From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH 05/34]bnx2x: Setting the GSO_TYPE with LRO Date: Wed, 14 Jan 2009 13:12:06 -0800 (PST) Message-ID: <20090114.131206.193936587.davem@davemloft.net> References: <20090114201826.GA23648@gondor.apana.org.au> <1231964842.3010.46.camel@achroite> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: herbert@gondor.apana.org.au, eilong@broadcom.com, netdev@vger.kernel.org To: bhutchings@solarflare.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:55885 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755831AbZANVMF (ORCPT ); Wed, 14 Jan 2009 16:12:05 -0500 In-Reply-To: <1231964842.3010.46.camel@achroite> Sender: netdev-owner@vger.kernel.org List-ID: From: Ben Hutchings Date: Wed, 14 Jan 2009 20:27:22 +0000 > On Thu, 2009-01-15 at 07:18 +1100, Herbert Xu wrote: > > Eilon Greenstein wrote: > > >> > > > This is far from bullet proof solution, but IMHO it is better set then > > > not this way, you stand a chance (depending on the output device > > > capabilities) > > > > The question is simple, does your hardware guarantee that on > > output GSO will turn the packet into exactly the same sequence > > of packets that was seen on input, with no changes (apart from > > what the stack would have done to them anyway, e.g., TTL update) > > whatsoever? > > > > If not then you mustn't set this and also you must disable it > > if forwarding/bridging is used. > > The driver just has to cooperate with dev_disable_lro() in order for the > forwarding/bridging code to disable it. Then skb_warn_if_lro() should > catch the case where the user mistakenly turns it back on. However, > setting gso_type on input subverts this check. Right, setting gso_type here is absolutely wrong.