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

[Ralph Campbell]

On 6/6/19 11:44 AM, Jason Gunthorpe wrote:
> From: Jason Gunthorpe <jgg at mellanox.com>
> 
> So we can check locking at runtime.
> 
> Signed-off-by: Jason Gunthorpe <jgg at mellanox.com>
> Reviewed-by: Jérôme Glisse <jglisse at redhat.com>

Reviewed-by: Ralph Campbell <rcampbell at nvidia.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;
>