net/smc: avoid fallback in case of non-blocking connect

net/smc: avoid fallback in case of non-blocking connect

FASTOPEN is not possible with SMC. sendmsg() with msg_flag MSG_FASTOPEN
triggers a fallback to TCP if the socket is in state SMC_INIT.
But if a nonblocking connect is already started, fallback to TCP
is no longer possible, even though the socket may still be in state
SMC_INIT.
And if a nonblocking connect is already started, a listen() call
does not make sense.

Reported-by: [email protected]
Fixes: 50717a37db032 ("net/smc: nonblocking connect rework")
Signed-off-by: Ursula Braun <[email protected]>
Signed-off-by: Karsten Graul <[email protected]>
Signed-off-by: David S. Miller <[email protected]>