[S390] cio: Register/unregister subchannels only from kslowcrw.

Make sure all subchannel handling is done on the slow path workqueue
so that we don't have races between an old subchannel unregistering
and a new subchannel with the same name registering.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/css.c

@@ -483,7 +483,7 @@ static DECLARE_WORK(css_reprobe_work, reprobe_all);
 void css_schedule_reprobe(void)
 {
 	need_reprobe = 1;
-	queue_work(ccw_device_work, &css_reprobe_work);
+	queue_work(slow_path_wq, &css_reprobe_work);
 }
 
 EXPORT_SYMBOL_GPL(css_schedule_reprobe);

drivers/s390/cio/device_fsm.c

@@ -1034,7 +1034,7 @@ device_trigger_reprobe(struct subchannel *sch)
 	if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {
 		PREPARE_WORK(&cdev->private->kick_work,
 			     ccw_device_move_to_orphanage);
-		queue_work(ccw_device_work, &cdev->private->kick_work);
+		queue_work(slow_path_wq, &cdev->private->kick_work);
 	} else
 		ccw_device_start_id(cdev, 0);
 }