inet: restore gso for vxlan
inet: restore gso for vxlan

Alexei reported a performance regression on vxlan, caused
by commit 3347c9602955 "ipv4: gso: make inet_gso_segment() stackable"

GSO vxlan packets were not properly segmented, adding IP fragments
while they were not expected.

Rename 'bool tunnel' to 'bool encap', and add a new boolean
to express the fact that UDP should be fragmented.
This fragmentation is triggered by skb->encapsulation being set.

Remove a "skb->encapsulation = 1" added in above commit,
as its not needed, as frags inherit skb->frag from original
GSO skb.

Reported-by: Alexei Starovoitov <c24c0248770ae98831f8a654310d4c2e07514c61@plumgrid.com>
Signed-off-by: Eric Dumazet <312c7d941f03386814be517ffdb3e0eb6624e275@google.com>
Tested-by: Alexei Starovoitov <c24c0248770ae98831f8a654310d4c2e07514c61@plumgrid.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs