releases/3.1.1/s390-gup_huge_pmd-return-0-if-pte-changes.patch

   1 From 0693bc9ce2cc4f6a1b9c3c05790fc149a74c0b87 Mon Sep 17 00:00:00 2001
   2 From: Andrea Arcangeli <aarcange@redhat.com>
   3 Date: Wed, 2 Nov 2011 13:37:28 -0700
   4 Subject: s390: gup_huge_pmd() return 0 if pte changes
   5
   6 From: Andrea Arcangeli <aarcange@redhat.com>
   7
   8 commit 0693bc9ce2cc4f6a1b9c3c05790fc149a74c0b87 upstream.
   9
  10 s390 didn't return 0 in that case, if it's rolling back the *nr pointer it
  11 should also return zero to avoid adding pages to the array at the wrong
  12 offset.
  13
  14 Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
  15 Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
  16 Cc: Hugh Dickins <hughd@google.com>
  17 Cc: Johannes Weiner <jweiner@redhat.com>
  18 Cc: Rik van Riel <riel@redhat.com>
  19 Cc: Mel Gorman <mgorman@suse.de>
  20 Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
  21 Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
  22 Cc: David Gibson <david@gibson.dropbear.id.au>
  23 Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
  24 Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
  25 Cc: David Miller <davem@davemloft.net>
  26 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  27 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  28 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  29
  30 ---
  31  arch/s390/mm/gup.c |   21 +++++++++++----------
  32  1 file changed, 11 insertions(+), 10 deletions(-)
  33
  34 --- a/arch/s390/mm/gup.c
  35 +++ b/arch/s390/mm/gup.c
  36 @@ -93,16 +93,17 @@ static inline int gup_huge_pmd(pmd_t *pm
  37                 *nr -= refs;
  38                 while (refs--)
  39                         put_page(head);
  40 -       } else {
  41 -               /*
  42 -                * Any tail page need their mapcount reference taken
  43 -                * before we return.
  44 -                */
  45 -               while (refs--) {
  46 -                       if (PageTail(tail))
  47 -                               get_huge_page_tail(tail);
  48 -                       tail++;
  49 -               }
  50 +               return 0;
  51 +       }
  52 +
  53 +       /*
  54 +        * Any tail page need their mapcount reference taken before we
  55 +        * return.
  56 +        */
  57 +       while (refs--) {
  58 +               if (PageTail(tail))
  59 +                       get_huge_page_tail(tail);
  60 +               tail++;
  61         }
  62
  63         return 1;