1246922Spjd/*-
2246922Spjd * Copyright (c) 2005 John Baldwin <jhb@FreeBSD.org>
3246922Spjd * All rights reserved.
4246922Spjd *
5246922Spjd * Redistribution and use in source and binary forms, with or without
6246922Spjd * modification, are permitted provided that the following conditions
7246922Spjd * are met:
8246922Spjd * 1. Redistributions of source code must retain the above copyright
9246922Spjd *    notice, this list of conditions and the following disclaimer.
10246922Spjd * 2. Redistributions in binary form must reproduce the above copyright
11246922Spjd *    notice, this list of conditions and the following disclaimer in the
12246922Spjd *    documentation and/or other materials provided with the distribution.
13246922Spjd *
14246922Spjd * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15246922Spjd * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16246922Spjd * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17246922Spjd * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18246922Spjd * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19246922Spjd * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20246922Spjd * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21246922Spjd * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22246922Spjd * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23246922Spjd * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24246922Spjd * SUCH DAMAGE.
25246922Spjd *
26246922Spjd * $FreeBSD$
27246922Spjd */
28246922Spjd
29246922Spjd#ifndef __REFCNT_H__
30246922Spjd#define __REFCNT_H__
31246922Spjd
32246922Spjd#include <machine/atomic.h>
33246922Spjd
34246922Spjd#include "pjdlog.h"
35246922Spjd
36246922Spjdstatic __inline void
37246922Spjdrefcnt_acquire(volatile unsigned int *count)
38246922Spjd{
39246922Spjd
40246922Spjd	atomic_add_acq_int(count, 1);
41246922Spjd}
42246922Spjd
43246922Spjdstatic __inline unsigned int
44246922Spjdrefcnt_release(volatile unsigned int *count)
45246922Spjd{
46246922Spjd	unsigned int old;
47246922Spjd
48246922Spjd	/* XXX: Should this have a rel membar? */
49246922Spjd	old = atomic_fetchadd_int(count, -1);
50246922Spjd	PJDLOG_ASSERT(old > 0);
51246922Spjd	return (old - 1);
52246922Spjd}
53246922Spjd
54246922Spjd#endif	/* ! __REFCNT_H__ */
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