Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
References: <20230706130930.64283-1-nmi@metaspace.dk>
 <20230706130930.64283-2-nmi@metaspace.dk>
 <51b660f3-8145-d35e-87b4-d9ac0623606d@kernel.org>
 <ZKdjVxMT/sVUA5BV@ovpn-8-34.pek2.redhat.com>
 <ZKuqt6QAXic3wuRX@infradead.org>
 <ZKvO+81b9fAx2L/r@ovpn-8-31.pek2.redhat.com>
 <ZKvQPAN9OkS3dZ4d@infradead.org> <87a5w3ymff.fsf@metaspace.dk>
 <ZK0RKkXFaQSotxVl@infradead.org>
User-agent: mu4e 1.10.4; emacs 28.2.50
From:   "Andreas Hindborg (Samsung)" <nmi@metaspace.dk>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Ming Lei <ming.lei@redhat.com>,
        Damien Le Moal <dlemoal@kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:BLOCK LAYER" <linux-block@vger.kernel.org>,
        Minwoo Im <minwoo.im.dev@gmail.com>,
        Matias Bjorling <Matias.Bjorling@wdc.com>,
        gost.dev@samsung.com, Jens Axboe <axboe@kernel.dk>,
        Aravind Ramesh <Aravind.Ramesh@wdc.com>,
        Johannes Thumshirn <jth@kernel.org>,
        Hans Holmberg <Hans.Holmberg@wdc.com>
Subject: Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT
Date:   Tue, 11 Jul 2023 11:02:15 +0200
In-reply-to: <ZK0RKkXFaQSotxVl@infradead.org>
Message-ID: <875y6qzufc.fsf@metaspace.dk>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Precedence: bulk


Christoph Hellwig <hch@infradead.org> writes:

> On Tue, Jul 11, 2023 at 08:23:40AM +0200, Andreas Hindborg (Samsung) wrot=
e:
>> 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.

>
>> I somewhat agree in the sense that for consistency, we should either
>> move zone management commands to the DRV_OUT range OR move report_zones
>> out of this special range and just next to the zone management
>> operations. I like the latter option better, and I would love to see the
>> block layer do the same at some point. It feels backwards that
>> report_zones get special treatment all over the place.
>
> DRV_IN/OUT is purely a Linux concept.  It doesn't make any sense for
> a wire protocol.

Ok =F0=9F=91=8D

BR Andreas