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-rw-r--r--net/8021q/vlan_dev.c10
-rw-r--r--net/8021q/vlan_netlink.c7
2 files changed, 11 insertions, 6 deletions
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index 86ae75b77390..516b0e73263c 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -146,10 +146,12 @@ static netdev_tx_t vlan_dev_hard_start_xmit(struct sk_buff *skb,
static int vlan_dev_change_mtu(struct net_device *dev, int new_mtu)
{
- /* TODO: gotta make sure the underlying layer can handle it,
- * maybe an IFF_VLAN_CAPABLE flag for devices?
- */
- if (vlan_dev_priv(dev)->real_dev->mtu < new_mtu)
+ struct net_device *real_dev = vlan_dev_priv(dev)->real_dev;
+ unsigned int max_mtu = real_dev->mtu;
+
+ if (netif_reduces_vlan_mtu(real_dev))
+ max_mtu -= VLAN_HLEN;
+ if (max_mtu < new_mtu)
return -ERANGE;
dev->mtu = new_mtu;
diff --git a/net/8021q/vlan_netlink.c b/net/8021q/vlan_netlink.c
index c92b52f37d38..1270207f3d7c 100644
--- a/net/8021q/vlan_netlink.c
+++ b/net/8021q/vlan_netlink.c
@@ -118,6 +118,7 @@ static int vlan_newlink(struct net *src_net, struct net_device *dev,
{
struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
struct net_device *real_dev;
+ unsigned int max_mtu;
__be16 proto;
int err;
@@ -144,9 +145,11 @@ static int vlan_newlink(struct net *src_net, struct net_device *dev,
if (err < 0)
return err;
+ max_mtu = netif_reduces_vlan_mtu(real_dev) ? real_dev->mtu - VLAN_HLEN :
+ real_dev->mtu;
if (!tb[IFLA_MTU])
- dev->mtu = real_dev->mtu;
- else if (dev->mtu > real_dev->mtu)
+ dev->mtu = max_mtu;
+ else if (dev->mtu > max_mtu)
return -EINVAL;
err = vlan_changelink(dev, tb, data);