346f906202aa60edc8f5c77628e18af5f130361a
[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 * Important !
36 *
37 * Each thread containing read-side critical sections must be registered
38 * with rcu_register_thread() before calling rcu_read_lock().
39 * rcu_unregister_thread() should be called before the thread exits.
40 */
41
42 #ifdef _LGPL_SOURCE
43
44 #include <urcu-qsbr-static.h>
45
46 /*
47 * Mappings for static use of the userspace RCU library.
48 * Should only be used in LGPL-compatible code.
49 */
50
51 #define rcu_dereference _rcu_dereference
52 #define rcu_read_lock _rcu_read_lock
53 #define rcu_read_unlock _rcu_read_unlock
54
55 #define rcu_quiescent_state _rcu_quiescent_state
56 #define rcu_thread_offline _rcu_thread_offline
57 #define rcu_thread_online _rcu_thread_online
58
59 #define rcu_assign_pointer _rcu_assign_pointer
60 #define rcu_xchg_pointer _rcu_xchg_pointer
61 #define rcu_publish_content _rcu_publish_content
62
63 #else /* !_LGPL_SOURCE */
64
65 /*
66 * library wrappers to be used by non-LGPL compatible source code.
67 */
68
69 /*
70 * QSBR read lock/unlock are guaranteed to be no-ops. Therefore, we expose them
71 * in the LGPL header for any code to use. However, the debug version is not
72 * nops and may contain sanity checks. To activate it, applications must be
73 * recompiled with -DURCU_DEBUG (even non-LGPL/GPL applications). This is the
74 * best trade-off between license/performance/code triviality and
75 * library debugging & tracing features we could come up with.
76 */
77
78 #if (!defined(BUILD_QSBR_LIB) && defined(URCU_DEBUG))
79
80 static inline void rcu_read_lock(void)
81 {
82 }
83
84 static inline void rcu_read_lock(void)
85 {
86 }
87
88 #else /* !URCU_DEBUG */
89
90 extern void rcu_read_lock(void);
91 extern void rcu_read_unlock(void);
92
93 #endif /* !URCU_DEBUG */
94
95 extern void *rcu_dereference(void *p);
96
97 extern void rcu_quiescent_state(void);
98 extern void rcu_thread_offline(void);
99 extern void rcu_thread_online(void);
100
101 extern void *rcu_assign_pointer_sym(void **p, void *v);
102
103 #define rcu_assign_pointer(p, v) \
104 rcu_assign_pointer_sym((void **)(p), (v))
105
106 extern void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new);
107 #define rcu_cmpxchg_pointer(p, old, _new) \
108 rcu_cmpxchg_pointer_sym((void **)(p), (old), (_new))
109
110 extern void *rcu_xchg_pointer_sym(void **p, void *v);
111 #define rcu_xchg_pointer(p, v) \
112 rcu_xchg_pointer_sym((void **)(p), (v))
113
114 extern void *rcu_publish_content_sym(void **p, void *v);
115 #define rcu_publish_content(p, v) \
116 rcu_publish_content_sym((void **)(p), (v))
117
118 #endif /* !_LGPL_SOURCE */
119
120 extern void synchronize_rcu(void);
121
122 /*
123 * Reader thread registration.
124 */
125 extern void rcu_register_thread(void);
126 extern void rcu_unregister_thread(void);
127
128 #endif /* _URCU_QSBR_H */
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