From 935874141df839c706cd6cdc438e85eb69d1525e Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Tue, 24 Nov 2009 08:45:24 -0500
Subject: [PATCH] fix pgoff in "have to relocate" case of mremap()

Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 mm/mremap.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 84efffb2d2c4..bbbbbf507ff3 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -495,7 +495,9 @@ unsigned long do_mremap(unsigned long addr,
 			map_flags |= MAP_SHARED;
 
 		new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
-					vma->vm_pgoff, map_flags);
+					vma->vm_pgoff +
+					((addr - vma->vm_start) >> PAGE_SHIFT),
+					map_flags);
 		if (new_addr & ~PAGE_MASK) {
 			ret = new_addr;
 			goto out;