rcu: Replace open-coded rcu_exp_need_qs() from rcu_exp_handler() with call

Currently, the preemptible implementation of rcu_exp_handler()
almost open-codes rcu_exp_need_qs().  A call to that function would be
shorter and would improve expediting in cases where rcu_exp_handler()
interrupted a preemption-disabled or bh-disabled region of code.
This commit therefore moves rcu_exp_need_qs() out of the non-preemptible
leg of the enclosing #ifdef and replaces the open coding in preemptible
rcu_exp_handler() with a call to rcu_exp_need_qs().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 5c4ea66cc00ddb633ee4354e9b4d1796ba082dba..f3884393b9477241383fa3c0f15009521b3fd828 100644 (file)
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -718,6 +718,16 @@ static void rcu_exp_sel_wait_wake(unsigned long s)
        rcu_exp_wait_wake(s);
 }
 
+/* Request an expedited quiescent state. */
+static void rcu_exp_need_qs(void)
+{
+       __this_cpu_write(rcu_data.cpu_no_qs.b.exp, true);
+       /* Store .exp before .rcu_urgent_qs. */
+       smp_store_release(this_cpu_ptr(&rcu_data.rcu_urgent_qs), true);
+       set_tsk_need_resched(current);
+       set_preempt_need_resched();
+}
+
 #ifdef CONFIG_PREEMPT_RCU
 
 /*
@@ -742,13 +752,10 @@ static void rcu_exp_handler(void *unused)
         */
        if (!depth) {
                if (!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)) ||
-                   rcu_is_cpu_rrupt_from_idle()) {
+                   rcu_is_cpu_rrupt_from_idle())
                        rcu_report_exp_rdp(rdp);
-               } else {
-                       WRITE_ONCE(rdp->cpu_no_qs.b.exp, true);
-                       set_tsk_need_resched(t);
-                       set_preempt_need_resched();
-               }
+               else
+                       rcu_exp_need_qs();
                return;
        }
 
@@ -841,16 +848,6 @@ static void rcu_exp_print_detail_task_stall_rnp(struct rcu_node *rnp)
 
 #else /* #ifdef CONFIG_PREEMPT_RCU */
 
-/* Request an expedited quiescent state. */
-static void rcu_exp_need_qs(void)
-{
-       __this_cpu_write(rcu_data.cpu_no_qs.b.exp, true);
-       /* Store .exp before .rcu_urgent_qs. */
-       smp_store_release(this_cpu_ptr(&rcu_data.rcu_urgent_qs), true);
-       set_tsk_need_resched(current);
-       set_preempt_need_resched();
-}
-
 /* Invoked on each online non-idle CPU for expedited quiescent state. */
 static void rcu_exp_handler(void *unused)
 {