net/rds: Add missing mutex_unlock

Add a mutex_unlock missing on the error path.  In each case, whenever the
label out is reached from elsewhere in the function, mutex is not locked.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression E1;
@@

* mutex_lock(E1);
  <+... when != E1
  if (...) {
    ... when != E1
*   return ...;
  }
  ...+>
* mutex_unlock(E1);
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Reviewed-by: Zach Brown <zach.brown@oracle.com>
Acked-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/ib_cm.c

@@ -475,6 +475,7 @@ int rds_ib_cm_handle_connect(struct rdma_cm_id *cm_id,
 	err = rds_ib_setup_qp(conn);
 	if (err) {
 		rds_ib_conn_error(conn, "rds_ib_setup_qp failed (%d)\n", err);
+		mutex_unlock(&conn->c_cm_lock);
 		goto out;
 	}
 

net/rds/iw_cm.c

@@ -452,6 +452,7 @@ int rds_iw_cm_handle_connect(struct rdma_cm_id *cm_id,
 	err = rds_iw_setup_qp(conn);
 	if (err) {
 		rds_iw_conn_error(conn, "rds_iw_setup_qp failed (%d)\n", err);
+		mutex_unlock(&conn->c_cm_lock);
 		goto out;
 	}