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1 | #ifndef _LTTNG_UST_URCU_POINTER_H |
2 | #define _LTTNG_UST_URCU_POINTER_H | |
3 | ||
4 | /* | |
5 | * lttng/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 | |
34 | extern "C" { | |
35 | #endif | |
36 | ||
37 | #if defined(_LGPL_SOURCE) || defined(LTTNG_UST_URCU_INLINE_SMALL_FUNCTIONS) | |
38 | ||
39 | #include <lttng/urcu/static/pointer.h> | |
40 | ||
41 | /* | |
42 | * lttng_ust_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 lttng_ust_rcu_dereference _lttng_ust_rcu_dereference | |
48 | ||
49 | /* | |
50 | * type *lttng_ust_rcu_cmpxchg_pointer(type **ptr, type *new, type *old) | |
51 | * type *lttng_ust_rcu_xchg_pointer(type **ptr, type *new) | |
52 | * void lttng_ust_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 lttng_ust_rcu_cmpxchg_pointer _lttng_ust_rcu_cmpxchg_pointer | |
62 | #define lttng_ust_rcu_xchg_pointer _lttng_ust_rcu_xchg_pointer | |
63 | #define lttng_ust_rcu_set_pointer _lttng_ust_rcu_set_pointer | |
64 | ||
65 | #else /* !(defined(_LGPL_SOURCE) || defined(LTTNG_UST_URCU_INLINE_SMALL_FUNCTIONS)) */ | |
66 | ||
67 | extern void *lttng_ust_rcu_dereference_sym(void *p); | |
68 | #define lttng_ust_rcu_dereference(p) \ | |
69 | __extension__ \ | |
70 | ({ \ | |
71 | __typeof__(p) _________p1 = URCU_FORCE_CAST(__typeof__(p), \ | |
72 | lttng_ust_rcu_dereference_sym(URCU_FORCE_CAST(void *, p))); \ | |
73 | (_________p1); \ | |
74 | }) | |
75 | ||
76 | extern void *lttng_ust_rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new); | |
77 | #define lttng_ust_rcu_cmpxchg_pointer(p, old, _new) \ | |
78 | __extension__ \ | |
79 | ({ \ | |
80 | __typeof__(*(p)) _________pold = (old); \ | |
81 | __typeof__(*(p)) _________pnew = (_new); \ | |
82 | __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \ | |
83 | lttng_ust_rcu_cmpxchg_pointer_sym(URCU_FORCE_CAST(void **, p), \ | |
84 | _________pold, \ | |
85 | _________pnew)); \ | |
86 | (_________p1); \ | |
87 | }) | |
88 | ||
89 | extern void *lttng_ust_rcu_xchg_pointer_sym(void **p, void *v); | |
90 | #define lttng_ust_rcu_xchg_pointer(p, v) \ | |
91 | __extension__ \ | |
92 | ({ \ | |
93 | __typeof__(*(p)) _________pv = (v); \ | |
94 | __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \ | |
95 | lttng_ust_rcu_xchg_pointer_sym(URCU_FORCE_CAST(void **, p), \ | |
96 | _________pv)); \ | |
97 | (_________p1); \ | |
98 | }) | |
99 | ||
100 | /* | |
101 | * Note: lttng_ust_rcu_set_pointer_sym returns @v because we don't want to break | |
102 | * the ABI. At the API level, lttng_ust_rcu_set_pointer() now returns void. Use of | |
103 | * the return value is therefore deprecated, and will cause a build | |
104 | * error. | |
105 | */ | |
106 | extern void *lttng_ust_rcu_set_pointer_sym(void **p, void *v); | |
107 | #define lttng_ust_rcu_set_pointer(p, v) \ | |
108 | do { \ | |
109 | __typeof__(*(p)) _________pv = (v); \ | |
110 | (void) lttng_ust_rcu_set_pointer_sym(URCU_FORCE_CAST(void **, p), \ | |
111 | _________pv); \ | |
112 | } while (0) | |
113 | ||
114 | #endif /* !(defined(_LGPL_SOURCE) || defined(LTTNG_UST_URCU_INLINE_SMALL_FUNCTIONS)) */ | |
115 | ||
116 | /* | |
117 | * void lttng_ust_rcu_assign_pointer(type *ptr, type *new) | |
118 | * | |
119 | * Same as lttng_ust_rcu_set_pointer, but takes the pointer to assign to rather than its | |
120 | * address as first parameter. Provided for compatibility with the Linux kernel | |
121 | * RCU semantic. | |
122 | */ | |
123 | #define lttng_ust_rcu_assign_pointer(p, v) lttng_ust_rcu_set_pointer((&p), (v)) | |
124 | ||
125 | #ifdef __cplusplus | |
126 | } | |
127 | #endif | |
128 | ||
129 | #endif /* _LTTNG_UST_URCU_POINTER_H */ |