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rhashtable: Factor out bucket_tail() function
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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>
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24#include <linux/random.h>
25#include <linux/rhashtable.h>
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26
27#define HASH_DEFAULT_SIZE 64UL
28#define HASH_MIN_SIZE 4UL
29
30#define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT))
31
32#ifdef CONFIG_PROVE_LOCKING
33int lockdep_rht_mutex_is_held(const struct rhashtable *ht)
34{
7b4ce235 35 return ht->p.mutex_is_held(ht->p.parent);
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36}
37EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held);
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38
39int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash)
40{
41 return 1;
42}
43EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held);
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44#endif
45
c91eee56 46static void *rht_obj(const struct rhashtable *ht, const struct rhash_head *he)
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47{
48 return (void *) he - ht->p.head_offset;
49}
7e1e7763 50
8d24c0b4 51static u32 rht_bucket_index(const struct bucket_table *tbl, u32 hash)
7e1e7763 52{
8d24c0b4 53 return hash & (tbl->size - 1);
7e1e7763 54}
7e1e7763 55
8d24c0b4 56static u32 obj_raw_hashfn(const struct rhashtable *ht, const void *ptr)
7e1e7763 57{
8d24c0b4 58 u32 hash;
7e1e7763 59
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60 if (unlikely(!ht->p.key_len))
61 hash = ht->p.obj_hashfn(ptr, ht->p.hash_rnd);
62 else
63 hash = ht->p.hashfn(ptr + ht->p.key_offset, ht->p.key_len,
64 ht->p.hash_rnd);
7e1e7763 65
8d24c0b4 66 return hash;
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67}
68
8d24c0b4 69static u32 key_hashfn(const struct rhashtable *ht, const void *key, u32 len)
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70{
71 struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
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72 u32 hash;
73
74 hash = ht->p.hashfn(key, len, ht->p.hash_rnd);
7e1e7763 75
8d24c0b4 76 return rht_bucket_index(tbl, hash);
7e1e7763 77}
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78
79static u32 head_hashfn(const struct rhashtable *ht,
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80 const struct bucket_table *tbl,
81 const struct rhash_head *he)
7e1e7763 82{
8d24c0b4 83 return rht_bucket_index(tbl, obj_raw_hashfn(ht, rht_obj(ht, he)));
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84}
85
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86static struct rhash_head __rcu **bucket_tail(struct bucket_table *tbl, u32 n)
87{
88 struct rhash_head __rcu **pprev;
89
90 for (pprev = &tbl->buckets[n];
91 rht_dereference_bucket(*pprev, tbl, n);
92 pprev = &rht_dereference_bucket(*pprev, tbl, n)->next)
93 ;
94
95 return pprev;
96}
97
6eba8224 98static struct bucket_table *bucket_table_alloc(size_t nbuckets)
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99{
100 struct bucket_table *tbl;
101 size_t size;
102
103 size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
6eba8224 104 tbl = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
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105 if (tbl == NULL)
106 tbl = vzalloc(size);
107
108 if (tbl == NULL)
109 return NULL;
110
111 tbl->size = nbuckets;
112
113 return tbl;
114}
115
116static void bucket_table_free(const struct bucket_table *tbl)
117{
118 kvfree(tbl);
119}
120
121/**
122 * rht_grow_above_75 - returns true if nelems > 0.75 * table-size
123 * @ht: hash table
124 * @new_size: new table size
125 */
126bool rht_grow_above_75(const struct rhashtable *ht, size_t new_size)
127{
128 /* Expand table when exceeding 75% load */
129 return ht->nelems > (new_size / 4 * 3);
130}
131EXPORT_SYMBOL_GPL(rht_grow_above_75);
132
133/**
134 * rht_shrink_below_30 - returns true if nelems < 0.3 * table-size
135 * @ht: hash table
136 * @new_size: new table size
