config root man

/*-
 * Copyright (c) 2002 David Xu (davidxu@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.
 *
 * 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/tools/KSE/ksetest/simplelock.h 110535 2003-02-08 06:33:37Z davidxu $
 */

#ifndef _SIMPLELOCK_H
#define _SIMPLELOCK_H

#include <machine/asmacros.h>
#include <machine/atomic.h>

struct simplelock {
	int s_lock;
};

static inline void
simplelock_init(struct simplelock *lock)
{
	lock->s_lock = 0;
}

static inline void
simplelock_lock(struct simplelock *lock)
{
	while (!atomic_cmpset_int(&lock->s_lock, 0, 1))
		;
}

static inline void
simplelock_unlock(struct simplelock *lock)
{
	atomic_store_rel_int(&lock->s_lock, 0);
}

#endif