Re: serial driver cleanups v2

From: Andy Shevchenko
Date: Fri Mar 15 2019 - 14:11:44 EST


On Fri, Mar 15, 2019 at 11:36:04AM +0100, Enrico Weigelt, metux IT consult wrote:
> On 15.03.19 10:12, Andy Shevchenko wrote:
>
> >> Part II will be about moving the mmio range from mapbase and
> >> mapsize (which are used quite inconsistently) to a struct resource
> >> and using helpers for that. But this one isn't finished yet.
> >> (if somebody likes to have a look at it, I can send it, too)
> >
> > Let's do that way you are preparing a branch somewhere and anounce
> > here as an RFC, since this was neither tested nor correct.
>
> Okay, here it is:
>
> I. https://github.com/metux/linux/tree/submit/serial-clean-v3
> --> general cleanups, as basis for II
>
> II. https://github.com/metux/linux/tree/wip/serial-res
> --> moving towards using struct resource consistently
>
> III. https://github.com/metux/linux/tree/hack/serial
> --> the final steps, which are yet completely broken
> (more a notepad for things still to do :o)
>
> The actual goal is generalizing the whole iomem handling, so individual
> usually just need to call some helpers that do most of the things.
> Finally, I also wanted to have all io region information consolidated
> in struct resource.

That's should be a selling point, not just conversion per se.

> > And selling point for many of them is not true: it doesn't make any
> > difference in the size in code, but increases a time to run
> > (devm_ioremap_resource() does more than plain devm_iomap() call).
>
> Okay, just seen it. Does the the runtime overhead cause any problems ?

You have to explain that in each commit message, that the change does bring a
possible new error message printed.

The performance side of the deal, you are lucky here, is not significant
because it's slow path.

--
With Best Regards,
Andy Shevchenko