vhost-scsi: remove extra flushes

The vhost work flush function was flushing the entire work queue, so
there is no need for the double vhost_work_dev_flush calls in
vhost_scsi_flush.

And we do not need to call vhost_poll_flush for each poller because
that call also ends up flushing the same work queue thread the
vhost_work_dev_flush call flushed.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210525174733.6212-3-michael.christie@oracle.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/scsi.c

@@ -1430,11 +1430,6 @@ static void vhost_scsi_handle_kick(struct vhost_work *work)
 	vhost_scsi_handle_vq(vs, vq);
 }
 
-static void vhost_scsi_flush_vq(struct vhost_scsi *vs, int index)
-{
-	vhost_poll_flush(&vs->vqs[index].vq.poll);
-}
-
 /* Callers must hold dev mutex */
 static void vhost_scsi_flush(struct vhost_scsi *vs)
 {
@@ -1453,9 +1448,6 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)
 		kref_put(&old_inflight[i]->kref, vhost_scsi_done_inflight);
 
 	/* Flush both the vhost poll and vhost work */
-	for (i = 0; i < VHOST_SCSI_MAX_VQ; i++)
-		vhost_scsi_flush_vq(vs, i);
-	vhost_work_dev_flush(&vs->dev);
 	vhost_work_dev_flush(&vs->dev);
 
 	/* Wait for all reqs issued before the flush to be finished */