[PATCH] mm/madvise: minor cleanup for swapin_walk_pmd_entry()

[Miaohe Lin <linmiaohe@huawei.com>]

Passing index to pte_offset_map_lock() directly so the below calculation
can be avoided. Rename orig_pte to ptep as it's not changed. Also use
helper is_swap_pte() to improve the readability. No functional change
intended.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 mm/madvise.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 7a8af04069b3..cf49e123991c 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -195,7 +195,7 @@ static int madvise_update_vma(struct vm_area_struct *vma,
 static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
 	unsigned long end, struct mm_walk *walk)
 {
-	pte_t *orig_pte;
+	pte_t *ptep;
 	struct vm_area_struct *vma = walk->private;
 	unsigned long index;
 	struct swap_iocb *splug = NULL;
@@ -209,11 +209,11 @@ static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
 		struct page *page;
 		spinlock_t *ptl;
 
-		orig_pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl);
-		pte = *(orig_pte + ((index - start) / PAGE_SIZE));
-		pte_unmap_unlock(orig_pte, ptl);
+		ptep = pte_offset_map_lock(vma->vm_mm, pmd, index, &ptl);
+		pte = *ptep;
+		pte_unmap_unlock(ptep, ptl);
 
-		if (pte_present(pte) || pte_none(pte))
+		if (!is_swap_pte(pte))
 			continue;
 		entry = pte_to_swp_entry(pte);
 		if (unlikely(non_swap_entry(entry)))
-- 
2.23.0