Re: [PATCH net-next v4 3/4] skbuff: Add a function to check if a page belongs to page_pool

[Yunsheng Lin <linyunsheng@huawei.com>]

On 2023/11/29 11:12, Liang Chen wrote:
> Wrap code for checking if a page is a page_pool page into a
> function for better readability and ease of reuse.
> 
> Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
> ---
>  net/core/skbuff.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index b157efea5dea..310207389f51 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -890,6 +890,11 @@ static void skb_clone_fraglist(struct sk_buff *skb)
>  		skb_get(list);
>  }
>  
> +static inline bool skb_frag_is_pp_page(struct page *page)

I am not sure about the 'skb_frag' part, But I am not able to come
up with a better name too:)

Also, Generally, 'inline' is not really encouraged in c file in
the networking unless there is a clear justification as the compiler
can make better decision about whether inlining most of the time.

Other than the 'inlining' part, LGTM.
Reviewed-by: Yunsheng Lin <linyunsheng@huawei.com>

> +{
> +	return (page->pp_magic & ~0x3UL) == PP_SIGNATURE;
> +}
> +
>  #if IS_ENABLED(CONFIG_PAGE_POOL)
>  bool napi_pp_put_page(struct page *page, bool napi_safe)
>  {
> @@ -905,7 +910,7 @@ bool napi_pp_put_page(struct page *page, bool napi_safe)
>  	 * and page_is_pfmemalloc() is checked in __page_pool_put_page()
>  	 * to avoid recycling the pfmemalloc page.
>  	 */
> -	if (unlikely((page->pp_magic & ~0x3UL) != PP_SIGNATURE))
> +	if (unlikely(!skb_frag_is_pp_page(page)))
>  		return false;
>  
>  	pp = page->pp;
>