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 /*
  41  * See urcu-pointer.h and urcu-pointer-static.h for pointer publication headers.
  42  */
  43 #include <urcu-pointer.h>
  44
  45 #ifdef __cplusplus
  46 extern "C" {
  47 #endif
  48
  49 /*
  50  * Important !
  51  *
  52  * Each thread containing read-side critical sections must be registered
  53  * with rcu_register_thread() before calling rcu_read_lock().
  54  * rcu_unregister_thread() should be called before the thread exits.
  55  */
  56
  57 #ifdef _LGPL_SOURCE
  58
  59 #include <urcu-bp-static.h>
  60
  61 /*
  62  * Mappings for static use of the userspace RCU library.
  63  * Should only be used in LGPL-compatible code.
  64  */
  65
  66 /*
  67  * rcu_read_lock()
  68  * rcu_read_unlock()
  69  *
  70  * Mark the beginning and end of a read-side critical section.
  71  */
  72 #define rcu_read_lock()         _rcu_read_lock()
  73 #define rcu_read_unlock()       _rcu_read_unlock()
  74
  75 #else /* !_LGPL_SOURCE */
  76
  77 /*
  78  * library wrappers to be used by non-LGPL compatible source code.
  79  * See LGPL-only urcu-pointer-static.h for documentation.
  80  */
  81
  82 extern void rcu_read_lock(void);
  83 extern void rcu_read_unlock(void);
  84
  85 #endif /* !_LGPL_SOURCE */
  86
  87 extern void synchronize_rcu(void);
  88
  89 /*
  90  * rcu_bp_before_fork, rcu_bp_after_fork_parent and rcu_bp_after_fork_child
  91  * should be called around fork() system calls when the child process is not
  92  * expected to immediately perform an exec(). For pthread users, see
  93  * pthread_atfork(3).
  94  */
  95 extern void rcu_bp_before_fork(void);
  96 extern void rcu_bp_after_fork_parent(void);
  97 extern void rcu_bp_after_fork_child(void);
  98
  99 /*
 100  * In the bulletproof version, the following functions are no-ops.
 101  */
 102 static inline void rcu_register_thread(void)
 103 {
 104 }
 105
 106 static inline void rcu_unregister_thread(void)
 107 {
 108 }
 109
 110 static inline void rcu_init(void)
 111 {
 112 }
 113
 114 #ifdef __cplusplus
 115 }
 116 #endif
 117
 118 #endif /* _URCU_BP_H */