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Date:   Tue, 22 Mar 2022 12:20:57 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     John Garry <john.garry@huawei.com>
Cc:     axboe@kernel.dk, damien.lemoal@opensource.wdc.com,
        bvanassche@acm.org, jejb@linux.ibm.com, martin.petersen@oracle.com,
        hch@lst.de, ming.lei@redhat.com, hare@suse.de,
        chenxiang66@hisilicon.com, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org,
        linux-scsi@vger.kernel.org, dm-devel@redhat.com, beanhuo@micron.com
Subject: Re: [PATCH 03/11] libata: Send internal commands through the block
 layer
Message-ID: <20220322112057.GC29270@lst.de>
References: <1647945585-197349-1-git-send-email-john.garry@huawei.com> <1647945585-197349-4-git-send-email-john.garry@huawei.com>
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On Tue, Mar 22, 2022 at 06:39:37PM +0800, John Garry wrote:
> When SCSI HBA device drivers are required to process an ATA internal
> command they still need a tag for the IO. This often requires the driver
> to set aside a set of tags for these sorts of IOs and manage the tags
> themselves.
> 
> If we associate a SCSI command (and request) with an ATA internal command
> then the tag is already provided, so introduce the change to send ATA
> internal commands through the block layer with a set of custom blk-mq ops.
> 
> note: I think that the timeout handling needs to be fixed up.

Any reason to not just send them through an ATA_16 passthrough CDB and
just use all the normal SCSI command handling?