net: ethernet: ti: davinci_emac: fix device reference leak

Make sure to drop the references taken by bus_find_device() before
returning from emac_dev_open().

Note that phy_connect still takes a reference to the phy device.

Fixes: 5d69e007 ("net: davinci_emac: switch to new mdio")
Cc: Mugunthan V N <mugunthanvnm@ti.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: linux-omap@vger.kernel.org
Signed-off-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/davinci_emac.c

@@ -1410,6 +1410,7 @@ static int emac_dev_open(struct net_device *ndev)
 	int i = 0;
 	struct emac_priv *priv = netdev_priv(ndev);
 	struct phy_device *phydev = NULL;
+	struct device *phy = NULL;
 
 	ret = pm_runtime_get_sync(&priv->pdev->dev);
 	if (ret < 0) {
@@ -1488,19 +1489,20 @@ static int emac_dev_open(struct net_device *ndev)
 
 	/* use the first phy on the bus if pdata did not give us a phy id */
 	if (!phydev && !priv->phy_id) {
-		struct device *phy;
-
 		phy = bus_find_device(&mdio_bus_type, NULL, NULL,
 				      match_first_device);
-		if (phy)
+		if (phy) {
 			priv->phy_id = dev_name(phy);
+			if (!priv->phy_id || !*priv->phy_id)
+				put_device(phy);
+		}
 	}
 
 	if (!phydev && priv->phy_id && *priv->phy_id) {
 		phydev = phy_connect(ndev, priv->phy_id,
 				     &emac_adjust_link,
 				     PHY_INTERFACE_MODE_MII);
-
+		put_device(phy);	/* reference taken by bus_find_device */
 		if (IS_ERR(phydev)) {
 			dev_err(emac_dev, "could not connect to phy %s\n",
 				priv->phy_id);