Re: [PATCH 4/5] genirq: Use the common function irq_expand_nr_irqs()

[Thomas Gleixner]

On Sun, Jan 29 2023 at 18:57, Shanker Donthineni wrote:

> Subject: genirq: Use the common function ...

  genirq: Unify irq_expand_nr_irqs()

  irq_expand_nr_irqs() is implemented as a stub function for !SPARSEIRQ
  builds. That's not necessary as the SPARSEIRQ version returns -ENOMEM
  correctly even for the !SPARSEIRQ case as the ....


But this common function is non-obvious for the !SPARSEIRQ case. It at
least needs a comment

> +static int irq_expand_nr_irqs(unsigned int nr)
> +{
> +	if (nr > MAX_SPARSE_IRQS)
> +		return -ENOMEM;
> +	nr_irqs = nr;
> +	return 0;
> +}

or preferrably something like this:

	if (!IS_ENABLED(CONFIG_SPARSEIRQ) || nr > MAX_SPARSE_IRQS)
		return -ENOMEM;

which makes it entirely clear and also allows the compiler to optimize
is down to a 'return -ENOMEM'.

Thanks,

        tglx