1 files changed, 25 insertions, 11 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 65439188c582..e992c6a05f86 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2367,29 +2367,43 @@ static void vxlan_set_multicast_list(struct net_device *dev)
 {
 }
 
-static int vxlan_change_mtu(struct net_device *dev, int new_mtu)
+static int __vxlan_change_mtu(struct net_device *dev,
+                              struct net_device *lowerdev,
+                              struct vxlan_rdst *dst, int new_mtu, bool strict)
 {
-        struct vxlan_dev *vxlan = netdev_priv(dev);
-        struct vxlan_rdst *dst = &vxlan->default_dst;
-        struct net_device *lowerdev;
-        int max_mtu;
+        int max_mtu = IP_MAX_MTU;
 
-        lowerdev = __dev_get_by_index(vxlan->net, dst->remote_ifindex);
-        if (lowerdev == NULL)
-                return eth_change_mtu(dev, new_mtu);
+        if (lowerdev)
+                max_mtu = lowerdev->mtu;
 
         if (dst->remote_ip.sa.sa_family == AF_INET6)
-                max_mtu = lowerdev->mtu - VXLAN6_HEADROOM;
+                max_mtu -= VXLAN6_HEADROOM;
         else
-                max_mtu = lowerdev->mtu - VXLAN_HEADROOM;
+                max_mtu -= VXLAN_HEADROOM;
 
-        if (new_mtu < 68 || new_mtu > max_mtu)
+        if (new_mtu < 68)
                 return -EINVAL;
 
+        if (new_mtu > max_mtu) {
+                if (strict)
+                        return -EINVAL;
+
+                new_mtu = max_mtu;
+        }
+
         dev->mtu = new_mtu;
         return 0;
 }
 
+static int vxlan_change_mtu(struct net_device *dev, int new_mtu)
+{
+        struct vxlan_dev *vxlan = netdev_priv(dev);
+        struct vxlan_rdst *dst = &vxlan->default_dst;
+        struct net_device *lowerdev = __dev_get_by_index(vxlan->net,
+                                                         dst->remote_ifindex);
+        return __vxlan_change_mtu(dev, lowerdev, dst, new_mtu, true);
+}
+
 static int egress_ipv4_tun_info(struct net_device *dev, struct sk_buff *skb,
                                 struct ip_tunnel_info *info,
                                 __be16 sport, __be16 dport)