rcu: Inline invoke_rcu_callbacks() into its sole remaining caller

This commit saves a few lines of code by inlining invoke_rcu_callbacks()
into its sole remaining caller.

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

kernel/rcu/tree.c

@@ -147,7 +147,6 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf);
 static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf);
 static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu);
 static void invoke_rcu_core(void);
-static void invoke_rcu_callbacks(struct rcu_data *rdp);
 static void rcu_report_exp_rdp(struct rcu_data *rdp);
 static void sync_sched_exp_online_cleanup(int cpu);
 
@@ -2296,8 +2295,9 @@ static __latent_entropy void rcu_core(void)
 	rcu_check_gp_start_stall(rnp, rdp, rcu_jiffies_till_stall_check());
 
 	/* If there are callbacks ready, invoke them. */
-	if (rcu_segcblist_ready_cbs(&rdp->cblist))
-		invoke_rcu_callbacks(rdp);
+	if (rcu_segcblist_ready_cbs(&rdp->cblist) &&
+	    likely(READ_ONCE(rcu_scheduler_fully_active)))
+		rcu_do_batch(rdp);
 
 	/* Do any needed deferred wakeups of rcuo kthreads. */
 	do_nocb_deferred_wakeup(rdp);
@@ -2332,20 +2332,6 @@ static void invoke_rcu_core_kthread(void)
 	local_irq_restore(flags);
 }
 
-/*
- * Do RCU callback invocation.  Not that if we are running !use_softirq,
- * we are already in the rcuc kthread.  If callbacks are offloaded, then
- * ->cblist is always empty, so we don't get here.  Therefore, we only
- * ever need to check for the scheduler being operational (some callbacks
- * do wakeups, so we do need the scheduler).
- */
-static void invoke_rcu_callbacks(struct rcu_data *rdp)
-{
-	if (unlikely(!READ_ONCE(rcu_scheduler_fully_active)))
-		return;
-	rcu_do_batch(rdp);
-}
-
 /*
  * Wake up this CPU's rcuc kthread to do RCU core processing.
  */