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>

2 files changed, 6 insertions, 2 deletions

diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 172031baedc1..44c15685ab86 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/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;
 
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 0ba3817cb6a7..5873240c3cea 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/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);