| 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 |
| 34 | extern "C" { |
| 35 | #endif |
| 36 | |
| 37 | #if defined(_LGPL_SOURCE) || defined(URCU_INLINE_SMALL_FUNCTIONS) |
| 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 | * type *rcu_cmpxchg_pointer(type **ptr, type *new, type *old) |
| 51 | * type *rcu_xchg_pointer(type **ptr, type *new) |
| 52 | * void 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 /* !(defined(_LGPL_SOURCE) || defined(URCU_INLINE_SMALL_FUNCTIONS)) */ |
| 66 | |
| 67 | extern void *rcu_dereference_sym(void *p); |
| 68 | #define rcu_dereference(p) \ |
| 69 | __extension__ \ |
| 70 | ({ \ |
| 71 | __typeof__(p) _________p1 = URCU_FORCE_CAST(__typeof__(p), \ |
| 72 | rcu_dereference_sym(URCU_FORCE_CAST(void *, p))); \ |
| 73 | (_________p1); \ |
| 74 | }) |
| 75 | |
| 76 | extern void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new); |
| 77 | #define 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 | rcu_cmpxchg_pointer_sym(URCU_FORCE_CAST(void **, p), \ |
| 84 | _________pold, \ |
| 85 | _________pnew)); \ |
| 86 | (_________p1); \ |
| 87 | }) |
| 88 | |
| 89 | extern void *rcu_xchg_pointer_sym(void **p, void *v); |
| 90 | #define rcu_xchg_pointer(p, v) \ |
| 91 | __extension__ \ |
| 92 | ({ \ |
| 93 | __typeof__(*(p)) _________pv = (v); \ |
| 94 | __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \ |
| 95 | rcu_xchg_pointer_sym(URCU_FORCE_CAST(void **, p), \ |
| 96 | _________pv)); \ |
| 97 | (_________p1); \ |
| 98 | }) |
| 99 | |
| 100 | /* |
| 101 | * Note: rcu_set_pointer_sym returns @v because we don't want to break |
| 102 | * the ABI. At the API level, 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 *rcu_set_pointer_sym(void **p, void *v); |
| 107 | #define rcu_set_pointer(p, v) \ |
| 108 | do { \ |
| 109 | __typeof__(*(p)) _________pv = (v); \ |
| 110 | (void) rcu_set_pointer_sym(URCU_FORCE_CAST(void **, p), \ |
| 111 | _________pv); \ |
| 112 | } while (0) |
| 113 | |
| 114 | #endif /* !(defined(_LGPL_SOURCE) || defined(URCU_INLINE_SMALL_FUNCTIONS)) */ |
| 115 | |
| 116 | /* |
| 117 | * void rcu_assign_pointer(type *ptr, type *new) |
| 118 | * |
| 119 | * Same as 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 rcu_assign_pointer(p, v) rcu_set_pointer((&p), (v)) |
| 124 | |
| 125 | #ifdef __cplusplus |
| 126 | } |
| 127 | #endif |
| 128 | |
| 129 | #endif /* _URCU_POINTER_H */ |