Commit | Line | Data |
---|---|---|
8ad4ce58 MD |
1 | #ifndef _URCU_WFCQUEUE_H |
2 | #define _URCU_WFCQUEUE_H | |
3 | ||
4 | /* | |
47215721 | 5 | * urcu/wfcqueue.h |
8ad4ce58 MD |
6 | * |
7 | * Userspace RCU library - Concurrent Queue with Wait-Free Enqueue/Blocking Dequeue | |
8 | * | |
9 | * Copyright 2010-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
10 | * Copyright 2011-2012 - Lai Jiangshan <laijs@cn.fujitsu.com> | |
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 | |
25 | */ | |
26 | ||
27 | #include <pthread.h> | |
8ad4ce58 MD |
28 | #include <stdbool.h> |
29 | #include <urcu/compiler.h> | |
30 | #include <urcu/arch.h> | |
31 | ||
32 | #ifdef __cplusplus | |
33 | extern "C" { | |
34 | #endif | |
35 | ||
36 | /* | |
37 | * Concurrent queue with wait-free enqueue/blocking dequeue. | |
38 | * | |
ebfd2673 MD |
39 | * This queue has been designed and implemented collaboratively by |
40 | * Mathieu Desnoyers and Lai Jiangshan. Inspired from | |
41 | * half-wait-free/half-blocking queue implementation done by Paul E. | |
42 | * McKenney. | |
8ad4ce58 MD |
43 | */ |
44 | ||
0b73c819 | 45 | #define CDS_WFCQ_WOULDBLOCK ((struct cds_wfcq_node *) -1UL) |
47215721 | 46 | |
23773356 | 47 | enum cds_wfcq_ret { |
f878b49e | 48 | CDS_WFCQ_RET_WOULDBLOCK = -1, |
23773356 MD |
49 | CDS_WFCQ_RET_DEST_EMPTY = 0, |
50 | CDS_WFCQ_RET_DEST_NON_EMPTY = 1, | |
51 | CDS_WFCQ_RET_SRC_EMPTY = 2, | |
52 | }; | |
53 | ||
eec791af MD |
54 | enum cds_wfcq_state { |
55 | CDS_WFCQ_STATE_LAST = (1U << 0), | |
56 | }; | |
57 | ||
8ad4ce58 MD |
58 | struct cds_wfcq_node { |
59 | struct cds_wfcq_node *next; | |
60 | }; | |
61 | ||
62 | /* | |
63 | * Do not put head and tail on the same cache-line if concurrent | |
64 | * enqueue/dequeue are expected from many CPUs. This eliminates | |
65 | * false-sharing between enqueue and dequeue. | |
66 | */ | |
f637f191 MD |
67 | struct __cds_wfcq_head { |
68 | struct cds_wfcq_node node; | |
69 | }; | |
70 | ||
8ad4ce58 MD |
71 | struct cds_wfcq_head { |
72 | struct cds_wfcq_node node; | |
73 | pthread_mutex_t lock; | |
74 | }; | |
75 | ||
4d0d7cbc | 76 | #ifndef __cplusplus |
f637f191 MD |
77 | /* |
78 | * The transparent union allows calling functions that work on both | |
79 | * struct cds_wfcq_head and struct __cds_wfcq_head on any of those two | |
80 | * types. | |
81 | */ | |
5135c0fd | 82 | typedef union { |
f637f191 MD |
83 | struct __cds_wfcq_head *_h; |
84 | struct cds_wfcq_head *h; | |
5135c0fd | 85 | } __attribute__((__transparent_union__)) cds_wfcq_head_ptr_t; |
f637f191 | 86 | |
4d0d7cbc MD |
87 | /* |
88 | * This static inline is only present for compatibility with C++. It is | |
89 | * effect-less in C. | |
90 | */ | |
91 | static inline struct __cds_wfcq_head *__cds_wfcq_head_cast(struct __cds_wfcq_head *head) | |
92 | { | |
93 | return head; | |
94 | } | |
95 | ||
96 | /* | |
97 | * This static inline is only present for compatibility with C++. It is | |
98 | * effect-less in C. | |
99 | */ | |
100 | static inline struct cds_wfcq_head *cds_wfcq_head_cast(struct cds_wfcq_head *head) | |
101 | { | |
102 | return head; | |
103 | } | |
104 | #else /* #ifndef __cplusplus */ | |
105 | ||
106 | /* C++ ignores transparent union. */ | |
107 | typedef union { | |
108 | struct __cds_wfcq_head *_h; | |
109 | struct cds_wfcq_head *h; | |
110 | } cds_wfcq_head_ptr_t; | |
111 | ||
