From: Kurt Van Dijck <kurt.van.dijck@eia.be>
To: Julia Lawall <julia@diku.dk>
Cc: hadi@cyberus.ca, netdev@vger.kernel.org
Subject: Re: question about nla_nest_cancel
Date: Thu, 27 Jan 2011 18:21:18 +0100 [thread overview]
Message-ID: <20110127172118.GA331@e-circ.dyndns.org> (raw)
In-Reply-To: <Pine.LNX.4.64.1101271804530.13796@pc-004.diku.dk>
On Thu, Jan 27, 2011 at 06:08:34PM +0100, Julia Lawall wrote:
>
> I find numerous occurrences of code like the following, in which nest ends
> up with the value NULL and then nla_nest_cancel is called with nest as the
> second argument. But nla_nest_cancel just calls nlmsg_trim with the same
> second argument, and nlmsg_trim does nothing if its second argument is
> NULL. Is there any reason to keep these calls?
I just learned this:
nla_nest_start() adds data to the skb.
nla_nest_end() 'commits' the proper length.
nla_nest_cancel() reverts skb to the state before nla_nest_start(),
as if nothing happened.
Kurt
next prev parent reply other threads:[~2011-01-27 17:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-27 17:08 question about nla_nest_cancel Julia Lawall
2011-01-27 17:21 ` Kurt Van Dijck [this message]
2011-01-27 17:25 ` Julia Lawall
2011-01-27 17:52 ` Ben Pfaff
2011-01-27 18:18 ` Julia Lawall
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