[PATCH v3 14/51] cpuidle, cpu_pm: Remove RCU fiddling from cpu_pm_{enter, exit}()

Peter Zijlstra
Thu, 12 Jan 2023 19:43:28 -0000

All callers should still have RCU enabled.

Signed-off-by: Peter Zijlstra (Intel) <peterz at infradead.org>
Reviewed-by: Ulf Hansson <ulf.hansson at linaro.org>
Acked-by: Mark Rutland <mark.rutland at arm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Acked-by: Frederic Weisbecker <frederic at kernel.org>
Tested-by: Tony Lindgren <tony at atomide.com>
Tested-by: Ulf Hansson <ulf.hansson at linaro.org>
---
 kernel/cpu_pm.c |    9 ---------
 1 file changed, 9 deletions(-)

--- a/kernel/cpu_pm.c
+++ b/kernel/cpu_pm.c
@@ -30,16 +30,9 @@ static int cpu_pm_notify(enum cpu_pm_eve
 {
 	int ret;

-	/*
-	 * This introduces a RCU read critical section, which could be
-	 * disfunctional in cpu idle. Copy RCU_NONIDLE code to let RCU know
-	 * this.
-	 */
-	ct_irq_enter_irqson();
 	rcu_read_lock();
 	ret = raw_notifier_call_chain(&cpu_pm_notifier.chain, event, NULL);
 	rcu_read_unlock();
-	ct_irq_exit_irqson();

 	return notifier_to_errno(ret);
 }
@@ -49,11 +42,9 @@ static int cpu_pm_notify_robust(enum cpu
 	unsigned long flags;
 	int ret;

-	ct_irq_enter_irqson();
 	raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags);
 	ret = raw_notifier_call_chain_robust(&cpu_pm_notifier.chain, event_up,
event_down, NULL);
 	raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
-	ct_irq_exit_irqson();

 	return notifier_to_errno(ret);
 }