handshake_req_submit() now verifies that the socket has a file.
Fixes: 3b3009ea8abb ("net/handshake: Create a NETLINK service for handling handshake requests") Reviewed-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>