[PATCH v6 04/15] userfaultfd: test uffd VMA flags through the vma_flags_t API

["Kiryl Shutsemau (Meta)" <kas@kernel.org>]

The uffd VMA-flag helpers read vma->vm_flags directly. Now that
config-gated per-mode masks exist, switch them to the vma_flags_t
accessor vma_test_any_mask(), which is the going-forward API and keeps a
single place (the VMA_UFFD_* masks) that knows which modes are available
on the current build.

No functional change: vma_flags_t is in union with vm_flags, so the same
bits are read, and the masks fold to the same code the open-coded
vm_flags tests produced -- verified identical on gcc and clang, 32- and
64-bit.

Suggested-by: Lorenzo Stoakes <ljs@kernel.org>
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Assisted-by: Claude:claude-opus-4-8
---
 include/linux/userfaultfd_k.h | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index 658740df2978..c4f2cc6dfcf0 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -178,7 +178,8 @@ static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  */
 static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma)
 {
-	return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR);
+	return vma_test_any_mask(vma,
+		mk_vma_flags_from_masks(VMA_UFFD_WP, VMA_UFFD_MINOR));
 }
 
 /*
@@ -190,22 +191,23 @@ static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma)
  */
 static inline bool uffd_disable_fault_around(struct vm_area_struct *vma)
 {
-	return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR);
+	return vma_test_any_mask(vma,
+		mk_vma_flags_from_masks(VMA_UFFD_WP, VMA_UFFD_MINOR));
 }
 
 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
 {
-	return vma->vm_flags & VM_UFFD_MISSING;
+	return vma_test_any_mask(vma, VMA_UFFD_MISSING);
 }
 
 static inline bool userfaultfd_wp(struct vm_area_struct *vma)
 {
-	return vma->vm_flags & VM_UFFD_WP;
+	return vma_test_any_mask(vma, VMA_UFFD_WP);
 }
 
 static inline bool userfaultfd_minor(struct vm_area_struct *vma)
 {
-	return vma->vm_flags & VM_UFFD_MINOR;
+	return vma_test_any_mask(vma, VMA_UFFD_MINOR);
 }
 
 static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
@@ -222,7 +224,7 @@ static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
 
 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
 {
-	return vma->vm_flags & __VM_UFFD_FLAGS;
+	return vma_test_any_mask(vma, __VMA_UFFD_FLAGS);
 }
 
 static inline bool vma_has_uffd_without_event_remap(struct vm_area_struct *vma)
-- 
2.54.0