diff options
| author | Oleg Nesterov <[email protected]> | 2014-01-21 15:49:04 -0800 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2014-01-21 16:19:43 -0800 |
| commit | 5eaf1a9e233d61438377f57facb167f8208ba9fd (patch) | |
| tree | c1455aa3d758ea5ebb5879f655b4e7ddf4079d94 | |
| parent | c728852f5dd41ce34e7ce0a179cf28cd5f4dc301 (diff) | |
mm: thp: turn compound_head() into BUG_ON(!PageTail) in get_huge_page_tail()
get_huge_page_tail()->compound_head() looks confusing. Every caller
must check PageTail(page), otherwise atomic_inc(&page->_mapcount) is
simply wrong if this page is compound-trans-head.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Dave Jones <[email protected]>
Cc: Darren Hart <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Mel Gorman <[email protected]>
Acked-by: Andrea Arcangeli <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | include/linux/mm.h | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index f95c71b7c1fd..58202c26c559 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -445,13 +445,12 @@ static inline bool compound_tail_refcounted(struct page *page) static inline void get_huge_page_tail(struct page *page) { /* - * __split_huge_page_refcount() cannot run - * from under us. - * In turn no need of compound_trans_head here. + * __split_huge_page_refcount() cannot run from under us. */ + VM_BUG_ON(!PageTail(page)); VM_BUG_ON(page_mapcount(page) < 0); VM_BUG_ON(atomic_read(&page->_count) != 0); - if (compound_tail_refcounted(compound_head(page))) + if (compound_tail_refcounted(page->first_page)) atomic_inc(&page->_mapcount); } |