[PATCH 4.17 002/324] vfio: ccw: fix error return in vfio_ccw_sch_event

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx>

[ Upstream commit 2c861d89ccda2fbcea9358eff9cc5f8fae548be5 ]

If the device has not been registered, or there is work pending,
we should reschedule a sch_event call again.

Signed-off-by: Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx>
Message-Id: <20180502072559.50691-1-bjsdjshi@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Signed-off-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/s390/cio/vfio_ccw_drv.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -177,6 +177,7 @@ static int vfio_ccw_sch_event(struct sub
 {
 	struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 	unsigned long flags;
+	int rc = -EAGAIN;
 
 	spin_lock_irqsave(sch->lock, flags);
 	if (!device_is_registered(&sch->dev))
@@ -187,6 +188,7 @@ static int vfio_ccw_sch_event(struct sub
 
 	if (cio_update_schib(sch)) {
 		vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
+		rc = 0;
 		goto out_unlock;
 	}
 
@@ -195,11 +197,12 @@ static int vfio_ccw_sch_event(struct sub
 		private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
 				 VFIO_CCW_STATE_STANDBY;
 	}
+	rc = 0;
 
 out_unlock:
 	spin_unlock_irqrestore(sch->lock, flags);
 
-	return 0;
+	return rc;
 }
 
 static struct css_device_id vfio_ccw_sch_ids[] = {