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Date: Tue, 6 Jun 2017 11:58:02 +0200
From: Christoph Hellwig <hch@lst.de>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, Tejun Heo <tj@kernel.org>,
        Scott Bauer <scott.bauer@intel.com>,
        Jonathan Derrick <jonathan.derrick@intel.com>,
        Rafael Antognolli <rafael.antognolli@intel.com>,
        Robert Elliott <elliott@hpe.com>, linux-ide@vger.kernel.org,
        linux-block@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: Re: [PATCH 6/6] sd: add support for TCG OPAL self encrypting disks
Message-ID: <20170606095802.GA20590@lst.de>
References: <20170604124225.27032-1-hch@lst.de> <20170604124225.27032-7-hch@lst.de> <yq1lgp6djr3.fsf@oracle.com>
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On Mon, Jun 05, 2017 at 08:48:00PM -0400, Martin K. Petersen wrote:
> For WRITE SAME, scsi_report_opcode() is gated not only by
> sdev->no_report_opcodes but by sdev->no_write_same.
> 
> I'm concerned about firing off REPORT OPCODES to random devices without
> a sufficiently good heuristic. Doesn't look like SAT has anything to
> offer in this department, though. Maybe it's time to consider a
> vendor-specific Linux VPD page...

Eww.  Given that as far as I can tell only ATA devices implement
OPAL we could key it off that for now.  But that's only going to
defer the problem until support for other security protocols comes
along for real SCSI devices.

But as we already set no_report_opcodes for all usb-storage and
quirked uas devices I think the worst offenders are already covered
anyway.