diff options
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index bb17e5c22759..23ef240ba48a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6780,11 +6780,20 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, } /* - * The memory barrier inside __folio_mark_uptodate makes sure that - * preceding stores to the page contents become visible before - * the set_pte_at() write. + * If we just allocated a new page, we need a memory barrier to ensure + * that preceding stores to the page become visible before the + * set_pte_at() write. The memory barrier inside __folio_mark_uptodate + * is what we need. + * + * In the case where we have not allocated a new page (is_continue), + * the page must already be uptodate. UFFDIO_CONTINUE already includes + * an earlier smp_wmb() to ensure that prior stores will be visible + * before the set_pte_at() write. */ - __folio_mark_uptodate(folio); + if (!is_continue) + __folio_mark_uptodate(folio); + else + WARN_ON_ONCE(!folio_test_uptodate(folio)); /* Add shared, newly allocated pages to the page cache. */ if (vm_shared && !is_continue) { |