net/sched: Replace call_rcu_bh() and rcu_barrier_bh()

Now that call_rcu()'s callback is not invoked until after bh-disable
regions of code have completed (in addition to explicitly marked
RCU read-side critical sections), call_rcu() can be used in place
of call_rcu_bh().  Similarly, rcu_barrier() can be used in place o
frcu_barrier_bh().  This commit therefore makes these changes.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <netdev@vger.kernel.org>

net/sched/sch_api.c

@@ -540,7 +540,7 @@ void qdisc_put_stab(struct qdisc_size_table *tab)
 
 	if (--tab->refcnt == 0) {
 		list_del(&tab->list);
-		call_rcu_bh(&tab->rcu, stab_kfree_rcu);
+		call_rcu(&tab->rcu, stab_kfree_rcu);
 	}
 }
 EXPORT_SYMBOL(qdisc_put_stab);