Re: [PATCH] fs/proc: task_mmu.c: Fix the error-unused variable 'migration'

From: Stephen Rothwell
Date: Tue Feb 08 2022 - 22:10:46 EST


Hi Cai,

On Wed, 9 Feb 2022 10:35:59 +0800 Cai Huoqing <cai.huoqing@xxxxxxxxx> wrote:
>
> Avoid the error-unused variable 'migration' when
> CONFIG_TRANSPARENT_HUGEPAGE and CONFIG_ARCH_ENABLE_THP_MIGRATION
> are not enabled.
>
> Signed-off-by: Cai Huoqing <cai.huoqing@xxxxxxxxx>
> ---
> fs/proc/task_mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index bc2f46033231..b055ff29204d 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -1441,7 +1441,7 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
> spinlock_t *ptl;
> pte_t *pte, *orig_pte;
> int err = 0;
> - bool migration = false;
> + bool migration __maybe_unused = false;
>
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> ptl = pmd_trans_huge_lock(pmdp, vma);
> --
> 2.25.1
>

This has already been fixed in Andrew's patch set by moving the "#ifdef
CONFIG_TRANSPARENT_HUGEPAGE" above the "migration" declaration.

--
Cheers,
Stephen Rothwell

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