Cleanup: fix cppcheck errors
[urcu.git] / urcu / rculfhash.h
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1#ifndef _URCU_RCULFHASH_H
2#define _URCU_RCULFHASH_H
ab7d5fc6 3
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4/*
5 * urcu/rculfhash.h
6 *
7 * Userspace RCU library - Lock-Free RCU Hash Table
8 *
9 * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
0dcf4847 10 * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com>
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11 *
12 * This library is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU Lesser General Public
14 * License as published by the Free Software Foundation; either
15 * version 2.1 of the License, or (at your option) any later version.
16 *
17 * This library is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * Lesser General Public License for more details.
21 *
22 * You should have received a copy of the GNU Lesser General Public
23 * License along with this library; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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25 *
26 * Include this file _after_ including your URCU flavor.
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27 */
28
674f7a69 29#include <stdint.h>
6d320126 30#include <urcu/compiler.h>
abc490a1 31#include <urcu-call-rcu.h>
7b17c13e 32#include <urcu-flavor.h>
abc490a1 33
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34#ifdef __cplusplus
35extern "C" {
36#endif
37
7f52427b 38/*
04db56f8 39 * cds_lfht_node: Contains the next pointers and reverse-hash
7f52427b 40 * value required for lookup and traversal of the hash table.
04db56f8 41 *
db00ccc3 42 * struct cds_lfht_node should be aligned on 8-bytes boundaries because
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43 * the three lower bits are used as flags. It is worth noting that the
44 * information contained within these three bits could be represented on
45 * two bits by re-using the same bit for REMOVAL_OWNER_FLAG and
46 * BUCKET_FLAG. This can be done if we ensure that no iterator nor
47 * updater check the BUCKET_FLAG after it detects that the REMOVED_FLAG
48 * is set. Given the minimum size of struct cds_lfht_node is 8 bytes on
49 * 32-bit architectures, we choose to go for simplicity and reserve
50 * three bits.
7f52427b 51 *
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52 * struct cds_lfht_node can be embedded into a structure (as a field).
53 * caa_container_of() can be used to get the structure from the struct
54 * cds_lfht_node after a lookup.
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55 *
56 * The structure which embeds it typically holds the key (or key-value
57 * pair) of the object. The caller code is responsible for calculation
58 * of the hash value for cds_lfht APIs.
ae62aa6a 59 */
14044b37 60struct cds_lfht_node {
3f2f3714 61 struct cds_lfht_node *next; /* ptr | REMOVAL_OWNER_FLAG | BUCKET_FLAG | REMOVED_FLAG */
04db56f8 62 unsigned long reverse_hash;
db00ccc3 63} __attribute__((aligned(8)));
abc490a1 64
7f52427b 65/* cds_lfht_iter: Used to track state while traversing a hash chain. */
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66struct cds_lfht_iter {
67 struct cds_lfht_node *node, *next;
68};
69
70static inline
71struct cds_lfht_node *cds_lfht_iter_get_node(struct cds_lfht_iter *iter)
72{
73 return iter->node;
74}
75
14044b37 76struct cds_lfht;
ab7d5fc6 77
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78/*
79 * Caution !
abc490a1 80 * Ensure reader and writer threads are registered as urcu readers.
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81 */
82
996ff57c 83typedef int (*cds_lfht_match_fct)(struct cds_lfht_node *node, const void *key);
abc490a1 84
f0c29ed7 85/*
14044b37 86 * cds_lfht_node_init - initialize a hash table node
0422d92c 87 * @node: the node to initialize.
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88 *
89 * This function is kept to be eventually used for debugging purposes
90 * (detection of memory corruption).
f0c29ed7 91 */
abc490a1 92static inline
04db56f8 93void cds_lfht_node_init(struct cds_lfht_node *node)
abc490a1 94{
abc490a1 95}
674f7a69 96
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97/*
98 * Hash table creation flags.
