Re: [PATCH v4 00/17] Add VFIO mediated device support and DEV-MSI support for the idxd driver

[Dave Jiang]

On 10/30/2020 11:58 AM, Jason Gunthorpe wrote:
> On Fri, Oct 30, 2020 at 11:50:47AM -0700, Dave Jiang wrote:
> >   .../ABI/stable/sysfs-driver-dma-idxd          |    6 +
> >   Documentation/driver-api/vfio/mdev-idxd.rst   |  404 ++++++
> >   MAINTAINERS                                   |    1 +
> >   drivers/dma/Kconfig                           |    9 +
> >   drivers/dma/idxd/Makefile                     |    2 +
> >   drivers/dma/idxd/cdev.c                       |    6 +-
> >   drivers/dma/idxd/device.c                     |  294 ++++-
> >   drivers/dma/idxd/idxd.h                       |   67 +-
> >   drivers/dma/idxd/init.c                       |   86 ++
> >   drivers/dma/idxd/irq.c                        |    6 +-
> >   drivers/dma/idxd/mdev.c                       | 1121 +++++++++++++++++
> >   drivers/dma/idxd/mdev.h                       |  116 ++
>
> Again, a subsytem driver belongs in the directory hierarchy of the
> subsystem, not in other random places. All this mdev stuff belongs
> under drivers/vfio

Alex seems to have disagreed last time....
https://lore.kernel.org/dmaengine/20200917113016.425dcde7@xxxxxxx/

And I do agree with his perspective. The mdev is an extension of the PF driver. 
It's a bit awkward to be a stand alone mdev driver under vfio/mdev/.

> Jason