948ac423f667b1810f1fccc3b77b40126a428ff1
[urcu.git] / urcu-pointer.h
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@polymtl.ca>
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_arch.h>
32
33 #ifdef _LGPL_SOURCE
34
35 #include <urcu-pointer-static.h>
36
37 /*
38 * rcu_dereference(ptr)
39 *
40 * Fetch a RCU-protected pointer. Typically used to copy the variable ptr to a
41 * local variable.
42 */
43 #define rcu_dereference _rcu_dereference
44
45 /*
46 * rcu_cmpxchg_pointer(type **ptr, type *new, type *old)
47 * type *rcu_xchg_pointer(type **ptr, type *new)
48 * type *rcu_set_pointer(type **ptr, type *new)
49 *
50 * RCU pointer updates.
51 * @ptr: address of the pointer to modify
52 * @new: new pointer value
53 * @old: old pointer value (expected)
54 *
55 * return: old pointer value
56 */
57 #define rcu_cmpxchg_pointer _rcu_cmpxchg_pointer
58 #define rcu_xchg_pointer _rcu_xchg_pointer
59 #define rcu_set_pointer _rcu_set_pointer
60
61 #else /* !_LGPL_SOURCE */
62
63 extern void *rcu_dereference_sym(void *p);
64 #define rcu_dereference(p) \
65 ({ \
66 typeof(p) _________p1 = \
67 rcu_dereference_sym((void *)(p)); \
68 (_________p1); \
69 })
70
71 extern void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new);
72 #define rcu_cmpxchg_pointer(p, old, _new) \
73 ({ \
74 typeof(*p) _________pold = (old); \
75 typeof(*p) _________pnew = (_new); \
76 typeof(*p) _________p1 = \
77 rcu_cmpxchg_pointer_sym((void **)(p), _________pold, \
78 _________pnew); \
79 (_________p1); \
80 })
81
82 extern void *rcu_xchg_pointer_sym(void **p, void *v);
83 #define rcu_xchg_pointer(p, v) \
84 ({ \
85 typeof(*p) _________pv = (v); \
86 typeof(*p) _________p1 = \
87 rcu_xchg_pointer_sym((void **)(p), _________pv); \
88 (_________p1); \
89 })
90
91 extern void *rcu_set_pointer_sym(void **p, void *v);
92 #define rcu_set_pointer(p, v) \
93 ({ \
94 typeof(*p) _________pv = (v); \
95 typeof(*p) _________p1 = \
96 rcu_set_pointer_sym((void **)(p), _________pv); \
97 })
98
99 #endif /* !_LGPL_SOURCE */
100
101 /*
102 * rcu_assign_pointer(type *ptr, type *new)
103 *
104 * Same as rcu_set_pointer, but takes the pointer to assign to rather than its
105 * address as first parameter. Provided for compatibility with the Linux kernel
106 * RCU semantic.
107 */
108 #define rcu_assign_pointer(p, v) rcu_set_pointer((&p), (v))
109
110 #endif /* _URCU_POINTER_H */
This page took 0.04175 seconds and 3 git commands to generate.