On 18.05.20 11:59, Anshuman Khandual wrote:
> Restrict elements in compound_page_dtors[] array per NR_COMPOUND_DTORS and
> explicitly position them according to enum compound_dtor_id. This improves
> protection against possible misalignment between compound_page_dtors[] and
> enum compound_dtor_id later on.
>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
> include/linux/mm.h | 2 +-
> mm/page_alloc.c | 10 +++++-----
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 688558c57751..d1bd7736a5e5 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -856,7 +856,7 @@ enum compound_dtor_id {
> #endif
> NR_COMPOUND_DTORS,
> };
> -extern compound_page_dtor * const compound_page_dtors[];
> +extern compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS];
>
> static inline void set_compound_page_dtor(struct page *page,
> enum compound_dtor_id compound_dtor)
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index cef05d3a23f5..2e4c23b34940 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -302,14 +302,14 @@ const char * const migratetype_names[MIGRATE_TYPES] = {
> #endif
> };
>
> -compound_page_dtor * const compound_page_dtors[] = {
> - NULL,
> - free_compound_page,
> +compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = {
> + [NULL_COMPOUND_DTOR] = NULL,
> + [COMPOUND_PAGE_DTOR] = free_compound_page,
> #ifdef CONFIG_HUGETLB_PAGE
> - free_huge_page,
> + [HUGETLB_PAGE_DTOR] = free_huge_page,
> #endif
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> - free_transhuge_page,
> + [TRANSHUGE_PAGE_DTOR] = free_transhuge_page,
> #endif
> };
>
>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David / dhildenb