137 */
138bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size)
139{
140 /* Shrink table beneath 30% load */
141 return ht->nelems < (new_size * 3 / 10);
142}
143EXPORT_SYMBOL_GPL(rht_shrink_below_30);
144
145static void hashtable_chain_unzip(const struct rhashtable *ht,
146 const struct bucket_table *new_tbl,
147 struct bucket_table *old_tbl, size_t n)
148{
149 struct rhash_head *he, *p, *next;
150 unsigned int h;
151
152 /* Old bucket empty, no work needed. */
153 p = rht_dereference(old_tbl->buckets[n], ht);
154 if (!p)
155 return;
156
157 /* Advance the old bucket pointer one or more times until it
158 * reaches a node that doesn't hash to the same bucket as the
159 * previous node p. Call the previous node p;
160 */
8d24c0b4 161 h = head_hashfn(ht, new_tbl, p);
88d6ed15 162 rht_for_each_continue(he, p->next, old_tbl, n) {
8d24c0b4 163 if (head_hashfn(ht, new_tbl, he) != h)
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164 break;
165 p = he;
166 }
167 RCU_INIT_POINTER(old_tbl->buckets[n], p->next);
168
169 /* Find the subsequent node which does hash to the same
170 * bucket as node P, or NULL if no such node exists.
171 */
172 next = NULL;
173 if (he) {
88d6ed15 174 rht_for_each_continue(he, he->next, old_tbl, n) {
8d24c0b4 175 if (head_hashfn(ht, new_tbl, he) == h) {
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176 next = he;
177 break;
178 }
179 }
180 }
181
182 /* Set p's next pointer to that subsequent node pointer,
183 * bypassing the nodes which do not hash to p's bucket
184 */
185 RCU_INIT_POINTER(p->next, next);
186}
187
188/**
189 * rhashtable_expand - Expand hash table while allowing concurrent lookups
190 * @ht: the hash table to expand
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191 *
192 * A secondary bucket array is allocated and the hash entries are migrated
193 * while keeping them on both lists until the end of the RCU grace period.
194 *
195 * This function may only be called in a context where it is safe to call
196 * synchronize_rcu(), e.g. not within a rcu_read_lock() section.
197 *
198 * The caller must ensure that no concurrent table mutations take place.
199 * It is however valid to have concurrent lookups if they are RCU protected.
200 */
6eba8224 201int rhashtable_expand(struct rhashtable *ht)
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202{
203 struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);
204 struct rhash_head *he;
205 unsigned int i, h;
206 bool complete;
207
208 ASSERT_RHT_MUTEX(ht);
209
210 if (ht->p.max_shift && ht->shift >= ht->p.max_shift)
211 return 0;
212
6eba8224 213 new_tbl = bucket_table_alloc(old_tbl->size * 2);
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214 if (new_tbl == NULL)
215 return -ENOMEM;
216
217 ht->shift++;
218
219 /* For each new bucket, search the corresponding old bucket
0c828f2f 220 * for the first entry that hashes to the new bucket, and
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221 * link the new bucket to that entry. Since all the entries
222 * which will end up in the new bucket appear in the same
223 * old bucket, this constructs an entirely valid new hash
224 * table, but with multiple buckets "zipped" together into a
225 * single imprecise chain.
226 */
227 for (i = 0; i < new_tbl->size; i++) {
8d24c0b4 228 h = rht_bucket_index(old_tbl, i);
88d6ed15 229 rht_for_each(he, old_tbl, h) {
8d24c0b4 230 if (head_hashfn(ht, new_tbl, he) == i) {
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231 RCU_INIT_POINTER(new_tbl->buckets[i], he);
232 break;
233 }
234 }
235 }
236
237 /* Publish the new table pointer. Lookups may now traverse
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238 * the new table, but they will not benefit from any
239 * additional efficiency until later steps unzip the buckets.
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240 */
241 rcu_assign_pointer(ht->tbl, new_tbl);
242
243 /* Unzip interleaved hash chains */
244 do {
245 /* Wait for readers. All new readers will see the new
246 * table, and thus no references to the old table will
247 * remain.
