From: Peter Xu <peterx@redhat.com>
Date: Tue, 4 Oct 2022 19:33:59 +0000 (-0400)
Subject: mm/hugetlb: use hugetlb_pte_stable in migration race check
X-Git-Tag: v6.1-rc5~170^2~3
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f9bf6c03eca1077cae8de0e6d86427656fa42a9b;p=platform%2Fkernel%2Flinux-starfive.git

mm/hugetlb: use hugetlb_pte_stable in migration race check

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

Link: https://lkml.kernel.org/r/20221004193400.110155-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index bf9d8d0..9b26055 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5634,11 +5634,10 @@ 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));