On Mon, Jan 16 2023 at 14:50, Johan Hovold wrote:
> Avoid looking for an existing mapping twice when creating a new mapping
> using irq_create_fwspec_mapping() by factoring out the actual allocation
> which is shared with irq_create_mapping_affinity().
This changelog is incomplete and it took me a while to figure out why
this is before the race fix.
The point is that you need __irq_create_mapping_affinity() later to fix
the shared mapping race. The double check avoidance is just a nice side
effect.
So please spell it out and make it clear that this needs to be
backported too, e.g. by adding:
The split out internal function will be used to fix a shared interrupt
mapping race. This change is therefore tagged with the same fixes tag.
Fixes: ....
>
> +static unsigned int __irq_create_mapping_affinity(struct irq_domain *domain,
> + irq_hw_number_t hwirq,
> + const struct irq_affinity_desc *affinity)
Please rename to irq_create_mapping_affinity_locked() so it's clear what
this is about and what the calling convention is. A lockdep assert to
that effect would be nice too.
Thanks,
tglx
