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Date:   Fri, 16 Aug 2019 15:16:06 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Marta Rybczynska <mrybczyn@kalray.eu>
Cc:     kbusch@kernel.org, axboe@fb.com, hch@lst.de, sagi@grimberg.me,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
        Samuel Jones <sjones@kalray.eu>,
        Guillaume Missonnier <gmissonnier@kalray.eu>
Subject: Re: [PATCH v2] nvme: allow 64-bit results in passthru commands
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Sorry for not replying to the earlier version, and thanks for doing
this work.

I wonder if instead of using our own structure we'd just use
a full nvme SQE for the input and CQE for that output.  Even if we
reserve a few fields that means we are ready for any newly used
field (at least until the SQE/CQE sizes are expanded..).

On Fri, Aug 16, 2019 at 11:47:21AM +0200, Marta Rybczynska wrote:
> It is not possible to get 64-bit results from the passthru commands,
> what prevents from getting for the Capabilities (CAP) property value.
> 
> As a result, it is not possible to implement IOL's NVMe Conformance
> test 4.3 Case 1 for Fabrics targets [1] (page 123).

Not that I'm not sure passing through fabrics commands is an all that
good idea.  But we have pending NVMe TPs that use 64-bit result
values as well, so this seems like a good idea in general.