From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Date: Tue, 11 May 2010 21:06:55 +0000 (-0700)
Subject: rmap: remove anon_vma check in page_address_in_vma()
X-Git-Tag: v2.6.34~40
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ab941e0fff3947b6dcc9c578d918d1bba54a6874;p=pandora-kernel.git

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>
---

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