vfio: ccw: fix error return in vfio_ccw_sch_event

[ 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@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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 82f05c4b8c526f73a52aed819eacb33cdfd18e3a..ae7a49ade414bd8e33356f47e954cfc27a2488a3 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -176,6 +176,7 @@ 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))
@@ -186,6 +187,7 @@ 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;
        }
 
@@ -194,11 +196,12 @@ 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[] = {