Merge branch 'gre-lwt-fixes'

Jiri Benc says:

====================
gre: fix lwtunnel support

This patchset fixes a few bugs in ipgre metadata mode implementation.

As an example, in this setup:

ip a a 192.168.1.1/24 dev eth0
ip l a gre1 type gre external
ip l s gre1 up
ip a a 192.168.99.1/24 dev gre1
ip r a 192.168.99.2/32 encap ip dst 192.168.1.2 ttl 10 dev gre1
ping 192.168.99.2

the traffic does not go through before this patchset and does as expected
with it applied.

v3: Back to v1 in order not to break existing users. Dropped patch 3, will
    be fixed in iproute2 instead.
v2: Rejecting invalid configuration, added patch 3, dropped patch for
    ETH_P_TEB (will target net-next).
====================

Signed-off-by: David S. Miller <davem@davemloft.net>