1 files changed, 17 insertions, 23 deletions

diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
index df96a0fe489..f148a0580e0 100644
--- a/drivers/acpi/acpi_pad.c
+++ b/drivers/acpi/acpi_pad.c
@@ -156,12 +156,13 @@ static int power_saving_thread(void *data)
 
 	while (!kthread_should_stop()) {
 		int cpu;
-		u64 expire_time;
+		unsigned long expire_time;
 
 		try_to_freeze();
 
 		/* round robin to cpus */
-		if (last_jiffies + round_robin_time * HZ < jiffies) {
+		expire_time = last_jiffies + round_robin_time * HZ;
+		if (time_before(expire_time, jiffies)) {
 			last_jiffies = jiffies;
 			round_robin_cpu(tsk_index);
 		}
@@ -200,7 +201,7 @@ static int power_saving_thread(void *data)
 					CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
 			local_irq_enable();
 
-			if (jiffies > expire_time) {
+			if (time_before(expire_time, jiffies)) {
 				do_sleep = 1;
 				break;
 			}
@@ -215,8 +216,15 @@ static int power_saving_thread(void *data)
 		 * borrow CPU time from this CPU and cause RT task use > 95%
 		 * CPU time. To make 'avoid starvation' work, takes a nap here.
 		 */
-		if (do_sleep)
+		if (unlikely(do_sleep))
 			schedule_timeout_killable(HZ * idle_pct / 100);
+
+		/* If an external event has set the need_resched flag, then
+		 * we need to deal with it, or this loop will continue to
+		 * spin without calling __mwait().
+		 */
+		if (unlikely(need_resched()))
+			schedule();
 	}
 
 	exit_round_robin(tsk_index);
@@ -408,28 +416,14 @@ static int acpi_pad_pur(acpi_handle handle)
 	return num;
 }
 
-/* Notify firmware how many CPUs are idle */
-static void acpi_pad_ost(acpi_handle handle, int stat,
-	uint32_t idle_cpus)
-{
-	union acpi_object params[3] = {
-		{.type = ACPI_TYPE_INTEGER,},
-		{.type = ACPI_TYPE_INTEGER,},
-		{.type = ACPI_TYPE_BUFFER,},
-	};
-	struct acpi_object_list arg_list = {3, params};
-
-	params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
-	params[1].integer.value =  stat;
-	params[2].buffer.length = 4;
-	params[2].buffer.pointer = (void *)&idle_cpus;
-	acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
-}
-
 static void acpi_pad_handle_notify(acpi_handle handle)
 {
 	int num_cpus;
 	uint32_t idle_cpus;
+	struct acpi_buffer param = {
+		.length = 4,
+		.pointer = (void *)&idle_cpus,
+	};
 
 	mutex_lock(&isolated_cpus_lock);
 	num_cpus = acpi_pad_pur(handle);
@@ -439,7 +433,7 @@ static void acpi_pad_handle_notify(acpi_handle handle)
 	}
 	acpi_pad_idle_cpus(num_cpus);
 	idle_cpus = acpi_pad_idle_cpus_num();
-	acpi_pad_ost(handle, 0, idle_cpus);
+	acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY, 0, &param);
 	mutex_unlock(&isolated_cpus_lock);
 }