urcu/ref.h

   1 #ifndef _URCU_REF_H
   2 #define _URCU_REF_H
   3
   4 /*
   5  * Userspace RCU - Reference counting
   6  *
   7  * Copyright (C) 2009 Novell Inc.
   8  * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * Author: Jan Blunck <jblunck@suse.de>
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU Lesser General Public License version 2.1 as
  14  * published by the Free  Software Foundation.
  15  */
  16
  17 #include <assert.h>
  18 #include <urcu/uatomic.h>
  19
  20 struct urcu_ref {
  21         long refcount; /* ATOMIC */
  22 };
  23
  24 static inline void urcu_ref_set(struct urcu_ref *ref, long val)
  25 {
  26         uatomic_set(&ref->refcount, val);
  27 }
  28
  29 static inline void urcu_ref_init(struct urcu_ref *ref)
  30 {
  31         urcu_ref_set(ref, 1);
  32 }
  33
  34 static inline void urcu_ref_get(struct urcu_ref *ref)
  35 {
  36         uatomic_add(&ref->refcount, 1);
  37 }
  38
  39 static inline void urcu_ref_put(struct urcu_ref *ref,
  40                                 void (*release)(struct urcu_ref *))
  41 {
  42         long res = uatomic_sub_return(&ref->refcount, 1);
  43         assert (res >= 0);
  44         if (res == 0)
  45                 release(ref);
  46 }
  47
  48 #endif /* _URCU_REF_H */