From: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
So we can check locking at runtime.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
---
mm/hmm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/hmm.c b/mm/hmm.c
index 2695925c0c5927..46872306f922bb 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -256,11 +256,11 @@ 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
