On Thu 09-03-17 15:02:26, Minchan Kim wrote:
[...]
> >From 38b10e560d066c2cef8f9d028e14008cefdaa3e0 Mon Sep 17 00:00:00 2001
> From: Minchan Kim <minc...@kernel.org>
> Date: Thu, 9 Mar 2017 14:58:23 +0900
> Subject: [PATCH] mm: do not use VM_WARN_ON_ONCE as if condition
>
> Sergey reported VM_WARN_ON_ONCE returns void with !CONFIG_DEBUG_VM
> so we cannot use it as if's condition unlike WARN_ON.
I would swear I've seen WARN_ON_ONCE there when looking at the previous
patch! Btw. could have simply s@VM_@@
> This patch fixes it.
>
> Signed-off-by: Minchan Kim <minc...@kernel.org>
Acked-by: Michal Hocko <mho...@suse.com>
> ---
> mm/rmap.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 1d82057144ba..7d24bb93445b 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1413,12 +1413,11 @@ static int try_to_unmap_one(struct page *page, struct
> vm_area_struct *vma,
> * Store the swap location in the pte.
> * See handle_pte_fault() ...
> */
> - if (VM_WARN_ON_ONCE(PageSwapBacked(page) !=
> - PageSwapCache(page))) {
> + if (unlikely(PageSwapBacked(page) !=
> PageSwapCache(page))) {
> + WARN_ON_ONCE(1);
> ret = SWAP_FAIL;
> page_vma_mapped_walk_done(&pvmw);
> break;
> -
> }
>
> /* MADV_FREE page check */
> --
> 2.7.4
--
Michal Hocko
SUSE Labs
