Merge struct rcu_table into struct cds_lfht
[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.
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41 *
42 * struct cds_lfht_node should be aligned on 4-bytes boundaries because
43 * the two lower bits are used as flags.
7f52427b 44 *
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45 * struct cds_lfht_node can be embedded into a structure (as a field).
46 * caa_container_of() can be used to get the structure from the struct
47 * cds_lfht_node after a lookup.
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48 *
49 * The structure which embeds it typically holds the key (or key-value
50 * pair) of the object. The caller code is responsible for calculation
51 * of the hash value for cds_lfht APIs.
ae62aa6a 52 */
14044b37 53struct cds_lfht_node {
1ee8f000 54 struct cds_lfht_node *next; /* ptr | BUCKET_FLAG | REMOVED_FLAG */
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55 unsigned long reverse_hash;
56} __attribute__((aligned(4)));
abc490a1 57
7f52427b 58/* cds_lfht_iter: Used to track state while traversing a hash chain. */
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59struct cds_lfht_iter {
60 struct cds_lfht_node *node, *next;
61};
62
63static inline
64struct cds_lfht_node *cds_lfht_iter_get_node(struct cds_lfht_iter *iter)
65{
66 return iter->node;
67}
68
14044b37 69struct cds_lfht;
ab7d5fc6 70
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71/*
72 * Caution !
abc490a1 73 * Ensure reader and writer threads are registered as urcu readers.
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74 */
75
996ff57c 76typedef int (*cds_lfht_match_fct)(struct cds_lfht_node *node, const void *key);
abc490a1 77
f0c29ed7 78/*
14044b37 79 * cds_lfht_node_init - initialize a hash table node
0422d92c 80 * @node: the node to initialize.
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81 *
82 * This function is kept to be eventually used for debugging purposes
83 * (detection of memory corruption).
f0c29ed7 84 */
abc490a1 85static inline
04db56f8 86void cds_lfht_node_init(struct cds_lfht_node *node)
abc490a1 87{
abc490a1 88}
674f7a69 89
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90/*
91 * Hash table creation flags.
92 */
93enum {
94 CDS_LFHT_AUTO_RESIZE = (1U << 0),
5afadd12 95 CDS_LFHT_ACCOUNTING = (1U << 1),
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96};
97
674f7a69 98/*
7a9dcf9b 99 * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly.
674f7a69 100 */
0422d92c 101struct cds_lfht *_cds_lfht_new(unsigned long init_size,
0722081a 102 unsigned long min_nr_alloc_buckets,
747d725c 103 unsigned long max_nr_buckets,
b8af5011 104 int flags,
7b17c13e 105 const struct rcu_flavor_struct *flavor,
b7d619b0 106 pthread_attr_t *attr);
ab7d5fc6 107
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108/*
109 * cds_lfht_new - allocate a hash table.
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110 * @init_size: number of buckets to allocate initially. Must be power of two.
111 * @min_nr_alloc_buckets: the minimum number of allocated buckets.
112 * (must be power of two)
113 * @max_nr_buckets: the maximum number of hash table buckets allowed.
114 * (must be power of two)
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115 * @flags: hash table creation flags (can be combined with bitwise or: '|').
116 * 0: no flags.
117 * CDS_LFHT_AUTO_RESIZE: automatically resize hash table.
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118 * CDS_LFHT_ACCOUNTING: count the number of node addition
119 * and removal in the table
b7d619b0 120 * @attr: optional resize worker thread attributes. NULL for default.
7a9dcf9b 121 *
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122 * Return NULL on error.
123 * Note: the RCU flavor must be already included before the hash table header.
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124 *
125 * The programmer is responsible for ensuring that resize operation has a
126 * priority equal to hash table updater threads. It should be performed by
127 * specifying the appropriate priority in the pthread "attr" argument, and,
128 * for CDS_LFHT_AUTO_RESIZE, by ensuring that call_rcu worker threads also have
129 * this priority level. Having lower priority for call_rcu and resize threads
130 * does not pose any correctness issue, but the resize operations could be
131 * starved by updates, thus leading to long hash table bucket chains.