112 | /* C++ ignores transparent union. Requires an explicit conversion. */ | |
113 | static inline cds_wfcq_head_ptr_t __cds_wfcq_head_cast(struct __cds_wfcq_head *head) | |
114 | { | |
115 | cds_wfcq_head_ptr_t ret = { ._h = head }; | |
116 | return ret; | |
117 | } | |
118 | /* C++ ignores transparent union. Requires an explicit conversion. */ | |
119 | static inline cds_wfcq_head_ptr_t cds_wfcq_head_cast(struct cds_wfcq_head *head) | |
120 | { | |
121 | cds_wfcq_head_ptr_t ret = { .h = head }; | |
122 | return ret; | |
123 | } | |
124 | #endif /* #else #ifndef __cplusplus */ | |
125 | ||
8ad4ce58 MD |
126 | struct cds_wfcq_tail { |
127 | struct cds_wfcq_node *p; | |
128 | }; | |
129 | ||
130 | #ifdef _LGPL_SOURCE | |
131 | ||
132 | #include <urcu/static/wfcqueue.h> | |
133 | ||
134 | #define cds_wfcq_node_init _cds_wfcq_node_init | |
135 | #define cds_wfcq_init _cds_wfcq_init | |
b4edfa81 | 136 | #define __cds_wfcq_init ___cds_wfcq_init |
200d100e | 137 | #define cds_wfcq_destroy _cds_wfcq_destroy |
8ad4ce58 MD |
138 | #define cds_wfcq_empty _cds_wfcq_empty |
139 | #define cds_wfcq_enqueue _cds_wfcq_enqueue | |
140 | ||
141 | /* Dequeue locking */ | |
142 | #define cds_wfcq_dequeue_lock _cds_wfcq_dequeue_lock | |
143 | #define cds_wfcq_dequeue_unlock _cds_wfcq_dequeue_unlock | |
144 | ||
145 | /* Locking performed within cds_wfcq calls. */ | |
146 | #define cds_wfcq_dequeue_blocking _cds_wfcq_dequeue_blocking | |
eec791af MD |
147 | #define cds_wfcq_dequeue_with_state_blocking \ |
148 | _cds_wfcq_dequeue_with_state_blocking | |
8ad4ce58 MD |
149 | #define cds_wfcq_splice_blocking _cds_wfcq_splice_blocking |
150 | #define cds_wfcq_first_blocking _cds_wfcq_first_blocking | |
151 | #define cds_wfcq_next_blocking _cds_wfcq_next_blocking | |
152 | ||
153 | /* Locking ensured by caller by holding cds_wfcq_dequeue_lock() */ | |
154 | #define __cds_wfcq_dequeue_blocking ___cds_wfcq_dequeue_blocking | |
eec791af MD |
155 | #define __cds_wfcq_dequeue_with_state_blocking \ |
156 | ___cds_wfcq_dequeue_with_state_blocking | |
8ad4ce58 MD |
157 | #define __cds_wfcq_splice_blocking ___cds_wfcq_splice_blocking |
158 | #define __cds_wfcq_first_blocking ___cds_wfcq_first_blocking | |
159 | #define __cds_wfcq_next_blocking ___cds_wfcq_next_blocking | |
160 | ||
47215721 MD |
161 | /* |
162 | * Locking ensured by caller by holding cds_wfcq_dequeue_lock(). | |
163 | * Non-blocking: deque, first, next return CDS_WFCQ_WOULDBLOCK if they | |
164 | * need to block. splice returns nonzero if it needs to block. | |
165 | */ | |
166 | #define __cds_wfcq_dequeue_nonblocking ___cds_wfcq_dequeue_nonblocking | |
eec791af MD |
167 | #define __cds_wfcq_dequeue_with_state_nonblocking \ |
168 | ___cds_wfcq_dequeue_with_state_nonblocking | |
47215721 MD |
169 | #define __cds_wfcq_splice_nonblocking ___cds_wfcq_splice_nonblocking |
170 | #define __cds_wfcq_first_nonblocking ___cds_wfcq_first_nonblocking | |
171 | #define __cds_wfcq_next_nonblocking ___cds_wfcq_next_nonblocking | |
172 | ||
8ad4ce58 MD |
173 | #else /* !_LGPL_SOURCE */ |
174 | ||
175 | /* | |
176 | * Mutual exclusion of cds_wfcq_* / __cds_wfcq_* API | |
177 | * | |
f878b49e MD |
178 | * Synchronization table: |
179 | * | |
180 | * External synchronization techniques described in the API below is | |
181 | * required between pairs marked with "X". No external synchronization | |
