refcnt.h revision 252386
1249259Sdim/*- 2249259Sdim * Copyright (c) 2005 John Baldwin <jhb@FreeBSD.org> 3249259Sdim * All rights reserved. 4249259Sdim * 5249259Sdim * Redistribution and use in source and binary forms, with or without 6249259Sdim * modification, are permitted provided that the following conditions 7249259Sdim * are met: 8249259Sdim * 1. Redistributions of source code must retain the above copyright 9249259Sdim * notice, this list of conditions and the following disclaimer. 10249259Sdim * 2. Redistributions in binary form must reproduce the above copyright 11249259Sdim * notice, this list of conditions and the following disclaimer in the 12249259Sdim * documentation and/or other materials provided with the distribution. 13249259Sdim * 3. Neither the name of the author nor the names of any co-contributors 14249259Sdim * may be used to endorse or promote products derived from this software 15249259Sdim * without specific prior written permission. 16249259Sdim * 17249259Sdim * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18249259Sdim * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19249259Sdim * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20249259Sdim * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21249259Sdim * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22249259Sdim * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23249259Sdim * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24249259Sdim * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25249259Sdim * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26249259Sdim * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27249259Sdim * SUCH DAMAGE. 28249259Sdim * 29249259Sdim * $FreeBSD: head/sbin/hastd/refcnt.h 252386 2013-06-29 20:13:39Z ed $ 30249259Sdim */ 31249259Sdim 32249259Sdim#ifndef __REFCNT_H__ 33249259Sdim#define __REFCNT_H__ 34249259Sdim 35249259Sdim#include <machine/atomic.h> 36249259Sdim 37249259Sdim#include "pjdlog.h" 38249259Sdim 39249259Sdimtypedef unsigned int refcnt_t; 40249259Sdim 41249259Sdimstatic __inline void 42249259Sdimrefcnt_init(refcnt_t *count, unsigned int v) 43249259Sdim{ 44249259Sdim 45249259Sdim *count = v; 46249259Sdim} 47263508Sdim 48263508Sdimstatic __inline void 49263508Sdimrefcnt_acquire(refcnt_t *count) 50249259Sdim{ 51249259Sdim 52249259Sdim atomic_add_acq_int(count, 1); 53249259Sdim} 54249259Sdim 55249259Sdimstatic __inline unsigned int 56249259Sdimrefcnt_release(refcnt_t *count) 57249259Sdim{ 58249259Sdim unsigned int old; 59249259Sdim 60249259Sdim /* XXX: Should this have a rel membar? */ 61249259Sdim old = atomic_fetchadd_int(count, -1); 62249259Sdim PJDLOG_ASSERT(old > 0); 63249259Sdim return (old - 1); 64249259Sdim} 65249259Sdim 66249259Sdim#endif /* ! __REFCNT_H__ */ 67249259Sdim