s390/dasd: Add 'timeout' attribute

This patch adds a 'timeout' attibute to the DASD driver.
When set to non-zero, the blk_timeout function will
be enabled with the timeout specified in the attribute.
Setting 'timeout' to '0' will disable block timeouts.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index b97624b..54f4bb8 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2894,6 +2894,8 @@
 		return BLK_EH_NOT_HANDLED;
 
 	device = cqr->startdev ? cqr->startdev : block->base;
+	if (!device->blk_timeout)
+		return BLK_EH_RESET_TIMER;
 	DBF_DEV_EVENT(DBF_WARNING, device,
 		      " dasd_times_out cqr %p status %x",
 		      cqr, cqr->status);