BackMerge tag 'v6.19-rc7' into drm-next

Linux 6.19-rc7

This is needed for msm and rust trees.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 9 insertions, 5 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 15076261d0c2..f0d5be9dc736 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -608,7 +608,11 @@ enum {
 /*
  * Flags which should result in page tables being copied on fork. These are
  * flags which indicate that the VMA maps page tables which cannot be
- * reconsistuted upon page fault, so necessitate page table copying upon
+ * reconsistuted upon page fault, so necessitate page table copying upon fork.
+ *
+ * Note that these flags should be compared with the DESTINATION VMA not the
+ * source, as VM_UFFD_WP may not be propagated to destination, while all other
+ * flags will be.
  *
  * VM_PFNMAP / VM_MIXEDMAP - These contain kernel-mapped data which cannot be
  *                           reasonably reconstructed on page fault.
@@ -2459,10 +2463,10 @@ static inline int folio_expected_ref_count(const struct folio *folio)
 	if (WARN_ON_ONCE(page_has_type(&folio->page) && !folio_test_hugetlb(folio)))
 		return 0;
 
-	if (folio_test_anon(folio)) {
-		/* One reference per page from the swapcache. */
-		ref_count += folio_test_swapcache(folio) << order;
-	} else {
+	/* One reference per page from the swapcache. */
+	ref_count += folio_test_swapcache(folio) << order;
+
+	if (!folio_test_anon(folio)) {
 		/* One reference per page from the pagecache. */
 		ref_count += !!folio->mapping << order;
 		/* One reference from PG_private. */