_tbl, new_hash, he);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200354 break;
355 }
356 }
Thomas Graf97defe12015-01-02 23:00:20 +0100357 spin_unlock_bh(old_bucket_lock);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200358 }
359
360 /* Publish the new table pointer. Lookups may now traverse
Herbert Xu0c828f22014-11-13 13:10:48 +0800361 * the new table, but they will not benefit from any
362 * additional efficiency until later steps unzip the buckets.
Thomas Graf7e1e7762014-08-02 11:47:44 +0200363 */
364 rcu_assign_pointer(ht->tbl, new_tbl);
365
366 /* Unzip interleaved hash chains */
Thomas Graf97defe12015-01-02 23:00:20 +0100367 while (!complete && !ht->being_destroyed) {
Thomas Graf7e1e7762014-08-02 11:47:44 +0200368 /* Wait for readers. All new readers will see the new
369 * table, and thus no references to the old table will
370 * remain.
371 */
372 synchronize_rcu();
373
374 /* For each bucket in the old table (each of which
375 * contains items from multiple buckets of the new
376 * table): ...
377 */
378 complete = true;
Thomas Graf97defe12015-01-02 23:00:20 +0100379 for (old_hash = 0; old_hash < old_tbl->size; old_hash++) {
Thomas Graff89bd6f2015-01-02 23:00:21 +0100380 struct rhash_head *head;
381
Thomas Graf97defe12015-01-02 23:00:20 +0100382 old_bucket_lock = bucket_lock(old_tbl, old_hash);
383 spin_lock_bh(old_bucket_lock);
384
385 hashtable_chain_unzip(ht, new_tbl, old_tbl, old_hash);
Thomas Graff89bd6f2015-01-02 23:00:21 +0100386 head = rht_dereference_bucket(old_tbl->buckets[old_hash],
387 old_tbl, old_hash);
388 if (!rht_is_a_nulls(head))
Thomas Graf7e1e7762014-08-02 11:47:44 +0200389 complete = false;
Thomas Graf97defe12015-01-02 23:00:20 +0100390
391 spin_unlock_bh(old_bucket_lock);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200392 }
Thomas Graf97defe12015-01-02 23:00:20 +0100393 }
Thomas Graf7e1e7762014-08-02 11:47:44 +0200394
395 bucket_table_free(old_tbl);
396 return 0;
397}
398EXPORT_SYMBOL_GPL(rhashtable_expand);
399
400/**
401 * rhashtable_shrink - Shrink hash table while allowing concurrent lookups
402 * @ht: the hash table to shrink
Thomas Graf7e1e7762014-08-02 11:47:44 +0200403 *
404 * This function may only be called in a context where it is safe to call
405 * synchronize_rcu(), e.g. not within a rcu_read_lock() section.
406 *
Thomas Graf97defe12015-01-02 23:00:20 +0100407 * The caller must ensure that no concurrent resizing occurs by holding
408 * ht->mutex.
409 *
Thomas Graf7e1e7762014-08-02 11:47:44 +0200410 * The caller must ensure that no concurrent table mutations take place.
411 * It is however valid to have concurrent lookups if they are RCU protected.
Thomas Graf97defe12015-01-02 23:00:20 +0100412 *
413 * It is valid to have concurrent insertions and deletions protected by per
414 * bucket locks or concurrent RCU protected lookups and traversals.
Thomas Graf7e1e7762014-08-02 11:47:44 +0200415 */
Thomas Graf6eba8222014-11-13 13:45:46 +0100416int rhashtable_shrink(struct rhashtable *ht)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200417{
Thomas Graf97defe12015-01-02 23:00:20 +0100418 struct bucket_table *new_tbl, *tbl = rht_dereference(ht->tbl, ht);
419 spinlock_t *new_bucket_lock, *old_bucket_lock1, *old_bucket_lock2;
420 unsigned int new_hash;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200421
422 ASSERT_RHT_MUTEX(ht);
423
Ying Xue94000172014-09-03 09:22:36 +0800424 if (ht->shift <= ht->p.min_shift)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200425 return 0;
426
Thomas Graf97defe12015-01-02 23:00:20 +0100427 new_tbl = bucket_table_alloc(ht, tbl->size / 2);
428 if (new_tbl == NULL)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200429 return -ENOMEM;
430
Thomas Graf97defe12015-01-02 23:00:20 +0100431 rcu_assign_pointer(ht->future_tbl, new_tbl);
432 synchronize_rcu();
Thomas Graf7e1e7762014-08-02 11:47:44 +0200433
Thomas Graf97defe12015-01-02 23:00:20 +0100434 /* Link the first entry in the old bucket to the end of the
435 * bucket in the new table. As entries are concurrently being
436 * added to the new table, lock down the new bucket. As we
437 * always divide the size in half when shrinking, each bucket
438 * in the new table maps to exactly two buckets in the old
439 * table.
