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

This reverts commit 5815901c29c2936d7acbed2683d5807b4ae53ede 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 5c5699c08575da33d6b1668bac06bfccc8ff260f..00d4371d457369f0f03bff69e26e3761e5b29085 100644 (file)
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -396,6 +396,7 @@ 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->addr_len           = 4;
        dev->features           |= NETIF_F_LLTX;