net/rds: do proper house keeping if connection fails in rds_tcp_conn_connect

I see two problems if we consider the sock->ops->connect attempt to fail in
rds_tcp_conn_connect. The first issue is that for example we don't remove the
previously added rds_tcp_connection item to rds_tcp_tc_list at
rds_tcp_set_callbacks, which means that on a next reconnect attempt for the
same rds_connection, when rds_tcp_conn_connect is called we can again call
rds_tcp_set_callbacks, resulting in duplicated items on rds_tcp_tc_list,
leading to list corruption: to avoid this just make sure we call
properly rds_tcp_restore_callbacks before we exit. The second issue
is that we should also release the sock properly, by setting sock = NULL
only if we are returning without error.

Signed-off-by: Herton R. Krzesinski <herton@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/tcp_connect.c

@@ -106,11 +106,14 @@ int rds_tcp_conn_connect(struct rds_connection *conn)
 	rds_tcp_set_callbacks(sock, conn);
 	ret = sock->ops->connect(sock, (struct sockaddr *)&dest, sizeof(dest),
 				 O_NONBLOCK);
-	sock = NULL;
 
 	rdsdebug("connect to address %pI4 returned %d\n", &conn->c_faddr, ret);
 	if (ret == -EINPROGRESS)
 		ret = 0;
+	if (ret == 0)
+		sock = NULL;
+	else
+		rds_tcp_restore_callbacks(sock, conn->c_transport_data);
 
 out:
 	if (sock)