99 */
100enum {
101 CDS_LFHT_AUTO_RESIZE = (1U << 0),
5afadd12 102 CDS_LFHT_ACCOUNTING = (1U << 1),
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103};
104
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105struct cds_lfht_mm_type {
106 struct cds_lfht *(*alloc_cds_lfht)(unsigned long min_nr_alloc_buckets,
107 unsigned long max_nr_buckets);
108 void (*alloc_bucket_table)(struct cds_lfht *ht, unsigned long order);
109 void (*free_bucket_table)(struct cds_lfht *ht, unsigned long order);
110 struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht,
111 unsigned long index);
112};
113
114extern const struct cds_lfht_mm_type cds_lfht_mm_order;
308d1cb3 115extern const struct cds_lfht_mm_type cds_lfht_mm_chunk;
b0b55251 116extern const struct cds_lfht_mm_type cds_lfht_mm_mmap;
0b6aa001 117
674f7a69 118/*
7a9dcf9b 119 * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly.
674f7a69 120 */
0422d92c 121struct cds_lfht *_cds_lfht_new(unsigned long init_size,
0722081a 122 unsigned long min_nr_alloc_buckets,
747d725c 123 unsigned long max_nr_buckets,
b8af5011 124 int flags,
0b6aa001 125 const struct cds_lfht_mm_type *mm,
7b17c13e 126 const struct rcu_flavor_struct *flavor,
b7d619b0 127 pthread_attr_t *attr);
ab7d5fc6 128
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129/*
130 * cds_lfht_new - allocate a hash table.
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131 * @init_size: number of buckets to allocate initially. Must be power of two.
132 * @min_nr_alloc_buckets: the minimum number of allocated buckets.
133 * (must be power of two)
134 * @max_nr_buckets: the maximum number of hash table buckets allowed.
135 * (must be power of two)
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136 * @flags: hash table creation flags (can be combined with bitwise or: '|').
137 * 0: no flags.
138 * CDS_LFHT_AUTO_RESIZE: automatically resize hash table.
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139 * CDS_LFHT_ACCOUNTING: count the number of node addition
140 * and removal in the table
b7d619b0 141 * @attr: optional resize worker thread attributes. NULL for default.
7a9dcf9b 142 *
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143 * Return NULL on error.
144 * Note: the RCU flavor must be already included before the hash table header.
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145 *
146 * The programmer is responsible for ensuring that resize operation has a
147 * priority equal to hash table updater threads. It should be performed by
148 * specifying the appropriate priority in the pthread "attr" argument, and,
149 * for CDS_LFHT_AUTO_RESIZE, by ensuring that call_rcu worker threads also have
150 * this priority level. Having lower priority for call_rcu and resize threads
151 * does not pose any correctness issue, but the resize operations could be
152 * starved by updates, thus leading to long hash table bucket chains.
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153 * Threads calling cds_lfht_new are NOT required to be registered RCU
154 * read-side threads. It can be called very early. (e.g. before RCU is
155 * initialized)
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156 */
157static inline
0422d92c 158struct cds_lfht *cds_lfht_new(unsigned long init_size,
0722081a 159 unsigned long min_nr_alloc_buckets,
747d725c 160 unsigned long max_nr_buckets,
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161 int flags,
162 pthread_attr_t *attr)
7a9dcf9b 163{
7b17c13e 164 return _cds_lfht_new(init_size, min_nr_alloc_buckets, max_nr_buckets,
c1888f3a 165 flags, NULL, &rcu_flavor, attr);
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166}
167
f0c29ed7 168/*
14044b37 169 * cds_lfht_destroy - destroy a hash table.
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170 * @ht: the hash table to destroy.
171 * @attr: (output) resize worker thread attributes, as received by cds_lfht_new.
172 * The caller will typically want to free this pointer if dynamically
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173 * allocated. The attr point can be NULL if the caller does not
174 * need to be informed of the value passed to cds_lfht_new().
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175 *
176 * Return 0 on success, negative error value on error.
3df0c49c 177 * Threads calling this API need to be registered RCU read-side threads.
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178 * cds_lfht_destroy should *not* be called from a RCU read-side critical
179 * section.
f0c29ed7 180 */
b7d619b0 181int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr);
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182
183/*
14044b37 184 * cds_lfht_count_nodes - count the number of nodes in the hash table.
7f52427b 185 * @ht: the hash table.
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186 * @split_count_before: sample the node count split-counter before traversal.
187 * @count: traverse the hash table, count the number of nodes observed.
188 * @split_count_after: sample the node count split-counter after traversal.
0422d92c 189 *
f0c29ed7 190 * Call with rcu_read_lock held.
3df0c49c 191 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 192 */
14044b37 193void cds_lfht_count_nodes(struct cds_lfht *ht,
7f52427b 194 long *split_count_before,
adc0de68 195 unsigned long *count,
7f52427b 196 long *split_count_after);
ab7d5fc6 197
f0c29ed7 198/*
14044b37 199 * cds_lfht_lookup - lookup a node by key.
