Re: [PATCH v1 1/1] irqchip/stm32-exti: Use INVALID_HWIRQ definition

[Marc Zyngier]

On Fri, 15 Jul 2022 21:52:03 +0100,
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> 
> Use specific definition for invalid IRQ. It makes the
> code uniform in respect to the constant used for that.
> No functional change intended.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
>  drivers/irqchip/irq-stm32-exti.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/irqchip/irq-stm32-exti.c b/drivers/irqchip/irq-stm32-exti.c
> index a73763d475f0..a6ae9f38aaf0 100644
> --- a/drivers/irqchip/irq-stm32-exti.c
> +++ b/drivers/irqchip/irq-stm32-exti.c
> @@ -170,7 +170,7 @@ static const struct stm32_exti_bank *stm32mp1_exti_banks[] = {
>  static struct irq_chip stm32_exti_h_chip;
>  static struct irq_chip stm32_exti_h_chip_direct;
>  
> -#define EXTI_INVALID_IRQ       U8_MAX
> +#define EXTI_INVALID_IRQ       ((u8)INVALID_HWIRQ)

This looks like a terrible idea. It gives the impression that you can
now rely on comparing the internal data structure field to
INVALID_HWIRQ. Which is of course bound to fail.

To be honest, I'd rather *kill* INVALID_HWIRQ, because apart from
cherryview, nobody even *checks* for this value by that name. So much
for the "code uniformity"...

	M.

-- 
Without deviation from the norm, progress is not possible.