rculfhash: number of logically removed nodes should not appear in API
[urcu.git] / urcu-pointer.h
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1#ifndef _URCU_POINTER_H
2#define _URCU_POINTER_H
3
4/*
5 * urcu-pointer.h
6 *
7 * Userspace RCU header. Operations on pointers.
8 *
9 * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
11 *
12 * This library is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU Lesser General Public
14 * License as published by the Free Software Foundation; either
15 * version 2.1 of the License, or (at your option) any later version.
16 *
17 * This library is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * Lesser General Public License for more details.
21 *
22 * You should have received a copy of the GNU Lesser General Public
23 * License along with this library; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 *
26 * IBM's contributions to this file may be relicensed under LGPLv2 or later.
27 */
28
29#include <urcu/compiler.h>
30#include <urcu/arch.h>
31#include <urcu/uatomic.h>
32
33#ifdef __cplusplus
34extern "C" {
35#endif
36
37#ifdef _LGPL_SOURCE
38
39#include <urcu/static/urcu-pointer.h>
40
41/*
42 * rcu_dereference(ptr)
43 *
44 * Fetch a RCU-protected pointer. Typically used to copy the variable ptr to a
45 * local variable.
46 */
47#define rcu_dereference _rcu_dereference
48
49/*
50 * rcu_cmpxchg_pointer(type **ptr, type *new, type *old)
51 * type *rcu_xchg_pointer(type **ptr, type *new)
52 * type *rcu_set_pointer(type **ptr, type *new)
53 *
54 * RCU pointer updates.
55 * @ptr: address of the pointer to modify
56 * @new: new pointer value
57 * @old: old pointer value (expected)
58 *
59 * return: old pointer value
60 */
61#define rcu_cmpxchg_pointer _rcu_cmpxchg_pointer
62#define rcu_xchg_pointer _rcu_xchg_pointer
63#define rcu_set_pointer _rcu_set_pointer
64
65#else /* !_LGPL_SOURCE */
66
67extern void *rcu_dereference_sym(void *p);
68#define rcu_dereference(p) \
69 ({ \
70 typeof(p) _________p1 = URCU_FORCE_CAST(typeof(p), \
71 rcu_dereference_sym(URCU_FORCE_CAST(void *, p))); \
72 (_________p1); \
73 })
74
75extern void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new);
76#define rcu_cmpxchg_pointer(p, old, _new) \
77 ({ \
78 typeof(*(p)) _________pold = (old); \
79 typeof(*(p)) _________pnew = (_new); \
80 typeof(*(p)) _________p1 = URCU_FORCE_CAST(typeof(*(p)), \
81 rcu_cmpxchg_pointer_sym(URCU_FORCE_CAST(void **, p),\
82 _________pold, \
83 _________pnew)); \
84 (_________p1); \
85 })
86
87extern void *rcu_xchg_pointer_sym(void **p, void *v);
88#define rcu_xchg_pointer(p, v) \
89 ({ \
90 typeof(*(p)) _________pv = (v); \
91 typeof(*(p)) _________p1 = URCU_FORCE_CAST(typeof(*(p)), \
92 rcu_xchg_pointer_sym(URCU_FORCE_CAST(void **, p), \
93 _________pv)); \
94 (_________p1); \
95 })
96
97extern void *rcu_set_pointer_sym(void **p, void *v);
98#define rcu_set_pointer(p, v) \
99 ({ \
100 typeof(*(p)) _________pv = (v); \
101 typeof(*(p)) _________p1 = URCU_FORCE_CAST(typeof(*(p)), \
102 rcu_set_pointer_sym(URCU_FORCE_CAST(void **, p), \
103 _________pv)); \
104 (_________p1); \
105 })
106
107#endif /* !_LGPL_SOURCE */
108
109/*
110 * rcu_assign_pointer(type *ptr, type *new)
111 *
112 * Same as rcu_set_pointer, but takes the pointer to assign to rather than its
113 * address as first parameter. Provided for compatibility with the Linux kernel
114 * RCU semantic.
115 */
116#define rcu_assign_pointer(p, v) rcu_set_pointer((&p), (v))
117
118#ifdef __cplusplus
119}
120#endif
121
122#endif /* _URCU_POINTER_H */
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