linux-kernel - Re: [PATCH] fs, dlm: Don't leak, don't do pointless NULL checks and use kzalloc

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Message-ID: <20110629221731.GB11350@redhat.com>
Date:	Wed, 29 Jun 2011 18:17:31 -0400
From:	David Teigland <teigland@...hat.com>
To:	Jesper Juhl <jj@...osbits.net>
Cc:	linux-kernel@...r.kernel.org, cluster-devel@...hat.com,
	Christine Caulfield <ccaulfie@...hat.com>
Subject: Re: [PATCH] fs, dlm: Don't leak, don't do pointless NULL checks and
 use kzalloc

On Wed, Jun 29, 2011 at 11:51:00PM +0200, Jesper Juhl wrote:
> > I don't think so; num_nodes won't be set to zero.
> 
> Hmm. How so?  Maybe I'm missing something obvious, but;
> num_nodes is initialized to zero at the beginning of the function, which 
> means that we'll definately do the first allocation in the loop.

Zero is meant to mean "first time through the loop".

> We then set num_nodes equal to ls->ls_num_nodes - what guarantees that 
> this will not be zero so we won't do a second allocation (and leak) the 
> second time through the loop?

That's just the nature of a lockspace, I guess -- it doesn't make sense or
exist without nodes in it.  I doubt any of the dlm code would work if that
weren't true.

Dave
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