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SubjectRe: [PATCH] platform: Provide a remove callback that returns no value
On Fri, Jan 13, 2023 at 12:43:39PM +0100, Greg Kroah-Hartman wrote:
> On Thu, Jan 12, 2023 at 09:20:29AM +0100, Uwe Kleine-König wrote:
> > Hello Greg,
> >
> > On Fri, Dec 09, 2022 at 05:15:42PM +0100, Greg Kroah-Hartman wrote:
> > > On Fri, Dec 09, 2022 at 04:52:07PM +0100, Uwe Kleine-König wrote:
> > > > On Fri, Dec 09, 2022 at 04:21:30PM +0100, Greg Kroah-Hartman wrote:
> > > > > On Fri, Dec 09, 2022 at 04:09:14PM +0100, Uwe Kleine-König wrote:
> > > > > > struct platform_driver::remove returning an integer made driver authors
> > > > > > expect that returning an error code was proper error handling. However
> > > > > > the driver core ignores the error and continues to remove the device
> > > > > > because there is nothing the core could do anyhow and reentering the
> > > > > > remove callback again is only calling for trouble.
> > > > > >
> > > > > > So this is an source for errors typically yielding resource leaks in the
> > > > > > error path.
> > > > > >
> > > > > > As there are too many platform drivers to neatly convert them all to
> > > > > > return void in a single go, do it in several steps after this patch:
> > > > > >
> > > > > > a) Convert all drivers to implement .remove_new() returning void instead
> > > > > > of .remove() returning int;
> > > > > > b) Change struct platform_driver::remove() to return void and so make
> > > > > > it identical to .remove_new();
> > > > > > c) Change all drivers back to .remove() now with the better prototype;
> > > > >
> > > > > Change c) seems like it will be just as much work as a), right?
> > > >
> > > > Yeah, but c) should be trivially doable per subsystem using coccinelle.
> > > > So my plan is to do a) per subsystem with one patch per driver and c)
> > > > with one patch per subsystem.
> > > >
> > > > > Who is going to do the work of the conversion to this new prototype?
> > > > > I'll be glad to take this, but I don't want to see a half-finished
> > > > > conversion happen and us stuck with a "new" and "old" call, as that
> > > > > would just be a mess.
> > > >
> > > > The idea is that this becomes my new pet project once
> > > > https://lore.kernel.org/lkml/20221118224540.619276-1-uwe@kleine-koenig.org
> > > > is complete. :-)
> > > >
> > > > I intend to work on that once the patch under discussion is included in
> > > > an -rc1.
> > >
> > > Ok, I'll wait to queue this up to my tree until after 6.2-rc1 is out,
> > > thanks.
> >
> > We're at v6.2-rc3 now. Is this patch still in your queue and you didn't
> > come around yet to apply it, or did it fell through the cracks?
>
> My queue is huge right now.
>
> I'll work on this "soon". Do you want this on a tag that others can
> pull into their trees, or just in my normal driver-core-next branch?
> Either is fine for me.

In my experience maintainers stumble when patches depend on patches that
are not in -rc1. So I will be patient until this hits an -rc1. Thanks
for the offer.

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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