0422d92c 200 * @ht: the hash table.
0422d92c 201 * @hash: the key hash.
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202 * @match: the key match function.
203 * @key: the current node key.
3a9c66db 204 * @iter: node, if found (output). *iter->node set to NULL if not found.
f0c29ed7 205 *
f0c29ed7 206 * Call with rcu_read_lock held.
3df0c49c 207 * Threads calling this API need to be registered RCU read-side threads.
7b783f81 208 * This function acts as a rcu_dereference() to read the node pointer.
f0c29ed7 209 */
6f554439 210void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash,
996ff57c 211 cds_lfht_match_fct match, const void *key,
6f554439 212 struct cds_lfht_iter *iter);
ab7d5fc6 213
f0c29ed7 214/*
3a9c66db 215 * cds_lfht_next_duplicate - get the next item with same key, after iterator.
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216 * @ht: the hash table.
217 * @match: the key match function.
04db56f8 218 * @key: the current node key.
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219 * @iter: input: current iterator.
220 * output: node, if found. *iter->node set to NULL if not found.
f0c29ed7 221 *
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222 * Uses an iterator initialized by a lookup or traversal. Important: the
223 * iterator _needs_ to be initialized before calling
224 * cds_lfht_next_duplicate.
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225 * Sets *iter-node to the following node with same key.
226 * Sets *iter->node to NULL if no following node exists with same key.
227 * RCU read-side lock must be held across cds_lfht_lookup and
228 * cds_lfht_next calls, and also between cds_lfht_next calls using the
229 * node returned by a previous cds_lfht_next.
230 * Call with rcu_read_lock held.
3df0c49c 231 * Threads calling this API need to be registered RCU read-side threads.
7b783f81 232 * This function acts as a rcu_dereference() to read the node pointer.
f0c29ed7 233 */
0422d92c 234void cds_lfht_next_duplicate(struct cds_lfht *ht,
996ff57c 235 cds_lfht_match_fct match, const void *key,
04db56f8 236 struct cds_lfht_iter *iter);
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237
238/*
239 * cds_lfht_first - get the first node in the table.
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240 * @ht: the hash table.
241 * @iter: First node, if exists (output). *iter->node set to NULL if not found.
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242 *
243 * Output in "*iter". *iter->node set to NULL if table is empty.
244 * Call with rcu_read_lock held.
3df0c49c 245 * Threads calling this API need to be registered RCU read-side threads.
7b783f81 246 * This function acts as a rcu_dereference() to read the node pointer.
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247 */
248void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter);
249
250/*
251 * cds_lfht_next - get the next node in the table.
0422d92c 252 * @ht: the hash table.
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253 * @iter: input: current iterator.
254 * output: next node, if exists. *iter->node set to NULL if not found.
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255 *
256 * Input/Output in "*iter". *iter->node set to NULL if *iter was
257 * pointing to the last table node.
258 * Call with rcu_read_lock held.
3df0c49c 259 * Threads calling this API need to be registered RCU read-side threads.
7b783f81 260 * This function acts as a rcu_dereference() to read the node pointer.
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261 */
262void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter);
ab7d5fc6 263
18117871 264/*
14044b37 265 * cds_lfht_add - add a node to the hash table.
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266 * @ht: the hash table.
267 * @hash: the key hash.
268 * @node: the node to add.
f0c29ed7 269 *
48ed1c18 270 * This function supports adding redundant keys into the table.
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271 * Call with rcu_read_lock held.
272 * Threads calling this API need to be registered RCU read-side threads.
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273 * This function issues a full memory barrier before and after its
274 * atomic commit.
f0c29ed7 275 */
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276void cds_lfht_add(struct cds_lfht *ht, unsigned long hash,
277 struct cds_lfht_node *node);
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278
279/*
14044b37 280 * cds_lfht_add_unique - add a node to hash table, if key is not present.
0422d92c 281 * @ht: the hash table.
6f554439 282 * @hash: the node's hash.
0422d92c 283 * @match: the key match function.
04db56f8 284 * @key: the node's key.
0422d92c 285 * @node: the node to try adding.
f0c29ed7 286 *
6878c72b 287 * Return the node added upon success.