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132 * Threads calling this API are NOT required to be registered RCU read-side
133 * threads. It can be called very early.(before rcu is initialized ...etc.)
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134 */
135static inline
0422d92c 136struct cds_lfht *cds_lfht_new(unsigned long init_size,
0722081a 137 unsigned long min_nr_alloc_buckets,
747d725c 138 unsigned long max_nr_buckets,
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139 int flags,
140 pthread_attr_t *attr)
7a9dcf9b 141{
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142 return _cds_lfht_new(init_size, min_nr_alloc_buckets, max_nr_buckets,
143 flags, &rcu_flavor, attr);
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144}
145
f0c29ed7 146/*
14044b37 147 * cds_lfht_destroy - destroy a hash table.
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148 * @ht: the hash table to destroy.
149 * @attr: (output) resize worker thread attributes, as received by cds_lfht_new.
150 * The caller will typically want to free this pointer if dynamically
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151 * allocated. The attr point can be NULL if the caller does not
152 * need to be informed of the value passed to cds_lfht_new().
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153 *
154 * Return 0 on success, negative error value on error.
3df0c49c 155 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 156 */
b7d619b0 157int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr);
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158
159/*
14044b37 160 * cds_lfht_count_nodes - count the number of nodes in the hash table.
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161 * @ht: the hash table.
162 * @split_count_before: Sample the node count split-counter before traversal.
163 * @count: Traverse the hash table, count the number of nodes observed.
164 * @removed: Number of logically removed nodes observed during traversal.
165 * @split_count_after: Sample the node count split-counter after traversal.
0422d92c 166 *
f0c29ed7 167 * Call with rcu_read_lock held.
3df0c49c 168 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 169 */
14044b37 170void cds_lfht_count_nodes(struct cds_lfht *ht,
7f52427b 171 long *split_count_before,
adc0de68 172 unsigned long *count,
973e5e1b 173 unsigned long *removed,
7f52427b 174 long *split_count_after);
ab7d5fc6 175
f0c29ed7 176/*
14044b37 177 * cds_lfht_lookup - lookup a node by key.
0422d92c 178 * @ht: the hash table.
0422d92c 179 * @hash: the key hash.
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180 * @match: the key match function.
181 * @key: the current node key.
0422d92c 182 * @iter: Node, if found (output). *iter->node set to NULL if not found.
f0c29ed7 183 *
f0c29ed7 184 * Call with rcu_read_lock held.
3df0c49c 185 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 186 */
6f554439 187void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash,
996ff57c 188 cds_lfht_match_fct match, const void *key,
6f554439 189 struct cds_lfht_iter *iter);
ab7d5fc6 190
f0c29ed7 191/*
3883c0e5 192 * cds_lfht_next_duplicate - get the next item with same key (after a lookup).
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193 * @ht: the hash table.
194 * @match: the key match function.
04db56f8 195 * @key: the current node key.
0422d92c 196 * @iter: Node, if found (output). *iter->node set to NULL if not found.
f0c29ed7 197 *
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198 * Uses an iterator initialized by a lookup.
199 * Sets *iter-node to the following node with same key.
200 * Sets *iter->node to NULL if no following node exists with same key.
201 * RCU read-side lock must be held across cds_lfht_lookup and
202 * cds_lfht_next calls, and also between cds_lfht_next calls using the
203 * node returned by a previous cds_lfht_next.
204 * Call with rcu_read_lock held.
3df0c49c 205 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 206 */
0422d92c 207void cds_lfht_next_duplicate(struct cds_lfht *ht,
996ff57c 208 cds_lfht_match_fct match, const void *key,
04db56f8 209 struct cds_lfht_iter *iter);
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210
211/*
212 * cds_lfht_first - get the first node in the table.
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213 * @ht: the hash table.
214 * @iter: First node, if exists (output). *iter->node set to NULL if not found.
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215 *
216 * Output in "*iter". *iter->node set to NULL if table is empty.
217 * Call with rcu_read_lock held.
