Christoph Hellwig [off-list ref] writes:

On Tue, Jul 11, 2023 at 08:23:40AM +0200, Andreas Hindborg (Samsung) wrote:

quoted

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.

quoted

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