if need_lock is true but folio_trylock fails, we should return false
instead of NULL to match the return value type exactly. No functional
change intended.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 mm/damon/paddr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index a01495cebdad..21474ae63bc7 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -152,7 +152,7 @@ static bool damon_pa_young(unsigned long paddr, unsigned long *page_sz)
 	need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
 	if (need_lock && !folio_trylock(folio)) {
 		folio_put(folio);
-		return NULL;
+		return false;
 	}
 
 	rmap_walk(folio, &rwc);
-- 
2.23.0

Hi Miaohe,


Thank you for this patch!

On Wed, 16 Mar 2022 16:15:28 +0800 Miaohe Lin <linmiaohe@huawei.com> wrote:

> if need_lock is true but folio_trylock fails, we should return false
> instead of NULL to match the return value type exactly. No functional
> change intended.
> 
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>

Reviewed-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

> ---
>  mm/damon/paddr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
> index a01495cebdad..21474ae63bc7 100644
> --- a/mm/damon/paddr.c
> +++ b/mm/damon/paddr.c
> @@ -152,7 +152,7 @@ static bool damon_pa_young(unsigned long paddr, unsigned long *page_sz)
>  	need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
>  	if (need_lock && !folio_trylock(folio)) {
>  		folio_put(folio);
> -		return NULL;
> +		return false;
>  	}
>  
>  	rmap_walk(folio, &rwc);
> 
> -- 
> 2.23.0
> 
> 
>

On Wed, Mar 16, 2022 at 04:15:28PM +0800, Miaohe Lin wrote:
> if need_lock is true but folio_trylock fails, we should return false
> instead of NULL to match the return value type exactly. No functional
> change intended.

Thanks.  Given the extensive changes I've made to this function for
this merge window, I've added it to my for-next tree.