From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935867Ab3DJNd1 (ORCPT ); Wed, 10 Apr 2013 09:33:27 -0400 Received: from smtp.eu.citrix.com ([46.33.159.39]:62759 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752466Ab3DJNdZ (ORCPT ); Wed, 10 Apr 2013 09:33:25 -0400 X-IronPort-AV: E=Sophos;i="4.87,447,1363132800"; d="scan'208";a="3417565" Message-ID: <1365600803.27868.60.camel@zakaz.uk.xensource.com> Subject: Re: [net-next 4/5] netback: set transport header before passing it to kernel From: Ian Campbell To: Jason Wang CC: "davem@davemloft.net" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "mst@redhat.com" , "Eric Dumazet" Date: Wed, 10 Apr 2013 14:33:23 +0100 In-Reply-To: <1364278799-37285-5-git-send-email-jasowang@redhat.com> References: <1364278799-37285-1-git-send-email-jasowang@redhat.com> <1364278799-37285-5-git-send-email-jasowang@redhat.com> Organization: Citrix Systems, Inc. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2013-03-26 at 06:19 +0000, Jason Wang wrote: > Currently, for the packets receives from netback, before doing header check, > kernel just reset the transport header in netif_receive_skb() which pretends non > l4 header. This is suboptimal for precise packet length estimation (introduced > in 1def9238: net_sched: more precise pkt_len computation) which needs correct l4 > header for gso packets. > > The patch just reuse the header probed by netback for partial checksum packets > and tries to use skb_flow_dissect() for other cases, if both fail, just pretend > no l4 header. > > Cc: Eric Dumazet > Cc: Ian Campbell > Signed-off-by: Jason Wang > --- > drivers/net/xen-netback/netback.c | 12 ++++++++++++ > 1 files changed, 12 insertions(+), 0 deletions(-) > > diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c > index aa28550..fc8faa7 100644 > --- a/drivers/net/xen-netback/netback.c > +++ b/drivers/net/xen-netback/netback.c > @@ -39,6 +39,7 @@ > #include > > #include > +#include > > #include > #include > @@ -1184,6 +1185,7 @@ static int checksum_setup(struct xenvif *vif, struct sk_buff *skb) > if (th >= skb_tail_pointer(skb)) > goto out; > > + skb_set_transport_header(skb, 4 * iph->ihl); > skb->csum_start = th - skb->head; Should the use of th here (and perhaps above) be replaced with skb_transport_header() too? > switch (iph->protocol) { > case IPPROTO_TCP: > @@ -1495,6 +1497,7 @@ static void xen_netbk_tx_submit(struct xen_netbk *netbk) > > skb->dev = vif->dev; > skb->protocol = eth_type_trans(skb, skb->dev); > + skb_reset_network_header(skb); > > if (checksum_setup(vif, skb)) { > netdev_dbg(vif->dev, > @@ -1503,6 +1506,15 @@ static void xen_netbk_tx_submit(struct xen_netbk *netbk) > continue; > } > > + if (!skb_transport_header_was_set(skb)) { > + struct flow_keys keys; > + > + if (skb_flow_dissect(skb, &keys)) > + skb_set_transport_header(skb, keys.thoff); > + else > + skb_reset_transport_header(skb); > + } > + > vif->dev->stats.rx_bytes += skb->len; > vif->dev->stats.rx_packets++; >