src/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 #define rcu_read_ongoing_qsbr           _rcu_read_ongoing
  78
  79 #define rcu_quiescent_state_qsbr        _rcu_quiescent_state
  80 #define rcu_thread_offline_qsbr         _rcu_thread_offline
  81 #define rcu_thread_online_qsbr          _rcu_thread_online
  82
  83 #else /* !_LGPL_SOURCE */
  84
  85 /*
  86  * library wrappers to be used by non-LGPL compatible source code.
  87  */
  88
  89 /*
  90  * QSBR read lock/unlock are guaranteed to be no-ops. Therefore, we expose them
  91  * in the LGPL header for any code to use. However, the debug version is not
  92  * nops and may contain sanity checks. To activate it, applications must be
  93  * recompiled with -DDEBUG_RCU (even non-LGPL/GPL applications), or
  94  * compiled against a urcu/config.h that has CONFIG_RCU_DEBUG defined.
  95  * This is the best trade-off between license/performance/code
  96  * triviality and library debugging & tracing features we could come up
  97  * with.
  98  */
  99
 100 #if (!defined(BUILD_QSBR_LIB) && !defined(DEBUG_RCU) && !defined(CONFIG_RCU_DEBUG))
 101
 102 static inline void rcu_read_lock(void)
 103 {
 104 }
 105
 106 static inline void rcu_read_unlock(void)
 107 {
 108 }
 109
 110 #else /* #if (!defined(BUILD_QSBR_LIB) && !defined(DEBUG_RCU) && !defined(CONFIG_RCU_DEBUG)) */
 111
 112 extern void rcu_read_lock(void);
 113 extern void rcu_read_unlock(void);
 114
 115 #endif /* #else #if (!defined(BUILD_QSBR_LIB) && !defined(DEBUG_RCU) && !defined(CONFIG_RCU_DEBUG)) */
 116
 117 extern int rcu_read_ongoing(void);
 118 extern void rcu_quiescent_state(void);
 119 extern void rcu_thread_offline(void);
 120 extern void rcu_thread_online(void);
 121
 122 #endif /* !_LGPL_SOURCE */
 123
 124 extern void synchronize_rcu(void);
 125
 126 /*
 127  * Reader thread registration.
 128  */
 129 extern void rcu_register_thread(void);
 130 extern void rcu_unregister_thread(void);
 131
 132 #ifdef __cplusplus
 133 }
 134 #endif
 135
 136 #include <urcu-call-rcu.h>
 137 #include <urcu-defer.h>
 138 #include <urcu-flavor.h>
 139
 140 #endif /* _URCU_QSBR_H */