440 *
441 * As removals can occur concurrently on the old table, we need
442 * to lock down both matching buckets in the old table.
Thomas Graf7e1e7762014-08-02 11:47:44 +0200443 */
Thomas Graf97defe12015-01-02 23:00:20 +0100444 for (new_hash = 0; new_hash < new_tbl->size; new_hash++) {
445 old_bucket_lock1 = bucket_lock(tbl, new_hash);
446 old_bucket_lock2 = bucket_lock(tbl, new_hash + new_tbl->size);
447 new_bucket_lock = bucket_lock(new_tbl, new_hash);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200448
Thomas Graf97defe12015-01-02 23:00:20 +0100449 spin_lock_bh(old_bucket_lock1);
450 spin_lock_bh_nested(old_bucket_lock2, RHT_LOCK_NESTED);
451 spin_lock_bh_nested(new_bucket_lock, RHT_LOCK_NESTED2);
452
453 rcu_assign_pointer(*bucket_tail(new_tbl, new_hash),
454 tbl->buckets[new_hash]);
455 rcu_assign_pointer(*bucket_tail(new_tbl, new_hash),
456 tbl->buckets[new_hash + new_tbl->size]);
457
458 spin_unlock_bh(new_bucket_lock);
459 spin_unlock_bh(old_bucket_lock2);
460 spin_unlock_bh(old_bucket_lock1);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200461 }
462
463 /* Publish the new, valid hash table */
Thomas Graf97defe12015-01-02 23:00:20 +0100464 rcu_assign_pointer(ht->tbl, new_tbl);
465 ht->shift--;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200466
467 /* Wait for readers. No new readers will have references to the
468 * old hash table.
469 */
470 synchronize_rcu();
471
472 bucket_table_free(tbl);
473
474 return 0;
475}
476EXPORT_SYMBOL_GPL(rhashtable_shrink);
477
Thomas Graf97defe12015-01-02 23:00:20 +0100478static void rht_deferred_worker(struct work_struct *work)
479{
480 struct rhashtable *ht;
481 struct bucket_table *tbl;
482
483 ht = container_of(work, struct rhashtable, run_work.work);
484 mutex_lock(&ht->mutex);
485 tbl = rht_dereference(ht->tbl, ht);
486
487 if (ht->p.grow_decision && ht->p.grow_decision(ht, tbl->size))
488 rhashtable_expand(ht);
489 else if (ht->p.shrink_decision && ht->p.shrink_decision(ht, tbl->size))
490 rhashtable_shrink(ht);
491
492 mutex_unlock(&ht->mutex);
493}
494
Thomas Graf7e1e7762014-08-02 11:47:44 +0200495/**
496 * rhashtable_insert - insert object into hash hash table
497 * @ht: hash table
498 * @obj: pointer to hash head inside object
Thomas Graf7e1e7762014-08-02 11:47:44 +0200499 *
Thomas Graf97defe12015-01-02 23:00:20 +0100500 * Will take a per bucket spinlock to protect against mutual mutations
501 * on the same bucket. Multiple insertions may occur in parallel unless
502 * they map to the same bucket lock.
Thomas Graf7e1e7762014-08-02 11:47:44 +0200503 *
Thomas Graf97defe12015-01-02 23:00:20 +0100504 * It is safe to call this function from atomic context.
505 *
506 * Will trigger an automatic deferred table resizing if the size grows
507 * beyond the watermark indicated by grow_decision() which can be passed
508 * to rhashtable_init().
