task #28910367
commit 724c15a43e2c7ac26e2d07abef99191162498fa9 upstream

While we wait for queue to finish draining, use completions instead of
usleep_range(). This is better way of waiting for event.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
(cherry picked from commit 724c15a43e2c7ac26e2d07abef99191162498fa9)
Signed-off-by: NLiu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>