On Wed, Mar 27, 2019 at 04:51:13PM +0800, Ming Lei wrote: > @@ -594,8 +594,11 @@ static void __blk_mq_complete_request(struct request *rq) > /* > * For a polled request, always complete locallly, it's pointless > * to redirect the completion. > + * > + * If driver requires to complete the request synchronously, > + * complete it locally, and it is usually done in error handler. > */ > - if ((rq->cmd_flags & REQ_HIPRI) || > + if ((rq->cmd_flags & REQ_HIPRI) || sync || > !test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) { > q->mq_ops->complete(rq); > return; I think this is fine and agree this is fixing a problem, but just considering an alternative: would it be okay to just temporarily clear QUEUE_FLAG_SAME_COMP in the necessary error handling that wants a sync completion so that we're not introducing an additional parameter?