[PATCH] mm: Add is_migrate_cma_page

[Kees Cook]

On Tue, Jul 19, 2016 at 3:00 PM, Laura Abbott <labbott at redhat.com> wrote:
> Code such as hardened user copy[1] needs a way to tell if a
> page is CMA or not. Add is_migrate_cma_page in a similar way
> to is_migrate_isolate_page.
>
> [1]http://article.gmane.org/gmane.linux.kernel.mm/155238
>
> Signed-off-by: Laura Abbott <labbott at redhat.com>

Great, thanks!

> ---
> Here's an explicit patch, slightly different than what I posted before. It can
> be kept separate or folded in as needed.

Assuming there's no objection, I'll add it to my tree and use the new macro.

-Kees

> ---
>  include/linux/mmzone.h | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 02069c2..c8478b2 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -68,8 +68,10 @@ extern char * const migratetype_names[MIGRATE_TYPES];
>
>  #ifdef CONFIG_CMA
>  #  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
> +#  define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
>  #else
>  #  define is_migrate_cma(migratetype) false
> +#  define is_migrate_cma_page(_page) false
>  #endif
>
>  #define for_each_migratetype_order(order, type) \
> --
> 2.7.4
>



-- 
Kees Cook
Chrome OS & Brillo Security