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Date:   Tue, 7 Apr 2020 09:30:33 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Hannes Reinecke <hare@suse.de>
Cc:     John Garry <john.garry@huawei.com>,
        Christoph Hellwig <hch@infradead.org>, axboe@kernel.dk,
        jejb@linux.ibm.com, martin.petersen@oracle.com,
        ming.lei@redhat.com, bvanassche@acm.org,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-scsi@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
        esc.storagedev@microsemi.com, chenxiang66@hisilicon.com,
        Hannes Reinecke <hare@suse.com>
Subject: Re: [PATCH RFC v2 02/24] scsi: allocate separate queue for reserved
 commands
Message-ID: <20200407163033.GA26568@infradead.org>
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On Tue, Apr 07, 2020 at 04:00:10PM +0200, Hannes Reinecke wrote:
> My concern is this:
> 
> struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
> {
> 	[ .. ]
> 	starget = scsi_alloc_target(&shost->shost_gendev, 0, shost->this_id);
> 	[ .. ]
> 
> and we have typically:
> 
> drivers/scsi/hisi_sas/hisi_sas_v3_hw.c: .this_id                = -1,
> 
> It's _very_ uncommon to have a negative number as the SCSI target device; in
> fact, it _is_ an unsigned int already.
> 
> But alright, I'll give it a go; let's see what I'll end up with.

But this shouldn't be exposed anywhere.  And I prefer that over having
magic requests/scsi_cmnd that do not have a valid ->device pointer.