git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From mgorman@suse.de  Tue Jan  7 10:38:11 2014
   2 From: Mel Gorman <mgorman@suse.de>
   3 Date: Tue,  7 Jan 2014 14:00:47 +0000
   4 Subject: mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates
   5 To: gregkh@linuxfoundation.org
   6 Cc: athorlton@sgi.com, riel@redhat.com, chegu_vinod@hp.com, Mel Gorman <mgorman@suse.de>, stable@vger.kernel.org
   7 Message-ID: <1389103248-17617-13-git-send-email-mgorman@suse.de>
   8
   9 From: Mel Gorman <mgorman@suse.de>
  10
  11 commit af2c1401e6f9177483be4fad876d0073669df9df upstream.
  12
  13 According to documentation on barriers, stores issued before a LOCK can
  14 complete after the lock implying that it's possible tlb_flush_pending
  15 can be visible after a page table update.  As per revised documentation,
  16 this patch adds a smp_mb__before_spinlock to guarantee the correct
  17 ordering.
  18
  19 Signed-off-by: Mel Gorman <mgorman@suse.de>
  20 Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
  21 Reviewed-by: Rik van Riel <riel@redhat.com>
  22 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  23 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25 ---
  26  include/linux/mm_types.h |    7 ++++++-
  27  1 file changed, 6 insertions(+), 1 deletion(-)
  28
  29 --- a/include/linux/mm_types.h
  30 +++ b/include/linux/mm_types.h
  31 @@ -478,7 +478,12 @@ static inline bool mm_tlb_flush_pending(
  32  static inline void set_tlb_flush_pending(struct mm_struct *mm)
  33  {
  34         mm->tlb_flush_pending = true;
  35 -       barrier();
  36 +
  37 +       /*
  38 +        * Guarantee that the tlb_flush_pending store does not leak into the
  39 +        * critical section updating the page tables
  40 +        */
  41 +       smp_mb__before_spinlock();
  42  }
  43  /* Clearing is done after a TLB flush, which also provides a barrier. */
  44  static inline void clear_tlb_flush_pending(struct mm_struct *mm)