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7e1e7763 TG |
1 | /* |
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> | |
87545899 | 23 | #include <linux/jhash.h> |
7e1e7763 TG |
24 | #include <linux/random.h> |
25 | #include <linux/rhashtable.h> | |
7e1e7763 TG |
26 | |
27 | #define HASH_DEFAULT_SIZE 64UL | |
28 | #define HASH_MIN_SIZE 4UL | |
97defe1e TG |
29 | #define BUCKET_LOCKS_PER_CPU 128UL |
30 | ||
f89bd6f8 TG |
31 | /* Base bits plus 1 bit for nulls marker */ |
32 | #define HASH_RESERVED_SPACE (RHT_BASE_BITS + 1) | |
33 | ||
97defe1e TG |
34 | enum { |
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 | */ | |
47 | static spinlock_t *bucket_lock(const struct bucket_table *tbl, u32 hash) | |
48 | { | |
49 | return &tbl->locks[hash & tbl->locks_mask]; | |
50 | } | |
7e1e7763 TG |
51 | |
52 | #define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT)) | |
97defe1e TG |
53 | #define ASSERT_BUCKET_LOCK(TBL, HASH) \ |
54 | BUG_ON(!lockdep_rht_bucket_is_held(TBL, HASH)) | |
7e1e7763 TG |
55 | |
56 | #ifdef CONFIG_PROVE_LOCKING | |
97defe1e | 57 | int lockdep_rht_mutex_is_held(struct rhashtable *ht) |
7e1e7763 | 58 | { |
97defe1e | 59 | return (debug_locks) ? lockdep_is_held(&ht->mutex) : 1; |
7e1e7763 TG |
60 | } |
61 | EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held); | |
88d6ed15 TG |
62 | |
63 | int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash) | |
64 | { | |
97defe1e TG |
65 | spinlock_t *lock = bucket_lock(tbl, hash); |
66 | ||
67 | return (debug_locks) ? lockdep_is_held(lock) : 1; | |
88d6ed15 TG |
68 | } |
69 | EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held); | |
7e1e7763 TG |
70 | #endif |
71 | ||
c91eee56 | 72 | static void *rht_obj(const struct rhashtable *ht, const struct rhash_head *he) |
7e1e7763 TG |
73 | { |
74 | return (void *) he - ht->p.head_offset; | |
75 | } | |
7e1e7763 | 76 | |
8d24c0b4 | 77 | static u32 rht_bucket_index(const struct bucket_table *tbl, u32 hash) |
7e1e7763 | 78 | { |
8d24c0b4 | 79 | return hash & (tbl->size - 1); |
7e1e7763 | 80 | } |
7e1e7763 | 81 | |
8d24c0b4 | 82 | static u32 obj_raw_hashfn(const struct rhashtable *ht, const void *ptr) |
7e1e7763 | 83 | { |
8d24c0b4 | 84 | u32 hash; |
7e1e7763 | 85 | |
8d24c0b4 TG |
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); | |
7e1e7763 | 91 | |
f89bd6f8 | 92 | return hash >> HASH_RESERVED_SPACE; |
7e1e7763 TG |
93 | } |
94 | ||
97defe1e | 95 | static u32 key_hashfn(struct rhashtable *ht, const void *key, u32 len) |
7e1e7763 TG |
96 | { |
97 | struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht); | |
8d24c0b4 TG |
98 | u32 hash; |
99 | ||
100 | hash = ht->p.hashfn(key, len, ht->p.hash_rnd); | |
f89bd6f8 | 101 | hash >>= HASH_RESERVED_SPACE; |
7e1e7763 | 102 | |
8d24c0b4 | 103 | return rht_bucket_index(tbl, hash); |
7e1e7763 | 104 | } |
7e1e7763 TG |
105 | |
106 | static u32 head_hashfn(const struct rhashtable *ht, | |
8d24c0b4 TG |
107 | const struct bucket_table *tbl, |
108 | const struct rhash_head *he) | |
7e1e7763 | 109 | { |
8d24c0b4 | 110 | return rht_bucket_index(tbl, obj_raw_hashfn(ht, rht_obj(ht, he))); |
7e1e7763 TG |
111 | } |
112 | ||
b8e1943e TG |
113 | static 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]; | |
f89bd6f8 | 118 | !rht_is_a_nulls(rht_dereference_bucket(*pprev, tbl, n)); |
b8e1943e TG |
119 | pprev = &rht_dereference_bucket(*pprev, tbl, n)->next) |
120 | ; | |
121 | ||
122 | return pprev; | |
123 | } | |
124 | ||
97defe1e TG |
125 | static 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 | ||
158 | static void bucket_table_free(const struct bucket_table *tbl) | |
159 | { | |
160 | if (tbl) | |
161 | kvfree(tbl->locks); | |
162 | ||
163 | kvfree(tbl); | |
164 | } | |
165 | ||
166 | static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, | |
167 | size_t nbuckets) | |
7e1e7763 TG |
168 | { |
169 | struct bucket_table *tbl; | |
170 | size_t size; | |
f89bd6f8 | 171 | int i; |
7e1e7763 TG |
172 | |
173 | size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]); | |
6eba8224 | 174 | tbl = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); |
7e1e7763 TG |
175 | if (tbl == NULL) |
176 | tbl = vzalloc(size); | |
177 | ||
178 | if (tbl == NULL) | |
179 | return NULL; | |
180 | ||
181 | tbl->size = nbuckets; | |
182 | ||
97defe1e TG |
183 | if (alloc_bucket_locks(ht, tbl) < 0) { |
184 | bucket_table_free(tbl); | |
185 | return NULL; | |
186 | } | |
7e1e7763 | 187 | |
f89bd6f8 TG |
188 | for (i = 0; i < nbuckets; i++) |
189 | INIT_RHT_NULLS_HEAD(tbl->buckets[i], ht, i); | |
190 | ||
97defe1e | 191 | return tbl; |
7e1e7763 TG |
192 | } |
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 | */ | |
199 | bool rht_grow_above_75(const struct rhashtable *ht, size_t new_size) | |
200 | { | |
201 | /* Expand table when exceeding 75% load */ | |
c0c09bfd YX |
202 | return atomic_read(&ht->nelems) > (new_size / 4 * 3) && |