Thomas Graf7e1e7762014-08-02 11:47:44 +0200509 */
Thomas Graf6eba8222014-11-13 13:45:46 +0100510void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200511{
Thomas Graf97defe12015-01-02 23:00:20 +0100512 struct bucket_table *tbl;
Thomas Graff89bd6f2015-01-02 23:00:21 +0100513 struct rhash_head *head;
Thomas Graf97defe12015-01-02 23:00:20 +0100514 spinlock_t *lock;
515 unsigned hash;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200516
Thomas Graf97defe12015-01-02 23:00:20 +0100517 rcu_read_lock();
Thomas Graf7e1e7762014-08-02 11:47:44 +0200518
Thomas Graf97defe12015-01-02 23:00:20 +0100519 tbl = rht_dereference_rcu(ht->future_tbl, ht);
Thomas Graf8d24c0b2015-01-02 23:00:14 +0100520 hash = head_hashfn(ht, tbl, obj);
Thomas Graf97defe12015-01-02 23:00:20 +0100521 lock = bucket_lock(tbl, hash);
522
523 spin_lock_bh(lock);
Thomas Graff89bd6f2015-01-02 23:00:21 +0100524 head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
525 if (rht_is_a_nulls(head))
526 INIT_RHT_NULLS_HEAD(obj->next, ht, hash);
527 else
528 RCU_INIT_POINTER(obj->next, head);
529
Thomas Graf7e1e7762014-08-02 11:47:44 +0200530 rcu_assign_pointer(tbl->buckets[hash], obj);
Thomas Graf97defe12015-01-02 23:00:20 +0100531 spin_unlock_bh(lock);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200532
Thomas Graf97defe12015-01-02 23:00:20 +0100533 atomic_inc(&ht->nelems);
534
535 /* Only grow the table if no resizing is currently in progress. */
536 if (ht->tbl != ht->future_tbl &&
537 ht->p.grow_decision && ht->p.grow_decision(ht, tbl->size))
538 schedule_delayed_work(&ht->run_work, 0);
539
540 rcu_read_unlock();
Thomas Graf7e1e7762014-08-02 11:47:44 +0200541}
542EXPORT_SYMBOL_GPL(rhashtable_insert);
543
544/**
Thomas Graf7e1e7762014-08-02 11:47:44 +0200545 * rhashtable_remove - remove object from hash table
546 * @ht: hash table
547 * @obj: pointer to hash head inside object
Thomas Graf7e1e7762014-08-02 11:47:44 +0200548 *
549 * Since the hash chain is single linked, the removal operation needs to
550 * walk the bucket chain upon removal. The removal operation is thus
551 * considerable slow if the hash table is not correctly sized.
552 *
553 * Will automatically shrink the table via rhashtable_expand() if the the
554 * shrink_decision function specified at rhashtable_init() returns true.
555 *
556 * The caller must ensure that no concurrent table mutations occur. It is
557 * however valid to have concurrent lookups if they are RCU protected.
558 */
Thomas Graf6eba8222014-11-13 13:45:46 +0100559bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200560{
Thomas Graf97defe12015-01-02 23:00:20 +0100561 struct bucket_table *tbl;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200562 struct rhash_head __rcu **pprev;
563 struct rhash_head *he;
Thomas Graf97defe12015-01-02 23:00:20 +0100564 spinlock_t *lock;
565 unsigned int hash;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200566
Thomas Graf97defe12015-01-02 23:00:20 +0100567 rcu_read_lock();
568 tbl = rht_dereference_rcu(ht->tbl, ht);
569 hash = head_hashfn(ht, tbl, obj);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200570
Thomas Graf97defe12015-01-02 23:00:20 +0100571 lock = bucket_lock(tbl, hash);
572 spin_lock_bh(lock);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200573
Thomas Graf97defe12015-01-02 23:00:20 +0100574restart:
575 pprev = &tbl->buckets[hash];
576 rht_for_each(he, tbl, hash) {
Thomas Graf7e1e7762014-08-02 11:47:44 +0200577 if (he != obj) {
578 pprev = &he->next;
579 continue;
580 }
