Re: [PATCH] block: Submit flush requests to the I/O scheduler

[Christoph Hellwig <hch@lst.de>]

On Fri, Aug 12, 2022 at 02:03:55PM -0700, Bart Van Assche wrote:
> When submitting a REQ_OP_WRITE | REQ_FUA request to a zoned storage
> device, these requests must be passed to the (mq-deadline) I/O scheduler
> to ensure that these happen at the write pointer.

Yes.

But maybe I'm stupid, but how is the patch related to fixing that?
blk_mq_plug_issue_direct is called from blk_mq_flush_plug_list for
only the !has_elevator case.  How does that change a thing?

Also please include a description of why these changes are otherwise
good and won't regress other cases.

> +		blk_mq_sched_insert_request(rq, /*at_head=*/false,
> +			/*run_queue=*/last, /*async=*/false);

I find thise comment style very hard to read.  Yes, maybe the three
bools here should become flags, but this is even worse than just
passing the arguments.