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Date:   Sat, 2 May 2020 10:48:36 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Hannes Reinecke <hare@suse.de>
Cc:     Christoph Hellwig <hch@lst.de>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        James Bottomley <james.bottomley@hansenpartnership.com>,
        John Garry <john.garry@huawei.com>,
        Ming Lei <ming.lei@redhat.com>,
        Bart van Assche <bvanassche@acm.org>,
        linux-scsi@vger.kernel.org, Hannes Reinecke <hare@suse.com>
Subject: Re: [PATCH RFC v3 02/41] scsi: add scsi_{get,put}_reserved_cmd()
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On Sat, May 02, 2020 at 10:45:24AM +0200, Hannes Reinecke wrote:
> Reserved commands just serve as a placeholder to get a valid tag from the 
> block layer; the SCSI commands themselves are never ever passed through the 
> whole stack, but rather allocated internally within the driver, and passed 
> to the hardware by driver-specific means.
> So really the SCSI specific parts of the commands are never used.
> We can add a check in queuecommand to abort reserved commands if that's 
> what you worried about, though.

How about an interface that just returns a tag then, so that it can't
be misused?