581
Thomas Graf97defe12015-01-02 23:00:20 +0100582 rcu_assign_pointer(*pprev, obj->next);
583 atomic_dec(&ht->nelems);
Thomas Graf897362e2015-01-02 23:00:18 +0100584
Thomas Graf97defe12015-01-02 23:00:20 +0100585 spin_unlock_bh(lock);
586
587 if (ht->tbl != ht->future_tbl &&
588 ht->p.shrink_decision &&
Thomas Graf897362e2015-01-02 23:00:18 +0100589 ht->p.shrink_decision(ht, tbl->size))
Thomas Graf97defe12015-01-02 23:00:20 +0100590 schedule_delayed_work(&ht->run_work, 0);
591
592 rcu_read_unlock();
Thomas Graf897362e2015-01-02 23:00:18 +0100593
Thomas Graf7e1e7762014-08-02 11:47:44 +0200594 return true;
595 }
596
Thomas Graf97defe12015-01-02 23:00:20 +0100597 if (tbl != rht_dereference_rcu(ht->tbl, ht)) {
598 spin_unlock_bh(lock);
599
600 tbl = rht_dereference_rcu(ht->tbl, ht);
601 hash = head_hashfn(ht, tbl, obj);
602
603 lock = bucket_lock(tbl, hash);
604 spin_lock_bh(lock);
605 goto restart;
606 }
607
608 spin_unlock_bh(lock);
609 rcu_read_unlock();
610
Thomas Graf7e1e7762014-08-02 11:47:44 +0200611 return false;
612}
613EXPORT_SYMBOL_GPL(rhashtable_remove);
614
615/**
616 * rhashtable_lookup - lookup key in hash table
617 * @ht: hash table
618 * @key: pointer to key
619 *
620 * Computes the hash value for the key and traverses the bucket chain looking
621 * for a entry with an identical key. The first matching entry is returned.
622 *
623 * This lookup function may only be used for fixed key hash table (key_len
624 * paramter set). It will BUG() if used inappropriately.
625 *
Thomas Graf97defe12015-01-02 23:00:20 +0100626 * Lookups may occur in parallel with hashtable mutations and resizing.
Thomas Graf7e1e7762014-08-02 11:47:44 +0200627 */
Thomas Graf97defe12015-01-02 23:00:20 +0100628void *rhashtable_lookup(struct rhashtable *ht, const void *key)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200629{
Thomas Graf97defe12015-01-02 23:00:20 +0100630 const struct bucket_table *tbl, *old_tbl;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200631 struct rhash_head *he;
Thomas Graf97defe12015-01-02 23:00:20 +0100632 u32 hash;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200633
634 BUG_ON(!ht->p.key_len);
635
Thomas Graf97defe12015-01-02 23:00:20 +0100636 rcu_read_lock();
637 old_tbl = rht_dereference_rcu(ht->tbl, ht);
638 tbl = rht_dereference_rcu(ht->future_tbl, ht);
639 hash = key_hashfn(ht, key, ht->p.key_len);
640restart:
641 rht_for_each_rcu(he, tbl, rht_bucket_index(tbl, hash)) {
Thomas Graf7e1e7762014-08-02 11:47:44 +0200642 if (memcmp(rht_obj(ht, he) + ht->p.key_offset, key,
643 ht->p.key_len))
644 continue;
Thomas Graf97defe12015-01-02 23:00:20 +0100645 rcu_read_unlock();
Thomas Grafa4b18cd2015-01-02 23:00:15 +0100646 return rht_obj(ht, he);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200647 }
648
Thomas Graf97defe12015-01-02 23:00:20 +0100649 if (unlikely(tbl != old_tbl)) {
650 tbl = old_tbl;
651 goto restart;
652 }
653
654 rcu_read_unlock();
Thomas Graf7e1e7762014-08-02 11:47:44 +0200655 return NULL;
656}
657EXPORT_SYMBOL_GPL(rhashtable_lookup);
658
659/**
660 * rhashtable_lookup_compare - search hash table with compare function
661 * @ht: hash table
Thomas Graf8d24c0b2015-01-02 23:00:14 +0100662 * @key: the pointer to the key
Thomas Graf7e1e7762014-08-02 11:47:44 +0200663 * @compare: compare function, must return true on match
664 * @arg: argument passed on to compare function
665 *
666 * Traverses the bucket chain behind the provided hash value and calls the
667 * specified compare function for each entry.
