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d3d3857f MJ |
1 | // SPDX-FileCopyrightText: 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
2 | // | |
3 | // SPDX-License-Identifier: LGPL-2.1-or-later | |
4 | ||
d3bfcb24 MD |
5 | #ifndef _URCU_LFSTACK_H |
6 | #define _URCU_LFSTACK_H | |
7 | ||
8 | /* | |
d3bfcb24 | 9 | * Userspace RCU library - Lock-Free Stack |
d3bfcb24 MD |
10 | */ |
11 | ||
12 | #ifdef __cplusplus | |
13 | extern "C" { | |
14 | #endif | |
15 | ||
7294103b MD |
16 | #include <stdbool.h> |
17 | #include <pthread.h> | |
18 | ||
19 | /* | |
20 | * Lock-free stack. | |
21 | * | |
22 | * Stack implementing push, pop, pop_all operations, as well as iterator | |
23 | * on the stack head returned by pop_all. | |
24 | * | |
25 | * Synchronization table: | |
26 | * | |
27 | * External synchronization techniques described in the API below is | |
28 | * required between pairs marked with "X". No external synchronization | |
29 | * required between pairs marked with "-". | |
30 | * | |
31 | * cds_lfs_push __cds_lfs_pop __cds_lfs_pop_all | |
32 | * cds_lfs_push - - - | |
33 | * __cds_lfs_pop - X X | |
34 | * __cds_lfs_pop_all - X - | |
35 | * | |
36 | * cds_lfs_pop_blocking and cds_lfs_pop_all_blocking use an internal | |
37 | * mutex to provide synchronization. | |
38 | */ | |
39 | ||
40 | /* | |
41 | * struct cds_lfs_node is returned by cds_lfs_pop, and also used as | |
42 | * iterator on stack. It is not safe to dereference the node next | |
43 | * pointer when returned by cds_lfs_pop. | |
44 | */ | |
d3bfcb24 MD |
45 | struct cds_lfs_node { |
46 | struct cds_lfs_node *next; | |
47 | }; | |
48 | ||
7294103b MD |
49 | /* |
50 | * struct cds_lfs_head is returned by __cds_lfs_pop_all, and can be used | |
51 | * to begin iteration on the stack. "node" needs to be the first field | |
52 | * of cds_lfs_head, so the end-of-stack pointer value can be used for | |
53 | * both types. | |
54 | */ | |
55 | struct cds_lfs_head { | |
56 | struct cds_lfs_node node; | |
57 | }; | |
58 | ||
48a8832b MD |
59 | struct __cds_lfs_stack { |
60 | struct cds_lfs_head *head; | |
61 | }; | |
62 | ||
d3bfcb24 | 63 | struct cds_lfs_stack { |
7294103b MD |
64 | struct cds_lfs_head *head; |
65 | pthread_mutex_t lock; | |
d3bfcb24 MD |
66 | }; |
67 | ||
48a8832b | 68 | /* |
e9349020 MD |
69 | * In C, the transparent union allows calling functions that work on |
70 | * both struct cds_lfs_stack and struct __cds_lfs_stack on any of those | |
71 | * two types. | |
28757437 | 72 | * |
e9349020 MD |
73 | * In C++, implement static inline wrappers using function overloading |
74 | * to obtain an API similar to C. | |
087bce43 MD |
75 | * |
76 | * Avoid complaints from clang++ not knowing the transparent union | |
77 | * attribute. | |
48a8832b | 78 | */ |
087bce43 MD |
79 | #if defined(__clang__) |
80 | #pragma clang diagnostic push | |
81 | #pragma clang diagnostic ignored "-Wignored-attributes" | |
82 | #endif | |
5135c0fd | 83 | typedef union { |
48a8832b MD |
84 | struct __cds_lfs_stack *_s; |
