vfio: ccw: fix error return in vfio_ccw_sch_event

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@linux.vnet.ibm.com>
Message-Id: <20180502072559.50691-1-bjsdjshi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index ea6a2d0b2894..770fa9cfc310 100644
--- 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 subchannel *sch, int process)
 {
         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 subchannel *sch, int process)
 
         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 subchannel *sch, int process)
                 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[] = {