net: dsa: move dsa slave destroy code to slave.c

Move dsa slave dedicated code from dsa_switch_destroy to a new
dsa_slave_destroy function in slave.c.
Add the netif_carrier_off and phy_disconnect calls in order to
correctly cleanup the netdev state and PHY state machine.
Signed-off-by: NFrode Isaksen <fisaksen@baylibre.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/dsa/dsa.c

@@ -456,8 +456,7 @@ static void dsa_switch_destroy(struct dsa_switch *ds)
 		if (!ds->ports[port])
 			continue;
 
-		unregister_netdev(ds->ports[port]);
-		free_netdev(ds->ports[port]);
+		dsa_slave_destroy(ds->ports[port]);
 	}
 
 	mdiobus_unregister(ds->slave_mii_bus);

net/dsa/dsa_priv.h

@@ -61,6 +61,7 @@ extern const struct dsa_device_ops notag_netdev_ops;
 void dsa_slave_mii_bus_init(struct dsa_switch *ds);
 int dsa_slave_create(struct dsa_switch *ds, struct device *parent,
 		     int port, char *name);
+void dsa_slave_destroy(struct net_device *slave_dev);
 int dsa_slave_suspend(struct net_device *slave_dev);
 int dsa_slave_resume(struct net_device *slave_dev);
 int dsa_slave_netdevice_event(struct notifier_block *unused,

net/dsa/slave.c

@@ -1212,6 +1212,17 @@ int dsa_slave_create(struct dsa_switch *ds, struct device *parent,
 	return 0;
 }
 
+void dsa_slave_destroy(struct net_device *slave_dev)
+{
+	struct dsa_slave_priv *p = netdev_priv(slave_dev);
+
+	netif_carrier_off(slave_dev);
+	if (p->phy)
+		phy_disconnect(p->phy);
+	unregister_netdev(slave_dev);
+	free_netdev(slave_dev);
+}
+
 static bool dsa_slave_dev_check(struct net_device *dev)
 {
 	return dev->netdev_ops == &dsa_slave_netdev_ops;