Re: [PATCH v9 1/5] firmware: add extensible driver data params

AKASHI Takahiro
2017-06-20T01:48:37Z

On Mon, Jun 19, 2017 at 05:51:08PM -0500, Li, Yi wrote:
> Hi Greg,
>
> On 6/17/2017 2:38 PM, Greg KH wrote:
> >On Tue, Jun 13, 2017 at 09:40:11PM +0200, Luis R. Rodriguez wrote:
> >>On Tue, Jun 13, 2017 at 11:05:48AM +0200, Greg KH wrote:
> >>>On Mon, Jun 05, 2017 at 02:39:33PM -0700, Luis R. Rodriguez wrote:
> >
> >>What you have to ask yourself really is if this makes it *less complex* and
> >>helps *clean things up* in a much better way than it was before. Also does it
> >>allow us to *pave the way for new functionality easily*, without creating
> >>further mess?
> >
> >I agree, that's what I'm saying here. I just do not see that happening
> >with your patch set at all. It's adding more code, a more complex way
> >to interact with the subsystem, and not making driver writer lives any
> >easier at all that I can see.
> >
> >Again, the code is now bigger, does more, with not even any real benefit
> >for existing users.
>
> I am still new to the upstreaming world, pardon me if my understanding is
> naive. :) My take with Luis's driver data API is that it adds a wrapper on
> top of the old request_firmware APIs, so the new features can be
> added/disabled by the parameters structures instead of adding/changing API
> functions. Agree that there is not much new for existing users. It adds more
> codes (not necessary more complex) but create a consistent way for extension
> IMO.

Most of code of my feature, firmware signing, is implemented in common
place between old and new APIs, while only new API has a parameter,
DRIVER_DATA_REQ_NO_SIG_CHECK, which allow users to enable/disable
this feature per-driver-datum. Simple enough.

So what matters is adding yet another variant of request_firmware_xx()
vs. adding a mere parameter?

Thanks,
-Takahiro AKASHI

> Below are 3 examples I tried to add streaming support to load large firmware
> files.
> Adding streaming with driver data API:
> https://patchwork.kernel.org/patch/9738503 . This patch series depends on
> non-cache patch series https://patchwork.kernel.org/patch/9793825 , which is
> bigger than it should be since it added some codes to test firmware caching.
> and pre-allocate buffer patch series
> https://patchwork.kernel.org/patch/9738487/
>
> By comparison, here is my old streaming RFC with original firmware class:
> https://lkml.org/lkml/2017/3/9/872
> Do you think this is the better way?
>
> Thanks,
> Yi