diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 006f1a603102..f36584616e7d 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2230,14 +2230,8 @@ static bool virtnet_validate_features(struct virtio_device *vdev) #define MIN_MTU ETH_MIN_MTU #define MAX_MTU ETH_MAX_MTU -static int virtnet_probe(struct virtio_device *vdev) +static int virtnet_validate(struct virtio_device *vdev) { - int i, err; - 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", __func__); @@ -2247,6 +2241,25 @@ static int virtnet_probe(struct virtio_device *vdev) if (!virtnet_validate_features(vdev)) return -EINVAL; + if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) { + int mtu = virtio_cread16(vdev, + offsetof(struct virtio_net_config, + mtu)); + if (mtu < MIN_MTU) + __virtio_clear_bit(vdev, VIRTIO_NET_F_MTU); + } + + return 0; +} + +static int virtnet_probe(struct virtio_device *vdev) +{ + int i, err; + struct net_device *dev; + struct virtnet_info *vi; + u16 max_queue_pairs; + int mtu; + /* Find if host supports multiqueue virtio_net device */ err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ, struct virtio_net_config, @@ -2362,12 +2375,17 @@ static int virtnet_probe(struct virtio_device *vdev) offsetof(struct virtio_net_config, mtu)); if (mtu < dev->min_mtu) { - __virtio_clear_bit(vdev, VIRTIO_NET_F_MTU); - } else { - dev->mtu = mtu; - dev->max_mtu = mtu; + /* Should never trigger: MTU was previously validated + * in virtnet_validate. + */ + dev_err(&vdev->dev, "device MTU appears to have changed " + "it is now %d < %d", mtu, dev->min_mtu); + goto free_stats; } + dev->mtu = mtu; + dev->max_mtu = mtu; + /* TODO: size buffers correctly in this case. */ if (dev->mtu > ETH_DATA_LEN) vi->big_packets = true; @@ -2548,6 +2566,7 @@ static struct virtio_driver virtio_net_driver = { .driver.name = KBUILD_MODNAME, .driver.owner = THIS_MODULE, .id_table = id_table, + .validate = virtnet_validate, .probe = virtnet_probe, .remove = virtnet_remove, .config_changed = virtnet_config_changed,