85 | struct cds_lfs_stack *s; | |
087bce43 MD |
86 | } __attribute__((__transparent_union__)) cds_lfs_stack_ptr_t; |
87 | #if defined(__clang__) | |
88 | #pragma clang diagnostic pop | |
89 | #endif | |
48a8832b | 90 | |
d3bfcb24 MD |
91 | #ifdef _LGPL_SOURCE |
92 | ||
93 | #include <urcu/static/lfstack.h> | |
94 | ||
95 | #define cds_lfs_node_init _cds_lfs_node_init | |
96 | #define cds_lfs_init _cds_lfs_init | |
200d100e | 97 | #define cds_lfs_destroy _cds_lfs_destroy |
817a0178 | 98 | #define __cds_lfs_init ___cds_lfs_init |
7294103b | 99 | #define cds_lfs_empty _cds_lfs_empty |
d3bfcb24 | 100 | #define cds_lfs_push _cds_lfs_push |
7294103b MD |
101 | |
102 | /* Locking performed internally */ | |
103 | #define cds_lfs_pop_blocking _cds_lfs_pop_blocking | |
104 | #define cds_lfs_pop_all_blocking _cds_lfs_pop_all_blocking | |
105 | ||
106 | /* Synchronize pop with internal mutex */ | |
107 | #define cds_lfs_pop_lock _cds_lfs_pop_lock | |
108 | #define cds_lfs_pop_unlock _cds_lfs_pop_unlock | |
109 | ||
110 | /* Synchronization ensured by the caller. See synchronization table. */ | |
111 | #define __cds_lfs_pop ___cds_lfs_pop | |
112 | #define __cds_lfs_pop_all ___cds_lfs_pop_all | |
d3bfcb24 MD |
113 | |
114 | #else /* !_LGPL_SOURCE */ | |
115 | ||
7294103b MD |
116 | /* |
117 | * cds_lfs_node_init: initialize lock-free stack node. | |
118 | */ | |
d3bfcb24 | 119 | extern void cds_lfs_node_init(struct cds_lfs_node *node); |
7294103b MD |
120 | |
121 | /* | |
200d100e MD |
122 | * cds_lfs_init: initialize lock-free stack (with locking). Pair with |
123 | * cds_lfs_destroy(). | |
7294103b | 124 | */ |
d3bfcb24 MD |
125 | extern void cds_lfs_init(struct cds_lfs_stack *s); |
126 | ||
48a8832b | 127 | /* |
200d100e MD |
128 | * cds_lfs_destroy: destroy lock-free stack (with lock). Pair with |
129 | * cds_lfs_init(). | |
130 | */ | |
131 | extern void cds_lfs_destroy(struct cds_lfs_stack *s); | |
132 | ||
133 | /* | |
134 | * __cds_lfs_init: initialize lock-free stack (without lock). | |
135 | * Don't pair with any destroy function. | |
48a8832b MD |
136 | */ |
137 | extern void __cds_lfs_init(struct __cds_lfs_stack *s); | |
138 | ||
7294103b MD |
139 | /* |
140 | * cds_lfs_empty: return whether lock-free stack is empty. | |
141 | * | |
142 | * No memory barrier is issued. No mutual exclusion is required. | |
143 | */ | |
48a8832b | 144 | extern bool cds_lfs_empty(cds_lfs_stack_ptr_t s); |
7294103b | 145 | |
d3bfcb24 MD |
146 | /* |
147 | * cds_lfs_push: push a node into the stack. | |
148 | * | |
149 | * Does not require any synchronization with other push nor pop. | |
150 | * | |
151 | * Returns 0 if the stack was empty prior to adding the node. | |
152 | * Returns non-zero otherwise. | |
153 | */ | |
48a8832b | 154 | extern bool cds_lfs_push(cds_lfs_stack_ptr_t s, |
d3bfcb24 MD |
155 | struct cds_lfs_node *node); |
156 | ||
157 | /* | |
7294103b MD |
158 | * cds_lfs_pop_blocking: pop a node from the stack. |
159 | * | |
160 | * Calls __cds_lfs_pop with an internal pop mutex held. | |
161 | */ | |
