rmap: resurrect page_address_in_vma anon_vma check

With root anon-vma it's trivial to keep doing the usual check as in
old-anon-vma code.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index f5d6799b8a74..2f855babfd06 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -364,9 +364,10 @@ vma_address(struct page *page, struct vm_area_struct *vma)
  */
 unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
 {
-        if (PageAnon(page))
-                ;
-        else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
+        if (PageAnon(page)) {
+                if (vma->anon_vma->root != page_anon_vma(page)->root)
+                        return -EFAULT;
+        } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
                 if (!vma->vm_file ||
                     vma->vm_file->f_mapping != page->mapping)
                         return -EFAULT;