qeth: avoid crash after detach of replugged device

If a qeth device is plugged off, setting the device online stops in
state HARDSETUP and a failure is reported to the base cio-layer
causing halt/clear to be invoked. Replugging the device again triggers
a qeth recovery without notification of the cio-layer. If a device
is ungrouped in this state, the qeth set_offline function is not
invoked, because the corresponding ccwgroup device is not in state
ONLINE. Then incoming traffic is still handled by the qdio layer
resulting in a crash in qeth_l<x>_qdio_input_handler, because (part
of) the qeth data structures for this device are already removed.
Solution: After replugging the device qeth recovery should lead to a
working net device. Thus a "LAN offline" result when setting a qeth
device online must not report a failure to the base cio-layer.

Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_l2_main.c

@@ -839,6 +839,7 @@ static void qeth_l2_remove_device(struct ccwgroup_device *cgdev)
 {
 	struct qeth_card *card = dev_get_drvdata(&cgdev->dev);
 
+	qeth_set_allowed_threads(card, 0, 1);
 	wait_event(card->wait_q, qeth_threads_running(card, 0xffffffff) == 0);
 
 	if (cgdev->state == CCWGROUP_ONLINE) {
@@ -974,8 +975,9 @@ static int __qeth_l2_set_online(struct ccwgroup_device *gdev, int recovery_mode)
 			dev_warn(&card->gdev->dev,
 				"The LAN is offline\n");
 			card->lan_online = 0;
+			return 0;
 		}
-		return rc;
+		goto out_remove;
 	} else
 		card->lan_online = 1;
 

drivers/s390/net/qeth_l3_main.c

@@ -3070,6 +3070,7 @@ static void qeth_l3_remove_device(struct ccwgroup_device *cgdev)
 {
 	struct qeth_card *card = dev_get_drvdata(&cgdev->dev);
 
+	qeth_set_allowed_threads(card, 0, 1);
 	wait_event(card->wait_q, qeth_threads_running(card, 0xffffffff) == 0);
 
 	if (cgdev->state == CCWGROUP_ONLINE) {
@@ -3141,8 +3142,9 @@ static int __qeth_l3_set_online(struct ccwgroup_device *gdev, int recovery_mode)
 			dev_warn(&card->gdev->dev,
 				"The LAN is offline\n");
 			card->lan_online = 0;
+			return 0;
 		}
-		return rc;
+		goto out_remove;
 	} else
 		card->lan_online = 1;
 	qeth_set_large_send(card, card->options.large_send);