Re: [PATCH v2 03/28] gup: Change the calling convention for compound_range_next()

[John Hubbard]

On 1/9/22 20:23, Matthew Wilcox (Oracle) wrote:
> Return the head page instead of storing it to a passed parameter.
> Pass the start page directly instead of passing a pointer to it.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---

Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>


thanks,
--
John Hubbard
NVIDIA

>   mm/gup.c | 11 +++++------
>   1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index 86f8d843de72..3c93d2fdf4da 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -229,21 +229,20 @@ void unpin_user_page(struct page *page)
>   }
>   EXPORT_SYMBOL(unpin_user_page);
>   
> -static inline void compound_range_next(unsigned long i, unsigned long npages,
> -				       struct page **list, struct page **head,
> -				       unsigned int *ntails)
> +static inline struct page *compound_range_next(unsigned long i,
> +		unsigned long npages, struct page *start, unsigned int *ntails)
>   {
>   	struct page *next, *page;
>   	unsigned int nr = 1;
>   
> -	next = *list + i;
> +	next = start + i;
>   	page = compound_head(next);
>   	if (PageCompound(page) && compound_order(page) >= 1)
>   		nr = min_t(unsigned int,
>   			   page + compound_nr(page) - next, npages - i);
>   
> -	*head = page;
>   	*ntails = nr;
> +	return page;
>   }
>   
>   static inline void compound_next(unsigned long i, unsigned long npages,
> @@ -355,7 +354,7 @@ void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
>   	unsigned int ntails;
>   
>   	for (index = 0; index < npages; index += ntails) {
> -		compound_range_next(index, npages, &page, &head, &ntails);
> +		head = compound_range_next(index, npages, page, &ntails);
>   		if (make_dirty && !PageDirty(head))
>   			set_page_dirty_lock(head);
>   		put_compound_head(head, ntails, FOLL_PIN);