On 04/18/2018 08:49 PM, Matthew Wilcox wrote:
> From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
>
> Now that we can represent the location of 'deferred_list' in C instead
> of comments, make use of that ability.
>
> Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> ---
> mm/huge_memory.c | 7 ++-----
> mm/page_alloc.c | 2 +-
> 2 files changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 14ed6ee5e02f..55ad852fbf17 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -483,11 +483,8 @@ pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
>
> static inline struct list_head *page_deferred_list(struct page *page)
> {
> - /*
> - * ->lru in the tail pages is occupied by compound_head.
> - * Let's use ->mapping + ->index in the second tail page as list_head.
> - */
> - return (struct list_head *)&page[2].mapping;
> + /* ->lru in the tail pages is occupied by compound_head. */
> + return &page[2].deferred_list;
> }
>
> void prep_transhuge_page(struct page *page)
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 88e817d7ccef..18720eccbce1 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -953,7 +953,7 @@ static int free_tail_pages_check(struct page *head_page, struct page *page)
> case 2:
> /*
> * the second tail page: ->mapping is
> - * page_deferred_list().next -- ignore value.
> + * deferred_list.next -- ignore value.
> */
> break;
> default:
>
