Re: [PATCH] mm/page_vma_mapped_walk: add missing pgtable entry accessors

Anshuman Khandual
2026-04-27T05:47:48Z

On 27/04/26 10:50 AM, Alexander Gordeev wrote:
> Convert pgtable direct entry dereferences to the corresponding
> pXdp_get() accessors. Use ptep_get_lockless() variant for PTE
> reads when no lock is taken.
>
> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
> ---
> mm/page_vma_mapped.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
> index b38a1d00c971..a4520bb10d2a 100644
> --- a/mm/page_vma_mapped.c
> +++ b/mm/page_vma_mapped.c
> @@ -41,7 +41,7 @@ static bool map_pte(struct page_vma_mapped_walk *pvmw, pmd_t *pmdvalp,
> if (!pvmw->pte)
> return false;
>
> - ptent = ptep_get(pvmw->pte);
> + ptent = ptep_get_lockless(pvmw->pte);
>
> if (pte_none(ptent)) {
> return false;
> @@ -219,17 +219,17 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
> restart:
> do {
> pgd = pgd_offset(mm, pvmw->address);
> - if (!pgd_present(*pgd)) {
> + if (!pgd_present(pgdp_get(pgd))) {
> step_forward(pvmw, PGDIR_SIZE);
> continue;
> }
> p4d = p4d_offset(pgd, pvmw->address);
> - if (!p4d_present(*p4d)) {
> + if (!p4d_present(p4dp_get(p4d))) {
> step_forward(pvmw, P4D_SIZE);
> continue;
> }
> pud = pud_offset(p4d, pvmw->address);
> - if (!pud_present(*pud)) {
> + if (!pud_present(pudp_get(pud))) {
> step_forward(pvmw, PUD_SIZE);
> continue;
> }
> @@ -244,7 +244,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
>
> if (pmd_trans_huge(pmde) || pmd_is_migration_entry(pmde)) {
> pvmw->ptl = pmd_lock(mm, pvmw->pmd);
> - pmde = *pvmw->pmd;
> + pmde = pmdp_get(pvmw->pmd);
> if (!pmd_present(pmde)) {
> softleaf_t entry;
>
> @@ -317,7 +317,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
> goto restart;
> }
> pvmw->pte++;
> - } while (pte_none(ptep_get(pvmw->pte)));
> + } while (pte_none(ptep_get_lockless(pvmw->pte)));
>
> if (!pvmw->ptl) {
> spin_lock(ptl);

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>