From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH] virtio: don't set VIRTIO_NET_HDR_F_DATA_VALID on xmit Date: Wed, 18 Jan 2017 11:54:21 +0800 Message-ID: <34158479-8d4a-3761-a02e-66c474aca53e@redhat.com> References: <20170117181351.98291-1-rolf.neugebauer@docker.com> <20170117202515-mutt-send-email-mst@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Cc: netdev@vger.kernel.org, davem@davemloft.net, rppt@linux.vnet.ibm.com To: "Michael S. Tsirkin" , Rolf Neugebauer Return-path: Received: from mx1.redhat.com ([209.132.183.28]:56914 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751132AbdARDyZ (ORCPT ); Tue, 17 Jan 2017 22:54:25 -0500 In-Reply-To: <20170117202515-mutt-send-email-mst@kernel.org> Sender: netdev-owner@vger.kernel.org List-ID: On 2017年01月18日 02:27, Michael S. Tsirkin wrote: > On Tue, Jan 17, 2017 at 06:13:51PM +0000, Rolf Neugebauer wrote: >> This patch part reverts fd2a0437dc33 and e858fae2b0b8 which introduced a >> subtle change in how the virtio_net flags are derived from the SKBs >> ip_summed field. >> >> With the above commits, the flags are set to VIRTIO_NET_HDR_F_DATA_VALID >> when ip_summed == CHECKSUM_UNNECESSARY, thus treating it differently to >> ip_summed == CHECKSUM_NONE, which should be the same. >> >> Further, the virtio spec 1.0 / CS04 explicitly says that >> VIRTIO_NET_HDR_F_DATA_VALID must not be set by the driver. >> >> Signed-off-by: Rolf Neugebauer > Fixes: fd2a0437dc33 ("virtio_net: introduce virtio_net_hdr_{from,to}_skb") > Fixes: e858fae2b0b8 (" virtio_net: use common code for virtio_net_hdr and skb GSO conversion") > Acked-by: Michael S. Tsirkin > > Should be backported into stable as well. Looks like a side effect is that we will never see this on receive path? We probably need a hint for virtio_net_hdr_from_skb(). Thanks > > >> --- >> include/linux/virtio_net.h | 2 -- >> 1 file changed, 2 deletions(-) >> >> diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h >> index 66204007d7ac..56436472ccc7 100644 >> --- a/include/linux/virtio_net.h >> +++ b/include/linux/virtio_net.h >> @@ -91,8 +91,6 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, >> skb_checksum_start_offset(skb)); >> hdr->csum_offset = __cpu_to_virtio16(little_endian, >> skb->csum_offset); >> - } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { >> - hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; >> } /* else everything is zero */ >> >> return 0; >> -- >> 2.11.0