248 */
249 synchronize_rcu();
250
251 /* For each bucket in the old table (each of which
252 * contains items from multiple buckets of the new
253 * table): ...
254 */
255 complete = true;
256 for (i = 0; i < old_tbl->size; i++) {
257 hashtable_chain_unzip(ht, new_tbl, old_tbl, i);
258 if (old_tbl->buckets[i] != NULL)
259 complete = false;
260 }
261 } while (!complete);
262
263 bucket_table_free(old_tbl);
264 return 0;
265}
266EXPORT_SYMBOL_GPL(rhashtable_expand);
267
268/**
269 * rhashtable_shrink - Shrink hash table while allowing concurrent lookups
270 * @ht: the hash table to shrink
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271 *
272 * This function may only be called in a context where it is safe to call
273 * synchronize_rcu(), e.g. not within a rcu_read_lock() section.
274 *
275 * The caller must ensure that no concurrent table mutations take place.
276 * It is however valid to have concurrent lookups if they are RCU protected.
277 */
6eba8224 278int rhashtable_shrink(struct rhashtable *ht)
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279{
280 struct bucket_table *ntbl, *tbl = rht_dereference(ht->tbl, ht);
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281 unsigned int i;
282
283 ASSERT_RHT_MUTEX(ht);
284
94000176 285 if (ht->shift <= ht->p.min_shift)
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286 return 0;
287
6eba8224 288 ntbl = bucket_table_alloc(tbl->size / 2);
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289 if (ntbl == NULL)
290 return -ENOMEM;
291
292 ht->shift--;
293
0c828f2f 294 /* Link each bucket in the new table to the first bucket
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295 * in the old table that contains entries which will hash
296 * to the new bucket.
297 */
298 for (i = 0; i < ntbl->size; i++) {
299 ntbl->buckets[i] = tbl->buckets[i];
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300 RCU_INIT_POINTER(*bucket_tail(ntbl, i),
301 tbl->buckets[i + ntbl->size]);
7e1e7763 302
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303 }
304
305 /* Publish the new, valid hash table */
306 rcu_assign_pointer(ht->tbl, ntbl);
307
308 /* Wait for readers. No new readers will have references to the
309 * old hash table.
310 */
311 synchronize_rcu();
312
313 bucket_table_free(tbl);
314
315 return 0;
316}
317EXPORT_SYMBOL_GPL(rhashtable_shrink);
318
319/**
320 * rhashtable_insert - insert object into hash hash table
321 * @ht: hash table
322 * @obj: pointer to hash head inside object
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323 *
324 * Will automatically grow the table via rhashtable_expand() if the the
325 * grow_decision function specified at rhashtable_init() returns true.
326 *
327 * The caller must ensure that no concurrent table mutations occur. It is
328 * however valid to have concurrent lookups if they are RCU protected.
329 */
6eba8224 330void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj)
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331{
332 struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
333 u32 hash;
334
335 ASSERT_RHT_MUTEX(ht);
336
8d24c0b4 337 hash = head_hashfn(ht, tbl, obj);
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338 RCU_INIT_POINTER(obj->next, tbl->buckets[hash]);
339 rcu_assign_pointer(tbl->buckets[hash], obj);
340 ht->nelems++;
341
342 if (ht->p.grow_decision && ht->p.grow_decision(ht, tbl->size))
6eba8224 343 rhashtable_expand(ht);
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344}
345EXPORT_SYMBOL_GPL(rhashtable_insert);
346
347/**
348 * rhashtable_remove_pprev - remove object from hash table given previous element
349 * @ht: hash table
350 * @obj: pointer to hash head inside object
351 * @pprev: pointer to previous element
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352 *
353 * Identical to rhashtable_remove() but caller is alreayd aware of the element
354 * in front of the element to be deleted. This is in particular useful for
355 * deletion when combined with walking or lookup.
