qeth: delete napi struct when removing a qeth device

commit 7831b4ff0d926e0deeaabef9db8800ed069a2757 upstream.

A qeth_card contains a napi_struct linked to the net_device during
device probing. This struct must be deleted when removing the qeth
device, otherwise Panic on oops can occur when qeth devices are
repeatedly removed and added.

Fixes: a1c3ed4 ("qeth: NAPI support for l2 and l3 discipline")
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Tested-by: Alexander Klein <ALKL@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Ursula Braun

drivers/s390/net/qeth_l2_main.c

@@ -1051,6 +1051,7 @@ static void qeth_l2_remove_device(struct ccwgroup_device *cgdev)
 		qeth_l2_set_offline(cgdev);
 
 	if (card->dev) {
+		netif_napi_del(&card->napi);
 		unregister_netdev(card->dev);
 		card->dev = NULL;
 	}

drivers/s390/net/qeth_l3_main.c

@@ -3246,6 +3246,7 @@ static void qeth_l3_remove_device(struct ccwgroup_device *cgdev)
 		qeth_l3_set_offline(cgdev);
 
 	if (card->dev) {
+		netif_napi_del(&card->napi);
 		unregister_netdev(card->dev);
 		card->dev = NULL;
 	}