203 | (ht->p.max_shift && atomic_read(&ht->shift) < ht->p.max_shift); | |
7e1e7763 TG |
204 | } |
205 | EXPORT_SYMBOL_GPL(rht_grow_above_75); | |
206 | ||
207 | /** | |
208 | * rht_shrink_below_30 - returns true if nelems < 0.3 * table-size | |
209 | * @ht: hash table | |
210 | * @new_size: new table size | |
211 | */ | |
212 | bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size) | |
213 | { | |
214 | /* Shrink table beneath 30% load */ | |
c0c09bfd YX |
215 | return atomic_read(&ht->nelems) < (new_size * 3 / 10) && |
216 | (atomic_read(&ht->shift) > ht->p.min_shift); | |
7e1e7763 TG |
217 | } |
218 | EXPORT_SYMBOL_GPL(rht_shrink_below_30); | |
219 | ||
220 | static void hashtable_chain_unzip(const struct rhashtable *ht, | |
221 | const struct bucket_table *new_tbl, | |
97defe1e TG |
222 | struct bucket_table *old_tbl, |
223 | size_t old_hash) | |
7e1e7763 TG |
224 | { |
225 | struct rhash_head *he, *p, *next; | |
97defe1e TG |
226 | spinlock_t *new_bucket_lock, *new_bucket_lock2 = NULL; |
227 | unsigned int new_hash, new_hash2; | |
228 | ||
229 | ASSERT_BUCKET_LOCK(old_tbl, old_hash); | |
7e1e7763 TG |
230 | |
231 | /* Old bucket empty, no work needed. */ | |
97defe1e TG |
232 | p = rht_dereference_bucket(old_tbl->buckets[old_hash], old_tbl, |
233 | old_hash); | |
f89bd6f8 | 234 | if (rht_is_a_nulls(p)) |
7e1e7763 TG |
235 | return; |
236 | ||
97defe1e TG |
237 | new_hash = new_hash2 = head_hashfn(ht, new_tbl, p); |
238 | new_bucket_lock = bucket_lock(new_tbl, new_hash); | |
239 | ||
7e1e7763 TG |
240 | /* Advance the old bucket pointer one or more times until it |
241 | * reaches a node that doesn't hash to the same bucket as the | |
242 | * previous node p. Call the previous node p; | |
243 | */ | |
97defe1e TG |
244 | rht_for_each_continue(he, p->next, old_tbl, old_hash) { |
245 | new_hash2 = head_hashfn(ht, new_tbl, he); | |
246 | if (new_hash != new_hash2) | |
7e1e7763 TG |
247 | break; |
248 | p = he; | |
249 | } | |
97defe1e TG |
250 | rcu_assign_pointer(old_tbl->buckets[old_hash], p->next); |
251 | ||
252 | spin_lock_bh_nested(new_bucket_lock, RHT_LOCK_NESTED); | |
253 | ||
254 | /* If we have encountered an entry that maps to a different bucket in | |
255 | * the new table, lock down that bucket as well as we might cut off | |
256 | * the end of the chain. | |
257 | */ | |
258 | new_bucket_lock2 = bucket_lock(new_tbl, new_hash); | |
259 | if (new_bucket_lock != new_bucket_lock2) | |
260 | spin_lock_bh_nested(new_bucket_lock2, RHT_LOCK_NESTED2); | |
7e1e7763 TG |
261 | |
262 | /* Find the subsequent node which does hash to the same | |
263 | * bucket as node P, or NULL if no such node exists. | |
264 | */ | |
f89bd6f8 TG |
265 | INIT_RHT_NULLS_HEAD(next, ht, old_hash); |
266 | if (!rht_is_a_nulls(he)) { | |
97defe1e TG |
267 | rht_for_each_continue(he, he->next, old_tbl, old_hash) { |
268 | if (head_hashfn(ht, new_tbl, he) == new_hash) { | |
7e1e7763 TG |
269 | next = he; |
270 | break; | |
271 | } | |
272 | } | |
273 | } | |
274 | ||
275 | /* Set p's next pointer to that subsequent node pointer, | |
276 | * bypassing the nodes which do not hash to p's bucket | |
277 | */ | |
97defe1e TG |
278 | rcu_assign_pointer(p->next, next); |
279 | ||
280 | if (new_bucket_lock != new_bucket_lock2) | |
281 | spin_unlock_bh(new_bucket_lock2); | |
282 | spin_unlock_bh(new_bucket_lock); | |
283 | } | |
284 | ||
285 | static void link_old_to_new(struct bucket_table *new_tbl, | |
286 | unsigned int new_hash, struct rhash_head *entry) | |
287 | { | |
288 | spinlock_t *new_bucket_lock; | |
289 | ||
290 | new_bucket_lock = bucket_lock(new_tbl, new_hash); | |
291 | ||
292 | spin_lock_bh_nested(new_bucket_lock, RHT_LOCK_NESTED); | |
293 | rcu_assign_pointer(*bucket_tail(new_tbl, new_hash), entry); | |
294 | spin_unlock_bh(new_bucket_lock); | |
7e1e7763 TG |
295 | } |
296 | ||
297 | /** | |
298 | * rhashtable_expand - Expand hash table while allowing concurrent lookups | |
299 | * @ht: the hash table to expand | |
7e1e7763 TG |
300 | * |
301 | * A secondary bucket array is allocated and the hash entries are migrated | |
302 | * while keeping them on both lists until the end of the RCU grace period. | |
303 | * | |
304 | * This function may only be called in a context where it is safe to call | |
305 | * synchronize_rcu(), e.g. not within a rcu_read_lock() section. | |
306 | * | |
97defe1e TG |
307 | * The caller must ensure that no concurrent resizing occurs by holding |
308 | * ht->mutex. | |
309 | * | |
310 | * It is valid to have concurrent insertions and deletions protected by per | |
311 | * bucket locks or concurrent RCU protected lookups and traversals. | |
7e1e7763 | 312 | */ |
6eba8224 | 313 | int rhashtable_expand(struct rhashtable *ht) |
7e1e7763 TG |
314 | { |
315 | struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht); | |
