Re: [PATCH v2 6/7] mm: Batch around can_change_pte_writable()

[David Hildenbrand <david@redhat.com>]

>   #include "internal.h"
>   
> -bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
> -			     pte_t pte)
> +bool can_change_ptes_writable(struct vm_area_struct *vma, unsigned long addr,
> +			      pte_t pte, struct folio *folio, unsigned int nr)
>   {
>   	struct page *page;
>   
> @@ -67,8 +67,9 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
>   		 * write-fault handler similarly would map them writable without
>   		 * any additional checks while holding the PT lock.
>   		 */
> -		page = vm_normal_page(vma, addr, pte);
> -		return page && PageAnon(page) && PageAnonExclusive(page);
> +		if (!folio)
> +			folio = vm_normal_folio(vma, addr, pte);
> +		return folio_test_anon(folio) && !folio_maybe_mapped_shared(folio);

Oh no, now I spot it. That is horribly wrong.

Please understand first what you are doing.

-- 
Cheers,

David / dhildenb