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-pointer-static.h for pointer publication headers.
  36  */
  37 #include <urcu-pointer.h>
  38
  39 #ifdef __cplusplus
  40 extern "C" {
  41 #endif
  42
  43 #include "urcu-qsbr-map.h"
  44
  45 /*
  46  * Important !
  47  *
  48  * Each thread containing read-side critical sections must be registered
  49  * with rcu_register_thread() before calling rcu_read_lock().
  50  * rcu_unregister_thread() should be called before the thread exits.
  51  */
  52
  53 #ifdef _LGPL_SOURCE
  54
  55 #include <urcu-qsbr-static.h>
  56
  57 /*
  58  * Mappings for static use of the userspace RCU library.
  59  * Should only be used in LGPL-compatible code.
  60  */
  61
  62 /*
  63  * rcu_read_lock()
  64  * rcu_read_unlock()
  65  *
  66  * Mark the beginning and end of a read-side critical section.
  67  * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread()
  68  * FOR EACH THREAD WITH READ-SIDE CRITICAL SECTION.
  69  */
  70 #define rcu_read_lock_qsbr              _rcu_read_lock
  71 #define rcu_read_unlock_qsbr            _rcu_read_unlock
  72
  73 #define rcu_quiescent_state_qsbr        _rcu_quiescent_state
  74 #define rcu_thread_offline_qsbr         _rcu_thread_offline
  75 #define rcu_thread_online_qsbr          _rcu_thread_online
  76
  77 #else /* !_LGPL_SOURCE */
  78
  79 /*
  80  * library wrappers to be used by non-LGPL compatible source code.
  81  */
  82
  83 /*
  84  * QSBR read lock/unlock are guaranteed to be no-ops. Therefore, we expose them
  85  * in the LGPL header for any code to use. However, the debug version is not
  86  * nops and may contain sanity checks. To activate it, applications must be
  87  * recompiled with -DRCU_DEBUG (even non-LGPL/GPL applications). This is the
  88  * best trade-off between license/performance/code triviality and
  89  * library debugging & tracing features we could come up with.
  90  */
  91
  92 #if (!defined(BUILD_QSBR_LIB) && defined(RCU_DEBUG))
  93
  94 static inline void rcu_read_lock(void)
  95 {
  96 }
  97
  98 static inline void rcu_read_lock(void)
  99 {
 100 }
 101
 102 #else /* !RCU_DEBUG */
 103
 104 extern void rcu_read_lock(void);
 105 extern void rcu_read_unlock(void);
 106
 107 #endif /* !RCU_DEBUG */
 108
 109 extern void rcu_quiescent_state(void);
 110 extern void rcu_thread_offline(void);
 111 extern void rcu_thread_online(void);
 112
 113 #endif /* !_LGPL_SOURCE */
 114
 115 extern void synchronize_rcu(void);
 116
 117 /*
 118  * Reader thread registration.
 119  */
 120 extern void rcu_register_thread(void);
 121 extern void rcu_unregister_thread(void);
 122
 123 #ifdef __cplusplus
 124 }
 125 #endif
 126
 127 #include "urcu-call-rcu.h"
 128 #include "urcu-defer.h"
 129
 130 #endif /* _URCU_QSBR_H */