[PATCH 4.6 20/81] vxlan: Accept user specified MTU value when create new vxlan link

[Greg Kroah-Hartman]

4.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chen Haiquan <oc@xxxxxxxxxx>

[ Upstream commit ce577668a426c6a9e2470a09dcd07fbd6e45272a ]

When create a new vxlan link, example:
  ip link add vtap mtu 1440 type vxlan vni 1 dev eth0

The argument "mtu" has no effect, because it is not set to conf->mtu. The
default value is used in vxlan_dev_configure function.

This problem was introduced by commit 0dfbdf4102b9 (vxlan: Factor out device
configuration).

Fixes: 0dfbdf4102b9 (vxlan: Factor out device configuration)
Signed-off-by:  Chen Haiquan <oc@xxxxxxxxxx>
Acked-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/vxlan.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2959,6 +2959,9 @@ static int vxlan_newlink(struct net *src
 	if (data[IFLA_VXLAN_REMCSUM_NOPARTIAL])
 		conf.flags |= VXLAN_F_REMCSUM_NOPARTIAL;
 
+	if (tb[IFLA_MTU])
+		conf.mtu = nla_get_u32(tb[IFLA_MTU]);
+
 	err = vxlan_dev_configure(src_net, dev, &conf);
 	switch (err) {
 	case -ENODEV: