[VM] Allow get_page_unless_zero on compound pages

SLUB uses compound pages for larger slabs. We need to increment
the page count of these pages in order to make sure that they are not
freed under us for reclaim from within lumpy reclaim.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

---
 include/linux/mm.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6/include/linux/mm.h
===================================================================
--- linux-2.6.orig/include/linux/mm.h	2007-08-08 19:55:28.000000000 -0700
+++ linux-2.6/include/linux/mm.h	2007-08-08 19:56:31.000000000 -0700
@@ -290,7 +290,7 @@ static inline int put_page_testzero(stru
  */
 static inline int get_page_unless_zero(struct page *page)
 {
-	VM_BUG_ON(PageCompound(page));
+	VM_BUG_ON(PageTail(page));
 	return atomic_inc_not_zero(&page->_count);
 }