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288 * Return the unique node already present upon failure. If
289 * cds_lfht_add_unique fails, the node passed as parameter should be
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290 * freed by the caller. In this case, the caller does NOT need to wait
291 * for a grace period before freeing the node.
f0c29ed7 292 * Call with rcu_read_lock held.
3df0c49c 293 * Threads calling this API need to be registered RCU read-side threads.
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294 *
295 * The semantic of this function is that if only this function is used
296 * to add keys into the table, no duplicated keys should ever be
297 * observable in the table. The same guarantee apply for combination of
9357c415 298 * add_unique and add_replace (see below).
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299 *
300 * Upon success, this function issues a full memory barrier before and
301 * after its atomic commit. Upon failure, this function acts like a
302 * simple lookup operation: it acts as a rcu_dereference() to read the
303 * node pointer. The failure case does not guarantee any other memory
304 * barrier.
18117871 305 */
adc0de68 306struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht,
6f554439 307 unsigned long hash,
0422d92c 308 cds_lfht_match_fct match,
996ff57c 309 const void *key,
adc0de68 310 struct cds_lfht_node *node);
3eca1b8c 311
48ed1c18 312/*
9357c415 313 * cds_lfht_add_replace - replace or add a node within hash table.
0422d92c 314 * @ht: the hash table.
6f554439 315 * @hash: the node's hash.
0422d92c 316 * @match: the key match function.
04db56f8 317 * @key: the node's key.
0422d92c 318 * @node: the node to add.
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319 *
320 * Return the node replaced upon success. If no node matching the key
321 * was present, return NULL, which also means the operation succeeded.
322 * This replacement operation should never fail.
323 * Call with rcu_read_lock held.
3df0c49c 324 * Threads calling this API need to be registered RCU read-side threads.
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325 * After successful replacement, a grace period must be waited for before
326 * freeing the memory reserved for the returned node.
327 *
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328 * The semantic of replacement vs lookups and traversals is the
329 * following: if lookups and traversals are performed between a key
330 * unique insertion and its removal, we guarantee that the lookups and
331 * traversals will always find exactly one instance of the key if it is
332 * replaced concurrently with the lookups.
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333 *
334 * Providing this semantic allows us to ensure that replacement-only
335 * schemes will never generate duplicated keys. It also allows us to
9357c415 336 * guarantee that a combination of add_replace and add_unique updates
48ed1c18 337 * will never generate duplicated keys.
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338 *
339 * This function issues a full memory barrier before and after its
340 * atomic commit.
48ed1c18 341 */
9357c415 342struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht,
6f554439 343 unsigned long hash,
0422d92c 344 cds_lfht_match_fct match,
996ff57c 345 const void *key,
adc0de68 346 struct cds_lfht_node *node);
48ed1c18 347
f0c29ed7 348/*
929ad508 349 * cds_lfht_replace - replace a node pointed to by iter within hash table.
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350 * @ht: the hash table.
351 * @old_iter: the iterator position of the node to replace.
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352 * @hash: the node's hash.
353 * @match: the key match function.
354 * @key: the node's key.
355 * @new_node: the new node to use as replacement.
f0c29ed7 356 *
9357c415 357 * Return 0 if replacement is successful, negative value otherwise.
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358 * Replacing a NULL old node or an already removed node will fail with
359 * -ENOENT.
360 * If the hash or value of the node to replace and the new node differ,
361 * this function returns -EINVAL without proceeding to the replacement.
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362 * Old node can be looked up with cds_lfht_lookup and cds_lfht_next.
363 * RCU read-side lock must be held between lookup and replacement.
364 * Call with rcu_read_lock held.
3df0c49c 365 * Threads calling this API need to be registered RCU read-side threads.
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366 * After successful replacement, a grace period must be waited for before
367 * freeing the memory reserved for the old node (which can be accessed
368 * with cds_lfht_iter_get_node).
369 *
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370 * The semantic of replacement vs lookups is the same as
371 * cds_lfht_add_replace().
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372 *
373 * Upon success, this function issues a full memory barrier before and
374 * after its atomic commit. Upon failure, this function does not issue
375 * any memory barrier.
9357c415 376 */
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377int cds_lfht_replace(struct cds_lfht *ht,
378 struct cds_lfht_iter *old_iter,
379 unsigned long hash,
380 cds_lfht_match_fct match,
381 const void *key,
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382 struct cds_lfht_node *new_node);
383
384/*
385 * cds_lfht_del - remove node pointed to by iterator from hash table.
