Re: [PATCH 11/17] gup: Convert gup_huge_pmd() to use a folio

[John Hubbard <jhubbard@nvidia.com>]

On 1/2/22 13:57, Matthew Wilcox (Oracle) wrote:
> Use the new folio-based APIs.  Also fix an assumption that memmap is
> contiguous.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>   mm/gup.c | 13 +++++++------
>   1 file changed, 7 insertions(+), 6 deletions(-)

Reviewed-by: John Hubbard <jhubbard@nvidia.com>


thanks,
-- 
John Hubbard
NVIDIA

> 
> diff --git a/mm/gup.c b/mm/gup.c
> index 1c7fb668b46d..be965c965484 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -2517,7 +2517,8 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
>   			unsigned long end, unsigned int flags,
>   			struct page **pages, int *nr)
>   {
> -	struct page *head, *page;
> +	struct page *page;
> +	struct folio *folio;
>   	int refs;
>   
>   	if (!pmd_access_permitted(orig, flags & FOLL_WRITE))
> @@ -2530,20 +2531,20 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
>   					     pages, nr);
>   	}
>   
> -	page = pmd_page(orig) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
> +	page = nth_page(pmd_page(orig), (addr & ~PMD_MASK) >> PAGE_SHIFT);
>   	refs = record_subpages(page, addr, end, pages + *nr);
>   
> -	head = try_grab_compound_head(pmd_page(orig), refs, flags);
> -	if (!head)
> +	folio = try_grab_folio(page, refs, flags);
> +	if (!folio)
>   		return 0;
>   
>   	if (unlikely(pmd_val(orig) != pmd_val(*pmdp))) {
> -		put_compound_head(head, refs, flags);
> +		gup_put_folio(folio, refs, flags);
>   		return 0;
>   	}
>   
>   	*nr += refs;
> -	SetPageReferenced(head);
> +	folio_set_referenced(folio);
>   	return 1;
>   }
>