21c2a2e0c9bf299804c4d6a40aa31a13e41d5186
[urcu.git] / urcu-qsbr.h
1 #ifndef _URCU_QSBR_H
2 #define _URCU_QSBR_H
3
4 /*
5 * urcu-qsbr.h
6 *
7 * Userspace RCU QSBR header.
8 *
9 * LGPL-compatible code should include this header with :
10 *
11 * #define _LGPL_SOURCE
12 * #include <urcu.h>
13 *
14 * This library is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU Lesser General Public
16 * License as published by the Free Software Foundation; either
17 * version 2.1 of the License, or (at your option) any later version.
18 *
19 * This library is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 * Lesser General Public License for more details.
23 *
24 * You should have received a copy of the GNU Lesser General Public
25 * License along with this library; if not, write to the Free Software
26 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 *
28 * IBM's contributions to this file may be relicensed under LGPLv2 or later.
29 */
30
31 #include <stdlib.h>
32 #include <pthread.h>
33
34 /*
35 * See urcu-pointer.h and urcu-pointer-static.h for pointer publication headers.
36 */
37 #include <urcu-pointer.h>
38
39 /*
40 * Important !
41 *
42 * Each thread containing read-side critical sections must be registered
43 * with rcu_register_thread() before calling rcu_read_lock().
44 * rcu_unregister_thread() should be called before the thread exits.
45 */
46
47 #ifdef _LGPL_SOURCE
48
49 #include <urcu-qsbr-static.h>
50
51 /*
52 * Mappings for static use of the userspace RCU library.
53 * Should only be used in LGPL-compatible code.
54 */
55
56 /*
57 * rcu_read_lock()
58 * rcu_read_unlock()
59 *
60 * Mark the beginning and end of a read-side critical section.
61 * DON'T FORGET TO USE RCU_REGISTER/UNREGISTER_THREAD() FOR EACH THREAD WITH
62 * READ-SIDE CRITICAL SECTION.
63 */
64 #define rcu_read_lock() _rcu_read_lock()
65 #define rcu_read_unlock() _rcu_read_unlock()
66
67 #define rcu_quiescent_state() _rcu_quiescent_state()
68 #define rcu_thread_offline() _rcu_thread_offline()
69 #define rcu_thread_online() _rcu_thread_online()
70
71 #else /* !_LGPL_SOURCE */
72
73 /*
74 * library wrappers to be used by non-LGPL compatible source code.
75 */
76
77 /*
78 * QSBR read lock/unlock are guaranteed to be no-ops. Therefore, we expose them
79 * in the LGPL header for any code to use. However, the debug version is not
80 * nops and may contain sanity checks. To activate it, applications must be
81 * recompiled with -DURCU_DEBUG (even non-LGPL/GPL applications). This is the
82 * best trade-off between license/performance/code triviality and
83 * library debugging & tracing features we could come up with.
84 */
85
86 #if (!defined(BUILD_QSBR_LIB) && defined(URCU_DEBUG))
87
88 static inline void rcu_read_lock(void)
89 {
90 }
91
92 static inline void rcu_read_lock(void)
93 {
94 }
95
96 #else /* !URCU_DEBUG */
97
98 extern void rcu_read_lock(void);
99 extern void rcu_read_unlock(void);
100
101 #endif /* !URCU_DEBUG */
102
103 extern void rcu_quiescent_state(void);
104 extern void rcu_thread_offline(void);
105 extern void rcu_thread_online(void);
106
107 #endif /* !_LGPL_SOURCE */
108
109 extern void synchronize_rcu(void);
110
111 /*
112 * Reader thread registration.
113 */
114 extern void rcu_register_thread(void);
115 extern void rcu_unregister_thread(void);
116
117 #endif /* _URCU_QSBR_H */
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