316 | struct rhash_head *he; | |
97defe1e TG |
317 | spinlock_t *old_bucket_lock; |
318 | unsigned int new_hash, old_hash; | |
319 | bool complete = false; | |
7e1e7763 TG |
320 | |
321 | ASSERT_RHT_MUTEX(ht); | |
322 | ||
97defe1e | 323 | new_tbl = bucket_table_alloc(ht, old_tbl->size * 2); |
7e1e7763 TG |
324 | if (new_tbl == NULL) |
325 | return -ENOMEM; | |
326 | ||
c0c09bfd | 327 | atomic_inc(&ht->shift); |
7e1e7763 | 328 | |
97defe1e TG |
329 | /* Make insertions go into the new, empty table right away. Deletions |
330 | * and lookups will be attempted in both tables until we synchronize. | |
331 | * The synchronize_rcu() guarantees for the new table to be picked up | |
332 | * so no new additions go into the old table while we relink. | |
333 | */ | |
334 | rcu_assign_pointer(ht->future_tbl, new_tbl); | |
335 | synchronize_rcu(); | |
336 | ||
337 | /* For each new bucket, search the corresponding old bucket for the | |
338 | * first entry that hashes to the new bucket, and link the end of | |
339 | * newly formed bucket chain (containing entries added to future | |
340 | * table) to that entry. Since all the entries which will end up in | |
341 | * the new bucket appear in the same old bucket, this constructs an | |
342 | * entirely valid new hash table, but with multiple buckets | |
343 | * "zipped" together into a single imprecise chain. | |
7e1e7763 | 344 | */ |
97defe1e TG |
345 | for (new_hash = 0; new_hash < new_tbl->size; new_hash++) { |
346 | old_hash = rht_bucket_index(old_tbl, new_hash); | |
347 | old_bucket_lock = bucket_lock(old_tbl, old_hash); | |
348 | ||
349 | spin_lock_bh(old_bucket_lock); | |
350 | rht_for_each(he, old_tbl, old_hash) { | |
351 | if (head_hashfn(ht, new_tbl, he) == new_hash) { | |
352 | link_old_to_new(new_tbl, new_hash, he); | |
7e1e7763 TG |
353 | break; |
354 | } | |
355 | } | |
97defe1e | 356 | spin_unlock_bh(old_bucket_lock); |
7e1e7763 TG |
357 | } |
358 | ||
359 | /* Publish the new table pointer. Lookups may now traverse | |
0c828f2f HX |
360 | * the new table, but they will not benefit from any |
361 | * additional efficiency until later steps unzip the buckets. | |
7e1e7763 TG |
362 | */ |
363 | rcu_assign_pointer(ht->tbl, new_tbl); | |
364 | ||
365 | /* Unzip interleaved hash chains */ | |
97defe1e | 366 | while (!complete && !ht->being_destroyed) { |
7e1e7763 TG |
367 | /* Wait for readers. All new readers will see the new |
368 | * table, and thus no references to the old table will | |
369 | * remain. | |
370 | */ | |
371 | synchronize_rcu(); | |
372 | ||
373 | /* For each bucket in the old table (each of which | |
374 | * contains items from multiple buckets of the new | |
375 | * table): ... | |
376 | */ | |
377 | complete = true; | |
97defe1e | 378 | for (old_hash = 0; old_hash < old_tbl->size; old_hash++) { |
f89bd6f8 TG |
379 | struct rhash_head *head; |
380 | ||
97defe1e TG |
381 | old_bucket_lock = bucket_lock(old_tbl, old_hash); |
382 | spin_lock_bh(old_bucket_lock); | |
383 | ||
384 | hashtable_chain_unzip(ht, new_tbl, old_tbl, old_hash); | |
f89bd6f8 TG |
385 | head = rht_dereference_bucket(old_tbl->buckets[old_hash], |
386 | old_tbl, old_hash); | |
387 | if (!rht_is_a_nulls(head)) | |
7e1e7763 | 388 | complete = false; |
97defe1e TG |
389 | |
390 | spin_unlock_bh(old_bucket_lock); | |
7e1e7763 | 391 | } |
97defe1e | 392 | } |
7e1e7763 TG |
393 | |
394 | bucket_table_free(old_tbl); | |
395 | return 0; | |
396 | } | |
397 | EXPORT_SYMBOL_GPL(rhashtable_expand); | |
398 | ||
399 | /** | |
400 | * rhashtable_shrink - Shrink hash table while allowing concurrent lookups | |
401 | * @ht: the hash table to shrink | |
7e1e7763 TG |
402 | * |
403 | * This function may only be called in a context where it is safe to call | |
404 | * synchronize_rcu(), e.g. not within a rcu_read_lock() section. | |
405 | * | |
97defe1e TG |
406 | * The caller must ensure that no concurrent resizing occurs by holding |
407 | * ht->mutex. | |
408 | * | |
7e1e7763 TG |
409 | * The caller must ensure that no concurrent table mutations take place. |
410 | * It is however valid to have concurrent lookups if they are RCU protected. | |
97defe1e TG |
411 | * |
412 | * It is valid to have concurrent insertions and deletions protected by per | |
413 | * bucket locks or concurrent RCU protected lookups and traversals. | |
7e1e7763 | 414 | */ |
6eba8224 | 415 | int rhashtable_shrink(struct rhashtable *ht) |
7e1e7763 | 416 | { |
97defe1e TG |
417 | struct bucket_table *new_tbl, *tbl = rht_dereference(ht->tbl, ht); |
418 | spinlock_t *new_bucket_lock, *old_bucket_lock1, *old_bucket_lock2; | |
419 | unsigned int new_hash; | |
7e1e7763 TG |
420 | |
421 | ASSERT_RHT_MUTEX(ht); | |
422 | ||
97defe1e TG |
423 | new_tbl = bucket_table_alloc(ht, tbl->size / 2); |
424 | if (new_tbl == NULL) | |
7e1e7763 TG |
425 | return -ENOMEM; |
426 | ||
97defe1e TG |