356 */
357void rhashtable_remove_pprev(struct rhashtable *ht, struct rhash_head *obj,
6eba8224 358 struct rhash_head __rcu **pprev)
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359{
360 struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
361
362 ASSERT_RHT_MUTEX(ht);
363
364 RCU_INIT_POINTER(*pprev, obj->next);
365 ht->nelems--;
366
367 if (ht->p.shrink_decision &&
368 ht->p.shrink_decision(ht, tbl->size))
6eba8224 369 rhashtable_shrink(ht);
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370}
371EXPORT_SYMBOL_GPL(rhashtable_remove_pprev);
372
373/**
374 * rhashtable_remove - remove object from hash table
375 * @ht: hash table
376 * @obj: pointer to hash head inside object
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377 *
378 * Since the hash chain is single linked, the removal operation needs to
379 * walk the bucket chain upon removal. The removal operation is thus
380 * considerable slow if the hash table is not correctly sized.
381 *
382 * Will automatically shrink the table via rhashtable_expand() if the the
383 * shrink_decision function specified at rhashtable_init() returns true.
384 *
385 * The caller must ensure that no concurrent table mutations occur. It is
386 * however valid to have concurrent lookups if they are RCU protected.
387 */
6eba8224 388bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj)
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389{
390 struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
391 struct rhash_head __rcu **pprev;
392 struct rhash_head *he;
393 u32 h;
394
395 ASSERT_RHT_MUTEX(ht);
396
8d24c0b4 397 h = head_hashfn(ht, tbl, obj);
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398
399 pprev = &tbl->buckets[h];
88d6ed15 400 rht_for_each(he, tbl, h) {
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401 if (he != obj) {
402 pprev = &he->next;
403 continue;
404 }
405
6eba8224 406 rhashtable_remove_pprev(ht, he, pprev);
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407 return true;
408 }
409
410 return false;
411}
412EXPORT_SYMBOL_GPL(rhashtable_remove);
413
414/**
415 * rhashtable_lookup - lookup key in hash table
416 * @ht: hash table
417 * @key: pointer to key
418 *
419 * Computes the hash value for the key and traverses the bucket chain looking
420 * for a entry with an identical key. The first matching entry is returned.
421 *
422 * This lookup function may only be used for fixed key hash table (key_len
423 * paramter set). It will BUG() if used inappropriately.
424 *
425 * Lookups may occur in parallel with hash mutations as long as the lookup is
426 * guarded by rcu_read_lock(). The caller must take care of this.
427 */
428void *rhashtable_lookup(const struct rhashtable *ht, const void *key)
429{
430 const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
431 struct rhash_head *he;
432 u32 h;
433
434 BUG_ON(!ht->p.key_len);
435
8d24c0b4 436 h = key_hashfn(ht, key, ht->p.key_len);
88d6ed15 437 rht_for_each_rcu(he, tbl, h) {
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438 if (memcmp(rht_obj(ht, he) + ht->p.key_offset, key,
439 ht->p.key_len))
440 continue;
a4b18cda 441 return rht_obj(ht, he);
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442 }
443
444 return NULL;
445}
446EXPORT_SYMBOL_GPL(rhashtable_lookup);
447
448/**
449 * rhashtable_lookup_compare - search hash table with compare function
450 * @ht: hash table
8d24c0b4 451 * @key: the pointer to the key
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452 * @compare: compare function, must return true on match
453 * @arg: argument passed on to compare function
454 *
455 * Traverses the bucket chain behind the provided hash value and calls the
456 * specified compare function for each entry.
457 *
458 * Lookups may occur in parallel with hash mutations as long as the lookup is
459 * guarded by rcu_read_lock(). The caller must take care of this.
460 *
461 * Returns the first entry on which the compare function returned true.
