[adding Thomas for a cpu hotplug questions]
> +static void bio_alloc_cache_destroy(struct bio_set *bs)
> +{
> + int cpu;
> +
> + if (!bs->cache)
> + return;
> +
> + preempt_disable();
> + cpuhp_state_remove_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);
> + for_each_possible_cpu(cpu) {
> + struct bio_alloc_cache *cache;
> +
> + cache = per_cpu_ptr(bs->cache, cpu);
> + bio_alloc_cache_prune(cache, -1U);
> + }
> + preempt_enable();
If I understand the cpu hotplug state machine we should not get any new
cpu down callbacks after cpuhp_state_remove_instance_nocalls returned,
so what do we need the preempt disable here for?
> + /*
> + * Hot un-plug notifier for the per-cpu cache, if used
> + */
> + struct hlist_node cpuhp_dead;
Nit, even if we don't need the cpu up notifaction the node actually
provides both. So I'd reword the comment drop the _dead from the
member name.
Otherwise looks good:
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
