From: Aaron Conole Date: Fri, 3 Jun 2016 20:57:12 +0000 (-0400) Subject: virtio-net: Add initial MTU advice feature X-Git-Tag: v4.1.12-111.0.20170918_2215~160 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=b17dcb3fe52ca2bd08f60d47e22394c7dfa7deea;p=users%2Fjedix%2Flinux-maple.git 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 (cherry picked from commit 14de9d114a82a564b94388c95af79a701dc93134) Orabug: 26584452 Signed-off-by: Si-Wei Liu Reviewed-by: Joao Martins --- diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 63e5510c7888e..4634cba53b703 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1719,6 +1719,7 @@ 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", @@ -1835,6 +1836,14 @@ 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; @@ -2025,6 +2034,7 @@ 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 = { diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h index 7bbee79ca2933..fb5d30aa114f1 100644 --- a/include/uapi/linux/virtio_net.h +++ b/include/uapi/linux/virtio_net.h @@ -54,6 +54,7 @@ #define VIRTIO_NET_F_MQ 22 /* Device supports Receive Flow * Steering */ #define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */ +#define VIRTIO_NET_F_MTU 25 /* Initial MTU advice */ #ifndef VIRTIO_NET_NO_LEGACY #define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */ @@ -72,6 +73,8 @@ struct virtio_net_config { * Legal values are between 1 and 0x8000 */ __u16 max_virtqueue_pairs; + /* Default maximum transmit unit advice */ + __u16 mtu; } __attribute__((packed)); /*