[PATCH v1 07/12] mm/page_vma_mapped: device-private entries are not migration entries

From: David Hildenbrand
Date: Wed Jan 29 2025 - 06:55:47 EST


It's unclear why they would be considered migration entries; they are
not.

Likely we'll never really trigger that case in practice, because
migration (including folio split) of a folio that has device-private
entries is never started, as we would detect "additional references":
device-private entries adjust the mapcount, but not the refcount.

Fixes: b756a3b5e7ea ("mm: device exclusive memory access")
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
mm/page_vma_mapped.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 81839a9e74f1..32679be22d30 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -111,8 +111,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw)
return false;
entry = pte_to_swp_entry(ptent);

- if (!is_migration_entry(entry) &&
- !is_device_exclusive_entry(entry))
+ if (!is_migration_entry(entry))
return false;

pfn = swp_offset_pfn(entry);
--
2.48.1