From: Joe Perches <joe@perches.com>
To: David Miller <davem@davemloft.net>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH] net: af_packet: Don't initialize vnet_hdr
Date: Thu, 12 May 2011 14:33:20 -0700 [thread overview]
Message-ID: <1305236000.6124.67.camel@Joe-Laptop> (raw)
In-Reply-To: <20110512.172623.220889608152651989.davem@davemloft.net>
On Thu, 2011-05-12 at 17:26 -0400, David Miller wrote:
> From: Joe Perches <joe@perches.com>
> Date: Thu, 12 May 2011 13:36:10 -0700
>
> > Save a memset, initialize only the portion necessary.
> >
> > packet_snd either gets this structure completely from
> > memcpy_fromiovec or uses only the hdr_len set to 0,
> > so don't always initialize the structure to 0.
> >
> > Signed-off-by: Joe Perches <joe@perches.com>
>
> On ARM this won't be tightly packed, therefore you'll leave
> uninitialized pieces of padding in this structure and this
> thing is an "on-the-wire" network header.
>
> I'm not applying this.
I believe that it's only sent when po->has_vnet_hdr
is set. In that case, it's completely filled from
memcpy_fromiovec. In the not set po->has_vnet_hdr case,
only vnet_hdr.hdr_len is accessed by packet_alloc_skb.
cheers, Joe
next prev parent reply other threads:[~2011-05-12 21:33 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-12 20:36 [PATCH] net: af_packet: Don't initialize vnet_hdr Joe Perches
2011-05-12 21:26 ` David Miller
2011-05-12 21:33 ` Joe Perches [this message]
2011-05-12 21:36 ` David Miller
2011-05-12 21:55 ` Joe Perches
2011-05-12 21:59 ` David Miller
2011-05-12 23:25 ` [PATCH net-next V3] net: af_packet: Untangle packet_snd by adding vpacket_snd Joe Perches
2011-05-13 5:11 ` Eric Dumazet
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