diff options
| -rw-r--r-- | include/linux/mm.h | 29 | ||||
| -rw-r--r-- | mm/swap.c | 2 |
2 files changed, 18 insertions, 13 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index d6777060449f..368600628d14 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -407,20 +407,25 @@ static inline void compound_unlock_irqrestore(struct page *page, #endif } +static inline struct page *compound_head_by_tail(struct page *tail) +{ + struct page *head = tail->first_page; + + /* + * page->first_page may be a dangling pointer to an old + * compound page, so recheck that it is still a tail + * page before returning. + */ + smp_rmb(); + if (likely(PageTail(tail))) + return head; + return tail; +} + static inline struct page *compound_head(struct page *page) { - if (unlikely(PageTail(page))) { - struct page *head = page->first_page; - - /* - * page->first_page may be a dangling pointer to an old - * compound page, so recheck that it is still a tail - * page before returning. - */ - smp_rmb(); - if (likely(PageTail(page))) - return head; - } + if (unlikely(PageTail(page))) + return compound_head_by_tail(page); return page; } diff --git a/mm/swap.c b/mm/swap.c index d089c5a0cf98..c8d6df556ce6 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -253,7 +253,7 @@ static void put_compound_page(struct page *page) * Case 3 is possible, as we may race with * __split_huge_page_refcount tearing down a THP page. */ - page_head = compound_head(page); + page_head = compound_head_by_tail(page); if (!__compound_tail_refcounted(page_head)) put_unrefcounted_compound_page(page_head, page); else |