From: Christoph Lameter <clameter@sgi.com>
Date: Tue, 5 Feb 2008 06:28:35 +0000 (-0800)
Subject: VM: allow get_page_unless_zero on compound pages
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=aec2c3ed01ed54d0cdf7f6b7c4be217c045ac5ea;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

VM: allow get_page_unless_zero on compound pages

Both slab defrag and the large blocksize patches need to ability to take
refcounts on compound pages.  May be useful in other places as well.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f28a0338574f..bcbe6979ff65 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -227,7 +227,7 @@ static inline int put_page_testzero(struct page *page)
  */
 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);
 }