Re: [PATCH] iio: light: isl29028: fix runtime PM reference leak on error paths

[Joshua Crofts]

On Mon, 7 Sep 2026 03:07:51 +0100
Jonathan Cameron <jic23@xxxxxxxxxx> wrote:

> On Mon,  7 Sep 2026 00:15:17 +0200
> Fabio Cesari <fabio.cesari@xxxxxxxxx> wrote:
> 
> > Hi Jonathan,
> > 
> > On Sun, 6 Sep 2026 18:43:58 +0100
> > Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> >   
> > > Whilst perhaps not best practice as such, it is pretty
> > > common to just not bother checking the return of pm_runtime_put_autosuspend()
> > > at least partly because of that annoying -ENOSYS result if runtime pm isn't
> > > enabled.  That is what happens with the ACQUIRE macros for instance.
> > >
> > > Do we have any particular reason to thing it is more likely to fail i this
> > > case than any other?    
> > 
> > No reason: both functions already returned that value to userspace before the
> > patch, and I left that unchanged only because the patch was aimed at the leak.
> > It makes sense to fix it as well.
> > 
> > v2 will take the reference with PM_RUNTIME_ACQUIRE_IF_ENABLED_AUTOSUSPEND() in
> > both functions, as Joshua Crofts suggested, so the value goes away along with
> > the manual put.  
> 
> Why the if enabled variant?  I think that only makes sense in places that can
> be hit prior to runtime pm being up and running. Maybe that's true here.

Yeah, my mistake, I suggested using the IF_ENABLED variant. All reads would fail
if PM is disabled since the macro would throw an error...

The regular PM_RUNTIME_ACQUIRE_AUTOSUSPEND() is adequate.

-- 
Kind regards,
Joshua Crofts