3 files changed, 9 insertions, 24 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 2532e584e95f..00a3ebca70b8 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -4166,7 +4166,7 @@ int rcutree_prepare_cpu(unsigned int cpu)
 	rdp->rcu_iw_gp_seq = rdp->gp_seq - 1;
 	trace_rcu_grace_period(rcu_state.name, rdp->gp_seq, TPS("cpuonl"));
 	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
-	rcu_prepare_kthreads(cpu);
+	rcu_spawn_one_boost_kthread(rnp);
 	rcu_spawn_cpu_nocb_kthread(cpu);
 	WRITE_ONCE(rcu_state.n_online_cpus, rcu_state.n_online_cpus + 1);
 
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 5fd0c443517e..b5508f44ff29 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -418,8 +418,8 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
 static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
 static bool rcu_is_callbacks_kthread(void);
 static void rcu_cpu_kthread_setup(unsigned int cpu);
+static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp);
 static void __init rcu_spawn_boost_kthreads(void);
-static void rcu_prepare_kthreads(int cpu);
 static void rcu_cleanup_after_idle(void);
 static void rcu_prepare_for_idle(void);
 static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index ef004cc7101d..3c90dad00d3c 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1198,22 +1198,16 @@ static void rcu_preempt_boost_start_gp(struct rcu_node *rnp)
  */
 static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp)
 {
-	int rnp_index = rnp - rcu_get_root();
 	unsigned long flags;
+	int rnp_index = rnp - rcu_get_root();
 	struct sched_param sp;
 	struct task_struct *t;
 
-	if (!IS_ENABLED(CONFIG_PREEMPT_RCU))
-		return;
-
-	if (!rcu_scheduler_fully_active || rcu_rnp_online_cpus(rnp) == 0)
+	if (rnp->boost_kthread_task || !rcu_scheduler_fully_active)
 		return;
 
 	rcu_state.boost = 1;
 
-	if (rnp->boost_kthread_task != NULL)
-		return;
-
 	t = kthread_create(rcu_boost_kthread, (void *)rnp,
 			   "rcub/%d", rnp_index);
 	if (WARN_ON_ONCE(IS_ERR(t)))
@@ -1265,17 +1259,8 @@ static void __init rcu_spawn_boost_kthreads(void)
 	struct rcu_node *rnp;
 
 	rcu_for_each_leaf_node(rnp)
-		rcu_spawn_one_boost_kthread(rnp);
-}
-
-static void rcu_prepare_kthreads(int cpu)
-{
-	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
-	struct rcu_node *rnp = rdp->mynode;
-
-	/* Fire up the incoming CPU's kthread and leaf rcu_node kthread. */
-	if (rcu_scheduler_fully_active)
-		rcu_spawn_one_boost_kthread(rnp);
+		if (rcu_rnp_online_cpus(rnp))
+			rcu_spawn_one_boost_kthread(rnp);
 }
 
 #else /* #ifdef CONFIG_RCU_BOOST */
@@ -1295,15 +1280,15 @@ static void rcu_preempt_boost_start_gp(struct rcu_node *rnp)
 {
 }
 
-static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
+static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp)
 {
 }
 
-static void __init rcu_spawn_boost_kthreads(void)
+static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
 {
 }
 
-static void rcu_prepare_kthreads(int cpu)
+static void __init rcu_spawn_boost_kthreads(void)
 {
 }