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Commit af2c1401 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates 



According to documentation on barriers, stores issued before a LOCK can
complete after the lock implying that it's possible tlb_flush_pending
can be visible after a page table update.  As per revised documentation,
this patch adds a smp_mb__before_spinlock to guarantee the correct
ordering.

Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
Acked-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarRik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 20841405

include/linux/mm_types.h

+6 −1
Original line number Diff line number Diff line
@@ -482,7 +482,12 @@ static inline bool mm_tlb_flush_pending(struct mm_struct *mm) 
static inline void set_tlb_flush_pending(struct mm_struct *mm)

{

	mm->tlb_flush_pending = true;

	barrier();



	/*

	 * Guarantee that the tlb_flush_pending store does not leak into the

	 * critical section updating the page tables

	 */

	smp_mb__before_spinlock();

}

/* Clearing is done after a TLB flush, which also provides a barrier. */

static inline void clear_tlb_flush_pending(struct mm_struct *mm)