Re: [PATCH 03/16] mm: add vma_desc_size(), vma_desc_pages() helpers

Lorenzo Stoakes
2025-09-08T15:34:57Z

On Mon, Sep 08, 2025 at 05:24:23PM +0200, David Hildenbrand wrote:
> >
> > > I think we need to be cautious of scope here :) I don't want to
> > > accidentally break things this way.
> >
> > IMHO it is worth doing when you get into more driver places it is far
> > more obvious why the VM_SHARED is being checked.
> >
> > > OK I think a sensible way forward - How about I add desc_is_cowable() or
> > > vma_desc_cowable() and only set this if I'm confident it's correct?
> >
> > I'm thinking to call it vma_desc_never_cowable() as that is much much
> > clear what the purpose is.
>
> Secretmem wants no private mappings. So we should check exactly that, not
> whether we might have a cow mapping.

Well then :)

Probably in most cases what Jason is saying is valid for drivers.

So I can add a helper for both.

Maybe vma_desc_is_private() for this one?

>
> --
> Cheers
>
> David / dhildenb
>