462 */
8d24c0b4 463void *rhashtable_lookup_compare(const struct rhashtable *ht, const void *key,
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464 bool (*compare)(void *, void *), void *arg)
465{
466 const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
467 struct rhash_head *he;
8d24c0b4 468 u32 hash;
7e1e7763 469
8d24c0b4 470 hash = key_hashfn(ht, key, ht->p.key_len);
88d6ed15 471 rht_for_each_rcu(he, tbl, hash) {
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472 if (!compare(rht_obj(ht, he), arg))
473 continue;
a4b18cda 474 return rht_obj(ht, he);
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475 }
476
477 return NULL;
478}
479EXPORT_SYMBOL_GPL(rhashtable_lookup_compare);
480
94000176 481static size_t rounded_hashtable_size(struct rhashtable_params *params)
7e1e7763 482{
94000176
YX
483 return max(roundup_pow_of_two(params->nelem_hint * 4 / 3),
484 1UL << params->min_shift);
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485}
486
487/**
488 * rhashtable_init - initialize a new hash table
489 * @ht: hash table to be initialized
490 * @params: configuration parameters
491 *
492 * Initializes a new hash table based on the provided configuration
493 * parameters. A table can be configured either with a variable or
494 * fixed length key:
495 *
496 * Configuration Example 1: Fixed length keys
497 * struct test_obj {
498 * int key;
499 * void * my_member;
500 * struct rhash_head node;
501 * };
502 *
503 * struct rhashtable_params params = {
504 * .head_offset = offsetof(struct test_obj, node),
505 * .key_offset = offsetof(struct test_obj, key),
506 * .key_len = sizeof(int),
87545899 507 * .hashfn = jhash,
1b2f309d 508 * #ifdef CONFIG_PROVE_LOCKING
7e1e7763 509 * .mutex_is_held = &my_mutex_is_held,
1b2f309d 510 * #endif
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511 * };
512 *
513 * Configuration Example 2: Variable length keys
514 * struct test_obj {
515 * [...]
516 * struct rhash_head node;
517 * };
518 *
519 * u32 my_hash_fn(const void *data, u32 seed)
520 * {
521 * struct test_obj *obj = data;
522 *
523 * return [... hash ...];
524 * }
525 *
526 * struct rhashtable_params params = {
527 * .head_offset = offsetof(struct test_obj, node),
87545899 528 * .hashfn = jhash,
7e1e7763 529 * .obj_hashfn = my_hash_fn,
1b2f309d 530 * #ifdef CONFIG_PROVE_LOCKING
7e1e7763 531 * .mutex_is_held = &my_mutex_is_held,
1b2f309d 532 * #endif
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533 * };
534 */
535int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params)
536{
537 struct bucket_table *tbl;
538 size_t size;
539
540 size = HASH_DEFAULT_SIZE;
541
542 if ((params->key_len && !params->hashfn) ||
543 (!params->key_len && !params->obj_hashfn))
544 return -EINVAL;
545
94000176
YX
546 params->min_shift = max_t(size_t, params->min_shift,
547 ilog2(HASH_MIN_SIZE));
548
7e1e7763 549 if (params->nelem_hint)
94000176 550 size = rounded_hashtable_size(params);
7e1e7763 551
6eba8224 552 tbl = bucket_table_alloc(size);
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553 if (tbl == NULL)
554 return -ENOMEM;
555
556 memset(ht, 0, sizeof(*ht));
557 ht->shift = ilog2(tbl->size);
558 memcpy(&ht->p, params, sizeof(*params));
559 RCU_INIT_POINTER(ht->tbl, tbl);
560
561 if (!ht->p.hash_rnd)
562 get_random_bytes(&ht->p.hash_rnd, sizeof(ht->p.hash_rnd));
563
564 return 0;
565}
566EXPORT_SYMBOL_GPL(rhashtable_init);
567
568/**
569 * rhashtable_destroy - destroy hash table
570 * @ht: the hash table to destroy
571 *
ae82ddcf
PNA
572 * Frees the bucket array. This function is not rcu safe, therefore the caller
573 * has to make sure that no resizing may happen by unpublishing the hashtable
574 * and waiting for the quiescent cycle before releasing the bucket array.
