urcu-qsbr.h

   1 #ifndef _URCU_QSBR_H
   2 #define _URCU_QSBR_H
   3
   4 /*
   5  * urcu-qsbr.h
   6  *
   7  * Userspace RCU QSBR header.
   8  *
   9  * LGPL-compatible code should include this header with :
  10  *
  11  * #define _LGPL_SOURCE
  12  * #include <urcu.h>
  13  *
  14  * This library is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU Lesser General Public
  16  * License as published by the Free Software Foundation; either
  17  * version 2.1 of the License, or (at your option) any later version.
  18  *
  19  * This library is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22  * Lesser General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Lesser General Public
  25  * License along with this library; if not, write to the Free Software
  26  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  27  *
  28  * IBM's contributions to this file may be relicensed under LGPLv2 or later.
  29  */
  30
  31 #include <stdlib.h>
  32 #include <pthread.h>
  33
  34 /*
  35  * See urcu-pointer.h and urcu/static/urcu-pointer.h for pointer
  36  * publication headers.
  37  */
  38 #include <urcu-pointer.h>
  39
  40 #ifdef __cplusplus
  41 extern "C" {
  42 #endif
  43
  44 #include <urcu/map/urcu-qsbr.h>
  45
  46 #ifdef RCU_DEBUG        /* For backward compatibility */
  47 #define DEBUG_RCU
  48 #endif
  49
  50 /*
  51  * Important !
  52  *
  53  * Each thread containing read-side critical sections must be registered
  54  * with rcu_register_thread() before calling rcu_read_lock().
  55  * rcu_unregister_thread() should be called before the thread exits.
  56  */
  57
  58 #ifdef _LGPL_SOURCE
  59
  60 #include <urcu/static/urcu-qsbr.h>
  61
  62 /*
  63  * Mappings for static use of the userspace RCU library.
  64  * Should only be used in LGPL-compatible code.
  65  */
  66
  67 /*
  68  * rcu_read_lock()
  69  * rcu_read_unlock()
  70  *
  71  * Mark the beginning and end of a read-side critical section.
  72  * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread()
  73  * FOR EACH THREAD WITH READ-SIDE CRITICAL SECTION.
  74  */
  75 #define rcu_read_lock_qsbr              _rcu_read_lock
  76 #define rcu_read_unlock_qsbr            _rcu_read_unlock
  77
  78 #define rcu_quiescent_state_qsbr        _rcu_quiescent_state
  79 #define rcu_thread_offline_qsbr         _rcu_thread_offline
  80 #define rcu_thread_online_qsbr          _rcu_thread_online
  81
  82 #else /* !_LGPL_SOURCE */
  83
  84 /*
  85  * library wrappers to be used by non-LGPL compatible source code.
  86  */
  87
  88 /*
  89  * QSBR read lock/unlock are guaranteed to be no-ops. Therefore, we expose them
  90  * in the LGPL header for any code to use. However, the debug version is not
  91  * nops and may contain sanity checks. To activate it, applications must be
  92  * recompiled with -DDEBUG_RCU (even non-LGPL/GPL applications). This is the
  93  * best trade-off between license/performance/code triviality and
  94  * library debugging & tracing features we could come up with.
  95  */
  96
  97 #if (!defined(BUILD_QSBR_LIB) && !defined(DEBUG_RCU))
  98
  99 static inline void rcu_read_lock(void)
 100 {
 101 }
 102
 103 static inline void rcu_read_unlock(void)
 104 {
 105 }
 106
 107 #else /* !DEBUG_RCU */
 108
 109 extern void rcu_read_lock(void);
 110 extern void rcu_read_unlock(void);
 111
 112 #endif /* !DEBUG_RCU */
 113
 114 extern void rcu_quiescent_state(void);
 115 extern void rcu_thread_offline(void);
 116 extern void rcu_thread_online(void);
 117
 118 #endif /* !_LGPL_SOURCE */
 119
 120 extern void synchronize_rcu(void);
 121
 122 /*
 123  * Reader thread registration.
 124  */
 125 extern void rcu_register_thread(void);
 126 extern void rcu_unregister_thread(void);
 127
 128 #ifdef __cplusplus
 129 }
 130 #endif
 131
 132 #include <urcu-call-rcu.h>
 133 #include <urcu-defer.h>
 134 #include <urcu-flavor.h>
 135
 136 #endif /* _URCU_QSBR_H */