3df0c49c 218 * Threads calling this API need to be registered RCU read-side threads.
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219 */
220void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter);
221
222/*
223 * cds_lfht_next - get the next node in the table.
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224 * @ht: the hash table.
225 * @iter: Next node, if exists (output). *iter->node set to NULL if not found.
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226 *
227 * Input/Output in "*iter". *iter->node set to NULL if *iter was
228 * pointing to the last table node.
229 * Call with rcu_read_lock held.
3df0c49c 230 * Threads calling this API need to be registered RCU read-side threads.
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231 */
232void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter);
ab7d5fc6 233
18117871 234/*
14044b37 235 * cds_lfht_add - add a node to the hash table.
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236 * @ht: the hash table.
237 * @hash: the key hash.
238 * @node: the node to add.
f0c29ed7 239 *
48ed1c18 240 * This function supports adding redundant keys into the table.
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241 * Call with rcu_read_lock held.
242 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 243 */
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244void cds_lfht_add(struct cds_lfht *ht, unsigned long hash,
245 struct cds_lfht_node *node);
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246
247/*
14044b37 248 * cds_lfht_add_unique - add a node to hash table, if key is not present.
0422d92c 249 * @ht: the hash table.
6f554439 250 * @hash: the node's hash.
0422d92c 251 * @match: the key match function.
04db56f8 252 * @key: the node's key.
0422d92c 253 * @node: the node to try adding.
f0c29ed7 254 *
6878c72b 255 * Return the node added upon success.
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256 * Return the unique node already present upon failure. If
257 * cds_lfht_add_unique fails, the node passed as parameter should be
258 * freed by the caller.
f0c29ed7 259 * Call with rcu_read_lock held.
3df0c49c 260 * Threads calling this API need to be registered RCU read-side threads.
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261 *
262 * The semantic of this function is that if only this function is used
263 * to add keys into the table, no duplicated keys should ever be
264 * observable in the table. The same guarantee apply for combination of
9357c415 265 * add_unique and add_replace (see below).
18117871 266 */
adc0de68 267struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht,
6f554439 268 unsigned long hash,
0422d92c 269 cds_lfht_match_fct match,
996ff57c 270 const void *key,
adc0de68 271 struct cds_lfht_node *node);
3eca1b8c 272
48ed1c18 273/*
9357c415 274 * cds_lfht_add_replace - replace or add a node within hash table.
0422d92c 275 * @ht: the hash table.
6f554439 276 * @hash: the node's hash.
0422d92c 277 * @match: the key match function.
04db56f8 278 * @key: the node's key.
0422d92c 279 * @node: the node to add.
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280 *
281 * Return the node replaced upon success. If no node matching the key
282 * was present, return NULL, which also means the operation succeeded.
283 * This replacement operation should never fail.
284 * Call with rcu_read_lock held.
3df0c49c 285 * Threads calling this API need to be registered RCU read-side threads.
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286 * After successful replacement, a grace period must be waited for before
287 * freeing the memory reserved for the returned node.
288 *
289 * The semantic of replacement vs lookups is the following: if lookups
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290 * are performed between a key unique insertion and its removal, we
291 * guarantee that the lookups and get next will always find exactly one
292 * instance of the key if it is replaced concurrently with the lookups.
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293 *
294 * Providing this semantic allows us to ensure that replacement-only
295 * schemes will never generate duplicated keys. It also allows us to
9357c415 296 * guarantee that a combination of add_replace and add_unique updates
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297 * will never generate duplicated keys.
298 */
9357c415 299struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht,
6f554439 300 unsigned long hash,
0422d92c 301 cds_lfht_match_fct match,
996ff57c 302 const void *key,
adc0de68 303 struct cds_lfht_node *node);
48ed1c18 304
f0c29ed7 305/*
9357c415 306 * cds_lfht_replace - replace a node pointer to by iter within hash table.
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307 * @ht: the hash table.
308 * @old_iter: the iterator position of the node to replace.
309 * @now_node: the new node to try using for replacement.
f0c29ed7 310 *
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311 * Return 0 if replacement is successful, negative value otherwise.
