From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <90fc526d76991a36a045593f14155a90@davidashen.net>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] qunlock
Date: Thu, 24 Jun 2004 01:11:54 +0500
From: dvd@davidashen.net
In-Reply-To: <29dbd0842758b89af800a214a30c9fac@vitanuova.com>
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> > calling qunlock on an unlocked QLock is no-op, isn't it?
> 
> i'd have thought it best to regard it as best avoided.
> does it happen, or was it something you wanted to do?
> 

I need to release a qlock in  a criticial session guarded by another lock,

QLock p,q;

void x() {
	qlock(&p);

	if(...)
		qunlock(&q);

	qunlock(&p);
}

void y() {
	qlock(&q);
	qlock(&p);

	qunlock(&p);
}

The question is whether the above is legal or should I write

if(...){
	canqlock(&q);
	qunlock(&q);
}

instead?