668 *
Thomas Graf97defe12015-01-02 23:00:20 +0100669 * Lookups may occur in parallel with hashtable mutations and resizing.
Thomas Graf7e1e7762014-08-02 11:47:44 +0200670 *
671 * Returns the first entry on which the compare function returned true.
672 */
Thomas Graf97defe12015-01-02 23:00:20 +0100673void *rhashtable_lookup_compare(struct rhashtable *ht, const void *key,
Thomas Graf7e1e7762014-08-02 11:47:44 +0200674 bool (*compare)(void *, void *), void *arg)
675{
Thomas Graf97defe12015-01-02 23:00:20 +0100676 const struct bucket_table *tbl, *old_tbl;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200677 struct rhash_head *he;
Thomas Graf8d24c0b2015-01-02 23:00:14 +0100678 u32 hash;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200679
Thomas Graf97defe12015-01-02 23:00:20 +0100680 rcu_read_lock();
681
682 old_tbl = rht_dereference_rcu(ht->tbl, ht);
683 tbl = rht_dereference_rcu(ht->future_tbl, ht);
Thomas Graf8d24c0b2015-01-02 23:00:14 +0100684 hash = key_hashfn(ht, key, ht->p.key_len);
Thomas Graf97defe12015-01-02 23:00:20 +0100685restart:
686 rht_for_each_rcu(he, tbl, rht_bucket_index(tbl, hash)) {
Thomas Graf7e1e7762014-08-02 11:47:44 +0200687 if (!compare(rht_obj(ht, he), arg))
688 continue;
Thomas Graf97defe12015-01-02 23:00:20 +0100689 rcu_read_unlock();
Thomas Grafa4b18cd2015-01-02 23:00:15 +0100690 return rht_obj(ht, he);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200691 }
692
Thomas Graf97defe12015-01-02 23:00:20 +0100693 if (unlikely(tbl != old_tbl)) {
694 tbl = old_tbl;
695 goto restart;
696 }
697 rcu_read_unlock();
698
Thomas Graf7e1e7762014-08-02 11:47:44 +0200699 return NULL;
700}
701EXPORT_SYMBOL_GPL(rhashtable_lookup_compare);
702
Ying Xue94000172014-09-03 09:22:36 +0800703static size_t rounded_hashtable_size(struct rhashtable_params *params)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200704{
Ying Xue94000172014-09-03 09:22:36 +0800705 return max(roundup_pow_of_two(params->nelem_hint * 4 / 3),
706 1UL << params->min_shift);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200707}
708
709/**
710 * rhashtable_init - initialize a new hash table
711 * @ht: hash table to be initialized
712 * @params: configuration parameters
713 *
714 * Initializes a new hash table based on the provided configuration
715 * parameters. A table can be configured either with a variable or
716 * fixed length key:
717 *
718 * Configuration Example 1: Fixed length keys
719 * struct test_obj {
720 * int key;
721 * void * my_member;
722 * struct rhash_head node;
723 * };
724 *
725 * struct rhashtable_params params = {
726 * .head_offset = offsetof(struct test_obj, node),
727 * .key_offset = offsetof(struct test_obj, key),
728 * .key_len = sizeof(int),
Daniel Borkmann87545892014-12-10 16:33:11 +0100729 * .hashfn = jhash,
Thomas Graff89bd6f2015-01-02 23:00:21 +0100730 * .nulls_base = (1U << RHT_BASE_SHIFT),
Thomas Graf7e1e7762014-08-02 11:47:44 +0200731 * };
732 *
733 * Configuration Example 2: Variable length keys
734 * struct test_obj {
735 * [...]
