diff options
| -rw-r--r-- | mm/internal.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/mm/internal.h b/mm/internal.h index 45383527e8b4..8ed127c1c808 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1005,6 +1005,16 @@ static inline bool gup_must_unshare(struct vm_area_struct *vma, smp_rmb(); /* + * During GUP-fast we might not get called on the head page for a + * hugetlb page that is mapped using cont-PTE, because GUP-fast does + * not work with the abstracted hugetlb PTEs that always point at the + * head page. For hugetlb, PageAnonExclusive only applies on the head + * page (as it cannot be partially COW-shared), so lookup the head page. + */ + if (unlikely(!PageHead(page) && PageHuge(page))) + page = compound_head(page); + + /* * Note that PageKsm() pages cannot be exclusive, and consequently, * cannot get pinned. */ |