blk-mq: refactor the DONTPREP/SOFTBARRIER andling in blk_mq_requeue_work

	spin_unlock_irq(&q->requeue_lock);

	list_for_each_entry_safe(rq, next, &rq_list, queuelist) {

		if (!(rq->rq_flags & (RQF_SOFTBARRIER | RQF_DONTPREP)))

			continue;

		rq->rq_flags &= ~RQF_SOFTBARRIER;

		list_del_init(&rq->queuelist);

		/*

		 * If RQF_DONTPREP, rq has contained some driver specific

		 * data, so insert it to hctx dispatch list to avoid any

		 * merge.

		 * If RQF_DONTPREP ist set, the request has been started by the

		 * driver already and might have driver-specific data allocated

		 * already.  Insert it into the hctx dispatch list to avoid

		 * block layer merges for the request.

		 */

		if (rq->rq_flags & RQF_DONTPREP)

		if (rq->rq_flags & RQF_DONTPREP) {

			rq->rq_flags &= ~RQF_SOFTBARRIER;

			list_del_init(&rq->queuelist);

			blk_mq_request_bypass_insert(rq, false, false);

		else

		} else if (rq->rq_flags & RQF_SOFTBARRIER) {

			rq->rq_flags &= ~RQF_SOFTBARRIER;

			list_del_init(&rq->queuelist);

			blk_mq_insert_request(rq, true, false, false);

		}

	}

	while (!list_empty(&rq_list)) {

		rq = list_entry(rq_list.next, struct request, queuelist);