dm: add missing memory barrier to dm_suspend

Add memory barrier to fix atomic_read of pending value.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index f2d24eb..466a6bf 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1410,6 +1410,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
        while (1) {
                set_current_state(TASK_INTERRUPTIBLE);
 
+               smp_mb();
                if (!atomic_read(&md->pending) || signal_pending(current))
                        break;