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SubjectRe: About irq_create_affinity_masks() for a platform device driver
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Hi Thomas,

>>
>> pirqs = kzalloc(*count * sizeof(int), GFP_KERNEL);
>> if (!pirqs)
>> return -ENOMEM;
>>
>> dev->desc = irq_create_affinity_masks(*count, affd);
>> if (!dev->desc) {
>> kfree(irqs);
>
> pirqs I assume and this also leaks the affinity masks and the pointer in
> dev.

Right

>
>> return -ENOMEM;
>> }
>>
>> for (i = 0; i < *count; i++) {
>> pirqs[i] = platform_get_irq(dev, i);
>> if (irqs[i] < 0) {
>> kfree(dev->desc);
>> kfree(irqs);
>> return -ENOMEM;
>
> That's obviously broken as well :)

Right, again

>
>> }
>> }
>>
>> *irqs = pirqs;
>>
>> return 0;
>> }
>> EXPORT_SYMBOL_GPL(platform_get_irqs_affinity);

[...]

>
> I wouldn't mind to expose a function which allows you to switch the
> allocated interrupts to managed. The reason why we do it in one go in
> the PCI code is that we get automatically the irq descriptors allocated
> on the correct node. So if the node aware allocation is not a
> showstopper

I wouldn't say so for now.

for this then your function would do:
>
> ...
> for (i = 0; i < count; i++) {
> pirqs[i] = platform_get_irq(dev, i);
>
> irq_update_affinity_desc(pirqs[i], affdescs + i);
>
> }
>
> int irq_update_affinity_desc(unsigned int irq, irq_affinity_desc *affinity)
> {
> unsigned long flags;
> struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
>
> if (!desc)
> return -EINVAL;
>
> if (affinity->is_managed) {
> irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
> irqd_set(&desc->irq_data, IRQD_IRQ_MASKED);

Are these correct? I assume we want to follow alloc_descs() here.

> }
> cpumask_copy(desc->irq_common_data.affinity, affinity);
> return 0;
> }

I see. So I made a couple of changes and it did work:

int irq_update_affinity_desc(unsigned int irq, struct irq_affinity_desc
*affinity)
{
unsigned long flags;
struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);

if (!desc)
return -EINVAL;

if (affinity->is_managed) {
irqd_set(&desc->irq_data, IRQD_AFFINITY_MANAGED);
irqd_set(&desc->irq_data, IRQD_MANAGED_SHUTDOWN);
}

cpumask_copy(desc->irq_common_data.affinity, &affinity->mask);
irq_put_desc_unlock(desc, flags);
return 0;
}

And if we were to go this way, then we don't need to add the pointer in
struct platform_device to hold affinity mask descriptors as we're using
them immediately. Or even have a single function to do it all in the irq
code (create the masks and update the affinity desc).

And since we're just updating the masks, I figure we shouldn't need to
add acpi_irq_get_count(), which I invented to get the irq count (without
creating the IRQ mapping).

Thanks,
John

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