[PATCH v2 2/3] mm/hugetlb: Use hugetlb_pte_stable in migration race check

From: Peter Xu
Date: Mon Oct 03 2022 - 20:37:55 EST


After hugetlb_pte_stable() introduced, we can also rewrite the migration
race condition against page allocation to use the new helper too.

Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
mm/hugetlb.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index fa3fcdb0c4b8..e762c5369a6f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5620,11 +5620,10 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
* here. Before returning error, get ptl and make
* sure there really is no pte entry.
*/
- ptl = huge_pte_lock(h, mm, ptep);
- ret = 0;
- if (huge_pte_none(huge_ptep_get(ptep)))
+ if (hugetlb_pte_stable(h, mm, ptep, old_pte))
ret = vmf_error(PTR_ERR(page));
- spin_unlock(ptl);
+ else
+ ret = 0;
goto out;
}
clear_huge_page(page, address, pages_per_huge_page(h));
--
2.37.3