Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Andreas Hindborg (Samsung)]

Christoph Hellwig <hch@xxxxxxxxxxxxx> 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.

>
>> 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 👍

BR Andreas