[PATCH v2 hmm 07/11] mm/hmm: Use lockdep instead of comments

[Souptick Joarder]

On Fri, Jun 7, 2019 at 12:15 AM Jason Gunthorpe <jgg at ziepe.ca> wrote:
>
> From: Jason Gunthorpe <jgg at mellanox.com>
>
> So we can check locking at runtime.

Little more descriptive change log would be helpful.
Acked-by: Souptick Joarder <jrdr.linux at gmail.com>

>
> Signed-off-by: Jason Gunthorpe <jgg at mellanox.com>
> Reviewed-by: Jérôme Glisse <jglisse at redhat.com>
> ---
> v2
> - Fix missing & in lockdeps (Jason)
> ---
>  mm/hmm.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/hmm.c b/mm/hmm.c
> index f67ba32983d9f1..c702cd72651b53 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -254,11 +254,11 @@ static const struct mmu_notifier_ops hmm_mmu_notifier_ops = {
>   *
>   * To start mirroring a process address space, the device driver must register
>   * an HMM mirror struct.
> - *
> - * THE mm->mmap_sem MUST BE HELD IN WRITE MODE !
>   */
>  int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm)
>  {
> +       lockdep_assert_held_exclusive(&mm->mmap_sem);
> +
>         /* Sanity check */
>         if (!mm || !mirror || !mirror->ops)
>                 return -EINVAL;
> --
> 2.21.0
>