include/urcu/urcu-qsbr.h

   1 // SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   2 // SPDX-FileCopyrightText: 2009 Paul E. McKenney, IBM Corporation.
   3 //
   4 // SPDX-License-Identifier: LGPL-2.1-or-later
   5
   6 #ifndef _URCU_QSBR_H
   7 #define _URCU_QSBR_H
   8
   9 /*
  10  * Userspace RCU QSBR header.
  11  *
  12  * LGPL-compatible code should include this header with :
  13  *
  14  * #define _LGPL_SOURCE
  15  * #include <urcu.h>
  16  *
  17  * IBM's contributions to this file may be relicensed under LGPLv2 or later.
  18  */
  19
  20 #include <stdlib.h>
  21 #include <pthread.h>
  22 #include <stdbool.h>
  23
  24 #include <urcu/config.h>
  25
  26 /*
  27  * See urcu/pointer.h and urcu/static/pointer.h for pointer
  28  * publication headers.
  29  */
  30 #include <urcu/pointer.h>
  31 #include <urcu/urcu-poll.h>
  32
  33 #ifdef __cplusplus
  34 extern "C" {
  35 #endif
  36
  37 #include <urcu/map/urcu-qsbr.h>
  38
  39 #ifdef RCU_DEBUG        /* For backward compatibility */
  40 #define DEBUG_RCU
  41 #endif
  42
  43 /*
  44  * Important !
  45  *
  46  * Each thread containing read-side critical sections must be registered
  47  * with rcu_register_thread() before calling rcu_read_lock().
  48  * rcu_unregister_thread() should be called before the thread exits.
  49  */
  50
  51 #ifdef _LGPL_SOURCE
  52
  53 #include <urcu/static/urcu-qsbr.h>
  54
  55 /*
  56  * Mappings for static use of the userspace RCU library.
  57  * Should only be used in LGPL-compatible code.
  58  */
  59
  60 /*
  61  * rcu_read_lock()
  62  * rcu_read_unlock()
  63  *
  64  * Mark the beginning and end of a read-side critical section.
  65  * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread()
  66  * FOR EACH THREAD WITH READ-SIDE CRITICAL SECTION.
  67  */
  68 #define urcu_qsbr_read_lock             _urcu_qsbr_read_lock
  69 #define urcu_qsbr_read_unlock           _urcu_qsbr_read_unlock
  70 #define urcu_qsbr_read_ongoing          _urcu_qsbr_read_ongoing
  71
  72 #define urcu_qsbr_quiescent_state       _urcu_qsbr_quiescent_state
  73 #define urcu_qsbr_thread_offline        _urcu_qsbr_thread_offline
  74 #define urcu_qsbr_thread_online         _urcu_qsbr_thread_online
  75
  76 #else /* !_LGPL_SOURCE */
  77
  78 /*
  79  * library wrappers to be used by non-LGPL compatible source code.
  80  */
  81
  82 /*
  83  * QSBR read lock/unlock are guaranteed to be no-ops. Therefore, we expose them
  84  * in the LGPL header for any code to use. However, the debug version is not
  85  * nops and may contain sanity checks. To activate it, applications must be
  86  * recompiled with -DDEBUG_RCU (even non-LGPL/GPL applications), or
  87  * compiled against a urcu/config.h that has CONFIG_RCU_DEBUG defined.
  88  * This is the best trade-off between license/performance/code
  89  * triviality and library debugging & tracing features we could come up
  90  * with.
  91  */
  92
  93 #if (!defined(BUILD_QSBR_LIB) && !defined(DEBUG_RCU) && !defined(CONFIG_RCU_DEBUG))
  94
  95 static inline void urcu_qsbr_read_lock(void)
  96 {
  97 }
  98
  99 static inline void urcu_qsbr_read_unlock(void)
 100 {
 101 }
 102
 103 #else /* #if (!defined(BUILD_QSBR_LIB) && !defined(DEBUG_RCU) && !defined(CONFIG_RCU_DEBUG)) */
 104
 105 extern void urcu_qsbr_read_lock(void);
 106 extern void urcu_qsbr_read_unlock(void);
 107
 108 #endif /* #else #if (!defined(BUILD_QSBR_LIB) && !defined(DEBUG_RCU) && !defined(CONFIG_RCU_DEBUG)) */
 109
 110 extern int urcu_qsbr_read_ongoing(void);
 111 extern void urcu_qsbr_quiescent_state(void);
 112 extern void urcu_qsbr_thread_offline(void);
 113 extern void urcu_qsbr_thread_online(void);
 114
 115 #endif /* !_LGPL_SOURCE */
 116
 117 extern void urcu_qsbr_synchronize_rcu(void);
 118
 119 /*
 120  * RCU grace period polling API.
 121  */
 122 extern struct urcu_gp_poll_state urcu_qsbr_start_poll_synchronize_rcu(void);
 123 extern bool urcu_qsbr_poll_state_synchronize_rcu(struct urcu_gp_poll_state state);
 124
 125 /*
 126  * Reader thread registration.
 127  */
 128 extern void urcu_qsbr_register_thread(void);
 129 extern void urcu_qsbr_unregister_thread(void);
 130
 131 #ifdef __cplusplus
 132 }
 133 #endif
 134
 135 #include <urcu/call-rcu.h>
 136 #include <urcu/defer.h>
 137 #include <urcu/flavor.h>
 138
 139 #ifndef URCU_API_MAP
 140 #include <urcu/map/clear.h>
 141 #endif
 142
 143 #endif /* _URCU_QSBR_H */