s390/cio: unregister device when the only path is gone

Currently, if the device is offline and all the channel paths are
either configured or varied offline, the associated subchannel gets
unregistered. Don't unregister the subchannel, instead unregister
offline device.
Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

drivers/s390/cio/device.c

@@ -1376,6 +1376,7 @@ void ccw_device_set_notoper(struct ccw_device *cdev)
 enum io_sch_action {
 	IO_SCH_UNREG,
 	IO_SCH_ORPH_UNREG,
+	IO_SCH_UNREG_CDEV,
 	IO_SCH_ATTACH,
 	IO_SCH_UNREG_ATTACH,
 	IO_SCH_ORPH_ATTACH,
@@ -1408,7 +1409,7 @@ static enum io_sch_action sch_get_action(struct subchannel *sch)
 	}
 	if ((sch->schib.pmcw.pam & sch->opm) == 0) {
 		if (ccw_device_notify(cdev, CIO_NO_PATH) != NOTIFY_OK)
-			return IO_SCH_UNREG;
+			return IO_SCH_UNREG_CDEV;
 		return IO_SCH_DISC;
 	}
 	if (device_is_disconnected(cdev))
@@ -1470,6 +1471,7 @@ static int io_subchannel_sch_event(struct subchannel *sch, int process)
 	case IO_SCH_ORPH_ATTACH:
 		ccw_device_set_disconnected(cdev);
 		break;
+	case IO_SCH_UNREG_CDEV:
 	case IO_SCH_UNREG_ATTACH:
 	case IO_SCH_UNREG:
 		if (!cdev)
@@ -1503,6 +1505,7 @@ static int io_subchannel_sch_event(struct subchannel *sch, int process)
 		if (rc)
 			goto out;
 		break;
+	case IO_SCH_UNREG_CDEV:
 	case IO_SCH_UNREG_ATTACH:
 		spin_lock_irqsave(sch->lock, flags);
 		sch_set_cdev(sch, NULL);