On Thu, Nov 24 2022 at 02:58, Kevin Tian wrote:
>> +
>> +/**
>> + * pci_msix_free_irq - Free an interrupt on a PCI/MSIX interrupt domain
>> + * which was allocated via pci_msix_alloc_irq_at()
>> + *
>> + * @dev: The PCI device to operate on
>> + * @map: A struct msi_map describing the interrupt to free
>> + * as returned from the allocation function.
>> + */
>
> Can this be used on preallocated descriptors? If not any guard required
> or just treat it as a driver responsibility to not misuse?
The preallocated descriptors are only relevant during setup, but not
post setup. So yes, you can do:
pci_alloc_irq_vectors(dev, 10, 10, PCI_IRQ_MSIX);
and then
map = { .index = 9, .virq = $IRQ };
pci_msix_free_irq(dev, &map);
It just works.
>> +void pci_msix_free_irq(struct pci_dev *dev, struct msi_map map)
>> +{
>> + if (WARN_ON_ONCE(map.index < 0 || map.virq <= 0))
>
> map.virq cannot be negative.
Why? Callers can make up whatever they want, no?
Thanks,
tglx
