urcu.h

   1 #ifndef _URCU_H
   2 #define _URCU_H
   3
   4 /*
   5  * urcu.h
   6  *
   7  * Userspace RCU header
   8  *
   9  * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  10  * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
  11  *
  12  * LGPL-compatible code should include this header with :
  13  *
  14  * #define _LGPL_SOURCE
  15  * #include <urcu.h>
  16  *
  17  * This library is free software; you can redistribute it and/or
  18  * modify it under the terms of the GNU Lesser General Public
  19  * License as published by the Free Software Foundation; either
  20  * version 2.1 of the License, or (at your option) any later version.
  21  *
  22  * This library is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  25  * Lesser General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU Lesser General Public
  28  * License along with this library; if not, write to the Free Software
  29  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  30  *
  31  * IBM's contributions to this file may be relicensed under LGPLv2 or later.
  32  */
  33
  34 #include <stdlib.h>
  35 #include <pthread.h>
  36
  37 /*
  38  * Important !
  39  *
  40  * Each thread containing read-side critical sections must be registered
  41  * with rcu_register_thread() before calling rcu_read_lock().
  42  * rcu_unregister_thread() should be called before the thread exits.
  43  */
  44
  45 #ifdef _LGPL_SOURCE
  46
  47 #include <urcu-static.h>
  48
  49 /*
  50  * Mappings for static use of the userspace RCU library.
  51  * Should only be used in LGPL-compatible code.
  52  */
  53
  54 #define rcu_dereference         _rcu_dereference
  55 #define rcu_read_lock           _rcu_read_lock
  56 #define rcu_read_unlock         _rcu_read_unlock
  57
  58 #define rcu_assign_pointer      _rcu_assign_pointer
  59 #define rcu_xchg_pointer        _rcu_xchg_pointer
  60 #define rcu_publish_content     _rcu_publish_content
  61
  62 #else /* !_LGPL_SOURCE */
  63
  64 /*
  65  * library wrappers to be used by non-LGPL compatible source code.
  66  */
  67
  68 extern void rcu_read_lock(void);
  69 extern void rcu_read_unlock(void);
  70
  71 extern void *rcu_dereference(void *p);
  72
  73 extern void *rcu_assign_pointer_sym(void **p, void *v);
  74
  75 #define rcu_assign_pointer(p, v)                        \
  76         rcu_assign_pointer_sym((void **)(p), (v))
  77
  78 extern void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new);
  79 #define rcu_cmpxchg_pointer(p, old, _new)               \
  80         rcu_cmpxchg_pointer_sym((void **)(p), (old), (_new))
  81
  82 extern void *rcu_xchg_pointer_sym(void **p, void *v);
  83 #define rcu_xchg_pointer(p, v)                          \
  84         rcu_xchg_pointer_sym((void **)(p), (v))
  85
  86 extern void *rcu_publish_content_sym(void **p, void *v);
  87 #define rcu_publish_content(p, v)                       \
  88         rcu_publish_content_sym((void **)(p), (v))
  89
  90 #endif /* !_LGPL_SOURCE */
  91
  92 extern void synchronize_rcu(void);
  93
  94 /*
  95  * Reader thread registration.
  96  */
  97 extern void rcu_register_thread(void);
  98 extern void rcu_unregister_thread(void);
  99
 100 #endif /* _URCU_H */