162 | extern struct cds_lfs_node *cds_lfs_pop_blocking(struct cds_lfs_stack *s); | |
163 | ||
164 | /* | |
165 | * cds_lfs_pop_all_blocking: pop all nodes from a stack. | |
166 | * | |
167 | * Calls __cds_lfs_pop_all with an internal pop mutex held. | |
168 | */ | |
169 | extern struct cds_lfs_head *cds_lfs_pop_all_blocking(struct cds_lfs_stack *s); | |
170 | ||
171 | /* | |
172 | * cds_lfs_pop_lock: lock stack pop-protection mutex. | |
173 | */ | |
174 | extern void cds_lfs_pop_lock(struct cds_lfs_stack *s); | |
175 | ||
176 | /* | |
177 | * cds_lfs_pop_unlock: unlock stack pop-protection mutex. | |
178 | */ | |
179 | extern void cds_lfs_pop_unlock(struct cds_lfs_stack *s); | |
180 | ||
181 | /* | |
182 | * __cds_lfs_pop: pop a node from the stack. | |
d3bfcb24 MD |
183 | * |
184 | * Returns NULL if stack is empty. | |
185 | * | |
7294103b | 186 | * __cds_lfs_pop needs to be synchronized using one of the following |
d3bfcb24 MD |
187 | * techniques: |
188 | * | |
f9b5c2b6 MD |
189 | * 1) Calling __cds_lfs_pop under rcu read lock critical section. |
190 | * Both __cds_lfs_pop and __cds_lfs_pop_all callers must wait for a | |
191 | * grace period to pass before freeing the returned node or pushing | |
192 | * the node back into the stack. It is valid to overwrite the content | |
193 | * of cds_lfs_node immediately after __cds_lfs_pop and | |
194 | * __cds_lfs_pop_all. | |
7294103b MD |
195 | * 2) Using mutual exclusion (e.g. mutexes) to protect __cds_lfs_pop |
196 | * and __cds_lfs_pop_all callers. | |
197 | * 3) Ensuring that only ONE thread can call __cds_lfs_pop() and | |
198 | * __cds_lfs_pop_all(). (multi-provider/single-consumer scheme). | |
d3bfcb24 | 199 | */ |
48a8832b | 200 | extern struct cds_lfs_node *__cds_lfs_pop(cds_lfs_stack_ptr_t s); |
7294103b MD |
201 | |
202 | /* | |
203 | * __cds_lfs_pop_all: pop all nodes from a stack. | |
204 | * | |
205 | * __cds_lfs_pop_all does not require any synchronization with other | |
206 | * push, nor with other __cds_lfs_pop_all, but requires synchronization | |
207 | * matching the technique used to synchronize __cds_lfs_pop: | |
208 | * | |
209 | * 1) If __cds_lfs_pop is called under rcu read lock critical section, | |
f9b5c2b6 MD |
210 | * both __cds_lfs_pop and __cds_lfs_pop_all callers must wait for a |
211 | * grace period to pass before freeing the returned node or pushing | |
212 | * the node back into the stack. It is valid to overwrite the content | |
213 | * of cds_lfs_node immediately after __cds_lfs_pop and | |
214 | * __cds_lfs_pop_all. No RCU read-side critical section is needed | |
215 | * around __cds_lfs_pop_all. | |
7294103b MD |
216 | * 2) Using mutual exclusion (e.g. mutexes) to protect __cds_lfs_pop and |
217 | * __cds_lfs_pop_all callers. | |
218 | * 3) Ensuring that only ONE thread can call __cds_lfs_pop() and | |
219 | * __cds_lfs_pop_all(). (multi-provider/single-consumer scheme). | |
220 | */ | |
48a8832b | 221 | extern struct cds_lfs_head *__cds_lfs_pop_all(cds_lfs_stack_ptr_t s); |
d3bfcb24 MD |
222 | |
223 | #endif /* !_LGPL_SOURCE */ | |
