From: Hans-Joachim Picht <hpicht@redhat.com>
Date: Tue, 20 May 2008 13:48:17 +0200
Subject: [s390] dasd: fix timeout handling in interrupt handler
Message-id: 20080520114817.GG16866@redhat.com
O-Subject: [RHEL5 U3 PATCH 2/4] s390 - dasd: fix timeout handling in interrupt handler
Bugzilla: 447316
RH-Acked-by: Pete Zaitcev <zaitcev@redhat.com>

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

I/O on a DASD blocks for about 5 minutes and then
continues with the following error message:
internal error - timeout (300s) expired

When the common I/O layer experiences a timeout it will
call the dasd_int_handler with an error code of
-ETIMEDOUT. The associated request will not get any
further notification and needs to be reset and
restarted. This handling is missing in the dasd device
driver and so it will continue to wait for an interrupt
until the drivers timout of 300 seconds is reached.

Whenever the dasd_int_handler is called with an error
code instead of an irb, the associated request should be
restarted.

Bugzilla
=========

BZ 447316
https://bugzilla.redhat.com/show_bug.cgi?id=447316

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

The patch is included in linux-2.6.26-rc3 as git
commit f16f5843507ceaea315dae82b9fee29a65b72f24

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

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

Please ACK.

With best regards,

Hans

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index e707723..59bca30 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -885,6 +885,8 @@ dasd_handle_killed_request(struct ccw_device *cdev, unsigned long intparm)
 	struct dasd_ccw_req *cqr;
 	struct dasd_device *device;
 
+	if (!intparm)
+		return;
 	cqr = (struct dasd_ccw_req *) intparm;
 	if (cqr->status != DASD_CQR_IN_IO) {
 		MESSAGE(KERN_DEBUG,
@@ -950,17 +952,16 @@ dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
 	if (IS_ERR(irb)) {
 		switch (PTR_ERR(irb)) {
 		case -EIO:
-			dasd_handle_killed_request(cdev, intparm);
 			break;
 		case -ETIMEDOUT:
 			printk(KERN_WARNING"%s(%s): request timed out\n",
 			       __FUNCTION__, cdev->dev.bus_id);
-			//FIXME - dasd uses own timeout interface...
 			break;
 		default:
 			printk(KERN_WARNING"%s(%s): unknown error %ld\n",
 			       __FUNCTION__, cdev->dev.bus_id, PTR_ERR(irb));
 		}
+		dasd_handle_killed_request(cdev, intparm);
 		return;
 	}