736 * struct rhash_head node;
737 * };
738 *
739 * u32 my_hash_fn(const void *data, u32 seed)
740 * {
741 * struct test_obj *obj = data;
742 *
743 * return [... hash ...];
744 * }
745 *
746 * struct rhashtable_params params = {
747 * .head_offset = offsetof(struct test_obj, node),
Daniel Borkmann87545892014-12-10 16:33:11 +0100748 * .hashfn = jhash,
Thomas Graf7e1e7762014-08-02 11:47:44 +0200749 * .obj_hashfn = my_hash_fn,
Thomas Graf7e1e7762014-08-02 11:47:44 +0200750 * };
751 */
752int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params)
753{
754 struct bucket_table *tbl;
755 size_t size;
756
757 size = HASH_DEFAULT_SIZE;
758
759 if ((params->key_len && !params->hashfn) ||
760 (!params->key_len && !params->obj_hashfn))
761 return -EINVAL;
762
Thomas Graff89bd6f2015-01-02 23:00:21 +0100763 if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT))
764 return -EINVAL;
765
Ying Xue94000172014-09-03 09:22:36 +0800766 params->min_shift = max_t(size_t, params->min_shift,
767 ilog2(HASH_MIN_SIZE));
768
Thomas Graf7e1e7762014-08-02 11:47:44 +0200769 if (params->nelem_hint)
Ying Xue94000172014-09-03 09:22:36 +0800770 size = rounded_hashtable_size(params);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200771
Thomas Graf97defe12015-01-02 23:00:20 +0100772 memset(ht, 0, sizeof(*ht));
773 mutex_init(&ht->mutex);
774 memcpy(&ht->p, params, sizeof(*params));
775
776 if (params->locks_mul)
777 ht->p.locks_mul = roundup_pow_of_two(params->locks_mul);
778 else
779 ht->p.locks_mul = BUCKET_LOCKS_PER_CPU;
780
781 tbl = bucket_table_alloc(ht, size);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200782 if (tbl == NULL)
783 return -ENOMEM;
784
Thomas Graf7e1e7762014-08-02 11:47:44 +0200785 ht->shift = ilog2(tbl->size);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200786 RCU_INIT_POINTER(ht->tbl, tbl);
Thomas Graf97defe12015-01-02 23:00:20 +0100787 RCU_INIT_POINTER(ht->future_tbl, tbl);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200788
789 if (!ht->p.hash_rnd)
790 get_random_bytes(&ht->p.hash_rnd, sizeof(ht->p.hash_rnd));
791
Thomas Graf97defe12015-01-02 23:00:20 +0100792 if (ht->p.grow_decision || ht->p.shrink_decision)
793 INIT_DEFERRABLE_WORK(&ht->run_work, rht_deferred_worker);
794
Thomas Graf7e1e7762014-08-02 11:47:44 +0200795 return 0;
796}
797EXPORT_SYMBOL_GPL(rhashtable_init);
798
799/**
800 * rhashtable_destroy - destroy hash table
801 * @ht: the hash table to destroy
802 *
Pablo Neira Ayusoae82ddc2014-09-02 00:26:05 +0200803 * Frees the bucket array. This function is not rcu safe, therefore the caller
804 * has to make sure that no resizing may happen by unpublishing the hashtable
805 * and waiting for the quiescent cycle before releasing the bucket array.
Thomas Graf7e1e7762014-08-02 11:47:44 +0200806 */
Thomas Graf97defe12015-01-02 23:00:20 +0100807void rhashtable_destroy(struct rhashtable *ht)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200808{
Thomas Graf97defe12015-01-02 23:00:20 +0100809 ht->being_destroyed = true;
810
811 mutex_lock(&ht->mutex);
812
813 cancel_delayed_work(&ht->run_work);
814 bucket_table_free(rht_dereference(ht->tbl, ht));
815
816 mutex_unlock(&ht->mutex);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200817}
818EXPORT_SYMBOL_GPL(rhashtable_destroy);
819
820/**************************************************************************
821 * Self Test
822 **************************************************************************/
