[PATCH v6 2/5] arm64: mm: factor out the address and ptep alignment into a new helper

Baolin Wang
2026-02-09T14:07:47Z

Factor out the contpte block's address and ptep alignment into a new helper,
and will be reused in the following patch.

No functional changes.

Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
---
arch/arm64/mm/contpte.c | 29 +++++++++++++++++++++--------
1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c
index 589bcf878938..e4ddeb46f25d 100644
--- a/arch/arm64/mm/contpte.c
+++ b/arch/arm64/mm/contpte.c
@@ -26,6 +26,26 @@ static inline pte_t *contpte_align_down(pte_t *ptep)
return PTR_ALIGN_DOWN(ptep, sizeof(*ptep) * CONT_PTES);
}

+static inline pte_t *contpte_align_addr_ptep(unsigned long *start,
+ unsigned long *end, pte_t *ptep,
+ unsigned int nr)
+{
+ /*
+ * Note: caller must ensure these nr PTEs are consecutive (present)
+ * PTEs that map consecutive pages of the same large folio within a
+ * single VMA and a single page table.
+ */
+ if (pte_cont(__ptep_get(ptep + nr - 1)))
+ *end = ALIGN(*end, CONT_PTE_SIZE);
+
+ if (pte_cont(__ptep_get(ptep))) {
+ *start = ALIGN_DOWN(*start, CONT_PTE_SIZE);
+ ptep = contpte_align_down(ptep);
+ }
+
+ return ptep;
+}
+
static void contpte_try_unfold_partial(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, unsigned int nr)
{
@@ -569,14 +589,7 @@ void contpte_clear_young_dirty_ptes(struct vm_area_struct *vma,
unsigned long start = addr;
unsigned long end = start + nr * PAGE_SIZE;

- if (pte_cont(__ptep_get(ptep + nr - 1)))
- end = ALIGN(end, CONT_PTE_SIZE);
-
- if (pte_cont(__ptep_get(ptep))) {
- start = ALIGN_DOWN(start, CONT_PTE_SIZE);
- ptep = contpte_align_down(ptep);
- }
-
+ ptep = contpte_align_addr_ptep(&start, &end, ptep, nr);
__clear_young_dirty_ptes(vma, start, ptep, (end - start) / PAGE_SIZE, flags);
}
EXPORT_SYMBOL_GPL(contpte_clear_young_dirty_ptes);
--
2.47.3