Re: [PATCH 6/6] mm: Constify page_count and page_ref_count

[Vlastimil Babka]

On 4/17/21 1:15 AM, Matthew Wilcox (Oracle) wrote:
> Now that compound_head() accepts a const struct page pointer, these two
> functions can be marked as not modifying the page pointer they are passed.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>

Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
>  include/linux/page_ref.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/page_ref.h b/include/linux/page_ref.h
> index f3318f34fc54..7ad46f45df39 100644
> --- a/include/linux/page_ref.h
> +++ b/include/linux/page_ref.h
> @@ -62,12 +62,12 @@ static inline void __page_ref_unfreeze(struct page *page, int v)
>  
>  #endif
>  
> -static inline int page_ref_count(struct page *page)
> +static inline int page_ref_count(const struct page *page)
>  {
>  	return atomic_read(&page->_refcount);
>  }
>  
> -static inline int page_count(struct page *page)
> +static inline int page_count(const struct page *page)
>  {
>  	return atomic_read(&compound_head(page)->_refcount);
>  }
>