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Date:   Tue, 15 Mar 2022 09:24:57 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Ondrej Zary <linux@zary.sk>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Christoph Hellwig <hch@lst.de>, Tim Waugh <tim@cyberelk.net>,
        linux-block@vger.kernel.org, linux-parport@lists.infradead.org,
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Subject: Re: [PATCH] pata_parport: add driver (PARIDE replacement)
Message-ID: <20220315082457.GB3502@lst.de>
References: <20220312144415.20010-1-linux@zary.sk> <202203132015.18183.linux@zary.sk> <5161ed17-5f55-e851-c2e2-5340cc62fa3b@kernel.dk> <202203142125.40532.linux@zary.sk> <f8c176d4-74f0-3e4f-446f-2a5f8ace3b28@kernel.dk>
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On Mon, Mar 14, 2022 at 02:29:20PM -0600, Jens Axboe wrote:
> The controller would set
> 
> ->needs_blocking_queue_rq = true;
> 
> or something, and we'd default to false. And if that is set, when the
> blk-mq queue is created, then we'd set BLK_MQ_F_BLOCKING upon creation
> if that flag is true.
> 
> That's the block layer side. Then in libata you'd need to ensure that
> you check that same setting and invoke ata_qc_issue() appropriately.
> 
> Very top level stuff, there might be more things lurking below. But
> you'll probably find them as you test this stuff...

FYI, this somewhat mistitled series:

https://lore.kernel.org/all/20220308003957.123312-1-michael.christie@oracle.com/

adds BLK_MQ_F_BLOCKING support to the scsi core.  Doing libata
should be fairly easy and can built ontop of that.