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

[ Upstream commit 89c0c62 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/s390/cio/device.c

@@ -1353,6 +1353,7 @@ 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,
@@ -1385,7 +1386,7 @@ 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))
@@ -1447,6 +1448,7 @@ 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)
@@ -1480,6 +1482,7 @@ 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);
 		if (cdev->private->flags.resuming) {