[S390] cio long busy in read configuration data.

Trying to set a DASD root device online can fail under some circumstances
with the message "Read configuration data returned error -5". The cause
is that read configuration data incorrectly aborts with -EIO when it
encounters a temporary busy condition at a storage server.
Perform retry when encountering temporary busy conditions.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/device_ops.c

@@ -270,7 +270,8 @@ ccw_device_wake_up(struct ccw_device *cdev, unsigned long ip, struct irb *irb)
 		 * We didn't get channel end / device end. Check if path
 		 * verification has been started; we can retry after it has
 		 * finished. We also retry unit checks except for command reject
-		 * or intervention required.
+		 * or intervention required. Also check for long busy
+		 * conditions.
 		 */
 		 if (cdev->private->flags.doverify ||
 			 cdev->private->state == DEV_STATE_VERIFY)
@@ -279,6 +280,10 @@ ccw_device_wake_up(struct ccw_device *cdev, unsigned long ip, struct irb *irb)
 		     !(irb->ecw[0] &
 		       (SNS0_CMD_REJECT | SNS0_INTERVENTION_REQ)))
 			 cdev->private->intparm = -EAGAIN;
+		else if ((irb->scsw.dstat & DEV_STAT_ATTENTION) &&
+			 (irb->scsw.dstat & DEV_STAT_DEV_END) &&
+			 (irb->scsw.dstat & DEV_STAT_UNIT_EXCEP))
+			cdev->private->intparm = -EAGAIN;
 		 else
 			 cdev->private->intparm = -EIO;