On Wed, 23 Dec 2015, Jiang Liu wrote:
> @@ -167,11 +170,13 @@ next:
>
> if (test_bit(vector, used_vectors))
> goto next;
> -
> for_each_cpu_and(new_cpu, vector_cpumask, cpu_online_mask) {
> if (!IS_ERR_OR_NULL(per_cpu(vector_irq,
> new_cpu)[vector]))
> goto next;
> }
> + if (apic->cpu_mask_to_apicid_and(mask, vector_cpumask, &dest))
> + goto next;
This is silly. If the checks in cpu_mask_to_apicid_and() fail, then there is
no point to try the next vector number simply because the checks will fail
with the next vector again. You need a new vector_cpumask() in order to make
progress.
> +
> /* Found one! */
> current_vector = vector;
> current_offset = offset;
> @@ -190,8 +195,7 @@ next:
>
> if (!err) {
> /* cache destination APIC IDs into cfg->dest_apicid */
> - err = apic->cpu_mask_to_apicid_and(mask, d->domain,
> - &d->cfg.dest_apicid);
I have serious doubts that this is the proper solution.
d->domain is @vector_cpumask. @vector_cpumask gets assigned by the call to
apic->vector_allocation_domain()
So the only way this can fail is when:
vector_cpumask & mask & cpu_online_mask == 0
So we can do that check way earlier, i.e. right after the call to
apic->vector_allocation_domain(). Once we have established that this check
does not fail, we know that the call to apic->cpu_mask_to_apicid_and() wont
fail either once we have a vector number to use.
Thanks,
tglx
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