On Fri, Apr 07, 2023 at 04:58:13PM -0700, Bart Van Assche wrote:
> - /*
> - * If RQF_DONTPREP, rq has contained some driver specific
> - * data, so insert it to hctx dispatch list to avoid any
> - * merge.
> - */
> - if (rq->rq_flags & RQF_DONTPREP)
> - blk_mq_request_bypass_insert(rq, false, false);
> - else
> - blk_mq_sched_insert_request(rq, true, false, false);
> + blk_mq_sched_insert_request(rq, /*at_head=*/true, false, false);
This effectively undoes commit aef1897cd36d, and instead you add
RQF_DONTPREP to RQF_NOMERGE_FLAGS. This makes sense to be, but should
probably be more clearly documented in the commit log.
> @@ -2065,9 +2057,14 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
> if (nr_budgets)
> blk_mq_release_budgets(q, list);
>
> - spin_lock(&hctx->lock);
> - list_splice_tail_init(list, &hctx->dispatch);
> - spin_unlock(&hctx->lock);
> + if (!q->elevator) {
> + spin_lock(&hctx->lock);
> + list_splice_tail_init(list, &hctx->dispatch);
> + spin_unlock(&hctx->lock);
> + } else {
> + q->elevator->type->ops.insert_requests(hctx, list,
> + /*at_head=*/true);
> + }
But I have no idea how this is related in any way.
