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Date:   Sat, 13 Aug 2022 08:41:42 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Bart Van Assche <bvanassche@acm.org>
Cc:     Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
        Christoph Hellwig <hch@lst.de>,
        Jaegeuk Kim <jaegeuk@kernel.org>,
        Ming Lei <ming.lei@redhat.com>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>
Subject: Re: [PATCH] block: Submit flush requests to the I/O scheduler
Message-ID: <20220813064142.GA10753@lst.de>
References: <20220812210355.2252143-1-bvanassche@acm.org>
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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.