312 * Replacing a NULL old node or an already removed node will fail with a
313 * negative value.
314 * Old node can be looked up with cds_lfht_lookup and cds_lfht_next.
315 * RCU read-side lock must be held between lookup and replacement.
316 * Call with rcu_read_lock held.
3df0c49c 317 * Threads calling this API need to be registered RCU read-side threads.
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318 * After successful replacement, a grace period must be waited for before
319 * freeing the memory reserved for the old node (which can be accessed
320 * with cds_lfht_iter_get_node).
321 *
322 * The semantic of replacement vs lookups is the following: if lookups
323 * are performed between a key unique insertion and its removal, we
324 * guarantee that the lookups and get next will always find exactly one
325 * instance of the key if it is replaced concurrently with the lookups.
326 *
327 * Providing this semantic allows us to ensure that replacement-only
328 * schemes will never generate duplicated keys. It also allows us to
329 * guarantee that a combination of add_replace and add_unique updates
330 * will never generate duplicated keys.
331 */
332int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter,
333 struct cds_lfht_node *new_node);
334
335/*
336 * cds_lfht_del - remove node pointed to by iterator from hash table.
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337 * @ht: the hash table.
338 * @iter: the iterator position of the node to delete.
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339 *
340 * Return 0 if the node is successfully removed, negative value
341 * otherwise.
342 * Replacing a NULL node or an already removed node will fail with a
343 * negative value.
344 * Node can be looked up with cds_lfht_lookup and cds_lfht_next.
345 * cds_lfht_iter_get_node.
346 * RCU read-side lock must be held between lookup and removal.
f0c29ed7 347 * Call with rcu_read_lock held.
3df0c49c 348 * Threads calling this API need to be registered RCU read-side threads.
48ed1c18 349 * After successful removal, a grace period must be waited for before
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350 * freeing the memory reserved for old node (which can be accessed with
351 * cds_lfht_iter_get_node).
f0c29ed7 352 */
9357c415 353int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter);
ab7d5fc6 354
f0c29ed7 355/*
14044b37 356 * cds_lfht_resize - Force a hash table resize
0422d92c 357 * @ht: the hash table.
1475579c 358 * @new_size: update to this hash table size.
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359 *
360 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 361 */
1475579c 362void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size);
464a1ec9 363
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364/*
365 * Note: cds_lfht_for_each are safe for element removal during
366 * iteration.
367 */
368#define cds_lfht_for_each(ht, iter, node) \
369 for (cds_lfht_first(ht, iter), \
370 node = cds_lfht_iter_get_node(iter); \
371 node != NULL; \
372 cds_lfht_next(ht, iter), \
373 node = cds_lfht_iter_get_node(iter))
374
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375#define cds_lfht_for_each_duplicate(ht, hash, match, key, iter, node) \
376 for (cds_lfht_lookup(ht, hash, match, key, iter), \
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377 node = cds_lfht_iter_get_node(iter); \
378 node != NULL; \
379 cds_lfht_next_duplicate(ht, match, key, iter), \
380 node = cds_lfht_iter_get_node(iter))
381
382#define cds_lfht_for_each_entry(ht, iter, pos, member) \
383 for (cds_lfht_first(ht, iter), \
384 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
385 typeof(*(pos)), member); \
0b0627bf 386 &(pos)->member != NULL; \
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387 cds_lfht_next(ht, iter), \
388 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
389 typeof(*(pos)), member))
390
6f554439 391#define cds_lfht_for_each_entry_duplicate(ht, hash, match, key, \
6d320126 392 iter, pos, member) \
6f554439 393 for (cds_lfht_lookup(ht, hash, match, key, iter), \
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394 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
395 typeof(*(pos)), member); \
0b0627bf 396 &(pos)->member != NULL; \
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397 cds_lfht_next_duplicate(ht, match, key, iter), \
398 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
399 typeof(*(pos)), member))
400
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401#ifdef __cplusplus
402}
403#endif
404
a42cc659 405#endif /* _URCU_RCULFHASH_H */
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