Re: [PATCH net-next 5/6] net: use core MTU range checking in virt drivers
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2016-10-19 14:16:57
Also in:
lkml, virtualization
On Tue, Oct 18, 2016 at 10:33:32PM -0400, Jarod Wilson wrote:
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index fad84f3..4885a42 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c@@ -1419,17 +1419,6 @@ static const struct ethtool_ops virtnet_ethtool_ops = { .set_settings = virtnet_set_settings, }; -#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 const struct net_device_ops virtnet_netdev = { .ndo_open = virtnet_open, .ndo_stop = virtnet_close,@@ -1437,7 +1426,6 @@ static const struct net_device_ops virtnet_netdev = { .ndo_validate_addr = eth_validate_addr, .ndo_set_mac_address = virtnet_set_mac_address, .ndo_set_rx_mode = virtnet_set_rx_mode, - .ndo_change_mtu = virtnet_change_mtu, .ndo_get_stats64 = virtnet_stats, .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid, .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,@@ -1748,6 +1736,9 @@ static bool virtnet_validate_features(struct virtio_device *vdev) return true; } +#define MIN_MTU ETH_MIN_MTU +#define MAX_MTU 65535 +
Do we need a common macro for this?
quoted hunk ↗ jump to hunk
static int virtnet_probe(struct virtio_device *vdev) { int i, err;@@ -1821,6 +1812,10 @@ static int virtnet_probe(struct virtio_device *vdev) dev->vlan_features = dev->features; + /* MTU range: 68 - 65535 */ + dev->min_mtu = MIN_MTU; + dev->max_mtu = MAX_MTU; + /* Configuration may specify what MAC to use. Otherwise random. */ if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) virtio_cread_bytes(vdev,@@ -1875,8 +1870,10 @@ static int virtnet_probe(struct virtio_device *vdev) mtu = virtio_cread16(vdev, offsetof(struct virtio_net_config, mtu)); - if (virtnet_change_mtu(dev, mtu)) + if (mtu >= dev->min_mtu && mtu <= dev->max_mtu) { + dev->mtu = mtu; __virtio_clear_bit(vdev, VIRTIO_NET_F_MTU);
I think the logic is wrong here: If mtu is legal, we set it but do not tell host. If it's out of range we tell host we use it but don't actually. Should be the reverse.
+ } } if (vi->any_header_sg)
-- MST