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. > > * Optional: only supported since gcc >= 15 > * Optional: only supported since clang >= 18 > > }; > >
Ok, what is this feature called in gcc parlance and where does this info come from? Bart
