net/core: Replace call_rcu_bh() and synchronize_rcu_bh()

Now that call_rcu()'s callback is not invoked until after all 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, synchronize_rcu() can be used in place of
synchronize_rcu_bh().  This commit therefore makes these changes.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: <netdev@vger.kernel.org>

net/core/netpoll.c

@@ -800,7 +800,7 @@ void __netpoll_cleanup(struct netpoll *np)
 			ops->ndo_netpoll_cleanup(np->dev);
 
 		RCU_INIT_POINTER(np->dev->npinfo, NULL);
-		call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
+		call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info);
 	} else
 		RCU_INIT_POINTER(np->dev->npinfo, NULL);
 }
@@ -811,7 +811,7 @@ void __netpoll_free(struct netpoll *np)
 	ASSERT_RTNL();
 
 	/* Wait for transmitting packets to finish before freeing. */
-	synchronize_rcu_bh();
+	synchronize_rcu();
 	__netpoll_cleanup(np);
 	kfree(np);
 }