From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934615Ab3CZPGy (ORCPT ); Tue, 26 Mar 2013 11:06:54 -0400 Received: from mail-pd0-f170.google.com ([209.85.192.170]:52928 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934567Ab3CZPGw (ORCPT ); Tue, 26 Mar 2013 11:06:52 -0400 Message-ID: <1364310407.1716.16.camel@edumazet-glaptop> Subject: Re: [net-next 1/5] macvtap: set transport header before passing skb to lower device From: Eric Dumazet To: Jason Wang Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, mst@redhat.com, Eric Dumazet Date: Tue, 26 Mar 2013 08:06:47 -0700 In-Reply-To: <1364278799-37285-2-git-send-email-jasowang@redhat.com> References: <1364278799-37285-1-git-send-email-jasowang@redhat.com> <1364278799-37285-2-git-send-email-jasowang@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2013-03-26 at 14:19 +0800, Jason Wang wrote: > Set the transport header for 1) some drivers (e.g ixgbe) needs l4 header 2) > precise packet length estimation (introduced in 1def9238) needs l4 header to > compute header length. > > For the packets with partial checksum, the patch just set the transport header > to csum_start. Otherwise tries to use skb_flow_dissect() to get l4 offset, if it > fails, just pretend no l4 header. > > Cc: Eric Dumazet > Signed-off-by: Jason Wang > --- > drivers/net/macvtap.c | 9 +++++++++ > 1 files changed, 9 insertions(+), 0 deletions(-) > > diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > index a449439..acf6450 100644 > --- a/drivers/net/macvtap.c > +++ b/drivers/net/macvtap.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > > /* > * A macvtap queue is the central object of this driver, it connects > @@ -645,6 +646,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, > int vnet_hdr_len = 0; > int copylen = 0; > bool zerocopy = false; > + struct flow_keys keys; > > if (q->flags & IFF_VNET_HDR) { > vnet_hdr_len = q->vnet_hdr_sz; > @@ -725,6 +727,13 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, > goto err_kfree; > } > > + if (skb->ip_summed == CHECKSUM_PARTIAL) where ip_summed is set to this value ? > + skb_set_transport_header(skb, skb_checksum_start_offset(skb)); > + else if (skb_flow_dissect(skb, &keys)) > + skb_set_transport_header(skb, keys.thoff); > + else > + skb_set_transport_header(skb, ETH_HLEN); > + > rcu_read_lock_bh(); > vlan = rcu_dereference_bh(q->vlan); > /* copy skb_ubuf_info for callback when skb has no error */ This driver has nice helpers. You should add this code in a helper as well. Because its not clear at this point if csum_start/csum_offset/ip_summed are consistent.