182 | * required between pairs marked with "-". | |
183 | * | |
184 | * Legend: | |
185 | * [1] cds_wfcq_enqueue | |
186 | * [2] __cds_wfcq_splice (destination queue) | |
187 | * [3] __cds_wfcq_dequeue | |
188 | * [4] __cds_wfcq_splice (source queue) | |
189 | * [5] __cds_wfcq_first | |
190 | * [6] __cds_wfcq_next | |
191 | * | |
192 | * [1] [2] [3] [4] [5] [6] | |
193 | * [1] - - - - - - | |
194 | * [2] - - - - - - | |
195 | * [3] - - X X X X | |
196 | * [4] - - X - X X | |
197 | * [5] - - X X - - | |
198 | * [6] - - X X - - | |
199 | * | |
8ad4ce58 MD |
200 | * Mutual exclusion can be ensured by holding cds_wfcq_dequeue_lock(). |
201 | * | |
202 | * For convenience, cds_wfcq_dequeue_blocking() and | |
203 | * cds_wfcq_splice_blocking() hold the dequeue lock. | |
1fe734e1 MD |
204 | * |
205 | * Besides locking, mutual exclusion of dequeue, splice and iteration | |
206 | * can be ensured by performing all of those operations from a single | |
207 | * thread, without requiring any lock. | |
8ad4ce58 MD |
208 | */ |
209 | ||
210 | /* | |
211 | * cds_wfcq_node_init: initialize wait-free queue node. | |
212 | */ | |
213 | extern void cds_wfcq_node_init(struct cds_wfcq_node *node); | |
214 | ||
215 | /* | |
200d100e MD |
216 | * cds_wfcq_init: initialize wait-free queue. Pair with |
217 | * cds_wfcq_destroy(). | |
8ad4ce58 MD |
218 | */ |
219 | extern void cds_wfcq_init(struct cds_wfcq_head *head, | |
220 | struct cds_wfcq_tail *tail); | |
221 | ||
f637f191 | 222 | /* |
200d100e MD |
223 | * cds_wfcq_destroy: destroy wait-free queue. Pair with |
224 | * cds_wfcq_init(). | |
225 | */ | |
226 | extern void cds_wfcq_destroy(struct cds_wfcq_head *head, | |
227 | struct cds_wfcq_tail *tail); | |
228 | ||
229 | /* | |
230 | * __cds_wfcq_init: initialize wait-free queue (without lock). Don't | |
231 | * pair with any destroy function. | |
f637f191 MD |
232 | */ |
233 | extern void __cds_wfcq_init(struct __cds_wfcq_head *head, | |
234 | struct cds_wfcq_tail *tail); | |
235 | ||
8ad4ce58 MD |
236 | /* |
237 | * cds_wfcq_empty: return whether wait-free queue is empty. | |
238 | * | |
239 | * No memory barrier is issued. No mutual exclusion is required. | |
240 | */ | |
f637f191 | 241 | extern bool cds_wfcq_empty(cds_wfcq_head_ptr_t head, |
8ad4ce58 MD |
242 | struct cds_wfcq_tail *tail); |
243 | ||
244 | /* | |
245 | * cds_wfcq_dequeue_lock: take the dequeue mutual exclusion lock. | |
246 | */ | |
247 | extern void cds_wfcq_dequeue_lock(struct cds_wfcq_head *head, | |
248 | struct cds_wfcq_tail *tail); | |
249 | ||
250 | /* | |
251 | * cds_wfcq_dequeue_unlock: release the dequeue mutual exclusion lock. | |
252 | */ | |
253 | extern void cds_wfcq_dequeue_unlock(struct cds_wfcq_head *head, | |
254 | struct cds_wfcq_tail *tail); | |
255 | ||
256 | /* | |
257 | * cds_wfcq_enqueue: enqueue a node into a wait-free queue. | |
258 | * | |
259 | * Issues a full memory barrier before enqueue. No mutual exclusion is | |
260 | * required. | |
23773356 MD |
261 | * |
262 | * Returns false if the queue was empty prior to adding the node. | |
263 | * Returns true otherwise. | |
8ad4ce58 | 264 | */ |
f637f191 | 265 | extern bool cds_wfcq_enqueue(cds_wfcq_head_ptr_t head, |
8ad4ce58 MD |
266 | struct cds_wfcq_tail *tail, |
267 | struct cds_wfcq_node *node); | |
268 | ||
269 | /* | |
270 | * cds_wfcq_dequeue_blocking: dequeue a node from a wait-free queue. | |
