question about arch/arm/mach-s3c24xx/irq.c

[Russell King - ARM Linux]

On Sun, Feb 24, 2013 at 12:45:11PM +0100, Julia Lawall wrote:
> The function s3c24xx_irq_map in arch/arm/mach-s3c24xx/irq.c contains the
> code:
> 
>                 parent_irq_data = &parent_intc->irqs[irq_data->parent_irq];
> 		if (!irq_data) {
>                         pr_err("irq-s3c24xx: no irq data found for hwirq %lu\n",
>                                hw);
>                         goto err;
> 		}
> 
> At this point irq_data has already been tested, so the null test on
> irq_data does not look correct.  But I wonder if parent_irq_data could
> ever be null here?

That would be really obscure - because that would require parent_intc to
be a "negative" pointer (to counter-act the indexing by
irq_data->parent_irq).  So it looks to me like the above is redundant.