net/smc: add receive timeout check

The SMC receive function currently lacks a timeout check under the
condition that no data were received and no data are available. This
patch adds such a check.
Signed-off-by: NHans Wippel <hwippel@linux.vnet.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/smc/smc_rx.c

@@ -148,6 +148,8 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, size_t len,
 				read_done = sock_intr_errno(timeo);
 				break;
 			}
+			if (!timeo)
+				return -EAGAIN;
 		}
 
 		if (!atomic_read(&conn->bytes_to_rcv)) {