enic: do not overwrite error code

BugLink: https://bugs.launchpad.net/bugs/1881356

commit 56f77227 upstream.

In failure path, we overwrite err to what vnic_rq_disable() returns. In
case it returns 0, enic_open() returns success in case of error.
Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Fixes: e8588e26 ("enic: enable rq before updating rq descriptors")
Signed-off-by: Govindarajulu Varadarajan <gvaradar@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

drivers/net/ethernet/cisco/enic/enic_main.c

@@ -1708,7 +1708,7 @@ static int enic_open(struct net_device *netdev)
 {
 	struct enic *enic = netdev_priv(netdev);
 	unsigned int i;
-	int err;
+	int err, ret;
 
 	err = enic_request_intr(enic);
 	if (err) {
@@ -1766,10 +1766,9 @@ static int enic_open(struct net_device *netdev)
 
 err_out_free_rq:
 	for (i = 0; i < enic->rq_count; i++) {
-		err = vnic_rq_disable(&enic->rq[i]);
-		if (err)
-			return err;
-		vnic_rq_clean(&enic->rq[i], enic_free_rq_buf);
+		ret = vnic_rq_disable(&enic->rq[i]);
+		if (!ret)
+			vnic_rq_clean(&enic->rq[i], enic_free_rq_buf);
 	}
 	enic_dev_notify_unset(enic);
 err_out_free_intr: