Re: [PATCH 2/3] mm, mmu_notifier: be explicit about range invalition non-blocking mode

Jerome Glisse
2018-08-27T13:42:37Z

On Mon, Aug 27, 2018 at 01:26:22PM +0200, Michal Hocko wrote:
> From: Michal Hocko <mhocko@suse.com>
>
> If invalidate_range_start is called for !blocking mode then all
> callbacks have to guarantee they will no block/sleep. The same obviously
> applies to invalidate_range_end because this operation pairs with the
> former and they are called from the same context. Make sure this is
> appropriately documented.
>
> Signed-off-by: Michal Hocko <mhocko@suse.com>

Reviewed-by: Jerome Glisse <jglisse@redhat.com>

> ---
> include/linux/mmu_notifier.h | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
> index 133ba78820ee..698e371aafe3 100644
> --- a/include/linux/mmu_notifier.h
> +++ b/include/linux/mmu_notifier.h
> @@ -153,7 +153,9 @@ struct mmu_notifier_ops {
> *
> * If blockable argument is set to false then the callback cannot
> * sleep and has to return with -EAGAIN. 0 should be returned
> - * otherwise.
> + * otherwise. Please note that if invalidate_range_start approves
> + * a non-blocking behavior then the same applies to
> + * invalidate_range_end.
> *
> */
> int (*invalidate_range_start)(struct mmu_notifier *mn,
> --
> 2.18.0
>