427 | rcu_assign_pointer(ht->future_tbl, new_tbl); |
428 | synchronize_rcu(); | |
7e1e7763 | 429 | |
97defe1e TG |
430 | /* Link the first entry in the old bucket to the end of the |
431 | * bucket in the new table. As entries are concurrently being | |
432 | * added to the new table, lock down the new bucket. As we | |
433 | * always divide the size in half when shrinking, each bucket | |
434 | * in the new table maps to exactly two buckets in the old | |
435 | * table. | |
436 | * | |
437 | * As removals can occur concurrently on the old table, we need | |
438 | * to lock down both matching buckets in the old table. | |
7e1e7763 | 439 | */ |
97defe1e TG |
440 | for (new_hash = 0; new_hash < new_tbl->size; new_hash++) { |
441 | old_bucket_lock1 = bucket_lock(tbl, new_hash); | |
442 | old_bucket_lock2 = bucket_lock(tbl, new_hash + new_tbl->size); | |
443 | new_bucket_lock = bucket_lock(new_tbl, new_hash); | |
444 | ||
445 | spin_lock_bh(old_bucket_lock1); | |
446 | spin_lock_bh_nested(old_bucket_lock2, RHT_LOCK_NESTED); | |
447 | spin_lock_bh_nested(new_bucket_lock, RHT_LOCK_NESTED2); | |
448 | ||
449 | rcu_assign_pointer(*bucket_tail(new_tbl, new_hash), | |
450 | tbl->buckets[new_hash]); | |
451 | rcu_assign_pointer(*bucket_tail(new_tbl, new_hash), | |
452 | tbl->buckets[new_hash + new_tbl->size]); | |
453 | ||
454 | spin_unlock_bh(new_bucket_lock); | |
455 | spin_unlock_bh(old_bucket_lock2); | |
456 | spin_unlock_bh(old_bucket_lock1); | |
7e1e7763 TG |
457 | } |
458 | ||
459 | /* Publish the new, valid hash table */ | |
97defe1e | 460 | rcu_assign_pointer(ht->tbl, new_tbl); |
c0c09bfd | 461 | atomic_dec(&ht->shift); |
7e1e7763 TG |
462 | |
463 | /* Wait for readers. No new readers will have references to the | |
464 | * old hash table. | |
465 | */ | |
466 | synchronize_rcu(); | |
467 | ||
468 | bucket_table_free(tbl); | |
469 | ||
470 | return 0; | |
471 | } | |
472 | EXPORT_SYMBOL_GPL(rhashtable_shrink); | |
473 | ||
97defe1e TG |
474 | static void rht_deferred_worker(struct work_struct *work) |
475 | { | |
476 | struct rhashtable *ht; | |
477 | struct bucket_table *tbl; | |
478 | ||
479 | ht = container_of(work, struct rhashtable, run_work.work); | |
480 | mutex_lock(&ht->mutex); | |
481 | tbl = rht_dereference(ht->tbl, ht); | |
482 | ||
483 | if (ht->p.grow_decision && ht->p.grow_decision(ht, tbl->size)) | |
484 | rhashtable_expand(ht); | |
485 | else if (ht->p.shrink_decision && ht->p.shrink_decision(ht, tbl->size)) | |
486 | rhashtable_shrink(ht); | |
487 | ||
488 | mutex_unlock(&ht->mutex); | |
489 | } | |
490 | ||
54c5b7d3 YX |
491 | static void rhashtable_wakeup_worker(struct rhashtable *ht) |
492 | { | |
493 | struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht); | |
494 | struct bucket_table *new_tbl = rht_dereference_rcu(ht->future_tbl, ht); | |
495 | size_t size = tbl->size; | |
496 | ||
497 | /* Only adjust the table if no resizing is currently in progress. */ | |
498 | if (tbl == new_tbl && | |
499 | ((ht->p.grow_decision && ht->p.grow_decision(ht, size)) || | |
500 | (ht->p.shrink_decision && ht->p.shrink_decision(ht, size)))) | |
501 | schedule_delayed_work(&ht->run_work, 0); | |
502 | } | |
503 | ||
db304854 YX |
504 | static void __rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj, |
505 | struct bucket_table *tbl, u32 hash) | |
506 | { | |
507 | struct rhash_head *head = rht_dereference_bucket(tbl->buckets[hash], | |
508 | tbl, hash); | |
509 | ||
510 | if (rht_is_a_nulls(head)) | |
511 | INIT_RHT_NULLS_HEAD(obj->next, ht, hash); | |
512 | else | |
513 | RCU_INIT_POINTER(obj->next, head); | |
514 | ||
515 | rcu_assign_pointer(tbl->buckets[hash], obj); | |
516 | ||
517 | atomic_inc(&ht->nelems); | |
518 | ||
519 | rhashtable_wakeup_worker(ht); | |
520 | } | |
521 | ||
7e1e7763 | 522 | /** |
db304854 | 523 | * rhashtable_insert - insert object into hash table |
7e1e7763 TG |
524 | * @ht: hash table |
525 | * @obj: pointer to hash head inside object | |
7e1e7763 | 526 | * |
97defe1e TG |
527 | * Will take a per bucket spinlock to protect against mutual mutations |
528 | * on the same bucket. Multiple insertions may occur in parallel unless | |
529 | * they map to the same bucket lock. | |
7e1e7763 | 530 | * |
97defe1e TG |
531 | * It is safe to call this function from atomic context. |
532 | * | |
533 | * Will trigger an automatic deferred table resizing if the size grows | |
534 | * beyond the watermark indicated by grow_decision() which can be passed | |
535 | * to rhashtable_init(). | |
7e1e7763 | 536 | */ |
6eba8224 | 537 | void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj) |
7e1e7763 | 538 | { |
97defe1e TG |
539 | struct bucket_table *tbl; |
540 | spinlock_t *lock; | |
541 | unsigned hash; | |
7e1e7763 | 542 | |
97defe1e | 543 | rcu_read_lock(); |
7e1e7763 | 544 | |
97defe1e | 545 | tbl = rht_dereference_rcu(ht->future_tbl, ht); |
