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>

1 files changed, 3 insertions, 1 deletions

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;