thp: share get_huge_page_tail()

[cascardo/linux.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f81b7b4..3dc3a8c 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -376,6 +376,17 @@ static inline int page_count(struct page *page)
        return atomic_read(&compound_head(page)->_count);
 }
 
+static inline void get_huge_page_tail(struct page *page)
+{
+       /*
+        * __split_huge_page_refcount() cannot run
+        * from under us.
+        */
+       VM_BUG_ON(page_mapcount(page) < 0);
+       VM_BUG_ON(atomic_read(&page->_count) != 0);
+       atomic_inc(&page->_mapcount);
+}
+
 extern bool __get_page_tail(struct page *page);
 
 static inline void get_page(struct page *page)