Re: [PATCH 1/9] mm: Convert ksm_might_need_to_copy() to work on folios

[David Hildenbrand <david@xxxxxxxxxx>]

> +++ b/mm/swapfile.c
> @@ -1749,11 +1749,13 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
>   	int ret = 1;
>   
>   	swapcache = page;
> -	page = ksm_might_need_to_copy(page, vma, addr);
> -	if (unlikely(!page))
> +	folio = ksm_might_need_to_copy(folio, vma, addr);
> +	if (unlikely(!folio))
>   		return -ENOMEM;
> -	else if (unlikely(PTR_ERR(page) == -EHWPOISON))
> +	else if (unlikely(folio == ERR_PTR(-EHWPOISON)))
>   		hwpoisoned = true;
> +	else
> +		page = folio_file_page(folio, swp_offset(entry));

Just to double-check:

assuming ksm_might_need_to_copy() in fact allocated a fresh (order-0) 
folio, folio_file_page() will simply translate to "folio_page(folio, 0)" 
and should be fine.

--
Cheers,

David / dhildenb