224 | ||
7294103b MD |
225 | /* |
226 | * cds_lfs_for_each: Iterate over all nodes returned by | |
227 | * __cds_lfs_pop_all. | |
228 | * @__head: node returned by __cds_lfs_pop_all (struct cds_lfs_head pointer). | |
229 | * @__node: node to use as iterator (struct cds_lfs_node pointer). | |
230 | * | |
231 | * Content written into each node before push is guaranteed to be | |
232 | * consistent, but no other memory ordering is ensured. | |
233 | */ | |
234 | #define cds_lfs_for_each(__head, __node) \ | |
235 | for (__node = &__head->node; \ | |
236 | __node != NULL; \ | |
237 | __node = __node->next) | |
238 | ||
239 | /* | |
240 | * cds_lfs_for_each_safe: Iterate over all nodes returned by | |
241 | * __cds_lfs_pop_all, safe against node deletion. | |
242 | * @__head: node returned by __cds_lfs_pop_all (struct cds_lfs_head pointer). | |
243 | * @__node: node to use as iterator (struct cds_lfs_node pointer). | |
244 | * @__n: struct cds_lfs_node pointer holding the next pointer (used | |
245 | * internally). | |
246 | * | |
247 | * Content written into each node before push is guaranteed to be | |
248 | * consistent, but no other memory ordering is ensured. | |
249 | */ | |
250 | #define cds_lfs_for_each_safe(__head, __node, __n) \ | |
251 | for (__node = &__head->node, __n = (__node ? __node->next : NULL); \ | |
252 | __node != NULL; \ | |
253 | __node = __n, __n = (__node ? __node->next : NULL)) | |
254 | ||
d3bfcb24 MD |
255 | #ifdef __cplusplus |
256 | } | |
e9349020 MD |
257 | |
258 | /* | |
259 | * In C++, implement static inline wrappers using function overloading | |
260 | * to obtain an API similar to C. | |
261 | */ | |
262 | ||
3a602ac1 | 263 | static inline cds_lfs_stack_ptr_t cds_lfs_stack_cast(struct __cds_lfs_stack *s) |
e9349020 MD |
264 | { |
265 | cds_lfs_stack_ptr_t ret = { | |
266 | ._s = s, | |
267 | }; | |
268 | return ret; | |
269 | } | |
270 | ||
271 | static inline cds_lfs_stack_ptr_t cds_lfs_stack_cast(struct cds_lfs_stack *s) | |
272 | { | |
273 | cds_lfs_stack_ptr_t ret = { | |
274 | .s = s, | |
275 | }; | |
276 | return ret; | |
277 | } | |
278 | ||
9298902c | 279 | template<typename T> static inline bool cds_lfs_empty(T s) |
e9349020 | 280 | { |
3a602ac1 | 281 | return cds_lfs_empty(cds_lfs_stack_cast(s)); |
e9349020 MD |
282 | } |
283 | ||
9298902c | 284 | template<typename T> static inline bool cds_lfs_push(T s, |
e9349020 MD |
285 | struct cds_lfs_node *node) |
286 | { | |
287 | return cds_lfs_push(cds_lfs_stack_cast(s), node); | |
288 | } | |
289 | ||
9298902c | 290 | template<typename T> static inline struct cds_lfs_node *__cds_lfs_pop(T s) |
e9349020 | 291 | { |
3a602ac1 | 292 | return __cds_lfs_pop(cds_lfs_stack_cast(s)); |
e9349020 MD |
293 | } |
294 | ||
9298902c | 295 | template<typename T> static inline struct cds_lfs_head *__cds_lfs_pop_all(T s) |
e9349020 MD |
296 | { |
297 | return __cds_lfs_pop_all(cds_lfs_stack_cast(s)); | |
298 | } | |
299 | ||
300 | #endif /* __cplusplus */ | |
d3bfcb24 MD |
301 | |
302 | #endif /* _URCU_LFSTACK_H */ |