[PATCH] mm, notifier: Fix early return case for new lockdep annotations

[Daniel Vetter]

I missed that when extending the lockdep annotations to the
nonblocking case.

I missed this while testing since in the i915 mmu notifiers is hitting
a nice lockdep splat already before the point of going into oom killer
mode :-/

Reported-by: syzbot+aaedc50d99a03250fe1f at syzkaller.appspotmail.com
Fixes: d2b219ed03d4 ("mm/mmu_notifiers: add a lockdep map for invalidate_range_start/end")
Cc: Jason Gunthorpe <jgg at mellanox.com>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: "Jérôme Glisse" <jglisse at redhat.com>
Cc: Ralph Campbell <rcampbell at nvidia.com>
Cc: Jason Gunthorpe <jgg at ziepe.ca>
Cc: Ira Weiny <ira.weiny at intel.com>
Cc: Michal Hocko <mhocko at suse.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Sean Christopherson <sean.j.christopherson at intel.com>
Cc: Jean-Philippe Brucker <jean-philippe at linaro.org>
Cc: linux-mm at kvack.org
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 include/linux/mmu_notifier.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index 5a03417e5bf7..4edd98b06834 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -356,13 +356,14 @@ mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range)
 static inline int
 mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range)
 {
+	int ret = 0;
 	lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
 	if (mm_has_notifiers(range->mm)) {
 		range->flags &= ~MMU_NOTIFIER_RANGE_BLOCKABLE;
-		return __mmu_notifier_invalidate_range_start(range);
+		ret = __mmu_notifier_invalidate_range_start(range);
 	}
 	lock_map_release(&__mmu_notifier_invalidate_range_start_map);
-	return 0;
+	return ret;
 }
 
 static inline void
-- 
2.23.0