Re: [PATCH v1] mm, hwpoison: add is_free_buddy_page() in HWPoisonHandlable()

[David Hildenbrand]

On 09.09.21 02:41, Naoya Horiguchi wrote:
> From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
>
> commit fcc00621d88b ("mm/hwpoison: retry with shake_page() for
> unhandlable pages") changes the return value of __get_hwpoison_page() to
> retry for transiently unhandlable cases.  However, __get_hwpoison_page()
> currently fails to properly judge buddy pages as handlable, so hard/soft
> offline for buddy pages always fail as "unhandlable page".  This is
> totally regrettable.
>
> So let's add is_free_buddy_page() in HWPoisonHandlable(), so that
> __get_hwpoison_page() returns different return values between buddy
> pages and unhandlable pages as intended.
>
> Fixes: fcc00621d88b ("mm/hwpoison: retry with shake_page() for unhandlable pages")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
> ---
>   mm/memory-failure.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git v5.14-rc7-mmotm-2021-08-23-16-42/mm/memory-failure.c v5.14-rc7-mmotm-2021-08-23-16-42_patched/mm/memory-failure.c
> index 60df8fcd0444..3416c55be810 100644
> --- v5.14-rc7-mmotm-2021-08-23-16-42/mm/memory-failure.c
> +++ v5.14-rc7-mmotm-2021-08-23-16-42_patched/mm/memory-failure.c
> @@ -1126,7 +1126,7 @@ static int page_action(struct page_state *ps, struct page *p,
>    */
>   static inline bool HWPoisonHandlable(struct page *page)
>   {
> -	return PageLRU(page) || __PageMovable(page);
> +	return PageLRU(page) || __PageMovable(page) || is_free_buddy_page(page);
>   }
>   
>   static int __get_hwpoison_page(struct page *page)

LGTM and I agree that code might desrve some cleanups.

Acked-by: David Hildenbrand <david@xxxxxxxxxx>

--
Thanks,

David / dhildenb