Commit 0f42194c authored by Ulf Hansson's avatar Ulf Hansson Committed by Rafael J. Wysocki
Browse files

PM: s2idle: Drop redundant locks when entering s2idle 



The calls to cpus_read_lock|unlock() protects us from getting CPUS
hotplugged, while entering suspend-to-idle. However, when s2idle_enter() is
called we should be far beyond the point when CPUs may be hotplugged.
Let's therefore simplify the code and drop the use of the lock.

Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/20250311160827.1129643-2-ulf.hansson@linaro.org


[ rjw: Rewrote the new comment ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 13b4f9e1

kernel/power/suspend.c

+6 −4
Original line number Diff line number Diff line
@@ -91,6 +91,12 @@ static void s2idle_enter(void) 
{

	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);



	/*

	 * The correctness of the code below depends on the number of online

	 * CPUs being stable, but CPUs cannot be taken offline or put online

	 * while it is running.

	 */



	raw_spin_lock_irq(&s2idle_lock);

	if (pm_wakeup_pending())

		goto out;
@@ -98,8 +104,6 @@ static void s2idle_enter(void) 
	s2idle_state = S2IDLE_STATE_ENTER;

	raw_spin_unlock_irq(&s2idle_lock);



	cpus_read_lock();



	/* Push all the CPUs into the idle loop. */

	wake_up_all_idle_cpus();

	/* Make the current CPU wait so it can enter the idle loop too. */
@@ -112,8 +116,6 @@ static void s2idle_enter(void) 
	 */

	wake_up_all_idle_cpus();



	cpus_read_unlock();



	raw_spin_lock_irq(&s2idle_lock);



 out: