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 /*
  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 #ifdef _LGPL_SOURCE
  55
  56 #include <urcu/static/urcu-qsbr.h>
  57
  58 /*
  59  * Mappings for static use of the userspace RCU library.
  60  * Should only be used in LGPL-compatible code.
  61  */
  62
  63 /*
  64  * rcu_read_lock()
  65  * rcu_read_unlock()
  66  *
  67  * Mark the beginning and end of a read-side critical section.
  68  * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread()
  69  * FOR EACH THREAD WITH READ-SIDE CRITICAL SECTION.
  70  */
  71 #define rcu_read_lock_qsbr              _rcu_read_lock
  72 #define rcu_read_unlock_qsbr            _rcu_read_unlock
  73
  74 #define rcu_quiescent_state_qsbr        _rcu_quiescent_state
  75 #define rcu_thread_offline_qsbr         _rcu_thread_offline
  76 #define rcu_thread_online_qsbr          _rcu_thread_online
  77
  78 #else /* !_LGPL_SOURCE */
  79
  80 /*
  81  * library wrappers to be used by non-LGPL compatible source code.
  82  */
  83
  84 /*
  85  * QSBR read lock/unlock are guaranteed to be no-ops. Therefore, we expose them
  86  * in the LGPL header for any code to use. However, the debug version is not
  87  * nops and may contain sanity checks. To activate it, applications must be
  88  * recompiled with -DRCU_DEBUG (even non-LGPL/GPL applications). This is the
  89  * best trade-off between license/performance/code triviality and
  90  * library debugging & tracing features we could come up with.
  91  */
  92
  93 #if (!defined(BUILD_QSBR_LIB) && defined(RCU_DEBUG))
  94
  95 static inline void rcu_read_lock(void)
  96 {
  97 }
  98
  99 static inline void rcu_read_unlock(void)
 100 {
 101 }
 102
 103 #else /* !RCU_DEBUG */
 104
 105 extern void rcu_read_lock(void);
 106 extern void rcu_read_unlock(void);
 107
 108 #endif /* !RCU_DEBUG */
 109
 110 extern void rcu_quiescent_state(void);
 111 extern void rcu_thread_offline(void);
 112 extern void rcu_thread_online(void);
 113
 114 #endif /* !_LGPL_SOURCE */
 115
 116 extern void synchronize_rcu(void);
 117
 118 /*
 119  * Reader thread registration.
 120  */
 121 extern void rcu_register_thread(void);
 122 extern void rcu_unregister_thread(void);
 123
 124 #ifdef __cplusplus
 125 }
 126 #endif
 127
 128 #include <urcu-call-rcu.h>
 129 #include <urcu-defer.h>
 130
 131 #endif /* _URCU_QSBR_H */