Re: [PATCH] mm: try_to_unmap() is now void

[Yang Shi]

On Wed, Jul 7, 2021 at 9:16 AM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
>
> Fix the "CONFIG_MMU is not set" case of converting
> try_to_unmap() from bool to void.
> (as seen on m68k/coldfire)
>
> In file included from ../mm/vmscan.c:33:
> ../mm/vmscan.c: In function 'shrink_page_list':
> ../include/linux/rmap.h:294:34: warning: statement with no effect [-Wunused-value]
>   294 | #define try_to_unmap(page, refs) false
>       |                                  ^~~~~
> ../mm/vmscan.c:1508:4: note: in expansion of macro 'try_to_unmap'
>  1508 |    try_to_unmap(page, flags);
>       |    ^~~~~~~~~~~~
>

Thanks for the patch. hch sent a similar patch
(https://lore.kernel.org/linux-mm/20210705053944.885828-1-hch@xxxxxx/)
and it has been in -mm tree.

> Fixes: 1fb08ac63bee ("mm: rmap: make try_to_unmap() void function")
> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Cc: Yang Shi <shy828301@xxxxxxxxx>
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Cc: Greg Ungerer <gerg@xxxxxxxxxxxxxx>
> Cc: linux-m68k@xxxxxxxxxxxxxxxxxxxx
> Cc: uclinux-dev@xxxxxxxxxxx
> ---
> v2: add linux-mm m.l.
>     add M68K/Coldfire Cc's
>     change to static inline function.
>
>  include/linux/rmap.h |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> --- linux-next-20210701.orig/include/linux/rmap.h
> +++ linux-next-20210701/include/linux/rmap.h
> @@ -291,7 +291,8 @@ static inline int page_referenced(struct
>         return 0;
>  }
>
> -#define try_to_unmap(page, refs) false
> +static inline void try_to_unmap(struct page *page, enum ttu_flags flags)
> +{}
>
>  static inline int page_mkclean(struct page *page)
>  {