rmap: remove anon_vma check in page_address_in_vma()
Currently page_address_in_vma() compares vma->anon_vma and
page_anon_vma(page) for parameter check, but in 2.6.34 a vma can have
multiple anon_vmas with anon_vma_chain, so current check does not work.
(For anonymous page shared by multiple processes, some verified (page,vma)
pairs return -EFAULT wrongly.)
We can go to checking all anon_vmas in the "same_vma" chain, but it needs
to meet lock requirement. Instead, we can remove anon_vma check safely
because page_address_in_vma() assumes that page and vma are already
checked to belong to the identical process.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/rmap.c b/mm/rmap.c
index 07fc947..0feeef8 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -336,14 +336,13 @@
/*
* At what user virtual address is page expected in vma?
- * checking that the page matches the vma.
+ * Caller should check the page is actually part of the vma.
*/
unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
{
- if (PageAnon(page)) {
- if (vma->anon_vma != page_anon_vma(page))
- return -EFAULT;
- } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
+ if (PageAnon(page))
+ ;
+ else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
if (!vma->vm_file ||
vma->vm_file->f_mapping != page->mapping)
return -EFAULT;
