Re: [PATCH V2 3/5] vDPA: introduce vDPA bus

From: Jason Gunthorpe
Date: Tue Feb 18 2020 - 08:56:18 EST

On Mon, Feb 17, 2020 at 02:08:03PM +0800, Jason Wang wrote:

> I thought you were copied in the patch [1], maybe we can move vhost related
> discussion there to avoid confusion.
> [1]

Wow, that is .. confusing.

So this is supposed to duplicate the uAPI of vhost-user? But it is
open coded and duplicated because .. vdpa?

> So it's cheaper and simpler to introduce a new bus instead of refactoring a
> well known bus and API where brunches of drivers and devices had been
> implemented for years.

If you reason for this approach is to ease the implementation then you
should talk about it in the cover letters/etc

Maybe it is reasonable to do this because the rework is too great, I
don't know, but to me this whole thing looks rather messy.

Remember this stuff is all uAPI as it shows up in sysfs, so you can
easilly get stuck with it forever.