Re: [PATCH v4 03/23] mm/gup: move try_get_compound_head() to top, fix minor issues

[Jan Kara]

On Tue 12-11-19 20:26:50, John Hubbard wrote:
> An upcoming patch uses try_get_compound_head() more widely,
> so move it to the top of gup.c.
> 
> Also fix a tiny spelling error and a checkpatch.pl warning.
> 
> Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>

Looks good. You can add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

								Honza

> ---
>  mm/gup.c | 29 +++++++++++++++--------------
>  1 file changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index 199da99e8ffc..933524de6249 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -29,6 +29,21 @@ struct follow_page_context {
>  	unsigned int page_mask;
>  };
>  
> +/*
> + * Return the compound head page with ref appropriately incremented,
> + * or NULL if that failed.
> + */
> +static inline struct page *try_get_compound_head(struct page *page, int refs)
> +{
> +	struct page *head = compound_head(page);
> +
> +	if (WARN_ON_ONCE(page_ref_count(head) < 0))
> +		return NULL;
> +	if (unlikely(!page_cache_add_speculative(head, refs)))
> +		return NULL;
> +	return head;
> +}
> +
>  /**
>   * put_user_pages_dirty_lock() - release and optionally dirty gup-pinned pages
>   * @pages:  array of pages to be maybe marked dirty, and definitely released.
> @@ -1793,20 +1808,6 @@ static void __maybe_unused undo_dev_pagemap(int *nr, int nr_start,
>  	}
>  }
>  
> -/*
> - * Return the compund head page with ref appropriately incremented,
> - * or NULL if that failed.
> - */
> -static inline struct page *try_get_compound_head(struct page *page, int refs)
> -{
> -	struct page *head = compound_head(page);
> -	if (WARN_ON_ONCE(page_ref_count(head) < 0))
> -		return NULL;
> -	if (unlikely(!page_cache_add_speculative(head, refs)))
> -		return NULL;
> -	return head;
> -}
> -
>  #ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
>  static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
>  			 unsigned int flags, struct page **pages, int *nr)
> -- 
> 2.24.0
> 
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR