/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include "iotrack.h"#include "dat.h"#include "fns.h" voidmlock(MLock *l){ 	if(l->key != 0 && l->key != 1)		panic("uninitialized lock");	if (l->key)		panic("lock");	l->key = 1;} voidunmlock(MLock *l){ 	if(l->key != 0 && l->key != 1)		panic("uninitialized unlock");	if (!l->key)		panic("unlock");	l->key = 0;} intcanmlock(MLock *l){	if(l->key != 0 && l->key != 1)		panic("uninitialized canlock");	if (l->key)		return 0;	l->key = 1;	return 1;}