On Tue, Mar 24, 2026 at 10:16 AM Bartosz Golaszewski <[email protected]> wrote:
>
> On Tue, Mar 24, 2026 at 4:56 PM Rosen Penev <[email protected]> wrote:
> >
> > On Tue, Mar 24, 2026 at 8:54 AM Bartosz Golaszewski <[email protected]> wrote:
> > >
> > > On Tue, Mar 24, 2026 at 4:52 PM Rosen Penev <[email protected]> wrote:
> > > >
> > > > On Tue, Mar 24, 2026 at 2:16 AM Bartosz Golaszewski <[email protected]>
> > > > wrote:
> > > > >
> > > > > On Mon, 23 Mar 2026 17:43:00 +0100, Rosen Penev <[email protected]>
> > > > > said:
> > > > > > On Mon, Mar 23, 2026 at 3:00 AM Bartosz Golaszewski
> > > > > > <[email protected]> wrote:
> > > > > >>
> > > > > >> On Sat, Mar 21, 2026 at 12:00 AM Rosen Penev <[email protected]>
> > > > > >> wrote:
> > > > > >> >
> > > > > >> > >
> > > > > >> > > static int gpio_mockup_probe(struct platform_device *pdev)
> > > > > >> > > {
> > > > > >> > > ...
> > > > > >> > > u16 ngpio;
> > > > > >> > > ...
> > > > > >> > > rv = device_property_read_u16(dev, "nr-gpios", &ngpio);
> > > > > >> > > ...
> > > > > >> > > gc->ngpio = ngpio;
> > > > > >> > > ...
> > > > > >> > > chip->lines = devm_kcalloc(dev, gc->ngpio,
> > > > > >> > > sizeof(*chip->lines),
> > > > > >> > > GFP_KERNEL);
> > > > > >> > >
> > > > > >> > > But this begs the question: why add nr_lines when ngpio is
> > > > > >> > > already part
> > > > > >> > > of the struct:
> > > > > >> > Maintainers for some inexplicable reason want an extra variable
> > > > > >> > for
> > > > > >> > __counted_by works.
> > > > > >>
> > > > > >> I believe what Kees means here is: you can use ngpio for
> > > > > >> __counted_by() like so:
> > > > > >>
> > > > > >> __counted_by(gc.ngpio)
> > > > > > __counted_by doesn't support nested variables like that.
> > > > > >
> > > > > > drivers/gpio/gpio-mockup.c:59:61: error: ‘gc’ undeclared here (not
> > > > > > in
> > > > > > a function)
> > > > > > 59 | struct gpio_mockup_line_status lines[]
> > > > > > __counted_by(gc.ngpio);
> > > > >
> > > > > The following spin on your patch builds fine for me:
> > > > >
> > > > > diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
> > > > > index a7d69f3835c1e..9427ab8c45f73 100644
> > > > > --- a/drivers/gpio/gpio-mockup.c
> > > > > +++ b/drivers/gpio/gpio-mockup.c
> > > > > @@ -52,10 +52,10 @@ struct gpio_mockup_line_status {
> > > > >
> > > > > struct gpio_mockup_chip {
> > > > > struct gpio_chip gc;
> > > > > - struct gpio_mockup_line_status *lines;
> > > > > struct irq_domain *irq_sim_domain;
> > > > > struct dentry *dbg_dir;
> > > > > struct mutex lock;
> > > > > + struct gpio_mockup_line_status lines[] __counted_by(gc.ngpio);
> > > > You're using an older compiler. This does not work at all.
> > > >
> > > > *
>
> Indeed, sorry. In that case I don't know what Kees meant. I'm fine
> with a new variable.
I think his comment is that there's already a counting variable, with
or without counted_by.
>
> Bartosz
