linux-kernel - Re: [PATCH] Reduce number of pointer dereferences in IPv6 netfilter LOG module function dump

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Date:	Mon, 15 Nov 2010 22:50:13 +0100 (CET)
From:	Jesper Juhl <jj@...osbits.net>
To:	Eric Dumazet <eric.dumazet@...il.com>
cc:	Netfilter Core Team <coreteam@...filter.org>,
	Jan Rekorajski <baggins@....org.pl>,
	"David S. Miller" <davem@...emloft.net>,
	netfilter-devel@...r.kernel.org, netfilter@...r.kernel.org,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Reduce number of pointer dereferences in IPv6 netfilter
 LOG module function dump_packet()

On Mon, 15 Nov 2010, Jesper Juhl wrote:

> On Mon, 15 Nov 2010, Eric Dumazet wrote:
> 
> > Le dimanche 14 novembre 2010 à 22:47 +0100, Jesper Juhl a écrit :
> > > By adding two pointer variables to 
> > > net/ipv6/netfilter/ip6t_LOG.c::dump_packet() we can save 19 bytes of .text 
> > > and many pointer dereferences.
> > > 
> > > before:
> > >    text    data     bss     dec     hex filename
> > >    6258     600    3088    9946    26da net/ipv6/netfilter/ip6t_LOG.o
> > > 
> > > after:
> > >    text    data     bss     dec     hex filename
> > >    6239     600    3088    9927    26c7 net/ipv6/netfilter/ip6t_LOG.o
> > > 
> > > 
> > > Please Cc me on replies.
> > > 
> > > 
> > > Signed-off-by: Jesper Juhl <jj@...osbits.net>
> > > ---
> > >  ip6t_LOG.c |   16 ++++++++++------
> > >  1 file changed, 10 insertions(+), 6 deletions(-)
> > > 
> > > diff --git a/net/ipv6/netfilter/ip6t_LOG.c b/net/ipv6/netfilter/ip6t_LOG.c
> > > index 09c8889..51d10a5 100644
> > > --- a/net/ipv6/netfilter/ip6t_LOG.c
> > > +++ b/net/ipv6/netfilter/ip6t_LOG.c
> [...]
> > 
> > Same comment than previous patch, you add a NULL dereference.
> > 
> Hopefully this is beter (same as change done to the other (ipv4) patch).
> 
> 
> 
> Fewer pointer derefs and smaller .text size for
> net/ipv4/netfilter/ipt_LOG.c::dump_packet()
> 
I'm an idiot, that should of course read

"net/ipv6/netfilter/ip6t_LOG.c::dump_packet()"

That'll teach me not to cut'n'paste descriptions :-(

-- 
Jesper Juhl <jj@...osbits.net>            http://www.chaosbits.net/
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please.