From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH 0/2] Disable forwarding of LRO skbs [2nd try] Date: Thu, 19 Jun 2008 14:50:09 -0700 Message-ID: <20080619145009.5b24f028@extreme> References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: David Miller , netdev@vger.kernel.org, linux-net-drivers@solarflare.com, Kieran Mansley , Herbert Xu To: Ben Hutchings Return-path: Received: from mail.vyatta.com ([216.93.170.194]:42946 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751598AbYFSVuQ (ORCPT ); Thu, 19 Jun 2008 17:50:16 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 19 Jun 2008 19:44:56 +0100 Ben Hutchings wrote: > [Re-sent with the correct Message-ID, previously eaten by mutt.] > > Large Receive Offload (LRO) destroys packet headers that should be > preserved when forwarding. Currently it also triggers a BUG() or WARN() > in skb_gso_segment(). We should disable it wherever forwarding is > enabled, and discard LRO skbs with a warning if it is turned back on. > > Since the previous version of these patches, I have: > - Tightened the test for LRO'd skbs, so it should not catch skbs from > VM guests that want GSO > - Made the test an inline function, with the warning a separate extern > function > - Rebased against net-next-2.6 > I like that it covers both cases and looks clean. If anyone ever gets around to rewriting the network device driver chapter in the linux kernel book(s) this should be covered in more detail.