Re: [PATCH v2 2/8] mm: Rename arguments to find_subpage

[Pankaj Gupta <pankaj.gupta.linux@gmail.com>]

> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> This isn't just a random struct page, it's known to be a head page,
> and calling it head makes the function better self-documenting.
> The pgoff_t is less confusing if it's named index instead of offset.
> Also add a couple of comments to explain why we're doing various things.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  include/linux/pagemap.h | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index b4ea3a5d00e5..68db0ed8535d 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -333,14 +333,19 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
>                         mapping_gfp_mask(mapping));
>  }
>
> -static inline struct page *find_subpage(struct page *page, pgoff_t offset)
> +/*
> + * Given the page we found in the page cache, return the page corresponding
> + * to this index in the file
> + */
> +static inline struct page *find_subpage(struct page *head, pgoff_t index)
>  {
> -       if (PageHuge(page))
> -               return page;
> +       /* HugeTLBfs wants the head page regardless */
> +       if (PageHuge(head))
> +               return head;
>
> -       VM_BUG_ON_PAGE(PageTail(page), page);
> +       VM_BUG_ON_PAGE(PageTail(head), head);
>
> -       return page + (offset & (compound_nr(page) - 1));
> +       return head + (index & (compound_nr(head) - 1));
>  }
>
>  struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
> --
> 2.25.1

Makes function much easier to understand. Thanks!
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>

>
>