urcu-bp.h

   1 #ifndef _URCU_BP_H
   2 #define _URCU_BP_H
   3
   4 /*
   5  * urcu-bp.h
   6  *
   7  * Userspace RCU header, "bulletproof" version.
   8  *
   9  * Slower RCU read-side adapted for tracing library. Does not require thread
  10  * registration nor unregistration. Also signal-safe.
  11  *
  12  * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  13  * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
  14  *
  15  * LGPL-compatible code should include this header with :
  16  *
  17  * #define _LGPL_SOURCE
  18  * #include <urcu.h>
  19  *
  20  * This library is free software; you can redistribute it and/or
  21  * modify it under the terms of the GNU Lesser General Public
  22  * License as published by the Free Software Foundation; either
  23  * version 2.1 of the License, or (at your option) any later version.
  24  *
  25  * This library is distributed in the hope that it will be useful,
  26  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  28  * Lesser General Public License for more details.
  29  *
  30  * You should have received a copy of the GNU Lesser General Public
  31  * License along with this library; if not, write to the Free Software
  32  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  33  *
  34  * IBM's contributions to this file may be relicensed under LGPLv2 or later.
  35  */
  36
  37 #include <stdlib.h>
  38 #include <pthread.h>
  39
  40 #ifdef __cplusplus
  41 extern "C" {
  42 #endif
  43
  44 #include <urcu/map/urcu-bp.h>
  45
  46 /*
  47  * Important !
  48  *
  49  * Each thread containing read-side critical sections must be registered
  50  * with rcu_register_thread() before calling rcu_read_lock().
  51  * rcu_unregister_thread() should be called before the thread exits.
  52  */
  53
  54 /*
  55  * See urcu-pointer.h and urcu/static/urcu-pointer.h for pointer
  56  * publication headers.
  57  */
  58 #include <urcu-pointer.h>
  59
  60 #ifdef _LGPL_SOURCE
  61
  62 #include <urcu/static/urcu-bp.h>
  63
  64 /*
  65  * Mappings for static use of the userspace RCU library.
  66  * Should only be used in LGPL-compatible code.
  67  */
  68
  69 /*
  70  * rcu_read_lock()
  71  * rcu_read_unlock()
  72  *
  73  * Mark the beginning and end of a read-side critical section.
  74  */
  75 #define rcu_read_lock_bp                _rcu_read_lock
  76 #define rcu_read_unlock_bp              _rcu_read_unlock
  77 #define rcu_read_ongoing_bp             _rcu_read_ongoing
  78
  79 #define rcu_dereference_bp              rcu_dereference
  80 #define rcu_cmpxchg_pointer_bp          rcu_cmpxchg_pointer
  81 #define rcu_xchg_pointer_bp             rcu_xchg_pointer
  82 #define rcu_set_pointer_bp              rcu_set_pointer
  83
  84 #else /* !_LGPL_SOURCE */
  85
  86 /*
  87  * library wrappers to be used by non-LGPL compatible source code.
  88  * See LGPL-only urcu/static/urcu-pointer.h for documentation.
  89  */
  90
  91 extern void rcu_read_lock(void);
  92 extern void rcu_read_unlock(void);
  93 extern int rcu_read_ongoing(void);
  94
  95 extern void *rcu_dereference_sym_bp(void *p);
  96 #define rcu_dereference_bp(p)                                                \
  97         __extension__                                                        \
  98         ({                                                                   \
  99                 __typeof__(p) _________p1 = URCU_FORCE_CAST(__typeof__(p),   \
 100                         rcu_dereference_sym_bp(URCU_FORCE_CAST(void *, p))); \
 101                 (_________p1);                                               \
 102         })
 103
 104 extern void *rcu_cmpxchg_pointer_sym_bp(void **p, void *old, void *_new);
 105 #define rcu_cmpxchg_pointer_bp(p, old, _new)                                 \
 106         __extension__                                                        \
 107         ({                                                                   \
 108                 __typeof__(*(p)) _________pold = (old);                      \
 109                 __typeof__(*(p)) _________pnew = (_new);                     \
 110                 __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \
 111                         rcu_cmpxchg_pointer_sym_bp(URCU_FORCE_CAST(void **, p), \
 112                                                 _________pold,               \
 113                                                 _________pnew));             \
 114                 (_________p1);                                               \
 115         })
 116
 117 extern void *rcu_xchg_pointer_sym_bp(void **p, void *v);
 118 #define rcu_xchg_pointer_bp(p, v)                                            \
 119         __extension__                                                        \
 120         ({                                                                   \
 121                 __typeof__(*(p)) _________pv = (v);                          \
 122                 __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)),\
 123                         rcu_xchg_pointer_sym_bp(URCU_FORCE_CAST(void **, p), \
 124                                              _________pv));                  \
 125                 (_________p1);                                               \
 126         })
 127
 128 extern void *rcu_set_pointer_sym_bp(void **p, void *v);
 129 #define rcu_set_pointer_bp(p, v)                                             \
 130         __extension__                                                        \
 131         ({                                                                   \
 132                 __typeof__(*(p)) _________pv = (v);                          \
 133                 __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \
 134                         rcu_set_pointer_sym_bp(URCU_FORCE_CAST(void **, p),  \
 135                                             _________pv));                   \
 136                 (_________p1);                                               \
 137         })
 138
 139 #endif /* !_LGPL_SOURCE */
 140
 141 extern void synchronize_rcu(void);
 142
 143 /*
 144  * rcu_bp_before_fork, rcu_bp_after_fork_parent and rcu_bp_after_fork_child
 145  * should be called around fork() system calls when the child process is not
 146  * expected to immediately perform an exec(). For pthread users, see
 147  * pthread_atfork(3).
 148  */
 149 extern void rcu_bp_before_fork(void);
 150 extern void rcu_bp_after_fork_parent(void);
 151 extern void rcu_bp_after_fork_child(void);
 152
 153 /*
 154  * In the bulletproof version, the following functions are no-ops.
 155  */
 156 static inline void rcu_register_thread(void)
 157 {
 158 }
 159
 160 static inline void rcu_unregister_thread(void)
 161 {
 162 }
 163
 164 static inline void rcu_init(void)
 165 {
 166 }
 167
 168 /*
 169  * Q.S. reporting are no-ops for these URCU flavors.
 170  */
 171 static inline void rcu_quiescent_state(void)
 172 {
 173 }
 174
 175 static inline void rcu_thread_offline(void)
 176 {
 177 }
 178
 179 static inline void rcu_thread_online(void)
 180 {
 181 }
 182
 183 #ifdef __cplusplus
 184 }
 185 #endif
 186
 187 #include <urcu-call-rcu.h>
 188 #include <urcu-defer.h>
 189 #include <urcu-flavor.h>
 190
 191 #endif /* _URCU_BP_H */