271 | * | |
272 | * Content written into the node before enqueue is guaranteed to be | |
273 | * consistent, but no other memory ordering is ensured. | |
274 | * It is valid to reuse and free a dequeued node immediately. | |
ffa11a18 | 275 | * Mutual exclusion with cds_wfcq_dequeue_blocking and dequeue lock is |
1fe734e1 | 276 | * ensured. |
8ad4ce58 MD |
277 | */ |
278 | extern struct cds_wfcq_node *cds_wfcq_dequeue_blocking( | |
279 | struct cds_wfcq_head *head, | |
280 | struct cds_wfcq_tail *tail); | |
281 | ||
eec791af MD |
282 | /* |
283 | * cds_wfcq_dequeue_with_state_blocking: dequeue with state. | |
284 | * | |
285 | * Same as cds_wfcq_dequeue_blocking, but saves whether dequeueing the | |
286 | * last node of the queue into state (CDS_WFCQ_STATE_LAST). | |
287 | */ | |
288 | extern struct cds_wfcq_node *cds_wfcq_dequeue_with_state_blocking( | |
289 | struct cds_wfcq_head *head, | |
290 | struct cds_wfcq_tail *tail, | |
291 | int *state); | |
292 | ||
8ad4ce58 MD |
293 | /* |
294 | * cds_wfcq_splice_blocking: enqueue all src_q nodes at the end of dest_q. | |
295 | * | |
296 | * Dequeue all nodes from src_q. | |
297 | * dest_q must be already initialized. | |
298 | * Content written into the node before enqueue is guaranteed to be | |
299 | * consistent, but no other memory ordering is ensured. | |
ffa11a18 | 300 | * Mutual exclusion with cds_wfcq_dequeue_blocking and dequeue lock is |
1fe734e1 | 301 | * ensured. |
23773356 MD |
302 | * |
303 | * Returns enum cds_wfcq_ret which indicates the state of the src or | |
b94aaf6f | 304 | * dest queue. |
8ad4ce58 | 305 | */ |
23773356 | 306 | extern enum cds_wfcq_ret cds_wfcq_splice_blocking( |
8ad4ce58 MD |
307 | struct cds_wfcq_head *dest_q_head, |
308 | struct cds_wfcq_tail *dest_q_tail, | |
309 | struct cds_wfcq_head *src_q_head, | |
310 | struct cds_wfcq_tail *src_q_tail); | |
311 | ||
312 | /* | |
47215721 | 313 | * __cds_wfcq_dequeue_blocking: dequeue a node from a wait-free queue. |
8ad4ce58 MD |
314 | * |
315 | * Content written into the node before enqueue is guaranteed to be | |
316 | * consistent, but no other memory ordering is ensured. | |
317 | * It is valid to reuse and free a dequeued node immediately. | |
1fe734e1 MD |
318 | * Dequeue/splice/iteration mutual exclusion should be ensured by the |
319 | * caller. | |
8ad4ce58 MD |
320 | */ |
321 | extern struct cds_wfcq_node *__cds_wfcq_dequeue_blocking( | |
f637f191 | 322 | cds_wfcq_head_ptr_t head, |
8ad4ce58 MD |
323 | struct cds_wfcq_tail *tail); |
324 | ||
eec791af MD |
325 | /* |
326 | * __cds_wfcq_dequeue_with_state_blocking: dequeue with state. | |
327 | * | |
328 | * Same as __cds_wfcq_dequeue_blocking, but saves whether dequeueing the | |
329 | * last node of the queue into state (CDS_WFCQ_STATE_LAST). | |
330 | */ | |
331 | extern struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_blocking( | |
f637f191 | 332 | cds_wfcq_head_ptr_t head, |
eec791af MD |
333 | struct cds_wfcq_tail *tail, |
334 | int *state); | |
335 | ||
47215721 MD |
336 | /* |
337 | * __cds_wfcq_dequeue_nonblocking: dequeue a node from a wait-free queue. | |
338 | * | |
339 | * Same as __cds_wfcq_dequeue_blocking, but returns CDS_WFCQ_WOULDBLOCK | |
340 | * if it needs to block. | |
341 | */ | |
342 | extern struct cds_wfcq_node *__cds_wfcq_dequeue_nonblocking( | |
f637f191 | 343 | cds_wfcq_head_ptr_t head, |
