[PATCH 2/2] PM: sleep: reset async_error with WRITE_ONCE()

[Jaidev Shastri via B4 Relay]

From: Jaidev Shastri <jaidevshastri@xxxxxx>

The device PM callbacks record failures with WRITE_ONCE(async_error, ...)
and every reader uses READ_ONCE(), but the six phase functions reset the
variable with a plain store before they schedule the asynchronous
callbacks.

Use WRITE_ONCE() for the reset so that every access to async_error
follows the same convention.

Found with MBCheck, a static herd7-based memory consistency checker.

Signed-off-by: Jaidev Shastri <jaidevshastri@xxxxxx>
---
 drivers/base/power/main.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index bf4b4fd1b..24b56aaa3 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -905,7 +905,7 @@ static void dpm_noirq_resume_devices(pm_message_t state)
 
 	trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, true);
 
-	async_error = 0;
+	WRITE_ONCE(async_error, 0);
 	/* Pairs with the smp_load_acquire() in dev_pm_skip_resume(). */
 	smp_store_release(&pm_transition.event, state.event);
 
@@ -1056,7 +1056,7 @@ void dpm_resume_early(pm_message_t state)
 
 	trace_suspend_resume(TPS("dpm_resume_early"), state.event, true);
 
-	async_error = 0;
+	WRITE_ONCE(async_error, 0);
 	/* Pairs with the smp_load_acquire() in dev_pm_skip_resume(). */
 	smp_store_release(&pm_transition.event, state.event);
 
@@ -1238,7 +1238,7 @@ void dpm_resume(pm_message_t state)
 
 	/* Pairs with the smp_load_acquire() in dev_pm_skip_resume(). */
 	smp_store_release(&pm_transition.event, state.event);
-	async_error = 0;
+	WRITE_ONCE(async_error, 0);
 
 	mutex_lock(&dpm_list_mtx);
 
@@ -1604,7 +1604,7 @@ static int dpm_noirq_suspend_devices(pm_message_t state)
 
 	/* Pairs with the smp_load_acquire() in dev_pm_skip_resume(). */
 	smp_store_release(&pm_transition.event, state.event);
-	async_error = 0;
+	WRITE_ONCE(async_error, 0);
 
 	mutex_lock(&dpm_list_mtx);
 
@@ -1808,7 +1808,7 @@ int dpm_suspend_late(pm_message_t state)
 
 	/* Pairs with the smp_load_acquire() in dev_pm_skip_resume(). */
 	smp_store_release(&pm_transition.event, state.event);
-	async_error = 0;
+	WRITE_ONCE(async_error, 0);
 
 	wake_up_all_idle_cpus();
 
@@ -2102,7 +2102,7 @@ int dpm_suspend(pm_message_t state)
 
 	/* Pairs with the smp_load_acquire() in dev_pm_skip_resume(). */
 	smp_store_release(&pm_transition.event, state.event);
-	async_error = 0;
+	WRITE_ONCE(async_error, 0);
 
 	mutex_lock(&dpm_list_mtx);
 

-- 
2.43.0