include/ust/kcompat/kref.h

   1 #ifndef _KCOMPAT_KREF_H
   2 #define _KCOMPAT_KREF_H
   3
   4 /*
   5  * Kernel sourcecode compatible reference counting implementation
   6  *
   7  * Copyright (C) 2009 Novell Inc.
   8  *
   9  * Author: Jan Blunck <jblunck@suse.de>
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU Lesser General Public License version 2.1 as
  13  * published by the Free  Software Foundation.
  14  */
  15
  16 #include <assert.h>
  17 #include <urcu/uatomic_arch.h>
  18
  19 struct kref {
  20         long refcount; /* ATOMIC */
  21 };
  22
  23 static inline void kref_set(struct kref *ref, int val)
  24 {
  25         uatomic_set(&ref->refcount, val);
  26 }
  27
  28 static inline void kref_init(struct kref *ref)
  29 {
  30         kref_set(ref, 1);
  31 }
  32
  33 static inline void kref_get(struct kref *ref)
  34 {
  35         long result = uatomic_add_return(&ref->refcount, 1);
  36         assert(result != 0);
  37 }
  38
  39 static inline void kref_put(struct kref *ref, void (*release)(struct kref *))
  40 {
  41         long res = uatomic_sub_return(&ref->refcount, 1);
  42         if (res == 0)
  43                 release(ref);
  44 }
  45
  46 #endif /* _KCOMPAT_KREF_H */