Re: [PATCH v2 05/28] gup: Change the calling convention for compound_next()

[John Hubbard <jhubbard@xxxxxxxxxx>]

On 1/9/22 20:23, Matthew Wilcox (Oracle) wrote:
> Return the head page instead of storing it to a passed parameter.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
>   mm/gup.c | 11 +++++------
>   1 file changed, 5 insertions(+), 6 deletions(-)


Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>


thanks,
--
John Hubbard
NVIDIA

> diff --git a/mm/gup.c b/mm/gup.c
> index 6eedca605b3d..8a0ea220ced1 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -245,9 +245,8 @@ static inline struct page *compound_range_next(unsigned long i,
>   	return page;
>   }
>   
> -static inline void compound_next(unsigned long i, unsigned long npages,
> -				 struct page **list, struct page **head,
> -				 unsigned int *ntails)
> +static inline struct page *compound_next(unsigned long i,
> +		unsigned long npages, struct page **list, unsigned int *ntails)
>   {
>   	struct page *page;
>   	unsigned int nr;
> @@ -258,8 +257,8 @@ static inline void compound_next(unsigned long i, unsigned long npages,
>   			break;
>   	}
>   
> -	*head = page;
>   	*ntails = nr - i;
> +	return page;
>   }
>   
>   /**
> @@ -297,7 +296,7 @@ void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
>   	}
>   
>   	for (index = 0; index < npages; index += ntails) {
> -		compound_next(index, npages, pages, &head, &ntails);
> +		head = compound_next(index, npages, pages, &ntails);
>   		/*
>   		 * Checking PageDirty at this point may race with
>   		 * clear_page_dirty_for_io(), but that's OK. Two key
> @@ -386,7 +385,7 @@ void unpin_user_pages(struct page **pages, unsigned long npages)
>   		return;
>   
>   	for (index = 0; index < npages; index += ntails) {
> -		compound_next(index, npages, pages, &head, &ntails);
> +		head = compound_next(index, npages, pages, &ntails);
>   		put_compound_head(head, ntails, FOLL_PIN);
>   	}
>   }