Re: [patch 00/37] genirq/msi, PCI/MSI: Spring cleaning - Part 2

Thomas Gleixner
2021-11-28T20:29:23Z

On Sat, Nov 27 2021 at 20:39, Jason Gunthorpe wrote:
> On Sat, Nov 27, 2021 at 02:21:17AM +0100, Thomas Gleixner wrote:
>> 4) Provide a function to retrieve the Linux interrupt number for a given
>> MSI index similar to pci_irq_vector() and cleanup all open coded
>> variants.
>
> The msi_get_virq() sure does make a big difference.. Though it does
> highlight there is some asymmetry with how platform and PCI works here
> where PCI fills some 'struct msix_entry *'. Many drivers would be
> quite happy to just call msi_get_virq() and avoid the extra memory, so
> I think the msi_get_virq() version is good.

struct msix_entry should just go away.

90+% of the use cases fill it with a linear index range 0...N and then
use the virq entry for request_irq(). So they can just use
pci_alloc_irs_vectors_affinity() and retrieve the interrupt number via
pci_irq_vector().

The few drivers which actually use it to allocate a sparse populated MSI
index, e.g. 0, 12, 14 can be converted over to alloc vector 0 and then
use the dynamic extenstion for the rest.

Thanks,

tglx