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575 */
576void rhashtable_destroy(const struct rhashtable *ht)
577{
ae82ddcf 578 bucket_table_free(ht->tbl);
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579}
580EXPORT_SYMBOL_GPL(rhashtable_destroy);
581
582/**************************************************************************
583 * Self Test
584 **************************************************************************/
585
586#ifdef CONFIG_TEST_RHASHTABLE
587
588#define TEST_HT_SIZE 8
589#define TEST_ENTRIES 2048
590#define TEST_PTR ((void *) 0xdeadbeef)
591#define TEST_NEXPANDS 4
592
1b2f309d 593#ifdef CONFIG_PROVE_LOCKING
7b4ce235 594static int test_mutex_is_held(void *parent)
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595{
596 return 1;
597}
1b2f309d 598#endif
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599
600struct test_obj {
601 void *ptr;
602 int value;
603 struct rhash_head node;
604};
605
606static int __init test_rht_lookup(struct rhashtable *ht)
607{
608 unsigned int i;
609
610 for (i = 0; i < TEST_ENTRIES * 2; i++) {
611 struct test_obj *obj;
612 bool expected = !(i % 2);
613 u32 key = i;
614
615 obj = rhashtable_lookup(ht, &key);
616
617 if (expected && !obj) {
618 pr_warn("Test failed: Could not find key %u\n", key);
619 return -ENOENT;
620 } else if (!expected && obj) {
621 pr_warn("Test failed: Unexpected entry found for key %u\n",
622 key);
623 return -EEXIST;
624 } else if (expected && obj) {
625 if (obj->ptr != TEST_PTR || obj->value != i) {
626 pr_warn("Test failed: Lookup value mismatch %p!=%p, %u!=%u\n",
627 obj->ptr, TEST_PTR, obj->value, i);
628 return -EINVAL;
629 }
630 }
631 }
632
633 return 0;
634}
635
3e7b2ec4 636static void test_bucket_stats(struct rhashtable *ht, bool quiet)
7e1e7763 637{
3e7b2ec4 638 unsigned int cnt, rcu_cnt, i, total = 0;
88d6ed15 639 struct rhash_head *pos;
7e1e7763 640 struct test_obj *obj;
3e7b2ec4 641 struct bucket_table *tbl;
7e1e7763 642
3e7b2ec4 643 tbl = rht_dereference_rcu(ht->tbl, ht);
7e1e7763 644 for (i = 0; i < tbl->size; i++) {
3e7b2ec4 645 rcu_cnt = cnt = 0;
7e1e7763
TG
646
647 if (!quiet)
648 pr_info(" [%#4x/%zu]", i, tbl->size);
649
88d6ed15 650 rht_for_each_entry_rcu(obj, pos, tbl, i, node) {
7e1e7763
TG
651 cnt++;
652 total++;
653 if (!quiet)
654 pr_cont(" [%p],", obj);
655 }
656
88d6ed15 657 rht_for_each_entry_rcu(obj, pos, tbl, i, node)
3e7b2ec4
TG
658 rcu_cnt++;
659
660 if (rcu_cnt != cnt)
661 pr_warn("Test failed: Chain count mismach %d != %d",
662 cnt, rcu_cnt);
663
7e1e7763
TG
664 if (!quiet)
665 pr_cont("\n [%#x] first element: %p, chain length: %u\n",
666 i, tbl->buckets[i], cnt);
667 }
668
669 pr_info(" Traversal complete: counted=%u, nelems=%zu, entries=%d\n",
670 total, ht->nelems, TEST_ENTRIES);
3e7b2ec4
TG
671
672 if (total != ht->nelems || total != TEST_ENTRIES)
673 pr_warn("Test failed: Total count mismatch ^^^");
