rmap: remove anon_vma check in page_address_in_vma()
authorNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Tue, 11 May 2010 21:06:55 +0000 (14:06 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 12 May 2010 00:33:42 +0000 (17:33 -0700)
commitab941e0fff3947b6dcc9c578d918d1bba54a6874
tree5157de1b28370136fde227ecbd7fd2d38c15d30a
parent4a6018f7f4f1075c1a5403b5ec0ee7262187b86c
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>
mm/rmap.c