From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753940AbaJ1TTt (ORCPT ); Tue, 28 Oct 2014 15:19:49 -0400 Received: from mail-pa0-f43.google.com ([209.85.220.43]:45870 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750979AbaJ1TTs (ORCPT ); Tue, 28 Oct 2014 15:19:48 -0400 Message-ID: <544FEC39.4060903@gmail.com> Date: Tue, 28 Oct 2014 12:19:21 -0700 From: Florian Fainelli User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Guenter Roeck , netdev@vger.kernel.org CC: "David S. Miller" , Andrew Lunn , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 01/15] net: dsa: Don't set skb->protocol on outgoing tagged packets References: <1414342365-27191-1-git-send-email-linux@roeck-us.net> <1414342365-27191-2-git-send-email-linux@roeck-us.net> In-Reply-To: <1414342365-27191-2-git-send-email-linux@roeck-us.net> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > > Signed-off-by: Guenter Roeck > --- > v2: > - No change > > net/dsa/tag_dsa.c | 2 -- > net/dsa/tag_edsa.c | 2 -- > net/dsa/tag_trailer.c | 2 -- > 3 files changed, 6 deletions(-) > > diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c > index ce90c8b..2dab270 100644 > --- a/net/dsa/tag_dsa.c > +++ b/net/dsa/tag_dsa.c > @@ -63,8 +63,6 @@ static netdev_tx_t dsa_xmit(struct sk_buff *skb, struct net_device *dev) > dsa_header[3] = 0x00; > } > > - skb->protocol = htons(ETH_P_DSA); > - > skb->dev = p->parent->dst->master_netdev; > dev_queue_xmit(skb); > > diff --git a/net/dsa/tag_edsa.c b/net/dsa/tag_edsa.c > index 94fcce7..9aeda59 100644 > --- a/net/dsa/tag_edsa.c > +++ b/net/dsa/tag_edsa.c > @@ -76,8 +76,6 @@ static netdev_tx_t edsa_xmit(struct sk_buff *skb, struct net_device *dev) > edsa_header[7] = 0x00; > } > > - skb->protocol = htons(ETH_P_EDSA); > - > skb->dev = p->parent->dst->master_netdev; > dev_queue_xmit(skb); > > diff --git a/net/dsa/tag_trailer.c b/net/dsa/tag_trailer.c > index 115fdca..e268f9d 100644 > --- a/net/dsa/tag_trailer.c > +++ b/net/dsa/tag_trailer.c > @@ -57,8 +57,6 @@ static netdev_tx_t trailer_xmit(struct sk_buff *skb, struct net_device *dev) > trailer[2] = 0x10; > trailer[3] = 0x00; > > - nskb->protocol = htons(ETH_P_TRAILER); > - > nskb->dev = p->parent->dst->master_netdev; > dev_queue_xmit(nskb); > >