rcu: Fix CPU offload boot message when no CPUs are offloaded

In CONFIG_RCU_NOCB_CPU=y kernels, if the boot parameters indicate that
none of the CPUs should in fact be offloaded, the following somewhat
obtuse message appears:

	Offload RCU callbacks from CPUs: .

This commit therefore makes the message at least grammatically correct
in this case:

	Offload RCU callbacks from CPUs: (none)

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index fb88a02..93f5649 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2312,8 +2312,11 @@ void __init rcu_init_nohz(void)
                cpumask_and(rcu_nocb_mask, cpu_possible_mask,
                            rcu_nocb_mask);
        }
-       pr_info("\tOffload RCU callbacks from CPUs: %*pbl.\n",
-               cpumask_pr_args(rcu_nocb_mask));
+       if (cpumask_empty(rcu_nocb_mask))
+               pr_info("\tOffload RCU callbacks from CPUs: (none).\n");
+       else
+               pr_info("\tOffload RCU callbacks from CPUs: %*pbl.\n",
+                       cpumask_pr_args(rcu_nocb_mask));
        if (rcu_nocb_poll)
                pr_info("\tPoll for callbacks from no-CBs CPUs.\n");