mm: rename uffd-wp PTE accessors to uffd

Userfaultfd RWP will reuse the uffd-wp PTE bit to mark access-tracking
PTEs, alongside the write-protected ones it already marks.  The bit's
meaning now depends on the VMA flag (WP or RWP), not on its name.

Rename the kernel-internal names that describe the bit:

  - pte/pmd/huge_pte accessors (and swap variants)
  - pgtable_supports_uffd() capability query
  - SCAN_PTE_UFFD khugepaged enum

The ftrace string emitted by mm_khugepaged_scan_pmd for this enum is
kept as "pte_uffd_wp" so existing trace-based tooling keeps matching.

Pure mechanical rename -- no behavior change.

Link: https://lore.kernel.org/20260708111417.173443-4-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Assisted-by: Claude:claude-opus-4-6
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: James Houghton <jthoughton@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index d3bd5cc8f552..0ac0d8f51b0c 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -327,8 +327,8 @@ static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw,
 
 	if (pte_swp_soft_dirty(old_pte))
 		newpte = pte_mksoft_dirty(newpte);
-	if (pte_swp_uffd_wp(old_pte))
-		newpte = pte_mkuffd_wp(newpte);
+	if (pte_swp_uffd(old_pte))
+		newpte = pte_mkuffd(newpte);
 
 	set_pte_at(pvmw->vma->vm_mm, pvmw->address, pvmw->pte, newpte);
 
@@ -396,8 +396,8 @@ static bool remove_migration_pte(struct folio *folio,
 
 		if (softleaf_is_migration_write(entry))
 			pte = pte_mkwrite(pte, vma);
-		else if (pte_swp_uffd_wp(old_pte))
-			pte = pte_mkuffd_wp(pte);
+		else if (pte_swp_uffd(old_pte))
+			pte = pte_mkuffd(pte);
 
 		if (folio_test_anon(folio) && !softleaf_is_migration_read(entry))
 			rmap_flags |= RMAP_EXCLUSIVE;
@@ -412,8 +412,8 @@ static bool remove_migration_pte(struct folio *folio,
 			pte = softleaf_to_pte(entry);
 			if (pte_swp_soft_dirty(old_pte))
 				pte = pte_swp_mksoft_dirty(pte);
-			if (pte_swp_uffd_wp(old_pte))
-				pte = pte_swp_mkuffd_wp(pte);
+			if (pte_swp_uffd(old_pte))
+				pte = pte_swp_mkuffd(pte);
 		}
 
 #ifdef CONFIG_HUGETLB_PAGE