1 files changed, 12 insertions, 7 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 11723c5b2b20..4fef9527a620 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -570,11 +570,19 @@ static void set_work_cwq(struct work_struct *work,
 static void set_work_cpu_and_clear_pending(struct work_struct *work,
                                            unsigned int cpu)
 {
+        /*
+         * The following wmb is paired with the implied mb in
+         * test_and_set_bit(PENDING) and ensures all updates to @work made
+         * here are visible to and precede any updates by the next PENDING
+         * owner.
+         */
+        smp_wmb();
         set_work_data(work, (unsigned long)cpu << WORK_OFFQ_CPU_SHIFT, 0);
 }
 
 static void clear_work_data(struct work_struct *work)
 {
+        smp_wmb();      /* see set_work_cpu_and_clear_pending() */
         set_work_data(work, WORK_STRUCT_NO_CPU, 0);
 }
 
@@ -2182,14 +2190,11 @@ __acquires(&gcwq->lock)
                 wake_up_worker(pool);
 
         /*
-         * Record the last CPU and clear PENDING.  The following wmb is
-         * paired with the implied mb in test_and_set_bit(PENDING) and
-         * ensures all updates to @work made here are visible to and
-         * precede any updates by the next PENDING owner.  Also, clear
-         * PENDING inside @gcwq->lock so that PENDING and queued state
-         * changes happen together while IRQ is disabled.
+         * Record the last CPU and clear PENDING which should be the last
+         * update to @work.  Also, do this inside @gcwq->lock so that
+         * PENDING and queued state changes happen together while IRQ is
+         * disabled.
          */
-        smp_wmb();
         set_work_cpu_and_clear_pending(work, gcwq->cpu);
 
         spin_unlock_irq(&gcwq->lock);