8d24c0b4 | 546 | hash = head_hashfn(ht, tbl, obj); |
97defe1e TG |
547 | lock = bucket_lock(tbl, hash); |
548 | ||
549 | spin_lock_bh(lock); | |
db304854 | 550 | __rhashtable_insert(ht, obj, tbl, hash); |
97defe1e | 551 | spin_unlock_bh(lock); |
7e1e7763 | 552 | |
97defe1e | 553 | rcu_read_unlock(); |
7e1e7763 TG |
554 | } |
555 | EXPORT_SYMBOL_GPL(rhashtable_insert); | |
556 | ||
7e1e7763 TG |
557 | /** |
558 | * rhashtable_remove - remove object from hash table | |
559 | * @ht: hash table | |
560 | * @obj: pointer to hash head inside object | |
7e1e7763 TG |
561 | * |
562 | * Since the hash chain is single linked, the removal operation needs to | |
563 | * walk the bucket chain upon removal. The removal operation is thus | |
564 | * considerable slow if the hash table is not correctly sized. | |
565 | * | |
db304854 | 566 | * Will automatically shrink the table via rhashtable_expand() if the |
7e1e7763 TG |
567 | * shrink_decision function specified at rhashtable_init() returns true. |
568 | * | |
569 | * The caller must ensure that no concurrent table mutations occur. It is | |
570 | * however valid to have concurrent lookups if they are RCU protected. | |
571 | */ | |
6eba8224 | 572 | bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj) |
7e1e7763 | 573 | { |
97defe1e | 574 | struct bucket_table *tbl; |
7e1e7763 TG |
575 | struct rhash_head __rcu **pprev; |
576 | struct rhash_head *he; | |
97defe1e TG |
577 | spinlock_t *lock; |
578 | unsigned int hash; | |
7e1e7763 | 579 | |
97defe1e TG |
580 | rcu_read_lock(); |
581 | tbl = rht_dereference_rcu(ht->tbl, ht); | |
582 | hash = head_hashfn(ht, tbl, obj); | |
7e1e7763 | 583 | |
97defe1e TG |
584 | lock = bucket_lock(tbl, hash); |
585 | spin_lock_bh(lock); | |
7e1e7763 | 586 | |
97defe1e TG |
587 | restart: |
588 | pprev = &tbl->buckets[hash]; | |
589 | rht_for_each(he, tbl, hash) { | |
7e1e7763 TG |
590 | if (he != obj) { |
591 | pprev = &he->next; | |
592 | continue; | |
593 | } | |
594 | ||
97defe1e TG |
595 | rcu_assign_pointer(*pprev, obj->next); |
596 | atomic_dec(&ht->nelems); | |
897362e4 | 597 | |
97defe1e TG |
598 | spin_unlock_bh(lock); |
599 | ||
54c5b7d3 | 600 | rhashtable_wakeup_worker(ht); |
97defe1e TG |
601 | |
602 | rcu_read_unlock(); | |
897362e4 | 603 | |
7e1e7763 TG |
604 | return true; |
605 | } | |
606 | ||
bd6d4db5 | 607 | if (tbl != rht_dereference_rcu(ht->future_tbl, ht)) { |
97defe1e TG |
608 | spin_unlock_bh(lock); |
609 | ||
bd6d4db5 | 610 | tbl = rht_dereference_rcu(ht->future_tbl, ht); |
97defe1e TG |
611 | hash = head_hashfn(ht, tbl, obj); |
612 | ||
613 | lock = bucket_lock(tbl, hash); | |
614 | spin_lock_bh(lock); | |
615 | goto restart; | |
616 | } | |
617 | ||
618 | spin_unlock_bh(lock); | |
619 | rcu_read_unlock(); | |
620 | ||
7e1e7763 TG |
621 | return false; |
622 | } | |
623 | EXPORT_SYMBOL_GPL(rhashtable_remove); | |
624 | ||
efb975a6 YX |
625 | struct rhashtable_compare_arg { |
626 | struct rhashtable *ht; | |
627 | const void *key; | |
628 | }; | |
629 | ||
630 | static bool rhashtable_compare(void *ptr, void *arg) | |
631 | { | |
632 | struct rhashtable_compare_arg *x = arg; | |
633 | struct rhashtable *ht = x->ht; | |
634 | ||
635 | return !memcmp(ptr + ht->p.key_offset, x->key, ht->p.key_len); | |
636 | } | |
637 | ||
7e1e7763 TG |
638 | /** |
639 | * rhashtable_lookup - lookup key in hash table | |
640 | * @ht: hash table | |
641 | * @key: pointer to key | |
642 | * | |
643 | * Computes the hash value for the key and traverses the bucket chain looking | |
644 | * for a entry with an identical key. The first matching entry is returned. | |
645 | * | |
646 | * This lookup function may only be used for fixed key hash table (key_len | |
db304854 | 647 | * parameter set). It will BUG() if used inappropriately. |
7e1e7763 | 648 | * |
97defe1e | 649 | * Lookups may occur in parallel with hashtable mutations and resizing. |
7e1e7763 | 650 | */ |
97defe1e | 651 | void *rhashtable_lookup(struct rhashtable *ht, const void *key) |
7e1e7763 | 652 | { |
efb975a6 YX |
653 | struct rhashtable_compare_arg arg = { |
654 | .ht = ht, | |
655 | .key = key, | |
656 | }; | |
7e1e7763 TG |
657 | |
658 | BUG_ON(!ht->p.key_len); | |
659 | ||
efb975a6 | 660 | return rhashtable_lookup_compare(ht, key, &rhashtable_compare, &arg); |
7e1e7763 TG |
661 | } |
662 | EXPORT_SYMBOL_GPL(rhashtable_lookup); | |
663 | ||
664 | /** | |
665 | * rhashtable_lookup_compare - search hash table with compare function | |
666 | * @ht: hash table | |
8d24c0b4 | 667 | * @key: the pointer to the key |
7e1e7763 TG |
668 | * @compare: compare function, must return true on match |
669 | * @arg: argument passed on to compare function | |
670 | * | |
671 | * Traverses the bucket chain behind the provided hash value and calls the | |
672 | * specified compare function for each entry. | |
673 | * | |
97defe1e | 674 | * Lookups may occur in parallel with hashtable mutations and resizing. |
