virtio_net: large tx MTU support

We don't really have a max tx packet size limit, so allow configuring
the device with up to 64k tx MTU.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index e6b5d6ef9ea8223868375a0d2f184869b200b447..71ca29cc184d84e4c4fdd0cbbda8656c3da6801a 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -613,6 +613,17 @@ static struct ethtool_ops virtnet_ethtool_ops = {
        .set_tso = ethtool_op_set_tso,
 };
 
+#define MIN_MTU 68
+#define MAX_MTU 65535
+
+static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
+{
+       if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
+               return -EINVAL;
+       dev->mtu = new_mtu;
+       return 0;
+}
+
 static int virtnet_probe(struct virtio_device *vdev)
 {
        int err;
@@ -628,6 +639,7 @@ static int virtnet_probe(struct virtio_device *vdev)
        dev->open = virtnet_open;
        dev->stop = virtnet_close;
        dev->hard_start_xmit = start_xmit;
+       dev->change_mtu = virtnet_change_mtu;
        dev->features = NETIF_F_HIGHDMA;
 #ifdef CONFIG_NET_POLL_CONTROLLER
        dev->poll_controller = virtnet_netpoll;