823
824#ifdef CONFIG_TEST_RHASHTABLE
825
826#define TEST_HT_SIZE 8
827#define TEST_ENTRIES 2048
828#define TEST_PTR ((void *) 0xdeadbeef)
829#define TEST_NEXPANDS 4
830
Thomas Graf7e1e7762014-08-02 11:47:44 +0200831struct test_obj {
832 void *ptr;
833 int value;
834 struct rhash_head node;
835};
836
837static int __init test_rht_lookup(struct rhashtable *ht)
838{
839 unsigned int i;
840
841 for (i = 0; i < TEST_ENTRIES * 2; i++) {
842 struct test_obj *obj;
843 bool expected = !(i % 2);
844 u32 key = i;
845
846 obj = rhashtable_lookup(ht, &key);
847
848 if (expected && !obj) {
849 pr_warn("Test failed: Could not find key %u\n", key);
850 return -ENOENT;
851 } else if (!expected && obj) {
852 pr_warn("Test failed: Unexpected entry found for key %u\n",
853 key);
854 return -EEXIST;
855 } else if (expected && obj) {
856 if (obj->ptr != TEST_PTR || obj->value != i) {
857 pr_warn("Test failed: Lookup value mismatch %p!=%p, %u!=%u\n",
858 obj->ptr, TEST_PTR, obj->value, i);
859 return -EINVAL;
860 }
861 }
862 }
863
864 return 0;
865}
866
Thomas Graf3e7b2ec2014-11-24 12:37:58 +0100867static void test_bucket_stats(struct rhashtable *ht, bool quiet)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200868{
Thomas Graf3e7b2ec2014-11-24 12:37:58 +0100869 unsigned int cnt, rcu_cnt, i, total = 0;
Thomas Graf88d6ed12015-01-02 23:00:16 +0100870 struct rhash_head *pos;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200871 struct test_obj *obj;
Thomas Graf3e7b2ec2014-11-24 12:37:58 +0100872 struct bucket_table *tbl;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200873
Thomas Graf3e7b2ec2014-11-24 12:37:58 +0100874 tbl = rht_dereference_rcu(ht->tbl, ht);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200875 for (i = 0; i < tbl->size; i++) {
Thomas Graf3e7b2ec2014-11-24 12:37:58 +0100876 rcu_cnt = cnt = 0;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200877
878 if (!quiet)
879 pr_info(" [%#4x/%zu]", i, tbl->size);
880
Thomas Graf88d6ed12015-01-02 23:00:16 +0100881 rht_for_each_entry_rcu(obj, pos, tbl, i, node) {
Thomas Graf7e1e7762014-08-02 11:47:44 +0200882 cnt++;
883 total++;
884 if (!quiet)
885 pr_cont(" [%p],", obj);
886 }
887
Thomas Graf88d6ed12015-01-02 23:00:16 +0100888 rht_for_each_entry_rcu(obj, pos, tbl, i, node)
Thomas Graf3e7b2ec2014-11-24 12:37:58 +0100889 rcu_cnt++;
890
891 if (rcu_cnt != cnt)
892 pr_warn("Test failed: Chain count mismach %d != %d",
893 cnt, rcu_cnt);
894
Thomas Graf7e1e7762014-08-02 11:47:44 +0200895 if (!quiet)
896 pr_cont("\n [%#x] first element: %p, chain length: %u\n",
897 i, tbl->buckets[i], cnt);
898 }
899
Thomas Graf97defe12015-01-02 23:00:20 +0100900 pr_info(" Traversal complete: counted=%u, nelems=%u, entries=%d\n",
901 total, atomic_read(&ht->nelems), TEST_ENTRIES);
Thomas Graf3e7b2ec2014-11-24 12:37:58 +0100902
Thomas Graf97defe12015-01-02 23:00:20 +0100903 if (total != atomic_read(&ht->nelems) || total != TEST_ENTRIES)
Thomas Graf3e7b2ec2014-11-24 12:37:58 +0100904 pr_warn("Test failed: Total count mismatch ^^^");
Thomas Graf7e1e7762014-08-02 11:47:44 +0200905}
906
907static int __init test_rhashtable(struct rhashtable *ht)
908{
909 struct bucket_table *tbl;
Thomas Graf88d6ed12015-01-02 23:00:16 +0100910 struct test_obj *obj;
911 struct rhash_head *pos, *next;
Thomas Graf7e1e7762014-08-02 11:47:44 +0200912 int err;
913 unsigned int i;
914
915 /*
916 * Insertion Test:
917 * Insert TEST_ENTRIES into table with all keys even numbers
