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d3bfcb24 MD |
1 | #ifndef _URCU_LFSTACK_H |
2 | #define _URCU_LFSTACK_H | |
3 | ||
4 | /* | |
5 | * lfstack.h | |
6 | * | |
7 | * Userspace RCU library - Lock-Free Stack | |
8 | * | |
9 | * Copyright 2010-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
10 | * | |
11 | * This library is free software; you can redistribute it and/or | |
12 | * modify it under the terms of the GNU Lesser General Public | |
13 | * License as published by the Free Software Foundation; either | |
14 | * version 2.1 of the License, or (at your option) any later version. | |
15 | * | |
16 | * This library is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
19 | * Lesser General Public License for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU Lesser General Public | |
22 | * License along with this library; if not, write to the Free Software | |
23 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
24 | */ | |
25 | ||
26 | #ifdef __cplusplus | |
27 | extern "C" { | |
28 | #endif | |
29 | ||
7294103b MD |
30 | #include <stdbool.h> |
31 | #include <pthread.h> | |
28757437 | 32 | #include <urcu/compiler.h> |
7294103b MD |
33 | |
34 | /* | |
35 | * Lock-free stack. | |
36 | * | |
37 | * Stack implementing push, pop, pop_all operations, as well as iterator | |
38 | * on the stack head returned by pop_all. | |
39 | * | |
40 | * Synchronization table: | |
41 | * | |
42 | * External synchronization techniques described in the API below is | |
43 | * required between pairs marked with "X". No external synchronization | |
44 | * required between pairs marked with "-". | |
45 | * | |
46 | * cds_lfs_push __cds_lfs_pop __cds_lfs_pop_all | |
47 | * cds_lfs_push - - - | |
48 | * __cds_lfs_pop - X X | |
49 | * __cds_lfs_pop_all - X - | |
50 | * | |
51 | * cds_lfs_pop_blocking and cds_lfs_pop_all_blocking use an internal | |
52 | * mutex to provide synchronization. | |
53 | */ | |
54 | ||
55 | /* | |
56 | * struct cds_lfs_node is returned by cds_lfs_pop, and also used as | |
57 | * iterator on stack. It is not safe to dereference the node next | |
58 | * pointer when returned by cds_lfs_pop. | |
59 | */ | |
d3bfcb24 MD |
60 | struct cds_lfs_node { |
61 | struct cds_lfs_node *next; | |
62 | }; | |
63 | ||
7294103b MD |
64 | /* |
65 | * struct cds_lfs_head is returned by __cds_lfs_pop_all, and can be used | |
66 | * to begin iteration on the stack. "node" needs to be the first field | |
67 | * of cds_lfs_head, so the end-of-stack pointer value can be used for | |
68 | * both types. | |
69 | */ | |
70 | struct cds_lfs_head { | |
71 | struct cds_lfs_node node; | |
72 | }; | |
73 | ||
48a8832b MD |
74 | struct __cds_lfs_stack { |
75 | struct cds_lfs_head *head; | |
76 | }; | |
77 | ||
d3bfcb24 | 78 | struct cds_lfs_stack { |
7294103b MD |
79 | struct cds_lfs_head *head; |
80 | pthread_mutex_t lock; | |
d3bfcb24 MD |
81 | }; |
82 | ||
48a8832b MD |
83 | /* |
84 | * The transparent union allows calling functions that work on both | |
85 | * struct cds_lfs_stack and struct __cds_lfs_stack on any of those two | |
86 | * types. | |
28757437 SM |
87 | * |
88 | * Avoid complaints from clang++ not knowing this attribute. | |
48a8832b | 89 | */ |
5135c0fd | 90 | typedef union { |
48a8832b MD |
91 | struct __cds_lfs_stack *_s; |
92 | struct cds_lfs_stack *s; | |
28757437 | 93 | } caa_c_transparent_union cds_lfs_stack_ptr_t; |
48a8832b | 94 | |
d3bfcb24 MD |
95 | #ifdef _LGPL_SOURCE |
96 | ||
97 | #include <urcu/static/lfstack.h> | |
98 | ||
99 | #define cds_lfs_node_init _cds_lfs_node_init | |
100 | #define cds_lfs_init _cds_lfs_init | |
