Re: [PATCH v2 00/17] net: introduce Qualcomm IPA driver

From: Arnd Bergmann
Date: Tue Jun 18 2019 - 09:53:55 EST

On Tue, Jun 18, 2019 at 3:16 PM Alex Elder <elder@xxxxxxxxxx> wrote:
> On 6/17/19 6:28 AM, Johannes Berg wrote:
> > On Tue, 2019-06-11 at 13:56 +0200, Arnd Bergmann wrote:
> I'm probably missing something, but I think the checksum
> offload could be handled by the IPA driver rather than
> rmnet. It seems to be an add-on that is completely
> independent of the multiplexing and aggregation capabilities
> that QMAP provides.

My best guess is that it is part of rmnet simply because this can
be done in a generic way for any qmap based back-end, and rmnet
was intended as the abstraction for qmap.

A better implementation of the checksumming might be to split
it out into a library that is in turn used by qmap drivers. Since this
should be transparent to the user interface, it can be moved
there later.

> >>> If true though, then I think this would be the killer argument *in
> >>> favour* of *not* merging this - because that would mean we *don't* have
> >>> to actually keep the rmnet API around for all foreseeable future.
> This is because it's a user space API? If so I now understand
> what you mean.

Yes, I think agreeing on the general user interface is (as usual) the
one thing that has to be done as a prerequisite. I had originally
hoped that by removing the ioctl interface portion of the driver,
this could be avoided, but that was before I had any idea on the
upper layers.