7e1e7763 TG |
675 | * |
676 | * Returns the first entry on which the compare function returned true. | |
677 | */ | |
97defe1e | 678 | void *rhashtable_lookup_compare(struct rhashtable *ht, const void *key, |
7e1e7763 TG |
679 | bool (*compare)(void *, void *), void *arg) |
680 | { | |
97defe1e | 681 | const struct bucket_table *tbl, *old_tbl; |
7e1e7763 | 682 | struct rhash_head *he; |
8d24c0b4 | 683 | u32 hash; |
7e1e7763 | 684 | |
97defe1e TG |
685 | rcu_read_lock(); |
686 | ||
687 | old_tbl = rht_dereference_rcu(ht->tbl, ht); | |
688 | tbl = rht_dereference_rcu(ht->future_tbl, ht); | |
8d24c0b4 | 689 | hash = key_hashfn(ht, key, ht->p.key_len); |
97defe1e TG |
690 | restart: |
691 | rht_for_each_rcu(he, tbl, rht_bucket_index(tbl, hash)) { | |
7e1e7763 TG |
692 | if (!compare(rht_obj(ht, he), arg)) |
693 | continue; | |
97defe1e | 694 | rcu_read_unlock(); |
a4b18cda | 695 | return rht_obj(ht, he); |
7e1e7763 TG |
696 | } |
697 | ||
97defe1e TG |
698 | if (unlikely(tbl != old_tbl)) { |
699 | tbl = old_tbl; | |
700 | goto restart; | |
701 | } | |
702 | rcu_read_unlock(); | |
703 | ||
7e1e7763 TG |
704 | return NULL; |
705 | } | |
706 | EXPORT_SYMBOL_GPL(rhashtable_lookup_compare); | |
707 | ||
db304854 YX |
708 | /** |
709 | * rhashtable_lookup_insert - lookup and insert object into hash table | |
710 | * @ht: hash table | |
711 | * @obj: pointer to hash head inside object | |
712 | * | |
713 | * Locks down the bucket chain in both the old and new table if a resize | |
714 | * is in progress to ensure that writers can't remove from the old table | |
715 | * and can't insert to the new table during the atomic operation of search | |
716 | * and insertion. Searches for duplicates in both the old and new table if | |
717 | * a resize is in progress. | |
718 | * | |
719 | * This lookup function may only be used for fixed key hash table (key_len | |
720 | * parameter set). It will BUG() if used inappropriately. | |
721 | * | |
722 | * It is safe to call this function from atomic context. | |
723 | * | |
724 | * Will trigger an automatic deferred table resizing if the size grows | |
725 | * beyond the watermark indicated by grow_decision() which can be passed | |
726 | * to rhashtable_init(). | |
727 | */ | |
728 | bool rhashtable_lookup_insert(struct rhashtable *ht, struct rhash_head *obj) | |
729 | { | |
730 | struct bucket_table *new_tbl, *old_tbl; | |
731 | spinlock_t *new_bucket_lock, *old_bucket_lock; | |
732 | u32 new_hash, old_hash; | |
733 | bool success = true; | |
734 | ||
735 | BUG_ON(!ht->p.key_len); | |
736 | ||
737 | rcu_read_lock(); | |
738 | ||
739 | old_tbl = rht_dereference_rcu(ht->tbl, ht); | |
740 | old_hash = head_hashfn(ht, old_tbl, obj); | |
741 | old_bucket_lock = bucket_lock(old_tbl, old_hash); | |
742 | spin_lock_bh(old_bucket_lock); | |
743 | ||
744 | new_tbl = rht_dereference_rcu(ht->future_tbl, ht); | |
745 | new_hash = head_hashfn(ht, new_tbl, obj); | |
746 | new_bucket_lock = bucket_lock(new_tbl, new_hash); | |
747 | if (unlikely(old_tbl != new_tbl)) | |
748 | spin_lock_bh_nested(new_bucket_lock, RHT_LOCK_NESTED); | |
749 | ||
750 | if (rhashtable_lookup(ht, rht_obj(ht, obj) + ht->p.key_offset)) { | |
751 | success = false; | |
752 | goto exit; | |
753 | } | |
754 | ||
755 | __rhashtable_insert(ht, obj, new_tbl, new_hash); | |
756 | ||
757 | exit: | |
758 | if (unlikely(old_tbl != new_tbl)) | |
759 | spin_unlock_bh(new_bucket_lock); | |
760 | spin_unlock_bh(old_bucket_lock); | |
761 | ||
762 | rcu_read_unlock(); | |
763 | ||
764 | return success; | |
765 | } | |
766 | EXPORT_SYMBOL_GPL(rhashtable_lookup_insert); | |
767 | ||
94000176 | 768 | static size_t rounded_hashtable_size(struct rhashtable_params *params) |
7e1e7763 | 769 | { |
94000176 YX |
770 | return max(roundup_pow_of_two(params->nelem_hint * 4 / 3), |
771 | 1UL << params->min_shift); | |
7e1e7763 TG |
772 | } |
773 | ||
774 | /** | |
775 | * rhashtable_init - initialize a new hash table | |
776 | * @ht: hash table to be initialized | |
777 | * @params: configuration parameters | |
778 | * | |
779 | * Initializes a new hash table based on the provided configuration | |
780 | * parameters. A table can be configured either with a variable or | |
781 | * fixed length key: | |
782 | * | |
783 | * Configuration Example 1: Fixed length keys | |
784 | * struct test_obj { | |
785 | * int key; | |
786 | * void * my_member; | |
787 | * struct rhash_head node; | |
788 | * }; | |
789 | * | |
790 | * struct rhashtable_params params = { | |
791 | * .head_offset = offsetof(struct test_obj, node), | |
792 | * .key_offset = offsetof(struct test_obj, key), | |
793 | * .key_len = sizeof(int), | |
87545899 | 794 | * .hashfn = jhash, |
f89bd6f8 | 795 | * .nulls_base = (1U << RHT_BASE_SHIFT), |
7e1e7763 TG |
796 | * }; |
797 | * | |
798 | * Configuration Example 2: Variable length keys | |
