From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753537AbcFBQRD (ORCPT ); Thu, 2 Jun 2016 12:17:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50532 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752251AbcFBQRA (ORCPT ); Thu, 2 Jun 2016 12:17:00 -0400 Date: Thu, 2 Jun 2016 19:16:57 +0300 From: "Michael S. Tsirkin" To: Aaron Conole Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH -next 2/2] virtio_net: Read the advised MTU Message-ID: <20160602191632-mutt-send-email-mst@redhat.com> References: <1464882211-18723-1-git-send-email-aconole@redhat.com> <1464882211-18723-3-git-send-email-aconole@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1464882211-18723-3-git-send-email-aconole@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 02 Jun 2016 16:17:00 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 02, 2016 at 11:43:31AM -0400, Aaron Conole wrote: > This patch checks the feature bit for the VIRTIO_NET_F_MTU feature. If it > exists, read the advised MTU and use it. > > No proper error handling is provided for the case where a user changes the > negotiated MTU. A future commit will add proper error handling. Instead, a > warning is emitted if the guest changes the device MTU after previously > being given advice. I don't see a warning and I don't think it's needed. Patch is ok commit log isn't. > Signed-off-by: Aaron Conole > --- > drivers/net/virtio_net.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index e0638e5..ef5ee01 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -1896,6 +1896,12 @@ static int virtnet_probe(struct virtio_device *vdev) > if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) > vi->has_cvq = true; > > + if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) { > + dev->mtu = virtio_cread16(vdev, > + offsetof(struct virtio_net_config, > + mtu)); > + } > + > if (vi->any_header_sg) > dev->needed_headroom = vi->hdr_len; > > @@ -2067,6 +2073,7 @@ static unsigned int features[] = { > VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, > VIRTIO_NET_F_CTRL_MAC_ADDR, > VIRTIO_F_ANY_LAYOUT, > + VIRTIO_NET_F_MTU, > }; > > static struct virtio_driver virtio_net_driver = { > -- > 2.5.5