Re: [PATCH V4 1/3] driver core: mark device as irq affinity managed if any irq is managed

Christoph Hellwig
2021-07-21T07:27:30Z

On Wed, Jul 21, 2021 at 09:20:00AM +0200, Thomas Gleixner wrote:
> > Just walking the list seems fine to me given that this is not a
> > performance criticial path. But what are the locking implications?
>
> At the moment there are none because the list is initialized in the
> setup path and never modified afterwards. Though that might change
> sooner than later to fix the virtio wreckage vs. MSI-X.

What is the issue there? Either way, if we keep the helper in the
IRQ code it should be easy to spot for anyone adding the locking.

> > Also does the above imply this won't work for your platform MSI case?
>
> The msi descriptors are attached to struct device and independent of
> platform/PCI/whatever.

That's what I assumed, but this text from John suggested there is
something odd about the platform case:

"Did you consider that for PCI .."