linux-kernel - Re: [PATCH v2 1/2] mm: Call pointers to ptes as ptep

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Message-ID: <CAGsJ_4yvS8REg=gef71A1gq37VPcDJY_2nMc3gwmOOcSuaKLiA@mail.gmail.com>
Date: Thu, 8 May 2025 13:05:29 +1200
From: Barry Song <21cnbao@...il.com>
To: Dev Jain <dev.jain@....com>
Cc: akpm@...ux-foundation.org, Liam.Howlett@...cle.com, 
	lorenzo.stoakes@...cle.com, vbabka@...e.cz, jannh@...gle.com, 
	pfalcato@...e.de, linux-mm@...ck.org, linux-kernel@...r.kernel.org, 
	david@...hat.com, peterx@...hat.com, ryan.roberts@....com, mingo@...nel.org, 
	libang.li@...group.com, maobibo@...ngson.cn, zhengqi.arch@...edance.com, 
	anshuman.khandual@....com, willy@...radead.org, ioworker0@...il.com, 
	yang@...amperecomputing.com, baolin.wang@...ux.alibaba.com, ziy@...dia.com, 
	hughd@...gle.com
Subject: Re: [PATCH v2 1/2] mm: Call pointers to ptes as ptep

On Wed, May 7, 2025 at 6:03 PM Dev Jain <dev.jain@....com> wrote:
>
> Avoid confusion between pte_t* and pte_t data types by suffixing pointer
> type variables with p. No functional change.
>
> Signed-off-by: Dev Jain <dev.jain@....com>

Reviewed-by: Barry Song <baohua@...nel.org>

> ---
>  mm/mremap.c | 29 +++++++++++++++--------------
>  1 file changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/mm/mremap.c b/mm/mremap.c
> index 7db9da609c84..0163e02e5aa8 100644
> --- a/mm/mremap.c
> +++ b/mm/mremap.c
> @@ -176,7 +176,8 @@ static int move_ptes(struct pagetable_move_control *pmc,
>         struct vm_area_struct *vma = pmc->old;
>         bool need_clear_uffd_wp = vma_has_uffd_without_event_remap(vma);
>         struct mm_struct *mm = vma->vm_mm;
> -       pte_t *old_pte, *new_pte, pte;
> +       pte_t *old_ptep, *new_ptep;
> +       pte_t pte;
>         pmd_t dummy_pmdval;
>         spinlock_t *old_ptl, *new_ptl;
>         bool force_flush = false;
> @@ -211,8 +212,8 @@ static int move_ptes(struct pagetable_move_control *pmc,
>          * We don't have to worry about the ordering of src and dst
>          * pte locks because exclusive mmap_lock prevents deadlock.
>          */
> -       old_pte = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl);
> -       if (!old_pte) {
> +       old_ptep = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl);
> +       if (!old_ptep) {
>                 err = -EAGAIN;
>                 goto out;
>         }
> @@ -223,10 +224,10 @@ static int move_ptes(struct pagetable_move_control *pmc,
>          * mmap_lock, so this new_pte page is stable, so there is no need to get
>          * pmdval and do pmd_same() check.
>          */
> -       new_pte = pte_offset_map_rw_nolock(mm, new_pmd, new_addr, &dummy_pmdval,
> +       new_ptep = pte_offset_map_rw_nolock(mm, new_pmd, new_addr, &dummy_pmdval,
>                                            &new_ptl);
> -       if (!new_pte) {
> -               pte_unmap_unlock(old_pte, old_ptl);
> +       if (!new_ptep) {
> +               pte_unmap_unlock(old_ptep, old_ptl);
>                 err = -EAGAIN;
>                 goto out;
>         }
> @@ -235,12 +236,12 @@ static int move_ptes(struct pagetable_move_control *pmc,
>         flush_tlb_batched_pending(vma->vm_mm);
>         arch_enter_lazy_mmu_mode();
>
> -       for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
> -                                  new_pte++, new_addr += PAGE_SIZE) {
> -               if (pte_none(ptep_get(old_pte)))
> +       for (; old_addr < old_end; old_ptep++, old_addr += PAGE_SIZE,
> +                                  new_ptep++, new_addr += PAGE_SIZE) {
> +               if (pte_none(ptep_get(old_ptep)))
>                         continue;
>
> -               pte = ptep_get_and_clear(mm, old_addr, old_pte);
> +               pte = ptep_get_and_clear(mm, old_addr, old_ptep);
>                 /*
>                  * If we are remapping a valid PTE, make sure
>                  * to flush TLB before we drop the PTL for the
> @@ -258,7 +259,7 @@ static int move_ptes(struct pagetable_move_control *pmc,
>                 pte = move_soft_dirty_pte(pte);
>
>                 if (need_clear_uffd_wp && pte_marker_uffd_wp(pte))
> -                       pte_clear(mm, new_addr, new_pte);
> +                       pte_clear(mm, new_addr, new_ptep);
>                 else {
>                         if (need_clear_uffd_wp) {
>                                 if (pte_present(pte))
> @@ -266,7 +267,7 @@ static int move_ptes(struct pagetable_move_control *pmc,
>                                 else if (is_swap_pte(pte))
>                                         pte = pte_swp_clear_uffd_wp(pte);
>                         }
> -                       set_pte_at(mm, new_addr, new_pte, pte);
> +                       set_pte_at(mm, new_addr, new_ptep, pte);
>                 }
>         }
>
> @@ -275,8 +276,8 @@ static int move_ptes(struct pagetable_move_control *pmc,
>                 flush_tlb_range(vma, old_end - len, old_end);
>         if (new_ptl != old_ptl)
>                 spin_unlock(new_ptl);
> -       pte_unmap(new_pte - 1);
> -       pte_unmap_unlock(old_pte - 1, old_ptl);
> +       pte_unmap(new_ptep - 1);
> +       pte_unmap_unlock(old_ptep - 1, old_ptl);
>  out:
>         if (pmc->need_rmap_locks)
>                 drop_rmap_locks(vma);
> --
> 2.30.2
>