799 | * struct test_obj { | |
800 | * [...] | |
801 | * struct rhash_head node; | |
802 | * }; | |
803 | * | |
804 | * u32 my_hash_fn(const void *data, u32 seed) | |
805 | * { | |
806 | * struct test_obj *obj = data; | |
807 | * | |
808 | * return [... hash ...]; | |
809 | * } | |
810 | * | |
811 | * struct rhashtable_params params = { | |
812 | * .head_offset = offsetof(struct test_obj, node), | |
87545899 | 813 | * .hashfn = jhash, |
7e1e7763 | 814 | * .obj_hashfn = my_hash_fn, |
7e1e7763 TG |
815 | * }; |
816 | */ | |
817 | int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) | |
818 | { | |
819 | struct bucket_table *tbl; | |
820 | size_t size; | |
821 | ||
822 | size = HASH_DEFAULT_SIZE; | |
823 | ||
824 | if ((params->key_len && !params->hashfn) || | |
825 | (!params->key_len && !params->obj_hashfn)) | |
826 | return -EINVAL; | |
827 | ||
f89bd6f8 TG |
828 | if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT)) |
829 | return -EINVAL; | |
830 | ||
94000176 YX |
831 | params->min_shift = max_t(size_t, params->min_shift, |
832 | ilog2(HASH_MIN_SIZE)); | |
833 | ||
7e1e7763 | 834 | if (params->nelem_hint) |
94000176 | 835 | size = rounded_hashtable_size(params); |
7e1e7763 | 836 | |
97defe1e TG |
837 | memset(ht, 0, sizeof(*ht)); |
838 | mutex_init(&ht->mutex); | |
839 | memcpy(&ht->p, params, sizeof(*params)); | |
840 | ||
841 | if (params->locks_mul) | |
842 | ht->p.locks_mul = roundup_pow_of_two(params->locks_mul); | |
843 | else | |
844 | ht->p.locks_mul = BUCKET_LOCKS_PER_CPU; | |
845 | ||
846 | tbl = bucket_table_alloc(ht, size); | |
7e1e7763 TG |
847 | if (tbl == NULL) |
848 | return -ENOMEM; | |
849 | ||
c0c09bfd | 850 | atomic_set(&ht->shift, ilog2(tbl->size)); |
7e1e7763 | 851 | RCU_INIT_POINTER(ht->tbl, tbl); |
97defe1e | 852 | RCU_INIT_POINTER(ht->future_tbl, tbl); |
7e1e7763 TG |
853 | |
854 | if (!ht->p.hash_rnd) | |
855 | get_random_bytes(&ht->p.hash_rnd, sizeof(ht->p.hash_rnd)); | |
856 | ||
97defe1e TG |
857 | if (ht->p.grow_decision || ht->p.shrink_decision) |
858 | INIT_DEFERRABLE_WORK(&ht->run_work, rht_deferred_worker); | |
859 | ||
7e1e7763 TG |
860 | return 0; |
861 | } | |
862 | EXPORT_SYMBOL_GPL(rhashtable_init); | |
863 | ||
864 | /** | |
865 | * rhashtable_destroy - destroy hash table | |
866 | * @ht: the hash table to destroy | |
867 | * | |
ae82ddcf PNA |
868 | * Frees the bucket array. This function is not rcu safe, therefore the caller |
869 | * has to make sure that no resizing may happen by unpublishing the hashtable | |
870 | * and waiting for the quiescent cycle before releasing the bucket array. | |
7e1e7763 | 871 | */ |
97defe1e | 872 | void rhashtable_destroy(struct rhashtable *ht) |
7e1e7763 | 873 | { |
97defe1e TG |
874 | ht->being_destroyed = true; |
875 | ||
876 | mutex_lock(&ht->mutex); | |
877 | ||
878 | cancel_delayed_work(&ht->run_work); | |
879 | bucket_table_free(rht_dereference(ht->tbl, ht)); | |
880 | ||
881 | mutex_unlock(&ht->mutex); | |
7e1e7763 TG |
882 | } |
883 | EXPORT_SYMBOL_GPL(rhashtable_destroy); | |
884 | ||
885 | /************************************************************************** | |
886 | * Self Test | |
887 | **************************************************************************/ | |
888 | ||
889 | #ifdef CONFIG_TEST_RHASHTABLE | |
890 | ||
891 | #define TEST_HT_SIZE 8 | |
892 | #define TEST_ENTRIES 2048 | |
893 | #define TEST_PTR ((void *) 0xdeadbeef) | |
894 | #define TEST_NEXPANDS 4 | |
895 | ||
7e1e7763 TG |
896 | struct test_obj { |
897 | void *ptr; | |
898 | int value; | |
899 | struct rhash_head node; | |
900 | }; | |
901 | ||
902 | static int __init test_rht_lookup(struct rhashtable *ht) | |
903 | { | |
904 | unsigned int i; | |
905 | ||
906 | for (i = 0; i < TEST_ENTRIES * 2; i++) { | |
907 | struct test_obj *obj; | |
908 | bool expected = !(i % 2); | |
909 | u32 key = i; | |
910 | ||
911 | obj = rhashtable_lookup(ht, &key); | |
912 | ||
913 | if (expected && !obj) { | |
914 | pr_warn("Test failed: Could not find key %u\n", key); | |
915 | return -ENOENT; | |
916 | } else if (!expected && obj) { | |
917 | pr_warn("Test failed: Unexpected entry found for key %u\n", | |
918 | key); | |
919 | return -EEXIST; | |
920 | } else if (expected && obj) { | |
921 | if (obj->ptr != TEST_PTR || obj->value != i) { | |
922 | pr_warn("Test failed: Lookup value mismatch %p!=%p, %u!=%u\n", | |
923 | obj->ptr, TEST_PTR, obj->value, i); | |
924 | return -EINVAL; | |
925 | } | |
926 | } | |
927 | } | |
928 | ||
929 | return 0; | |
930 | } | |
931 | ||
3e7b2ec4 | 932 | static void test_bucket_stats(struct rhashtable *ht, bool quiet) |
7e1e7763 | 933 | { |
3e7b2ec4 | 934 | unsigned int cnt, rcu_cnt, i, total = 0; |
88d6ed15 | 935 | struct rhash_head *pos; |
7e1e7763 | 936 | struct test_obj *obj; |
3e7b2ec4 | 937 | struct bucket_table *tbl; |
7e1e7763 | 938 | |
3e7b2ec4 | 939 | tbl = rht_dereference_rcu(ht->tbl, ht); |
