Re: [PATCH v1] mm/pagewalk: fix usage of pmd_leaf()/pud_leaf() without present check

[David Hildenbrand]

On 15.10.24 16:32, Kirill A. Shutemov wrote:
> On Tue, Oct 15, 2024 at 01:12:36PM +0200, David Hildenbrand wrote:
> > pmd_leaf()/pud_leaf() only implies a pmd_present()/pud_present() check on
> > some architectures.
>
> Should we clarify what behaviour we actually want from arch code?

We probably should document somewhere that things like pmd_special(), 
pmd_leaf() ... should only be used when we know that the PMD is present.

I wonder if we should even add ways to detect mis-use

Jann also raised that recently in a private message, that it is rather 
unclear (well, and repeatedly leads to issues) when pmd_leaf() is valid 
to be called.

Thanks!

--
Cheers,

David / dhildenb