mm: introduce is_huge_pmd() helper

Currently we have some times the following judgments repeated in the
code:

	is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)

which is to determine whether the *pmd is a huge pmd, so introduce
is_huge_pmd() helper to deduplicate them.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>

include/linux/huge_mm.h

@@ -199,8 +199,7 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 #define split_huge_pmd(__vma, __pmd, __address)				\
 	do {								\
 		pmd_t *____pmd = (__pmd);				\
-		if (is_swap_pmd(*____pmd) || pmd_trans_huge(*____pmd)	\
-					|| pmd_devmap(*____pmd))	\
+		if (is_huge_pmd(*____pmd))				\
 			__split_huge_pmd(__vma, __pmd, __address,	\
 						false, NULL);		\
 	}  while (0)
@@ -232,11 +231,16 @@ static inline int is_swap_pmd(pmd_t pmd)
 	return !pmd_none(pmd) && !pmd_present(pmd);
 }
 
+static inline int is_huge_pmd(pmd_t pmd)
+{
+	return is_swap_pmd(pmd) || pmd_trans_huge(pmd) || pmd_devmap(pmd);
+}
+
 /* mmap_lock must be held on entry */
 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) || pmd_devmap(*pmd))
+	if (is_huge_pmd(*pmd))
 		return __pmd_trans_huge_lock(pmd, vma);
 	else
 		return NULL;

mm/huge_memory.c

@@ -1832,8 +1832,7 @@ 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) ||
-			pmd_devmap(*pmd)))
+	if (likely(is_huge_pmd(*pmd)))
 		return ptl;
 	spin_unlock(ptl);
 	return NULL;

mm/memory.c

@@ -1146,8 +1146,7 @@ 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)
-			|| pmd_devmap(*src_pmd)) {
+		if (is_huge_pmd(*src_pmd)) {
 			int err;
 			VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma);
 			err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd,
@@ -1441,7 +1440,7 @@ 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) || pmd_devmap(*pmd)) {
+		if (is_huge_pmd(*pmd)) {
 			if (next - addr != HPAGE_PMD_SIZE)
 				__split_huge_pmd(vma, pmd, addr, false, NULL);
 			else if (zap_huge_pmd(tlb, vma, pmd, addr))

mm/mprotect.c

@@ -257,7 +257,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
 			mmu_notifier_invalidate_range_start(&range);
 		}
 
-		if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
+		if (is_huge_pmd(*pmd)) {
 			if (next - addr != HPAGE_PMD_SIZE) {
 				__split_huge_pmd(vma, pmd, addr, false, NULL);
 			} else {

mm/mremap.c

@@ -532,8 +532,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
 		new_pmd = alloc_new_pmd(vma->vm_mm, vma, new_addr);
 		if (!new_pmd)
 			break;
-		if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd) ||
-		    pmd_devmap(*old_pmd)) {
+		if (is_huge_pmd(*old_pmd)) {
 			if (extent == HPAGE_PMD_SIZE &&
 			    move_pgt_entry(HPAGE_PMD, vma, old_addr, new_addr,
 					   old_pmd, new_pmd, need_rmap_locks))