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From: Neil Horman <nhorman@tuxdriver.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Alexander Holler <holler@ahsoftware.de>,
	linux-kernel@vger.kernel.org, David Miller <davem@davemloft.net>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	netdev@vger.kernel.org
Subject: Re: bridge/netfilter: regression in 2.6.39.1
Date: Mon, 6 Jun 2011 13:07:46 -0400	[thread overview]
Message-ID: <20110606170746.GD1000@hmsreliant.think-freely.org> (raw)
In-Reply-To: <1307376705.3098.58.camel@edumazet-laptop>

On Mon, Jun 06, 2011 at 06:11:45PM +0200, Eric Dumazet wrote:
> Le lundi 06 juin 2011 à 11:32 -0400, Neil Horman a écrit :
> 
> > Not to drag this out further, but since you illustrated the correct way to do
> > this with the blackhole_ops test, and this modification now gives us two
> > instances of that case, would it perhaps be better to just do this in
> > dst_metrics_write_ptr:
> > 
> > return dst->ops->cow_metrics ? return dst->ops->cow_metrics(dst, p) : NULL;
> > 
> > Then we could eliminate the two functions that do nothing be retun NULL (along
> > with their respective call instructions), and save any future users from having
> > to remember to include a dummy cow_metrics method if they happen to set the read
> > only flag on thier dst_ops?
> 
> Well, I prefer how David coded the thing.
> We can add selective traces where we want.
> 
> Having a default behavior might give much more work to find a bug in
> this area. A NULL pointer access gives us an immediate indication.
> 
> Its a bit late to add an "if (dst->ops->cow_metrics)" test now that we
> covered all call sites ;)
> 
> But we probably have more bugs elsewhere, because of many dst changes in
> 2.6.39
Ok, sounds reasonable to me.

Reviewed-by: Neil Horman <nhorman@tuxdriver.com>

> 
> 
> --
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  reply	other threads:[~2011-06-06 17:08 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-03 19:21 bridge/netfilter: regression in 2.6.39.1 Alexander Holler
2011-06-03 19:34 ` Eric Dumazet
2011-06-03 19:42   ` Alexander Holler
2011-06-03 19:51   ` Alexander Holler
2011-06-03 19:55     ` Eric Dumazet
2011-06-04 12:04       ` Alexander Holler
2011-06-06  6:57         ` Alexander Holler
2011-06-03 22:31   ` Ben Hutchings
2011-06-06 11:15 ` Neil Horman
2011-06-06 11:48   ` Alexander Holler
2011-06-06 12:12     ` Eric Dumazet
2011-06-06 12:49       ` Alexander Holler
2011-06-06 13:13         ` Neil Horman
2011-06-06 13:18           ` Eric Dumazet
2011-06-06 13:16         ` Eric Dumazet
2011-06-06 13:29           ` Alexander Holler
2011-06-06 14:26             ` Eric Dumazet
2011-06-06 15:32               ` Neil Horman
2011-06-06 16:11                 ` Eric Dumazet
2011-06-06 17:07                   ` Neil Horman [this message]
2011-06-07  7:52               ` David Miller
2011-06-06 13:09       ` Eric Dumazet

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