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SubjectRe: [PATCH] block: insert a general SMP memory barrier before wake_up_bit()
On Thu, Aug 13, 2020 at 10:44:38AM +0800, Jacob Wen wrote:
> wake_up_bit() uses waitqueue_active() that needs the explicit smp_mb().

Sounds like the barrier should go into wake_up_bit then..

>
> Signed-off-by: Jacob Wen <jian.w.wen@oracle.com>
> ---
> fs/block_dev.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index 0ae656e022fd..e74980848a2a 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -1175,6 +1175,7 @@ static void bd_clear_claiming(struct block_device *whole, void *holder)
> /* tell others that we're done */
> BUG_ON(whole->bd_claiming != holder);
> whole->bd_claiming = NULL;
> + smp_mb();
> wake_up_bit(&whole->bd_claiming, 0);
> }
>
> --
> 2.17.1
>
---end quoted text---

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