| Current Path : /sys/amd64/compile/hs32/modules/usr/src/sys/modules/i2c/iicbb/@/sys/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //sys/amd64/compile/hs32/modules/usr/src/sys/modules/i2c/iicbb/@/sys/refcount.h |
/*-
* Copyright (c) 2005 John Baldwin <jhb@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: release/9.1.0/sys/sys/refcount.h 180763 2008-07-23 16:44:20Z des $
*/
#ifndef __SYS_REFCOUNT_H__
#define __SYS_REFCOUNT_H__
#include <machine/atomic.h>
#ifdef _KERNEL
#include <sys/systm.h>
#else
#define KASSERT(exp, msg) /* */
#endif
static __inline void
refcount_init(volatile u_int *count, u_int value)
{
*count = value;
}
static __inline void
refcount_acquire(volatile u_int *count)
{
atomic_add_acq_int(count, 1);
}
static __inline int
refcount_release(volatile u_int *count)
{
u_int old;
/* XXX: Should this have a rel membar? */
old = atomic_fetchadd_int(count, -1);
KASSERT(old > 0, ("negative refcount %p", count));
return (old == 1);
}
#endif /* ! __SYS_REFCOUNT_H__ */