Re: [PATCH v15 7/9] nvmet-passthru: Add passthru code to process commands

[Keith Busch]

On Mon, Jul 20, 2020 at 05:01:19PM -0600, Logan Gunthorpe wrote:
> On 2020-07-20 4:35 p.m., Sagi Grimberg wrote:
>
> > passthru commands are in essence REQ_OP_DRV_IN/REQ_OP_DRV_OUT, which
> > means that the driver shouldn't need the ns at all. So if you have a
> > dedicated request queue (mapped to the I/O tagset), you don't need the
> > ns->queue and we can lose the ns lookup altogether.

We still need a request_queue to dispatch the command. I guess you could
make a generic one for the controller that isn't tied to a namespace,
but we lose the fair shared tag allocation.
 
> Thanks, that helps clarify things a bit, but which xarray were you
> talking about

That was something that was replacing the list lookup:

  http://lists.infradead.org/pipermail/linux-nvme/2020-July/018242.html