[PATCH] mm: Add missing mmu_notifier_clear_young for !MMU_NOTIFIER

[James Houghton]

Remove the now unnecessary ifdef in mm/damon/vaddr.c as well.

Signed-off-by: James Houghton <jthoughton@xxxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
---

Notes:
    This patch is originally from this series[1]. I've split up the MM and
    KVM bits of the series, and I have already sent the MGLRU changes
    here[2]. That leaves this small cleanup for DAMON.
    
    [1]: https://lore.kernel.org/kvm/20240926013506.860253-1-jthoughton@xxxxxxxxxx/
    [2]: https://lore.kernel.org/kvm/20241019012940.3656292-1-jthoughton@xxxxxxxxxx/

 include/linux/mmu_notifier.h | 7 +++++++
 mm/damon/vaddr.c             | 2 --
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index d39ebb10caeb..e2dd57ca368b 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -606,6 +606,13 @@ static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
 	return 0;
 }
 
+static inline int mmu_notifier_clear_young(struct mm_struct *mm,
+					   unsigned long start,
+					   unsigned long end)
+{
+	return 0;
+}
+
 static inline int mmu_notifier_test_young(struct mm_struct *mm,
 					  unsigned long address)
 {
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 08cfd22b5249..821990d0141a 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -353,11 +353,9 @@ static void damon_hugetlb_mkold(pte_t *pte, struct mm_struct *mm,
 		set_huge_pte_at(mm, addr, pte, entry, psize);
 	}
 
-#ifdef CONFIG_MMU_NOTIFIER
 	if (mmu_notifier_clear_young(mm, addr,
 				     addr + huge_page_size(hstate_vma(vma))))
 		referenced = true;
-#endif /* CONFIG_MMU_NOTIFIER */
 
 	if (referenced)
 		folio_set_young(folio);

base-commit: b5d43fad926a3f542cd06f3c9d286f6f489f7129
-- 
2.47.0.105.g07ac214952-goog