From 14de9d114a82a564b94388c95af79a701dc93134 Mon Sep 17 00:00:00 2001 From: Aaron Conole Date: Fri, 3 Jun 2016 16:57:12 -0400 Subject: virtio-net: Add initial MTU advice feature This commit adds the feature bit and associated mtu device entry for the virtio network device. When a virtio device comes up, it checks the feature bit for the VIRTIO_NET_F_MTU feature. If such feature bit is enabled, the driver will read the advised MTU and use it as the initial value. Signed-off-by: Aaron Conole Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'drivers') diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index e0638e556fe7..192f321247b9 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1780,6 +1780,7 @@ static int virtnet_probe(struct virtio_device *vdev) struct net_device *dev; struct virtnet_info *vi; u16 max_queue_pairs; + int mtu; if (!vdev->config->get) { dev_err(&vdev->dev, "%s failure: config access disabled\n", @@ -1896,6 +1897,14 @@ 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)) { + mtu = virtio_cread16(vdev, + offsetof(struct virtio_net_config, + mtu)); + if (virtnet_change_mtu(dev, mtu)) + __virtio_clear_bit(vdev, VIRTIO_NET_F_MTU); + } + if (vi->any_header_sg) dev->needed_headroom = vi->hdr_len; @@ -2067,6 +2076,7 @@ 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 = { -- cgit v1.2.3