add rcu_cmpxchg_pointer
[urcu.git] / urcu-qsbr.h
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1#ifndef _URCU_QSBR_H
2#define _URCU_QSBR_H
3
4/*
7ac06cef 5 * urcu-qsbr.h
420e5b92 6 *
7ac06cef 7 * Userspace RCU QSBR header.
420e5b92 8 *
7ac06cef 9 * LGPL-compatible code should include this header with :
420e5b92 10 *
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11 * #define _LGPL_SOURCE
12 * #include <urcu.h>
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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>
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33
34/*
7ac06cef 35 * Important !
420e5b92 36 *
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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.
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40 */
41
7ac06cef 42#ifdef _LGPL_SOURCE
420e5b92 43
7ac06cef 44#include <urcu-qsbr-static.h>
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45
46/*
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47 * Mappings for static use of the userspace RCU library.
48 * Should only be used in LGPL-compatible code.
420e5b92 49 */
420e5b92 50
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51#define rcu_dereference _rcu_dereference
52#define rcu_read_lock _rcu_read_lock
53#define rcu_read_unlock _rcu_read_unlock
fb6e510b 54
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55#define rcu_quiescent_state _rcu_quiescent_state
56#define rcu_thread_offline _rcu_thread_offline
57#define rcu_thread_online _rcu_thread_online
420e5b92 58
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59#define rcu_assign_pointer _rcu_assign_pointer
60#define rcu_xchg_pointer _rcu_xchg_pointer
61#define rcu_publish_content _rcu_publish_content
420e5b92 62
7ac06cef 63#else /* !_LGPL_SOURCE */
420e5b92 64
420e5b92 65/*
7ac06cef 66 * library wrappers to be used by non-LGPL compatible source code.
420e5b92 67 */
420e5b92 68
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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
80static inline void rcu_read_lock(void)
81{
82}
83
84static inline void rcu_read_lock(void)
85{
86}
87
88#else /* !URCU_DEBUG */
89
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90extern void rcu_read_lock(void);
91extern void rcu_read_unlock(void);
420e5b92 92
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93#endif /* !URCU_DEBUG */
94
7ac06cef 95extern void *rcu_dereference(void *p);
420e5b92 96
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97extern void rcu_quiescent_state(void);
98extern void rcu_thread_offline(void);
99extern void rcu_thread_online(void);
420e5b92 100
7ac06cef 101extern void *rcu_assign_pointer_sym(void **p, void *v);
420e5b92 102
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103#define rcu_assign_pointer(p, v) \
104 rcu_assign_pointer_sym((void **)(p), (v))
420e5b92 105
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106extern 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
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110extern void *rcu_xchg_pointer_sym(void **p, void *v);
111#define rcu_xchg_pointer(p, v) \
112 rcu_xchg_pointer_sym((void **)(p), (v))
420e5b92 113
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114extern void *rcu_publish_content_sym(void **p, void *v);
115#define rcu_publish_content(p, v) \
116 rcu_publish_content_sym((void **)(p), (v))
420e5b92 117
7ac06cef 118#endif /* !_LGPL_SOURCE */
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119
120extern void synchronize_rcu(void);
121
122/*
123 * Reader thread registration.
124 */
125extern void rcu_register_thread(void);
126extern void rcu_unregister_thread(void);
127
128#endif /* _URCU_QSBR_H */
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