47215721 MD |
344 | struct cds_wfcq_tail *tail); |
345 | ||
eec791af MD |
346 | /* |
347 | * __cds_wfcq_dequeue_with_state_blocking: dequeue with state. | |
348 | * | |
349 | * Same as __cds_wfcq_dequeue_nonblocking, but saves whether dequeueing | |
350 | * the last node of the queue into state (CDS_WFCQ_STATE_LAST). | |
351 | */ | |
352 | extern struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_nonblocking( | |
f637f191 | 353 | cds_wfcq_head_ptr_t head, |
eec791af MD |
354 | struct cds_wfcq_tail *tail, |
355 | int *state); | |
356 | ||
8ad4ce58 MD |
357 | /* |
358 | * __cds_wfcq_splice_blocking: enqueue all src_q nodes at the end of dest_q. | |
359 | * | |
360 | * Dequeue all nodes from src_q. | |
361 | * dest_q must be already initialized. | |
f878b49e MD |
362 | * Mutual exclusion for src_q should be ensured by the caller as |
363 | * specified in the "Synchronisation table". | |
23773356 | 364 | * Returns enum cds_wfcq_ret which indicates the state of the src or |
f878b49e | 365 | * dest queue. Never returns CDS_WFCQ_RET_WOULDBLOCK. |
8ad4ce58 | 366 | */ |
23773356 | 367 | extern enum cds_wfcq_ret __cds_wfcq_splice_blocking( |
f637f191 | 368 | cds_wfcq_head_ptr_t dest_q_head, |
8ad4ce58 | 369 | struct cds_wfcq_tail *dest_q_tail, |
f637f191 | 370 | cds_wfcq_head_ptr_t src_q_head, |
8ad4ce58 MD |
371 | struct cds_wfcq_tail *src_q_tail); |
372 | ||
47215721 MD |
373 | /* |
374 | * __cds_wfcq_splice_nonblocking: enqueue all src_q nodes at the end of dest_q. | |
375 | * | |
23773356 MD |
376 | * Same as __cds_wfcq_splice_blocking, but returns |
377 | * CDS_WFCQ_RET_WOULDBLOCK if it needs to block. | |
47215721 | 378 | */ |
23773356 | 379 | extern enum cds_wfcq_ret __cds_wfcq_splice_nonblocking( |
f637f191 | 380 | cds_wfcq_head_ptr_t dest_q_head, |
47215721 | 381 | struct cds_wfcq_tail *dest_q_tail, |
f637f191 | 382 | cds_wfcq_head_ptr_t src_q_head, |
47215721 MD |
383 | struct cds_wfcq_tail *src_q_tail); |
384 | ||
8ad4ce58 MD |
385 | /* |
386 | * __cds_wfcq_first_blocking: get first node of a queue, without dequeuing. | |
387 | * | |
388 | * Content written into the node before enqueue is guaranteed to be | |
389 | * consistent, but no other memory ordering is ensured. | |
1fe734e1 MD |
390 | * Dequeue/splice/iteration mutual exclusion should be ensured by the |
391 | * caller. | |
f94061a3 MD |
392 | * |
393 | * Used by for-like iteration macros: | |
394 | * __cds_wfcq_for_each_blocking() | |
395 | * __cds_wfcq_for_each_blocking_safe() | |
131a29a6 MD |
396 | * |
397 | * Returns NULL if queue is empty, first node otherwise. | |
8ad4ce58 MD |
398 | */ |
399 | extern struct cds_wfcq_node *__cds_wfcq_first_blocking( | |
f637f191 | 400 | cds_wfcq_head_ptr_t head, |
8ad4ce58 MD |
401 | struct cds_wfcq_tail *tail); |
402 | ||
47215721 MD |
403 | /* |
404 | * __cds_wfcq_first_nonblocking: get first node of a queue, without dequeuing. | |
405 | * | |
406 | * Same as __cds_wfcq_first_blocking, but returns CDS_WFCQ_WOULDBLOCK if | |
407 | * it needs to block. | |
408 | */ | |
409 | extern struct cds_wfcq_node *__cds_wfcq_first_nonblocking( | |
f637f191 | 410 | cds_wfcq_head_ptr_t head, |
47215721 MD |
411 | struct cds_wfcq_tail *tail); |
412 | ||
8ad4ce58 MD |
413 | /* |
414 | * __cds_wfcq_next_blocking: get next node of a queue, without dequeuing. | |
415 | * | |
416 | * Content written into the node before enqueue is guaranteed to be | |
417 | * consistent, but no other memory ordering is ensured. | |
1fe734e1 MD |
418 | * Dequeue/splice/iteration mutual exclusion should be ensured by the |
419 | * caller. | |
f94061a3 MD |
420 | * |
421 | * Used by for-like iteration macros: | |
422 | * __cds_wfcq_for_each_blocking() | |
423 | * __cds_wfcq_for_each_blocking_safe() | |
131a29a6 MD |
424 | * |
425 | * Returns NULL if reached end of queue, non-NULL next queue node | |
426 | * otherwise. | |
8ad4ce58 MD |
427 | */ |
428 | extern struct cds_wfcq_node *__cds_wfcq_next_blocking( | |
f637f191 | 429 | cds_wfcq_head_ptr_t head, |
8ad4ce58 MD |
430 | struct cds_wfcq_tail *tail, |
431 | struct cds_wfcq_node *node); | |
432 | ||
47215721 MD |
433 | /* |
434 | * __cds_wfcq_next_blocking: get next node of a queue, without dequeuing. | |
435 | * | |
436 | * Same as __cds_wfcq_next_blocking, but returns CDS_WFCQ_WOULDBLOCK if | |
437 | * it needs to block. | |
438 | */ | |
439 | extern struct cds_wfcq_node *__cds_wfcq_next_nonblocking( | |
f637f191 | 440 | cds_wfcq_head_ptr_t head, |
47215721 MD |
441 | struct cds_wfcq_tail *tail, |
442 | struct cds_wfcq_node *node); | |
443 | ||
8ad4ce58 MD |
444 | #endif /* !_LGPL_SOURCE */ |
445 | ||
446 | /* | |
447 | * __cds_wfcq_for_each_blocking: Iterate over all nodes in a queue, | |
448 | * without dequeuing them. | |
f637f191 | 449 | * @head: head of the queue (struct cds_wfcq_head or __cds_wfcq_head pointer). |
8ad4ce58 MD |
450 | * @tail: tail of the queue (struct cds_wfcq_tail pointer). |
451 | * @node: iterator on the queue (struct cds_wfcq_node pointer). | |
452 | * | |
453 | * Content written into each node before enqueue is guaranteed to be | |
454 | * consistent, but no other memory ordering is ensured. | |
1fe734e1 MD |
455 | * Dequeue/splice/iteration mutual exclusion should be ensured by the |
456 | * caller. | |
8ad4ce58 MD |
457 | */ |
458 | #define __cds_wfcq_for_each_blocking(head, tail, node) \ | |
459 | for (node = __cds_wfcq_first_blocking(head, tail); \ | |
460 | node != NULL; \ | |
461 | node = __cds_wfcq_next_blocking(head, tail, node)) | |
462 | ||
463 | /* | |
464 | * __cds_wfcq_for_each_blocking_safe: Iterate over all nodes in a queue, | |
465 | * without dequeuing them. Safe against deletion. | |
f637f191 | 466 | * @head: head of the queue (struct cds_wfcq_head or __cds_wfcq_head pointer). |
8ad4ce58 MD |
467 | * @tail: tail of the queue (struct cds_wfcq_tail pointer). |
468 | * @node: iterator on the queue (struct cds_wfcq_node pointer). | |
469 | * @n: struct cds_wfcq_node pointer holding the next pointer (used | |
470 | * internally). | |
471 | * | |
472 | * Content written into each node before enqueue is guaranteed to be | |
473 | * consistent, but no other memory ordering is ensured. | |
1fe734e1 MD |
474 | * Dequeue/splice/iteration mutual exclusion should be ensured by the |
475 | * caller. | |
8ad4ce58 MD |
476 | */ |
477 | #define __cds_wfcq_for_each_blocking_safe(head, tail, node, n) \ | |
478 | for (node = __cds_wfcq_first_blocking(head, tail), \ | |
479 | n = (node ? __cds_wfcq_next_blocking(head, tail, node) : NULL); \ | |
480 | node != NULL; \ | |
481 | node = n, n = (node ? __cds_wfcq_next_blocking(head, tail, node) : NULL)) | |
482 | ||
483 | #ifdef __cplusplus | |
484 | } | |
485 | #endif | |
486 | ||
487 | #endif /* _URCU_WFCQUEUE_H */ |