[S390] dasd: unit check handling during internal cio I/O

React on unit checks during cio internal I/O.
Handle as unsolicited interrupt and advice cio to retry.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/block/dasd.c

@@ -1186,6 +1186,29 @@ void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
 	dasd_schedule_device_bh(device);
 }
 
+enum uc_todo dasd_generic_uc_handler(struct ccw_device *cdev, struct irb *irb)
+{
+	struct dasd_device *device;
+
+	device = dasd_device_from_cdev_locked(cdev);
+
+	if (IS_ERR(device))
+		goto out;
+	if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
+	   device->state != device->target ||
+	   !device->discipline->handle_unsolicited_interrupt){
+		dasd_put_device(device);
+		goto out;
+	}
+
+	dasd_device_clear_timer(device);
+	device->discipline->handle_unsolicited_interrupt(device, irb);
+	dasd_put_device(device);
+out:
+	return UC_TODO_RETRY;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_uc_handler);
+
 /*
  * If we have an error on a dasd_block layer request then we cancel
  * and return all further requests from the same dasd_block as well.

drivers/s390/block/dasd_eckd.c

@@ -3436,6 +3436,7 @@ static struct ccw_driver dasd_eckd_driver = {
 	.freeze      = dasd_generic_pm_freeze,
 	.thaw	     = dasd_generic_restore_device,
 	.restore     = dasd_generic_restore_device,
+	.uc_handler  = dasd_generic_uc_handler,
 };
 
 /*

drivers/s390/block/dasd_int.h

@@ -617,6 +617,7 @@ int dasd_generic_notify(struct ccw_device *, int);
 void dasd_generic_handle_state_change(struct dasd_device *);
 int dasd_generic_pm_freeze(struct ccw_device *);
 int dasd_generic_restore_device(struct ccw_device *);
+enum uc_todo dasd_generic_uc_handler(struct ccw_device *, struct irb *);
 
 int dasd_generic_read_dev_chars(struct dasd_device *, int, void *, int);
 char *dasd_get_sense(struct irb *);