0422d92c 386 * @ht: the hash table.
bc8c3c74 387 * @node: the node to delete.
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388 *
389 * Return 0 if the node is successfully removed, negative value
390 * otherwise.
bc8c3c74 391 * Deleting a NULL node or an already removed node will fail with a
9357c415 392 * negative value.
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393 * Node can be looked up with cds_lfht_lookup and cds_lfht_next,
394 * followed by use of cds_lfht_iter_get_node.
9357c415 395 * RCU read-side lock must be held between lookup and removal.
f0c29ed7 396 * Call with rcu_read_lock held.
3df0c49c 397 * Threads calling this API need to be registered RCU read-side threads.
48ed1c18 398 * After successful removal, a grace period must be waited for before
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399 * freeing the memory reserved for old node (which can be accessed with
400 * cds_lfht_iter_get_node).
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401 * Upon success, this function issues a full memory barrier before and
402 * after its atomic commit. Upon failure, this function does not issue
403 * any memory barrier.
f0c29ed7 404 */
bc8c3c74 405int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_node *node);
ab7d5fc6 406
df55172a 407/*
3a9c66db 408 * cds_lfht_is_node_deleted - query whether a node is removed from hash table.
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409 *
410 * Return non-zero if the node is deleted from the hash table, 0
411 * otherwise.
412 * Node can be looked up with cds_lfht_lookup and cds_lfht_next,
413 * followed by use of cds_lfht_iter_get_node.
414 * RCU read-side lock must be held between lookup and call to this
415 * function.
416 * Call with rcu_read_lock held.
417 * Threads calling this API need to be registered RCU read-side threads.
7b783f81 418 * This function does not issue any memory barrier.
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419 */
420int cds_lfht_is_node_deleted(struct cds_lfht_node *node);
421
f0c29ed7 422/*
14044b37 423 * cds_lfht_resize - Force a hash table resize
0422d92c 424 * @ht: the hash table.
1475579c 425 * @new_size: update to this hash table size.
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426 *
427 * Threads calling this API need to be registered RCU read-side threads.
7b783f81 428 * This function does not (necessarily) issue memory barriers.
f0c29ed7 429 */
1475579c 430void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size);
464a1ec9 431
6d320126 432/*
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433 * Note: it is safe to perform element removal (del), replacement, or
434 * any hash table update operation during any of the following hash
435 * table traversals.
7b783f81 436 * These functions act as rcu_dereference() to read the node pointers.
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437 */
438#define cds_lfht_for_each(ht, iter, node) \
439 for (cds_lfht_first(ht, iter), \
440 node = cds_lfht_iter_get_node(iter); \
441 node != NULL; \
442 cds_lfht_next(ht, iter), \
443 node = cds_lfht_iter_get_node(iter))
444
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445#define cds_lfht_for_each_duplicate(ht, hash, match, key, iter, node) \
446 for (cds_lfht_lookup(ht, hash, match, key, iter), \
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447 node = cds_lfht_iter_get_node(iter); \
448 node != NULL; \
449 cds_lfht_next_duplicate(ht, match, key, iter), \
450 node = cds_lfht_iter_get_node(iter))
451
452#define cds_lfht_for_each_entry(ht, iter, pos, member) \
453 for (cds_lfht_first(ht, iter), \
454 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
bdffa73a 455 __typeof__(*(pos)), member); \
0b0627bf 456 &(pos)->member != NULL; \
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457 cds_lfht_next(ht, iter), \
458 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
bdffa73a 459 __typeof__(*(pos)), member))
6d320126 460
6f554439 461#define cds_lfht_for_each_entry_duplicate(ht, hash, match, key, \
6d320126 462 iter, pos, member) \
6f554439 463 for (cds_lfht_lookup(ht, hash, match, key, iter), \
6d320126 464 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
bdffa73a 465 __typeof__(*(pos)), member); \
0b0627bf 466 &(pos)->member != NULL; \
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467 cds_lfht_next_duplicate(ht, match, key, iter), \
468 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
bdffa73a 469 __typeof__(*(pos)), member))
6d320126 470
01389791
MD
471#ifdef __cplusplus
472}
473#endif
474
a42cc659 475#endif /* _URCU_RCULFHASH_H */
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