918 */
919 pr_info(" Adding %d keys\n", TEST_ENTRIES);
920 for (i = 0; i < TEST_ENTRIES; i++) {
921 struct test_obj *obj;
922
923 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
924 if (!obj) {
925 err = -ENOMEM;
926 goto error;
927 }
928
929 obj->ptr = TEST_PTR;
930 obj->value = i * 2;
931
Thomas Graf6eba8222014-11-13 13:45:46 +0100932 rhashtable_insert(ht, &obj->node);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200933 }
934
935 rcu_read_lock();
Thomas Graf3e7b2ec2014-11-24 12:37:58 +0100936 test_bucket_stats(ht, true);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200937 test_rht_lookup(ht);
938 rcu_read_unlock();
939
940 for (i = 0; i < TEST_NEXPANDS; i++) {
941 pr_info(" Table expansion iteration %u...\n", i);
Thomas Graf97defe12015-01-02 23:00:20 +0100942 mutex_lock(&ht->mutex);
Thomas Graf6eba8222014-11-13 13:45:46 +0100943 rhashtable_expand(ht);
Thomas Graf97defe12015-01-02 23:00:20 +0100944 mutex_unlock(&ht->mutex);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200945
946 rcu_read_lock();
947 pr_info(" Verifying lookups...\n");
948 test_rht_lookup(ht);
949 rcu_read_unlock();
950 }
951
952 for (i = 0; i < TEST_NEXPANDS; i++) {
953 pr_info(" Table shrinkage iteration %u...\n", i);
Thomas Graf97defe12015-01-02 23:00:20 +0100954 mutex_lock(&ht->mutex);
Thomas Graf6eba8222014-11-13 13:45:46 +0100955 rhashtable_shrink(ht);
Thomas Graf97defe12015-01-02 23:00:20 +0100956 mutex_unlock(&ht->mutex);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200957
958 rcu_read_lock();
959 pr_info(" Verifying lookups...\n");
960 test_rht_lookup(ht);
961 rcu_read_unlock();
962 }
963
Thomas Graf3e7b2ec2014-11-24 12:37:58 +0100964 rcu_read_lock();
965 test_bucket_stats(ht, true);
966 rcu_read_unlock();
967
Thomas Graf7e1e7762014-08-02 11:47:44 +0200968 pr_info(" Deleting %d keys\n", TEST_ENTRIES);
969 for (i = 0; i < TEST_ENTRIES; i++) {
970 u32 key = i * 2;
971
972 obj = rhashtable_lookup(ht, &key);
973 BUG_ON(!obj);
974
Thomas Graf6eba8222014-11-13 13:45:46 +0100975 rhashtable_remove(ht, &obj->node);
Thomas Graf7e1e7762014-08-02 11:47:44 +0200976 kfree(obj);
977 }
978
979 return 0;
980
981error:
982 tbl = rht_dereference_rcu(ht->tbl, ht);
983 for (i = 0; i < tbl->size; i++)
Thomas Graf88d6ed12015-01-02 23:00:16 +0100984 rht_for_each_entry_safe(obj, pos, next, tbl, i, node)
Thomas Graf7e1e7762014-08-02 11:47:44 +0200985 kfree(obj);
986
987 return err;
988}
989
990static int __init test_rht_init(void)
991{
992 struct rhashtable ht;
993 struct rhashtable_params params = {
994 .nelem_hint = TEST_HT_SIZE,
995 .head_offset = offsetof(struct test_obj, node),
996 .key_offset = offsetof(struct test_obj, value),
997 .key_len = sizeof(int),
Daniel Borkmann87545892014-12-10 16:33:11 +0100998 .hashfn = jhash,
Thomas Graff89bd6f2015-01-02 23:00:21 +0100999 .nulls_base = (3U << RHT_BASE_SHIFT),
Thomas Graf7e1e7762014-08-02 11:47:44 +02001000 .grow_decision = rht_grow_above_75,
1001 .shrink_decision = rht_shrink_below_30,
1002 };
1003 int err;
1004
1005 pr_info("Running resizable hashtable tests...\n");
1006
1007 err = rhashtable_init(&ht, &params);
1008 if (err < 0) {
1009 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
1010 err);
1011 return err;
1012 }
1013
1014 err = test_rhashtable(&ht);
1015
1016 rhashtable_destroy(&ht);
1017
1018 return err;
1019}
1020
1021subsys_initcall(test_rht_init);
1022
1023#endif /* CONFIG_TEST_RHASHTABLE */