Add missing REMOVAL_OWNER_FLAG comment to cds_lfht_node comment
[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 *
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42 * struct cds_lfht_node should be aligned on 8-bytes boundaries because
43 * the three 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 {
3f2f3714 54 struct cds_lfht_node *next; /* ptr | REMOVAL_OWNER_FLAG | BUCKET_FLAG | REMOVED_FLAG */
04db56f8 55 unsigned long reverse_hash;
db00ccc3 56} __attribute__((aligned(8)));
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
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98struct cds_lfht_mm_type {
99 struct cds_lfht *(*alloc_cds_lfht)(unsigned long min_nr_alloc_buckets,
100 unsigned long max_nr_buckets);
101 void (*alloc_bucket_table)(struct cds_lfht *ht, unsigned long order);
102 void (*free_bucket_table)(struct cds_lfht *ht, unsigned long order);
103 struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht,
104 unsigned long index);
105};
106
107extern const struct cds_lfht_mm_type cds_lfht_mm_order;
308d1cb3 108extern const struct cds_lfht_mm_type cds_lfht_mm_chunk;
b0b55251 109extern const struct cds_lfht_mm_type cds_lfht_mm_mmap;
0b6aa001 110
674f7a69 111/*
7a9dcf9b 112 * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly.
674f7a69 113 */
0422d92c 114struct cds_lfht *_cds_lfht_new(unsigned long init_size,
0722081a 115 unsigned long min_nr_alloc_buckets,
747d725c 116 unsigned long max_nr_buckets,
b8af5011 117 int flags,
0b6aa001 118 const struct cds_lfht_mm_type *mm,
7b17c13e 119 const struct rcu_flavor_struct *flavor,
b7d619b0 120 pthread_attr_t *attr);
ab7d5fc6 121
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122/*
123 * cds_lfht_new - allocate a hash table.
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124 * @init_size: number of buckets to allocate initially. Must be power of two.
125 * @min_nr_alloc_buckets: the minimum number of allocated buckets.
126 * (must be power of two)
127 * @max_nr_buckets: the maximum number of hash table buckets allowed.
128 * (must be power of two)
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129 * @flags: hash table creation flags (can be combined with bitwise or: '|').
130 * 0: no flags.
131 * CDS_LFHT_AUTO_RESIZE: automatically resize hash table.
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132 * CDS_LFHT_ACCOUNTING: count the number of node addition
133 * and removal in the table
b7d619b0 134 * @attr: optional resize worker thread attributes. NULL for default.
7a9dcf9b 135 *
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136 * Return NULL on error.
137 * Note: the RCU flavor must be already included before the hash table header.
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138 *
139 * The programmer is responsible for ensuring that resize operation has a
140 * priority equal to hash table updater threads. It should be performed by
141 * specifying the appropriate priority in the pthread "attr" argument, and,
142 * for CDS_LFHT_AUTO_RESIZE, by ensuring that call_rcu worker threads also have
143 * this priority level. Having lower priority for call_rcu and resize threads
144 * does not pose any correctness issue, but the resize operations could be
145 * starved by updates, thus leading to long hash table bucket chains.
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146 * Threads calling this API are NOT required to be registered RCU read-side
147 * threads. It can be called very early.(before rcu is initialized ...etc.)
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148 */
149static inline
0422d92c 150struct cds_lfht *cds_lfht_new(unsigned long init_size,
0722081a 151 unsigned long min_nr_alloc_buckets,
747d725c 152 unsigned long max_nr_buckets,
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153 int flags,
154 pthread_attr_t *attr)
7a9dcf9b 155{
7b17c13e 156 return _cds_lfht_new(init_size, min_nr_alloc_buckets, max_nr_buckets,
c1888f3a 157 flags, NULL, &rcu_flavor, attr);
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158}
159
f0c29ed7 160/*
14044b37 161 * cds_lfht_destroy - destroy a hash table.
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162 * @ht: the hash table to destroy.
163 * @attr: (output) resize worker thread attributes, as received by cds_lfht_new.
164 * The caller will typically want to free this pointer if dynamically
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165 * allocated. The attr point can be NULL if the caller does not
166 * need to be informed of the value passed to cds_lfht_new().
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167 *
168 * Return 0 on success, negative error value on error.
3df0c49c 169 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 170 */
b7d619b0 171int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr);
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172
173/*
14044b37 174 * cds_lfht_count_nodes - count the number of nodes in the hash table.
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175 * @ht: the hash table.
176 * @split_count_before: Sample the node count split-counter before traversal.
177 * @count: Traverse the hash table, count the number of nodes observed.
178 * @removed: Number of logically removed nodes observed during traversal.
179 * @split_count_after: Sample the node count split-counter after traversal.
0422d92c 180 *
f0c29ed7 181 * Call with rcu_read_lock held.
3df0c49c 182 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 183 */
14044b37 184void cds_lfht_count_nodes(struct cds_lfht *ht,
7f52427b 185 long *split_count_before,
adc0de68 186 unsigned long *count,
973e5e1b 187 unsigned long *removed,
7f52427b 188 long *split_count_after);
ab7d5fc6 189
f0c29ed7 190/*
14044b37 191 * cds_lfht_lookup - lookup a node by key.
