dummy: Add ndo_uninit().

In register_netdevice(), when ndo_init() is successful and later
some error occurred, ndo_uninit() will be called.
So dummy deivce is desirable to implement ndo_uninit() method
to free percpu stats for this case.
And, ndo_uninit() is also called along with dev->destructor() when
device is unregistered, so in order to prevent dev->dstats from
being freed twice, dev->destructor is modified to free_netdev().

Signed-off-by: Hiroaki SHIMODA <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/dummy.c

···
 	return 0;
 }
 
-static void dummy_dev_free(struct net_device *dev)
+static void dummy_dev_uninit(struct net_device *dev)
 {
 	free_percpu(dev->dstats);
-	free_netdev(dev);
 }
 
 static const struct net_device_ops dummy_netdev_ops = {
 	.ndo_init		= dummy_dev_init,
+	.ndo_uninit		= dummy_dev_uninit,
 	.ndo_start_xmit		= dummy_xmit,
 	.ndo_validate_addr	= eth_validate_addr,
 	.ndo_set_rx_mode	= set_multicast_list,
···
 
 	/* Initialize the device structure. */
 	dev->netdev_ops = &dummy_netdev_ops;
-	dev->destructor = dummy_dev_free;
+	dev->destructor = free_netdev;
 
 	/* Fill in device structure with ethernet-generic values. */
 	dev->tx_queue_len = 0;