From: Hans-Joachim Picht <hpicht@redhat.com>
Date: Tue, 20 Jan 2009 16:58:46 +0100
Subject: [s390] qeth: crash in case of layer mismatch for VSWITCH
Message-id: 20090120155846.GE21694@redhat.com
O-Subject: [RHEL5 U4 PATCH 5/8] s390 - qeth: avoid crash in case of layer mismatch for VSWITCH
Bugzilla: 476205
RH-Acked-by: Pete Zaitcev <zaitcev@redhat.com>

Description
============

For z/VM GuestLAN or VSWITCH devices the transport layer is
configured in z/VM. The layer2 attribute of a participating Linux
device has to match the z/VM definition. In case of a mismatch
Linux currently crashes in qeth recovery due to a reference to the
not yet existing net_device.
Solution: add a check for existence of net_device and add a message
pointing to the mismatch of layer definitions in Linux and z/VM.

Bugzilla
=========

BZ 476205
https://bugzilla.redhat.com/show_bug.cgi?id=476205

Upstream status of the patch:
=============================

The patch is upstream as of git commit
fc9c24603c4b93d84160e14c0a98a754d4328d15

Test status:
============

The patch has been tested and fixes the problem.
The fix has been verified by the IBM test department.

Please ACK.

With best regards,

	--Hans

diff --git a/drivers/s390/net/qeth_main.c b/drivers/s390/net/qeth_main.c
index 791c771..0abc754 100644
--- a/drivers/s390/net/qeth_main.c
+++ b/drivers/s390/net/qeth_main.c
@@ -975,9 +975,11 @@ qeth_recover(void *ptr)
 		PRINT_INFO("Device %s successfully recovered!\n",
 			   CARD_BUS_ID(card));
 	else {
-		rtnl_lock();
-		dev_close(card->dev);
-		rtnl_unlock();
+		if (card->dev) {
+			rtnl_lock();
+			dev_close(card->dev);
+			rtnl_unlock();
+		}
 		PRINT_INFO("Device %s could not be recovered!\n",
 			   CARD_BUS_ID(card));
 	}
@@ -1725,6 +1727,10 @@ qeth_send_control_data_cb(struct qeth_channel *channel,
 	card = CARD_FROM_CDEV(channel->ccwdev);
 	if (qeth_check_idx_response(iob->data)) {
 		qeth_clear_ipacmd_list(card);
+		if (((iob->data[2] & 0xc0) == 0xc0) && iob->data[4] == 0xf6)
+			PRINT_ERR("The qeth device %s is not configured "
+				"for the OSI layer required by z/VM\n",
+				CARD_BUS_ID(card));
 		qeth_schedule_recovery(card);
 		goto out;
 	}