include/urcu/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/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 urcu_bp_read_lock               _urcu_bp_read_lock
  76 #define urcu_bp_read_unlock             _urcu_bp_read_unlock
  77 #define urcu_bp_read_ongoing            _urcu_bp_read_ongoing
  78
  79 #define urcu_bp_dereference             rcu_dereference
  80 #define urcu_bp_cmpxchg_pointer         rcu_cmpxchg_pointer
  81 #define urcu_bp_xchg_pointer            rcu_xchg_pointer
  82 #define urcu_bp_set_pointer             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/pointer.h for documentation.
  89  */
  90
  91 extern void urcu_bp_read_lock(void);
  92 extern void urcu_bp_read_unlock(void);
  93 extern int urcu_bp_read_ongoing(void);
  94
  95 extern void *urcu_bp_dereference_sym(void *p);
  96 #define urcu_bp_dereference(p)                                               \
  97         __extension__                                                        \
  98         ({                                                                   \
  99                 __typeof__(p) _________p1 = URCU_FORCE_CAST(__typeof__(p),   \
 100                         urcu_bp_dereference_sym(URCU_FORCE_CAST(void *, p))); \
 101                 (_________p1);                                               \
 102         })
 103
 104 extern void *urcu_bp_cmpxchg_pointer_sym(void **p, void *old, void *_new);
 105 #define urcu_bp_cmpxchg_pointer(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                         urcu_bp_cmpxchg_pointer_sym(URCU_FORCE_CAST(void **, p), \
 112                                                 _________pold,               \
 113                                                 _________pnew));             \
 114                 (_________p1);                                               \
 115         })
 116
 117 extern void *urcu_bp_xchg_pointer_sym(void **p, void *v);
 118 #define urcu_bp_xchg_pointer(p, v)                                           \
 119         __extension__                                                        \
 120         ({                                                                   \
 121                 __typeof__(*(p)) _________pv = (v);                          \
 122                 __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)),\
 123                         urcu_bp_xchg_pointer_sym(URCU_FORCE_CAST(void **, p), \
 124                                              _________pv));                  \
 125                 (_________p1);                                               \
 126         })
 127
 128 extern void *urcu_bp_set_pointer_sym(void **p, void *v);
 129 #define urcu_bp_set_pointer(p, v)                                            \
 130         __extension__                                                        \
 131         ({                                                                   \
 132                 __typeof__(*(p)) _________pv = (v);                          \
 133                 __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \
 134                         urcu_bp_set_pointer_sym(URCU_FORCE_CAST(void **, p), \
 135                                             _________pv));                   \
 136                 (_________p1);                                               \
 137         })
 138
 139 #endif /* !_LGPL_SOURCE */
 140
 141 extern void urcu_bp_synchronize_rcu(void);
 142
 143 /*
 144  * urcu_bp_before_fork, urcu_bp_after_fork_parent and urcu_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 urcu_bp_before_fork(void);
 150 extern void urcu_bp_after_fork_parent(void);
 151 extern void urcu_bp_after_fork_child(void);
 152
 153 /*
 154  * In the bulletproof version, thread registration is performed lazily,
 155  * but it can be forced by issuing an explicit urcu_bp_register_thread().
 156  */
 157 extern void urcu_bp_register_thread(void);
 158
 159 /*
 160  * In the bulletproof version, the following functions are no-ops.
 161  */
 162 static inline void urcu_bp_unregister_thread(void)
 163 {
 164 }
 165
 166 static inline void urcu_bp_init(void)
 167 {
 168 }
 169
 170 /*
 171  * Q.S. reporting are no-ops for these URCU flavors.
 172  */
 173 static inline void urcu_bp_quiescent_state(void)
 174 {
 175 }
 176
 177 static inline void urcu_bp_thread_offline(void)
 178 {
 179 }
 180
 181 static inline void urcu_bp_thread_online(void)
 182 {
 183 }
 184
 185 #ifdef __cplusplus
 186 }
 187 #endif
 188
 189 #include <urcu/call-rcu.h>
 190 #include <urcu/defer.h>
 191 #include <urcu/flavor.h>
 192
 193 #ifndef URCU_API_MAP
 194 #include <urcu/map/clear.h>
 195 #endif
 196
 197 #endif /* _URCU_BP_H */