7e1e7763 | 940 | for (i = 0; i < tbl->size; i++) { |
3e7b2ec4 | 941 | rcu_cnt = cnt = 0; |
7e1e7763 TG |
942 | |
943 | if (!quiet) | |
944 | pr_info(" [%#4x/%zu]", i, tbl->size); | |
945 | ||
88d6ed15 | 946 | rht_for_each_entry_rcu(obj, pos, tbl, i, node) { |
7e1e7763 TG |
947 | cnt++; |
948 | total++; | |
949 | if (!quiet) | |
950 | pr_cont(" [%p],", obj); | |
951 | } | |
952 | ||
88d6ed15 | 953 | rht_for_each_entry_rcu(obj, pos, tbl, i, node) |
3e7b2ec4 TG |
954 | rcu_cnt++; |
955 | ||
956 | if (rcu_cnt != cnt) | |
957 | pr_warn("Test failed: Chain count mismach %d != %d", | |
958 | cnt, rcu_cnt); | |
959 | ||
7e1e7763 TG |
960 | if (!quiet) |
961 | pr_cont("\n [%#x] first element: %p, chain length: %u\n", | |
962 | i, tbl->buckets[i], cnt); | |
963 | } | |
964 | ||
97defe1e TG |
965 | pr_info(" Traversal complete: counted=%u, nelems=%u, entries=%d\n", |
966 | total, atomic_read(&ht->nelems), TEST_ENTRIES); | |
3e7b2ec4 | 967 | |
97defe1e | 968 | if (total != atomic_read(&ht->nelems) || total != TEST_ENTRIES) |
3e7b2ec4 | 969 | pr_warn("Test failed: Total count mismatch ^^^"); |
7e1e7763 TG |
970 | } |
971 | ||
972 | static int __init test_rhashtable(struct rhashtable *ht) | |
973 | { | |
974 | struct bucket_table *tbl; | |
88d6ed15 TG |
975 | struct test_obj *obj; |
976 | struct rhash_head *pos, *next; | |
7e1e7763 TG |
977 | int err; |
978 | unsigned int i; | |
979 | ||
980 | /* | |
981 | * Insertion Test: | |
982 | * Insert TEST_ENTRIES into table with all keys even numbers | |
983 | */ | |
984 | pr_info(" Adding %d keys\n", TEST_ENTRIES); | |
985 | for (i = 0; i < TEST_ENTRIES; i++) { | |
986 | struct test_obj *obj; | |
987 | ||
988 | obj = kzalloc(sizeof(*obj), GFP_KERNEL); | |
989 | if (!obj) { | |
990 | err = -ENOMEM; | |
991 | goto error; | |
992 | } | |
993 | ||
994 | obj->ptr = TEST_PTR; | |
995 | obj->value = i * 2; | |
996 | ||
6eba8224 | 997 | rhashtable_insert(ht, &obj->node); |
7e1e7763 TG |
998 | } |
999 | ||
1000 | rcu_read_lock(); | |
3e7b2ec4 | 1001 | test_bucket_stats(ht, true); |
7e1e7763 TG |
1002 | test_rht_lookup(ht); |
1003 | rcu_read_unlock(); | |
1004 | ||
1005 | for (i = 0; i < TEST_NEXPANDS; i++) { | |
1006 | pr_info(" Table expansion iteration %u...\n", i); | |
97defe1e | 1007 | mutex_lock(&ht->mutex); |
6eba8224 | 1008 | rhashtable_expand(ht); |
97defe1e | 1009 | mutex_unlock(&ht->mutex); |
7e1e7763 TG |
1010 | |
1011 | rcu_read_lock(); | |
1012 | pr_info(" Verifying lookups...\n"); | |
1013 | test_rht_lookup(ht); | |
1014 | rcu_read_unlock(); | |
1015 | } | |
1016 | ||
1017 | for (i = 0; i < TEST_NEXPANDS; i++) { | |
1018 | pr_info(" Table shrinkage iteration %u...\n", i); | |
97defe1e | 1019 | mutex_lock(&ht->mutex); |
6eba8224 | 1020 | rhashtable_shrink(ht); |
97defe1e | 1021 | mutex_unlock(&ht->mutex); |
7e1e7763 TG |
1022 | |
1023 | rcu_read_lock(); | |
1024 | pr_info(" Verifying lookups...\n"); | |
1025 | test_rht_lookup(ht); | |
1026 | rcu_read_unlock(); | |
1027 | } | |
1028 | ||
3e7b2ec4 TG |
1029 | rcu_read_lock(); |
1030 | test_bucket_stats(ht, true); | |
1031 | rcu_read_unlock(); | |
1032 | ||
7e1e7763 TG |
1033 | pr_info(" Deleting %d keys\n", TEST_ENTRIES); |
1034 | for (i = 0; i < TEST_ENTRIES; i++) { | |
1035 | u32 key = i * 2; | |
1036 | ||
1037 | obj = rhashtable_lookup(ht, &key); | |
1038 | BUG_ON(!obj); | |
1039 | ||
6eba8224 | 1040 | rhashtable_remove(ht, &obj->node); |
7e1e7763 TG |
1041 | kfree(obj); |
1042 | } | |
1043 | ||
1044 | return 0; | |
1045 | ||
1046 | error: | |
1047 | tbl = rht_dereference_rcu(ht->tbl, ht); | |
1048 | for (i = 0; i < tbl->size; i++) | |
88d6ed15 | 1049 | rht_for_each_entry_safe(obj, pos, next, tbl, i, node) |
7e1e7763 TG |
1050 | kfree(obj); |
1051 | ||
1052 | return err; | |
1053 | } | |
1054 | ||
1055 | static int __init test_rht_init(void) | |
1056 | { | |
1057 | struct rhashtable ht; | |
1058 | struct rhashtable_params params = { | |
1059 | .nelem_hint = TEST_HT_SIZE, | |
1060 | .head_offset = offsetof(struct test_obj, node), | |
1061 | .key_offset = offsetof(struct test_obj, value), | |
1062 | .key_len = sizeof(int), | |
87545899 | 1063 | .hashfn = jhash, |
f89bd6f8 | 1064 | .nulls_base = (3U << RHT_BASE_SHIFT), |
7e1e7763 TG |
1065 | .grow_decision = rht_grow_above_75, |
1066 | .shrink_decision = rht_shrink_below_30, | |
1067 | }; | |
1068 | int err; | |
1069 | ||
1070 | pr_info("Running resizable hashtable tests...\n"); | |
1071 | ||
1072 | err = rhashtable_init(&ht, ¶ms); | |
1073 | if (err < 0) { | |
1074 | pr_warn("Test failed: Unable to initialize hashtable: %d\n", | |
1075 | err); | |
1076 | return err; | |
1077 | } | |
1078 | ||
1079 | err = test_rhashtable(&ht); | |
1080 | ||
1081 | rhashtable_destroy(&ht); | |
1082 | ||
1083 | return err; | |
1084 | } | |
1085 | ||
1086 | subsys_initcall(test_rht_init); | |
1087 | ||
1088 | #endif /* CONFIG_TEST_RHASHTABLE */ |