Re: [PATCH v9 01/13] set_memory: add folio_{zap, restore}_direct_map helpers

[Nikita Kalyazin]

On 15/01/2026 15:55, Matthew Wilcox wrote:
> On Wed, Jan 14, 2026 at 01:45:23PM +0000, Kalyazin, Nikita wrote:
> > +int folio_zap_direct_map(struct folio *folio)
> > +{
> > +     return set_direct_map_valid_noflush(folio_page(folio, 0),
> > +                                         folio_nr_pages(folio), false);
> > +}
>
> The implementation isn't the greatest.  None of the implementations
> of set_direct_map_valid_noflush() actually do anything with the struct
> page; they all call page_address() or page_to_virt() (fundamentally the
> same thing).  So converting folio->page->address is a bit inefficient.
>
> It feels like we should change set_direct_map_valid_noflush() to take a
> const void * and pass either page_address() or folio_address(), depending
> whether the caller has a page or a folio.  What do you think?

I have nothing against that.  execmem_set_direct_map_valid() appears to 
be the only other user of set_direct_map_valid_noflush() so it isn't 
going to be a broad change.