From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: [PATCH v2 01/15] net: dsa: Don't set skb->protocol on outgoing tagged packets Date: Tue, 28 Oct 2014 12:23:05 -0700 Message-ID: <20141028192305.GB12033@roeck-us.net> References: <1414342365-27191-1-git-send-email-linux@roeck-us.net> <1414342365-27191-2-git-send-email-linux@roeck-us.net> <544FEC39.4060903@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, "David S. Miller" , Andrew Lunn , linux-kernel@vger.kernel.org To: Florian Fainelli Return-path: Received: from bh-25.webhostbox.net ([208.91.199.152]:56681 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750727AbaJ1TXJ (ORCPT ); Tue, 28 Oct 2014 15:23:09 -0400 Received: from mailnull by bh-25.webhostbox.net with sa-checked (Exim 4.82) (envelope-from ) id 1XjCMG-003QF9-QU for netdev@vger.kernel.org; Tue, 28 Oct 2014 19:23:08 +0000 Content-Disposition: inline In-Reply-To: <544FEC39.4060903@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Oct 28, 2014 at 12:19:21PM -0700, Florian Fainelli wrote: > On 10/26/2014 09:52 AM, Guenter Roeck wrote: > > Setting skb->protocol to a private protocol type may result in warning > > messages such as > > e1000e 0000:00:19.0 em1: checksum_partial proto=dada! > > > > This happens if the L3 protocol is IP or IPv6 and skb->ip_summed is set > > to CHECKSUM_PARTIAL. Looking through the code, it appears that changing > > skb->protocol for transmitted packets is not necessary and may actually > > be harmful. Drop it. > > You could emphasize that overriding skb->protocol prevents purposely > unmodified (from a DSA perspective) network drivers from properly > setting up their transmit checksum offload pointers since they inspect > skb->protocol to setup the IPv4 header or IPv6 header pointers. > Ok, I'll do that. Thanks, Guenter