net: dsa: fix a leaked reference by adding missing of_node_put

The call to of_parse_phandle returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.

Detected by coccinelle with the following warnings:
./net/dsa/port.c:294:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 284, but without a corresponding object release within this function.
./net/dsa/dsa2.c:627:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 618, but without a corresponding object release within this function.
./net/dsa/dsa2.c:630:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 618, but without a corresponding object release within this function.
./net/dsa/dsa2.c:636:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 618, but without a corresponding object release within this function.
./net/dsa/dsa2.c:639:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 618, but without a corresponding object release within this function.
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Vivien Didelot <vivien.didelot@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Vivien Didelot <vivien.didelot@gmail.com>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/dsa2.c

@@ -612,8 +612,8 @@ static int dsa_switch_parse_ports_of(struct dsa_switch *ds,
 {
 	struct device_node *ports, *port;
 	struct dsa_port *dp;
+	int err = 0;
 	u32 reg;
-	int err;
 
 	ports = of_get_child_by_name(dn, "ports");
 	if (!ports) {
@@ -624,19 +624,23 @@ static int dsa_switch_parse_ports_of(struct dsa_switch *ds,
 	for_each_available_child_of_node(ports, port) {
 		err = of_property_read_u32(port, "reg", &reg);
 		if (err)
-			return err;
+			goto out_put_node;
 
-		if (reg >= ds->num_ports)
-			return -EINVAL;
+		if (reg >= ds->num_ports) {
+			err = -EINVAL;
+			goto out_put_node;
+		}
 
 		dp = &ds->ports[reg];
 
 		err = dsa_port_parse_of(dp, port);
 		if (err)
-			return err;
+			goto out_put_node;
 	}
 
-	return 0;
+out_put_node:
+	of_node_put(ports);
+	return err;
 }
 
 static int dsa_switch_parse_member_of(struct dsa_switch *ds,

net/dsa/port.c

@@ -292,6 +292,7 @@ static struct phy_device *dsa_port_get_phy_device(struct dsa_port *dp)
 		return ERR_PTR(-EPROBE_DEFER);
 	}
 
+	of_node_put(phy_dn);
 	return phydev;
 }