Revert "vti4: Don't override MTU passed on link creation via IFLA_MTU"

This reverts commit 08a049c84408dfd0240a3340681486779c167cc8 which is
03080e5ec727 ("vti4: Don't override MTU passed on link creation via
IFLA_MTU") upstream as it causes test failures.

This commit should not have been backported to anything older than 4.16,
despite what the changelog said as the mtu must be set in older kernels,
unlike is needed in 4.16 and newer.

Thanks to Alistair Strachan for the debugging help figuring this out,
and for 'git bisect' for making my life a whole lot easier.

Cc: Alistair Strachan <astrachan@google.com>
Cc: Stefano Brivio <sbrivio@redhat.com>
Cc: Sabrina Dubroca <sd@queasysnail.net>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index a3df032522a92875a3720d8b381b9ed7334d2e59..c35e0aa57e66c260700927e90bcd45d6f8df0424 100644 (file)
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -365,6 +365,7 @@ static int vti_tunnel_init(struct net_device *dev)
        memcpy(dev->dev_addr, &iph->saddr, 4);
        memcpy(dev->broadcast, &iph->daddr, 4);
 
+       dev->mtu                = ETH_DATA_LEN;
        dev->flags              = IFF_NOARP;
        dev->iflink             = 0;
        dev->addr_len           = 4;