200d100e | 101 | #define cds_lfs_destroy _cds_lfs_destroy |
817a0178 | 102 | #define __cds_lfs_init ___cds_lfs_init |
7294103b | 103 | #define cds_lfs_empty _cds_lfs_empty |
d3bfcb24 | 104 | #define cds_lfs_push _cds_lfs_push |
7294103b MD |
105 | |
106 | /* Locking performed internally */ | |
107 | #define cds_lfs_pop_blocking _cds_lfs_pop_blocking | |
108 | #define cds_lfs_pop_all_blocking _cds_lfs_pop_all_blocking | |
109 | ||
110 | /* Synchronize pop with internal mutex */ | |
111 | #define cds_lfs_pop_lock _cds_lfs_pop_lock | |
112 | #define cds_lfs_pop_unlock _cds_lfs_pop_unlock | |
113 | ||
114 | /* Synchronization ensured by the caller. See synchronization table. */ | |
115 | #define __cds_lfs_pop ___cds_lfs_pop | |
116 | #define __cds_lfs_pop_all ___cds_lfs_pop_all | |
d3bfcb24 MD |
117 | |
118 | #else /* !_LGPL_SOURCE */ | |
119 | ||
7294103b MD |
120 | /* |
121 | * cds_lfs_node_init: initialize lock-free stack node. | |
122 | */ | |
d3bfcb24 | 123 | extern void cds_lfs_node_init(struct cds_lfs_node *node); |
7294103b MD |
124 | |
125 | /* | |
200d100e MD |
126 | * cds_lfs_init: initialize lock-free stack (with locking). Pair with |
127 | * cds_lfs_destroy(). | |
7294103b | 128 | */ |
d3bfcb24 MD |
129 | extern void cds_lfs_init(struct cds_lfs_stack *s); |
130 | ||
48a8832b | 131 | /* |
200d100e MD |
132 | * cds_lfs_destroy: destroy lock-free stack (with lock). Pair with |
133 | * cds_lfs_init(). | |
134 | */ | |
135 | extern void cds_lfs_destroy(struct cds_lfs_stack *s); | |
136 | ||
137 | /* | |
138 | * __cds_lfs_init: initialize lock-free stack (without lock). | |
139 | * Don't pair with any destroy function. | |
48a8832b MD |
140 | */ |
141 | extern void __cds_lfs_init(struct __cds_lfs_stack *s); | |
142 | ||
7294103b MD |
143 | /* |
144 | * cds_lfs_empty: return whether lock-free stack is empty. | |
145 | * | |
146 | * No memory barrier is issued. No mutual exclusion is required. | |
147 | */ | |
48a8832b | 148 | extern bool cds_lfs_empty(cds_lfs_stack_ptr_t s); |
7294103b | 149 | |
d3bfcb24 MD |
150 | /* |
151 | * cds_lfs_push: push a node into the stack. | |
152 | * | |
153 | * Does not require any synchronization with other push nor pop. | |
154 | * | |
155 | * Returns 0 if the stack was empty prior to adding the node. | |
156 | * Returns non-zero otherwise. | |
157 | */ | |
48a8832b | 158 | extern bool cds_lfs_push(cds_lfs_stack_ptr_t s, |
d3bfcb24 MD |
159 | struct cds_lfs_node *node); |
160 | ||
161 | /* | |
7294103b MD |
162 | * cds_lfs_pop_blocking: pop a node from the stack. |
163 | * | |
164 | * Calls __cds_lfs_pop with an internal pop mutex held. | |
165 | */ | |
166 | extern struct cds_lfs_node *cds_lfs_pop_blocking(struct cds_lfs_stack *s); | |
167 | ||
168 | /* | |
169 | * cds_lfs_pop_all_blocking: pop all nodes from a stack. | |
170 | * | |
171 | * Calls __cds_lfs_pop_all with an internal pop mutex held. | |
172 | */ | |
173 | extern struct cds_lfs_head *cds_lfs_pop_all_blocking(struct cds_lfs_stack *s); | |
174 | ||
175 | /* | |
176 | * cds_lfs_pop_lock: lock stack pop-protection mutex. | |
177 | */ | |
178 | extern void cds_lfs_pop_lock(struct cds_lfs_stack *s); | |
179 | ||
180 | /* | |
181 | * cds_lfs_pop_unlock: unlock stack pop-protection mutex. | |
182 | */ | |
183 | extern void cds_lfs_pop_unlock(struct cds_lfs_stack *s); | |
184 | ||
185 | /* | |
186 | * __cds_lfs_pop: pop a node from the stack. | |
d3bfcb24 MD |
187 | * |
188 | * Returns NULL if stack is empty. | |
189 | * | |
7294103b | 190 | * __cds_lfs_pop needs to be synchronized using one of the following |
d3bfcb24 MD |
191 | * techniques: |
192 | * | |
f9b5c2b6 MD |
