From: Andrea Arcangeli <aarcange@redhat.com>
Date: Tue, 21 Jan 2014 23:48:49 +0000 (-0800)
Subject: mm: hugetlb: use get_page_foll() in follow_hugetlb_page()
X-Git-Tag: v3.14-rc1~134^2~87
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a0368d4e48fc9ad65a66f6819a801f3f542b4f0f;p=kernel%2Fkernel-generic.git

mm: hugetlb: use get_page_foll() in follow_hugetlb_page()

get_page_foll() is more optimal and is always safe to use under the PT
lock.  More so for hugetlbfs as there's no risk of race conditions with
split_huge_page regardless of the PT lock.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Pravin Shelar <pshelar@nicira.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index dee6cf4..7596e10 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3079,7 +3079,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 same_page:
 		if (pages) {
 			pages[i] = mem_map_offset(page, pfn_offset);
-			get_page(pages[i]);
+			get_page_foll(pages[i]);
 		}
 
 		if (vmas)