Add lock-free RCU queue and stack

[urcu.git] / urcu / urcu_ref.h

diff --git a/urcu/urcu_ref.h b/urcu/urcu_ref.h
new file mode 100644 (file)
index 0000000..bce7116
--- /dev/null
+++ b/urcu/urcu_ref.h
@@ -0,0 +1,47 @@
+#ifndef _URCU_REF_H
+#define _URCU_REF_H
+
+/*
+ * Userspace RCU - Reference counting
+ *
+ * Copyright (C) 2009 Novell Inc.
+ * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Author: Jan Blunck <jblunck@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 2.1 as
+ * published by the Free  Software Foundation.
+ */
+
+#include <assert.h>
+#include <urcu/uatomic_arch.h>
+
+struct urcu_ref {
+       long refcount; /* ATOMIC */
+};
+
+static inline void urcu_ref_set(struct urcu_ref *ref, long val)
+{
+       uatomic_set(&ref->refcount, val);
+}
+
+static inline void urcu_ref_init(struct urcu_ref *ref)
+{
+       urcu_ref_set(ref, 1);
+}
+
+static inline void urcu_ref_get(struct urcu_ref *ref)
+{
+       long res = uatomic_add_return(&ref->refcount, 1);
+       assert(res != 0);
+}
+
+static inline void urcu_ref_put(struct urcu_ref *ref,
+                               void (*release)(struct urcu_ref *))
+{
+       if (!uatomic_sub_return(&ref->refcount, 1))
+               release(ref);
+}
+
+#endif /* _URCU_REF_H */