Re: [PATCH v6 3/4] iommu: debug-pagealloc: Track IOMMU pages

[Mostafa Saleh]

On Wed, Jan 14, 2026 at 5:30 PM David Hildenbrand (Red Hat)
<david@xxxxxxxxxx> wrote:
>
> On 1/13/26 16:08, Jason Gunthorpe wrote:
> > On Tue, Jan 13, 2026 at 10:49:28AM +0000, Mostafa Saleh wrote:
> >> Would you have a problem if we added a new function in page_ext
> >> "page_ext_from_phys()" as Jason suggested?
> >
> > Given the hidden complexity that David just pointed out I think this
> > is essential to encapsulate it in a function.
> >
> > The function must be able to accept any phys_addr_t and safely returns
> > NULL if page_ext cannot be used for some reason.
>
> Right. I think pfn_to_online_page() is the appropriate check.
>
> @Mostafa, I saw you already sent a v7, is the pfn_to_online_page() stuff
> handled in there?
>

Yes, it's in the first patch in function page_ext_get_phys().  After
spending some time looking into it, that was my conclusion also.

Thanks,
Mostafa

> --
> Cheers
>
> David