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 #include <stdbool.h>
  40
  41 #include <urcu/map/urcu-bp.h>
  42
  43 /*
  44  * Important !
  45  *
  46  * Each thread containing read-side critical sections must be registered
  47  * with rcu_register_thread() before calling rcu_read_lock().
  48  * rcu_unregister_thread() should be called before the thread exits.
  49  */
  50
  51 /*
  52  * See urcu/pointer.h and urcu/static/pointer.h for pointer
  53  * publication headers.
  54  */
  55 #include <urcu/pointer.h>
  56 #include <urcu/urcu-poll.h>
  57
  58 #ifdef __cplusplus
  59 extern "C" {
  60 #endif
  61
  62 #ifdef _LGPL_SOURCE
  63
  64 #include <urcu/static/urcu-bp.h>
  65
  66 /*
  67  * Mappings for static use of the userspace RCU library.
  68  * Should only be used in LGPL-compatible code.
  69  */
  70
  71 /*
  72  * rcu_read_lock()
  73  * rcu_read_unlock()
  74  *
  75  * Mark the beginning and end of a read-side critical section.
  76  */
  77 #define urcu_bp_read_lock               _urcu_bp_read_lock
  78 #define urcu_bp_read_unlock             _urcu_bp_read_unlock
  79 #define urcu_bp_read_ongoing            _urcu_bp_read_ongoing
  80
  81 #define urcu_bp_dereference             rcu_dereference
  82 #define urcu_bp_cmpxchg_pointer         rcu_cmpxchg_pointer
  83 #define urcu_bp_xchg_pointer            rcu_xchg_pointer
  84 #define urcu_bp_set_pointer             rcu_set_pointer
  85
  86 #else /* !_LGPL_SOURCE */
  87
  88 /*
  89  * library wrappers to be used by non-LGPL compatible source code.
  90  * See LGPL-only urcu/static/pointer.h for documentation.
  91  */
  92
  93 extern void urcu_bp_read_lock(void);
  94 extern void urcu_bp_read_unlock(void);
  95 extern int urcu_bp_read_ongoing(void);
  96
  97 extern void *urcu_bp_dereference_sym(void *p);
  98 #define urcu_bp_dereference(p)                                               \
  99         __extension__                                                        \
 100         ({                                                                   \
 101                 __typeof__(p) _________p1 = URCU_FORCE_CAST(__typeof__(p),   \
 102                         urcu_bp_dereference_sym(URCU_FORCE_CAST(void *, p))); \
 103                 (_________p1);                                               \
 104         })
 105
 106 extern void *urcu_bp_cmpxchg_pointer_sym(void **p, void *old, void *_new);
 107 #define urcu_bp_cmpxchg_pointer(p, old, _new)                                \
 108         __extension__                                                        \
 109         ({                                                                   \
 110                 __typeof__(*(p)) _________pold = (old);                      \
 111                 __typeof__(*(p)) _________pnew = (_new);                     \
 112                 __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \
 113                         urcu_bp_cmpxchg_pointer_sym(URCU_FORCE_CAST(void **, p), \
 114                                                 _________pold,               \
 115                                                 _________pnew));             \
 116                 (_________p1);                                               \
 117         })
 118
 119 extern void *urcu_bp_xchg_pointer_sym(void **p, void *v);
 120 #define urcu_bp_xchg_pointer(p, v)                                           \
 121         __extension__                                                        \
 122         ({                                                                   \
 123                 __typeof__(*(p)) _________pv = (v);                          \
 124                 __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)),\
 125                         urcu_bp_xchg_pointer_sym(URCU_FORCE_CAST(void **, p), \
 126                                              _________pv));                  \
 127                 (_________p1);                                               \
 128         })
 129
 130 extern void *urcu_bp_set_pointer_sym(void **p, void *v);
 131 #define urcu_bp_set_pointer(p, v)                                            \
 132         __extension__                                                        \
 133         ({                                                                   \
 134                 __typeof__(*(p)) _________pv = (v);                          \
 135                 __typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \
 136                         urcu_bp_set_pointer_sym(URCU_FORCE_CAST(void **, p), \
 137                                             _________pv));                   \
 138                 (_________p1);                                               \
 139         })
 140
 141 #endif /* !_LGPL_SOURCE */
 142
 143 extern void urcu_bp_synchronize_rcu(void);
 144
 145 /*
 146  * RCU grace period polling API.
 147  */
 148 extern struct urcu_gp_poll_state urcu_bp_start_poll_synchronize_rcu(void);
 149 extern bool urcu_bp_poll_state_synchronize_rcu(struct urcu_gp_poll_state state);
 150
 151 /*
 152  * urcu_bp_before_fork, urcu_bp_after_fork_parent and urcu_bp_after_fork_child
 153  * should be called around fork() system calls when the child process is not
 154  * expected to immediately perform an exec(). For pthread users, see
 155  * pthread_atfork(3).
 156  */
 157 extern void urcu_bp_before_fork(void);
 158 extern void urcu_bp_after_fork_parent(void);
 159 extern void urcu_bp_after_fork_child(void);
 160
 161 /*
 162  * In the bulletproof version, thread registration is performed lazily,
 163  * but it can be forced by issuing an explicit urcu_bp_register_thread().
 164  */
 165 extern void urcu_bp_register_thread(void);
 166
 167 /*
 168  * In the bulletproof version, the following functions are no-ops.
 169  */
 170 static inline void urcu_bp_unregister_thread(void)
 171 {
 172 }
 173
 174 static inline void urcu_bp_init(void)
 175 {
 176 }
 177
 178 /*
 179  * Q.S. reporting are no-ops for these URCU flavors.
 180  */
 181 static inline void urcu_bp_quiescent_state(void)
 182 {
 183 }
 184
 185 static inline void urcu_bp_thread_offline(void)
 186 {
 187 }
 188
 189 static inline void urcu_bp_thread_online(void)
 190 {
 191 }
 192
 193 #ifdef __cplusplus
 194 }
 195 #endif
 196
 197 #include <urcu/call-rcu.h>
 198 #include <urcu/defer.h>
 199 #include <urcu/flavor.h>
 200
 201 #ifndef URCU_API_MAP
 202 #include <urcu/map/clear.h>
 203 #endif
 204
 205 #endif /* _URCU_BP_H */