On Sat, 18 Jun 2022 17:05:27 +0800 Miaohe Lin <linmiaohe@xxxxxxxxxx> wrote:
> 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.
>
> ...
>
> --- 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)))
Also...
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm-madvise-minor-cleanup-for-swapin_walk_pmd_entry-fix
Date: Sat Jun 18 11:58:03 AM PDT 2022
reduce scope of `ptep'
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/madvise.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/madvise.c~mm-madvise-minor-cleanup-for-swapin_walk_pmd_entry-fix
+++ a/mm/madvise.c
@@ -195,7 +195,6 @@ success:
static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
unsigned long end, struct mm_walk *walk)
{
- pte_t *ptep;
struct vm_area_struct *vma = walk->private;
unsigned long index;
struct swap_iocb *splug = NULL;
@@ -208,6 +207,7 @@ static int swapin_walk_pmd_entry(pmd_t *
swp_entry_t entry;
struct page *page;
spinlock_t *ptl;
+ pte_t *ptep;
ptep = pte_offset_map_lock(vma->vm_mm, pmd, index, &ptl);
pte = *ptep;
_
