diff mbox series

[v4,hmm,08/12] mm/hmm: Use lockdep instead of comments

Message ID 20190624210110.5098-9-jgg@ziepe.ca (mailing list archive)
State New, archived
Headers show
Series [v4,hmm,01/12] mm/hmm: fix use after free with struct hmm in the mmu notifiers | expand

Commit Message

Jason Gunthorpe June 24, 2019, 9:01 p.m. UTC 
From: Jason Gunthorpe <jgg@mellanox.com>

So we can check locking at runtime.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Acked-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Philip Yang <Philip.Yang@amd.com>
---
v2
- Fix missing & in lockdeps (Jason)
---
 mm/hmm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/mm/hmm.c b/mm/hmm.c
index 1eddda45cefae7..6f5dc6d568feb1 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -246,11 +246,11 @@  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;