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

   1 From af2c1401e6f9177483be4fad876d0073669df9df Mon Sep 17 00:00:00 2001
   2 From: Mel Gorman <mgorman@suse.de>
   3 Date: Wed, 18 Dec 2013 17:08:45 -0800
   4 Subject: mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates
   5
   6 From: Mel Gorman <mgorman@suse.de>
   7
   8 commit af2c1401e6f9177483be4fad876d0073669df9df upstream.
   9
  10 According to documentation on barriers, stores issued before a LOCK can
  11 complete after the lock implying that it's possible tlb_flush_pending
  12 can be visible after a page table update.  As per revised documentation,
  13 this patch adds a smp_mb__before_spinlock to guarantee the correct
  14 ordering.
  15
  16 Signed-off-by: Mel Gorman <mgorman@suse.de>
  17 Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
  18 Reviewed-by: Rik van Riel <riel@redhat.com>
  19 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  20 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  21 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  22
  23 ---
  24  include/linux/mm_types.h |    7 ++++++-
  25  1 file changed, 6 insertions(+), 1 deletion(-)
  26
  27 --- a/include/linux/mm_types.h
  28 +++ b/include/linux/mm_types.h
  29 @@ -478,7 +478,12 @@ static inline bool mm_tlb_flush_pending(
  30  static inline void set_tlb_flush_pending(struct mm_struct *mm)
  31  {
  32         mm->tlb_flush_pending = true;
  33 -       barrier();
  34 +
  35 +       /*
  36 +        * Guarantee that the tlb_flush_pending store does not leak into the
  37 +        * critical section updating the page tables
  38 +        */
  39 +       smp_mb__before_spinlock();
  40  }
  41  /* Clearing is done after a TLB flush, which also provides a barrier. */
  42  static inline void clear_tlb_flush_pending(struct mm_struct *mm)