7e1e7763
TG
674}
675
676static int __init test_rhashtable(struct rhashtable *ht)
677{
678 struct bucket_table *tbl;
88d6ed15
TG
679 struct test_obj *obj;
680 struct rhash_head *pos, *next;
7e1e7763
TG
681 int err;
682 unsigned int i;
683
684 /*
685 * Insertion Test:
686 * Insert TEST_ENTRIES into table with all keys even numbers
687 */
688 pr_info(" Adding %d keys\n", TEST_ENTRIES);
689 for (i = 0; i < TEST_ENTRIES; i++) {
690 struct test_obj *obj;
691
692 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
693 if (!obj) {
694 err = -ENOMEM;
695 goto error;
696 }
697
698 obj->ptr = TEST_PTR;
699 obj->value = i * 2;
700
6eba8224 701 rhashtable_insert(ht, &obj->node);
7e1e7763
TG
702 }
703
704 rcu_read_lock();
3e7b2ec4 705 test_bucket_stats(ht, true);
7e1e7763
TG
706 test_rht_lookup(ht);
707 rcu_read_unlock();
708
709 for (i = 0; i < TEST_NEXPANDS; i++) {
710 pr_info(" Table expansion iteration %u...\n", i);
6eba8224 711 rhashtable_expand(ht);
7e1e7763
TG
712
713 rcu_read_lock();
714 pr_info(" Verifying lookups...\n");
715 test_rht_lookup(ht);
716 rcu_read_unlock();
717 }
718
719 for (i = 0; i < TEST_NEXPANDS; i++) {
720 pr_info(" Table shrinkage iteration %u...\n", i);
6eba8224 721 rhashtable_shrink(ht);
7e1e7763
TG
722
723 rcu_read_lock();
724 pr_info(" Verifying lookups...\n");
725 test_rht_lookup(ht);
726 rcu_read_unlock();
727 }
728
3e7b2ec4
TG
729 rcu_read_lock();
730 test_bucket_stats(ht, true);
731 rcu_read_unlock();
732
7e1e7763
TG
733 pr_info(" Deleting %d keys\n", TEST_ENTRIES);
734 for (i = 0; i < TEST_ENTRIES; i++) {
735 u32 key = i * 2;
736
737 obj = rhashtable_lookup(ht, &key);
738 BUG_ON(!obj);
739
6eba8224 740 rhashtable_remove(ht, &obj->node);
7e1e7763
TG
741 kfree(obj);
742 }
743
744 return 0;
745
746error:
747 tbl = rht_dereference_rcu(ht->tbl, ht);
748 for (i = 0; i < tbl->size; i++)
88d6ed15 749 rht_for_each_entry_safe(obj, pos, next, tbl, i, node)
7e1e7763
TG
750 kfree(obj);
751
752 return err;
753}
754
755static int __init test_rht_init(void)
756{
757 struct rhashtable ht;
758 struct rhashtable_params params = {
759 .nelem_hint = TEST_HT_SIZE,
760 .head_offset = offsetof(struct test_obj, node),
761 .key_offset = offsetof(struct test_obj, value),
762 .key_len = sizeof(int),
87545899 763 .hashfn = jhash,
1b2f309d 764#ifdef CONFIG_PROVE_LOCKING
7e1e7763 765 .mutex_is_held = &test_mutex_is_held,
1b2f309d 766#endif
7e1e7763
TG
767 .grow_decision = rht_grow_above_75,
768 .shrink_decision = rht_shrink_below_30,
769 };
770 int err;
771
772 pr_info("Running resizable hashtable tests...\n");
773
774 err = rhashtable_init(&ht, &params);
775 if (err < 0) {
776 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
777 err);
778 return err;
779 }
780
781 err = test_rhashtable(&ht);
782
783 rhashtable_destroy(&ht);
784
785 return err;
786}
787
788subsys_initcall(test_rht_init);
789
790#endif /* CONFIG_TEST_RHASHTABLE */