0422d92c 192 * @ht: the hash table.
0422d92c 193 * @hash: the key hash.
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194 * @match: the key match function.
195 * @key: the current node key.
0422d92c 196 * @iter: Node, if found (output). *iter->node set to NULL if not found.
f0c29ed7 197 *
f0c29ed7 198 * Call with rcu_read_lock held.
3df0c49c 199 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 200 */
6f554439 201void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash,
996ff57c 202 cds_lfht_match_fct match, const void *key,
6f554439 203 struct cds_lfht_iter *iter);
ab7d5fc6 204
f0c29ed7 205/*
3883c0e5 206 * cds_lfht_next_duplicate - get the next item with same key (after a lookup).
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207 * @ht: the hash table.
208 * @match: the key match function.
04db56f8 209 * @key: the current node key.
0422d92c 210 * @iter: Node, if found (output). *iter->node set to NULL if not found.
f0c29ed7 211 *
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212 * Uses an iterator initialized by a lookup.
213 * Sets *iter-node to the following node with same key.
214 * Sets *iter->node to NULL if no following node exists with same key.
215 * RCU read-side lock must be held across cds_lfht_lookup and
216 * cds_lfht_next calls, and also between cds_lfht_next calls using the
217 * node returned by a previous cds_lfht_next.
218 * Call with rcu_read_lock held.
3df0c49c 219 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 220 */
0422d92c 221void cds_lfht_next_duplicate(struct cds_lfht *ht,
996ff57c 222 cds_lfht_match_fct match, const void *key,
04db56f8 223 struct cds_lfht_iter *iter);
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224
225/*
226 * cds_lfht_first - get the first node in the table.
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227 * @ht: the hash table.
228 * @iter: First node, if exists (output). *iter->node set to NULL if not found.
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229 *
230 * Output in "*iter". *iter->node set to NULL if table is empty.
231 * Call with rcu_read_lock held.
3df0c49c 232 * Threads calling this API need to be registered RCU read-side threads.
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233 */
234void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter);
235
236/*
237 * cds_lfht_next - get the next node in the table.
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238 * @ht: the hash table.
239 * @iter: Next node, if exists (output). *iter->node set to NULL if not found.
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240 *
241 * Input/Output in "*iter". *iter->node set to NULL if *iter was
242 * pointing to the last table node.
243 * Call with rcu_read_lock held.
3df0c49c 244 * Threads calling this API need to be registered RCU read-side threads.
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245 */
246void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter);
ab7d5fc6 247
18117871 248/*
14044b37 249 * cds_lfht_add - add a node to the hash table.
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250 * @ht: the hash table.
251 * @hash: the key hash.
252 * @node: the node to add.
f0c29ed7 253 *
48ed1c18 254 * This function supports adding redundant keys into the table.
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255 * Call with rcu_read_lock held.
256 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 257 */
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258void cds_lfht_add(struct cds_lfht *ht, unsigned long hash,
259 struct cds_lfht_node *node);
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260
261/*
14044b37 262 * cds_lfht_add_unique - add a node to hash table, if key is not present.
0422d92c 263 * @ht: the hash table.
6f554439 264 * @hash: the node's hash.
0422d92c 265 * @match: the key match function.
04db56f8 266 * @key: the node's key.
0422d92c 267 * @node: the node to try adding.
f0c29ed7 268 *
6878c72b 269 * Return the node added upon success.
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270 * Return the unique node already present upon failure. If
271 * cds_lfht_add_unique fails, the node passed as parameter should be
272 * freed by the caller.
f0c29ed7 273 * Call with rcu_read_lock held.
3df0c49c 274 * Threads calling this API need to be registered RCU read-side threads.
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275 *
276 * The semantic of this function is that if only this function is used
277 * to add keys into the table, no duplicated keys should ever be
278 * observable in the table. The same guarantee apply for combination of
9357c415 279 * add_unique and add_replace (see below).
18117871 280 */
adc0de68 281struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht,
6f554439 282 unsigned long hash,
0422d92c 283 cds_lfht_match_fct match,
996ff57c 284 const void *key,
adc0de68 285 struct cds_lfht_node *node);
3eca1b8c 286
48ed1c18 287/*
9357c415 288 * cds_lfht_add_replace - replace or add a node within hash table.
0422d92c 289 * @ht: the hash table.
6f554439 290 * @hash: the node's hash.
0422d92c 291 * @match: the key match function.
04db56f8 292 * @key: the node's key.
0422d92c 293 * @node: the node to add.
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294 *
295 * Return the node replaced upon success. If no node matching the key
296 * was present, return NULL, which also means the operation succeeded.
297 * This replacement operation should never fail.
298 * Call with rcu_read_lock held.
3df0c49c 299 * Threads calling this API need to be registered RCU read-side threads.
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300 * After successful replacement, a grace period must be waited for before
301 * freeing the memory reserved for the returned node.
302 *
303 * The semantic of replacement vs lookups is the following: if lookups
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304 * are performed between a key unique insertion and its removal, we
305 * guarantee that the lookups and get next will always find exactly one
306 * instance of the key if it is replaced concurrently with the lookups.
