On 6/10/2025 12:38 PM, David Hildenbrand wrote:

On 09.06.25 19:08, Shivank Garg wrote:

quoted

Replace open-coded folio reference count calculations with the
folio_expected_ref_count() helper to improve code maintainability
and reduce duplication.

No functional changes intended.

Signed-off-by: Shivank Garg <redacted>
---
  kernel/events/uprobes.c | 5 +++--
  mm/memfd.c              | 4 ++--
  2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 4c965ba77f9f..c978c8c27340 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c

@@ -434,10 +434,11 @@ static int __uprobe_write_opcode(struct vm_area_struct *vma,

      /*
       * When unregistering, we may only zap a PTE if uffd is disabled and
       * there are no unexpected folio references ...
+     * Expected refs: mappings + swapcache.
+     * We hold one additional reference (+1).
       */
      if (is_register || userfaultfd_missing(vma) ||
-        (folio_ref_count(folio) != folio_mapcount(folio) + 1 +
-         folio_test_swapcache(folio) * folio_nr_pages(folio)))
+        (folio_ref_count(folio) != folio_expected_ref_count(folio) + 1))
          goto remap;
  

With the comment removed (the caller holds a reference from GUP) or simplified ("Caller holds an additional folio reference.")

Sure, I'll make this change in revision.

Acked-by: David Hildenbrand <redacted>

Thank you!

Best Regards,
Shivank