net/smc: recvmsg and splice_read should return 0 after shutdown

When a socket was connected and is now shut down for read, return 0 to
indicate end of data in recvmsg and splice_read (like TCP) and do not
return ENOTCONN. This behavior is required by the socket api.
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/af_smc.c

@@ -1505,6 +1505,11 @@ static int smc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 
 	smc = smc_sk(sk);
 	lock_sock(sk);
+	if (sk->sk_state == SMC_CLOSED && (sk->sk_shutdown & RCV_SHUTDOWN)) {
+		/* socket was connected before, no more data to read */
+		rc = 0;
+		goto out;
+	}
 	if ((sk->sk_state == SMC_INIT) ||
 	    (sk->sk_state == SMC_LISTEN) ||
 	    (sk->sk_state == SMC_CLOSED))
@@ -1840,7 +1845,11 @@ static ssize_t smc_splice_read(struct socket *sock, loff_t *ppos,
 
 	smc = smc_sk(sk);
 	lock_sock(sk);
-
+	if (sk->sk_state == SMC_CLOSED && (sk->sk_shutdown & RCV_SHUTDOWN)) {
+		/* socket was connected before, no more data to read */
+		rc = 0;
+		goto out;
+	}
 	if (sk->sk_state == SMC_INIT ||
 	    sk->sk_state == SMC_LISTEN ||
 	    sk->sk_state == SMC_CLOSED)