e rechecked after they are
+ * acquired.
+ *
+ * Returns: true if this PMD is huge, false otherwise.
+ */
+static inline bool is_huge_pmd(pmd_t pmd)
+{
+	if (pmd_present(pmd)) {
+		return pmd_trans_huge(pmd);
+	} else if (!pmd_none(pmd)) {
+		/*
+		 * Non-present PMDs must be valid huge non-present entries. We
+		 * cannot assert that here due to header dependency issues.
+		 */
+		return true;
+	}
+
+	return false;
+}
+
 #define split_huge_pmd(__vma, __pmd, __address)				\
 	do {								\
 		pmd_t *____pmd = (__pmd);				\
-		if (is_swap_pmd(*____pmd) || pmd_trans_huge(*____pmd))	\
+		if (is_huge_pmd(*____pmd))				\
 			__split_huge_pmd(__vma, __pmd, __address,	\
 					 false);			\
 	}  while (0)
@@ -466,10 +493,10 @@ static inline int is_swap_pmd(pmd_t pmd)
 static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,
 		struct vm_area_struct *vma)
 {
-	if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd))
+	if (is_huge_pmd(*pmd))
 		return __pmd_trans_huge_lock(pmd, vma);
-	else
-		return NULL;
+
+	return NULL;
 }
 static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
 		struct vm_area_struct *vma)
@@ -734,6 +761,11 @@ static inline struct folio *get_persistent_huge_zero_folio(void)
 {
 	return NULL;
 }
+
+static inline bool is_huge_pmd(pmd_t pmd)
+{
+	return false;
+}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 static inline int split_folio_to_list_to_order(struct folio *folio,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a59718f85ec3..e0fe1c3e01c9 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2799,8 +2799,9 @@ int move_pages_huge_pmd(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd, pm
 spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
 {
 	spinlock_t *ptl;
+
 	ptl = pmd_lock(vma->vm_mm, pmd);
-	if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd)))
+	if (likely(is_huge_pmd(*pmd)))
 		return ptl;
 	spin_unlock(ptl);
 	return NULL;
diff --git a/mm/memory.c b/mm/memory.c
index 83828548ef5f..cc163060933f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1373,7 +1373,7 @@ copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
 	src_pmd = pmd_offset(src_pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
-		if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd)) {
+		if (is_huge_pmd(*src_pmd)) {
 			int err;
 
 			VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma);
@@ -1921,7 +1921,7 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
 	pmd = pmd_offset(pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
-		if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd)) {
+		if (is_huge_pmd(*pmd)) {
 			if (next - addr != HPAGE_PMD_SIZE)
 				__split_huge_pmd(vma, pmd, addr, false);
 			else if (zap_huge_pmd(tlb, vma, pmd, addr)) {
diff --git a/mm/mprotect.c b/mm/mprotect.c
index e25ac9835cc2..c1d640758b60 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -522,7 +522,7 @@ static inline long change_pmd_range(struct mmu_gather *tlb,
 			goto next;
 
 		_pmd = pmdp_get_lockless(pmd);
-		if (is_swap_pmd(_pmd) || pmd_trans_huge(_pmd)) {
+		if (is_huge_pmd(_pmd)) {
 			if ((next - addr != HPAGE_PMD_SIZE) ||
 			    pgtable_split_needed(vma, cp_flags)) {
 				__split_huge_pmd(vma, pmd, addr, false);
diff --git a/mm/mremap.c b/mm/mremap.c
index f01c74add990..070ba5a85824 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -850,7 +850,7 @@ unsigned long move_page_tables(struct pagetable_move_control *pmc)
 		if (!new_pmd)
 			break;
 again:
-		if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) {
+		if (is_huge_pmd(*old_pmd)) {
 			if (extent == HPAGE_PMD_SIZE &&
 			    move_pgt_entry(pmc, HPAGE_PMD, old_pmd, new_pmd))
 				continue;
-- 
2.51.0[RFC PATCH 07/12] mm: introduce is_huge_pmd() and use where appropriateLorenzo Stoakes <lorenzo.stoakes@oracle.com> undefinedAndrew Morton <akpm@linux-foundation.org> undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefinedŸ)ƒÃV