Re: [PATCH v3 00/18] Add VFIO mediated device support and DEV-MSI support for the idxd driver

[Jason Gunthorpe]

On Thu, Sep 17, 2020 at 11:30:16AM -0600, Alex Williamson wrote:
> On Thu, 17 Sep 2020 10:15:24 -0700
> Dave Jiang <dave.jiang@xxxxxxxxx> wrote:
> 
> > On 9/17/2020 8:06 AM, Jason Gunthorpe wrote:
> > > On Tue, Sep 15, 2020 at 04:27:35PM -0700, Dave Jiang wrote:  
> > >>   drivers/dma/idxd/idxd.h                            |   65 +
> > >>   drivers/dma/idxd/init.c                            |  100 ++
> > >>   drivers/dma/idxd/irq.c                             |    6
> > >>   drivers/dma/idxd/mdev.c                            | 1089 ++++++++++++++++++++
> > >>   drivers/dma/idxd/mdev.h                            |  118 ++  
> > > 
> > > It is common that drivers of a subsystem will be under that
> > > subsystem's directory tree. This allows the subsystem community to
> > > manage pages related to their subsystem and it's drivers.
> > > 
> > > Should the mdev parts be moved there?  
> > 
> > I personally don't have a preference. I'll defer to Alex or Kirti to provide 
> > that guidance. It may make certains things like dealing with dma fault regions 
> > and etc easier using vfio calls from vfio_pci_private.h later on for vSVM 
> > support. It also may be the better code review and maintenance domain and 
> > alleviate Vinod having to deal with that portion since it's not dmaengine domain.
> 
> TBH, I'd expect an mdev driver to be co-located with the remainder of
> its parent driver. 

Multifunction drivers are always split up according to the subsystem
their functions are part of.

See the recent lost argument about the Habanalab NIC driver not being
under net/ even though the rest of the driver is in misc/

Jason