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307 *
308 * Providing this semantic allows us to ensure that replacement-only
309 * schemes will never generate duplicated keys. It also allows us to
9357c415 310 * guarantee that a combination of add_replace and add_unique updates
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311 * will never generate duplicated keys.
312 */
9357c415 313struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht,
6f554439 314 unsigned long hash,
0422d92c 315 cds_lfht_match_fct match,
996ff57c 316 const void *key,
adc0de68 317 struct cds_lfht_node *node);
48ed1c18 318
f0c29ed7 319/*
9357c415 320 * cds_lfht_replace - replace a node pointer to by iter within hash table.
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321 * @ht: the hash table.
322 * @old_iter: the iterator position of the node to replace.
323 * @now_node: the new node to try using for replacement.
f0c29ed7 324 *
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325 * Return 0 if replacement is successful, negative value otherwise.
326 * Replacing a NULL old node or an already removed node will fail with a
327 * negative value.
328 * Old node can be looked up with cds_lfht_lookup and cds_lfht_next.
329 * RCU read-side lock must be held between lookup and replacement.
330 * Call with rcu_read_lock held.
3df0c49c 331 * Threads calling this API need to be registered RCU read-side threads.
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332 * After successful replacement, a grace period must be waited for before
333 * freeing the memory reserved for the old node (which can be accessed
334 * with cds_lfht_iter_get_node).
335 *
336 * The semantic of replacement vs lookups is the following: if lookups
337 * are performed between a key unique insertion and its removal, we
338 * guarantee that the lookups and get next will always find exactly one
339 * instance of the key if it is replaced concurrently with the lookups.
340 *
341 * Providing this semantic allows us to ensure that replacement-only
342 * schemes will never generate duplicated keys. It also allows us to
343 * guarantee that a combination of add_replace and add_unique updates
344 * will never generate duplicated keys.
345 */
346int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter,
347 struct cds_lfht_node *new_node);
348
349/*
350 * cds_lfht_del - remove node pointed to by iterator from hash table.
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351 * @ht: the hash table.
352 * @iter: the iterator position of the node to delete.
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353 *
354 * Return 0 if the node is successfully removed, negative value
355 * otherwise.
356 * Replacing a NULL node or an already removed node will fail with a
357 * negative value.
358 * Node can be looked up with cds_lfht_lookup and cds_lfht_next.
359 * cds_lfht_iter_get_node.
360 * RCU read-side lock must be held between lookup and removal.
f0c29ed7 361 * Call with rcu_read_lock held.
3df0c49c 362 * Threads calling this API need to be registered RCU read-side threads.
48ed1c18 363 * After successful removal, a grace period must be waited for before
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364 * freeing the memory reserved for old node (which can be accessed with
365 * cds_lfht_iter_get_node).
f0c29ed7 366 */
9357c415 367int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter);
ab7d5fc6 368
f0c29ed7 369/*
14044b37 370 * cds_lfht_resize - Force a hash table resize
0422d92c 371 * @ht: the hash table.
1475579c 372 * @new_size: update to this hash table size.
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373 *
374 * Threads calling this API need to be registered RCU read-side threads.
f0c29ed7 375 */
1475579c 376void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size);
464a1ec9 377
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378/*
379 * Note: cds_lfht_for_each are safe for element removal during
380 * iteration.
381 */
382#define cds_lfht_for_each(ht, iter, node) \
383 for (cds_lfht_first(ht, iter), \
384 node = cds_lfht_iter_get_node(iter); \
385 node != NULL; \
386 cds_lfht_next(ht, iter), \
387 node = cds_lfht_iter_get_node(iter))
388
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389#define cds_lfht_for_each_duplicate(ht, hash, match, key, iter, node) \
390 for (cds_lfht_lookup(ht, hash, match, key, iter), \
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391 node = cds_lfht_iter_get_node(iter); \
392 node != NULL; \
393 cds_lfht_next_duplicate(ht, match, key, iter), \
394 node = cds_lfht_iter_get_node(iter))
395
396#define cds_lfht_for_each_entry(ht, iter, pos, member) \
397 for (cds_lfht_first(ht, iter), \
398 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
399 typeof(*(pos)), member); \
0b0627bf 400 &(pos)->member != NULL; \
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401 cds_lfht_next(ht, iter), \
402 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
403 typeof(*(pos)), member))
404
6f554439 405#define cds_lfht_for_each_entry_duplicate(ht, hash, match, key, \
6d320126 406 iter, pos, member) \
6f554439 407 for (cds_lfht_lookup(ht, hash, match, key, iter), \
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408 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
409 typeof(*(pos)), member); \
0b0627bf 410 &(pos)->member != NULL; \
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411 cds_lfht_next_duplicate(ht, match, key, iter), \
412 pos = caa_container_of(cds_lfht_iter_get_node(iter), \
413 typeof(*(pos)), member))
414
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415#ifdef __cplusplus
416}
417#endif
418
a42cc659 419#endif /* _URCU_RCULFHASH_H */
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