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Date:   Tue, 11 Jul 2023 02:27:14 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     "Andreas Hindborg (Samsung)" <nmi@metaspace.dk>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Ming Lei <ming.lei@redhat.com>,
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Subject: Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT
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On Tue, Jul 11, 2023 at 11:02:15AM +0200, Andreas Hindborg (Samsung) wrote:
> 
> Christoph Hellwig <hch@infradead.org> writes:
> 
> > On Tue, Jul 11, 2023 at 08:23:40AM +0200, Andreas Hindborg (Samsung) wrote:
> >> Yet most on-the-wire protocols for actual hardware does support this
> >> some way or another.
> >
> > Supports what?  Passthrough?  No.
> 
> Both SCSI and NVMe has command identifier ranges reserved for vendor
> specific commands. I would assume that one use of these is to implement
> passthrough channels to a device for testing out new interfaces. Just
> guessing though.

Vendor specific commands is an entirely different concept from Linux
passthrough requests.