193 | * 1) Calling __cds_lfs_pop under rcu read lock critical section. |
194 | * Both __cds_lfs_pop and __cds_lfs_pop_all callers must wait for a | |
195 | * grace period to pass before freeing the returned node or pushing | |
196 | * the node back into the stack. It is valid to overwrite the content | |
197 | * of cds_lfs_node immediately after __cds_lfs_pop and | |
198 | * __cds_lfs_pop_all. | |
7294103b MD |
199 | * 2) Using mutual exclusion (e.g. mutexes) to protect __cds_lfs_pop |
200 | * and __cds_lfs_pop_all callers. | |
201 | * 3) Ensuring that only ONE thread can call __cds_lfs_pop() and | |
202 | * __cds_lfs_pop_all(). (multi-provider/single-consumer scheme). | |
d3bfcb24 | 203 | */ |
48a8832b | 204 | extern struct cds_lfs_node *__cds_lfs_pop(cds_lfs_stack_ptr_t s); |
7294103b MD |
205 | |
206 | /* | |
207 | * __cds_lfs_pop_all: pop all nodes from a stack. | |
208 | * | |
209 | * __cds_lfs_pop_all does not require any synchronization with other | |
210 | * push, nor with other __cds_lfs_pop_all, but requires synchronization | |
211 | * matching the technique used to synchronize __cds_lfs_pop: | |
212 | * | |
213 | * 1) If __cds_lfs_pop is called under rcu read lock critical section, | |
f9b5c2b6 MD |
214 | * both __cds_lfs_pop and __cds_lfs_pop_all callers must wait for a |
215 | * grace period to pass before freeing the returned node or pushing | |
216 | * the node back into the stack. It is valid to overwrite the content | |
217 | * of cds_lfs_node immediately after __cds_lfs_pop and | |
218 | * __cds_lfs_pop_all. No RCU read-side critical section is needed | |
219 | * around __cds_lfs_pop_all. | |
7294103b MD |
220 | * 2) Using mutual exclusion (e.g. mutexes) to protect __cds_lfs_pop and |
221 | * __cds_lfs_pop_all callers. | |
222 | * 3) Ensuring that only ONE thread can call __cds_lfs_pop() and | |
223 | * __cds_lfs_pop_all(). (multi-provider/single-consumer scheme). | |
224 | */ | |
48a8832b | 225 | extern struct cds_lfs_head *__cds_lfs_pop_all(cds_lfs_stack_ptr_t s); |
d3bfcb24 MD |
226 | |
227 | #endif /* !_LGPL_SOURCE */ | |
228 | ||
7294103b MD |
229 | /* |
230 | * cds_lfs_for_each: Iterate over all nodes returned by | |
231 | * __cds_lfs_pop_all. | |
232 | * @__head: node returned by __cds_lfs_pop_all (struct cds_lfs_head pointer). | |
233 | * @__node: node to use as iterator (struct cds_lfs_node pointer). | |
234 | * | |
235 | * Content written into each node before push is guaranteed to be | |
236 | * consistent, but no other memory ordering is ensured. | |
237 | */ | |
238 | #define cds_lfs_for_each(__head, __node) \ | |
239 | for (__node = &__head->node; \ | |
240 | __node != NULL; \ | |
241 | __node = __node->next) | |
242 | ||
243 | /* | |
244 | * cds_lfs_for_each_safe: Iterate over all nodes returned by | |
245 | * __cds_lfs_pop_all, safe against node deletion. | |
246 | * @__head: node returned by __cds_lfs_pop_all (struct cds_lfs_head pointer). | |
247 | * @__node: node to use as iterator (struct cds_lfs_node pointer). | |
248 | * @__n: struct cds_lfs_node pointer holding the next pointer (used | |
249 | * internally). | |
250 | * | |
251 | * Content written into each node before push is guaranteed to be | |
252 | * consistent, but no other memory ordering is ensured. | |
253 | */ | |
254 | #define cds_lfs_for_each_safe(__head, __node, __n) \ | |
255 | for (__node = &__head->node, __n = (__node ? __node->next : NULL); \ | |
256 | __node != NULL; \ | |
257 | __node = __n, __n = (__node ? __node->next : NULL)) | |
258 | ||
d3bfcb24 MD |
259 | #ifdef __cplusplus |
260 | } | |
261 | #endif | |
262 | ||
263 | #endif /* _URCU_LFSTACK_H */ |