PM: QoS: Make CPU latency QoS depend on CONFIG_CPU_IDLE

Because cpuidle is the only user of the effective constraint coming
from the CPU latency QoS, add #ifdef CONFIG_CPU_IDLE around that code
to avoid building it unnecessarily.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Tested-by: Amit Kucheria <amit.kucheria@linaro.org>

include/linux/pm_qos.h

@@ -143,11 +143,24 @@ bool pm_qos_update_flags(struct pm_qos_flags *pqf,
 			 struct pm_qos_flags_request *req,
 			 enum pm_qos_req_action action, s32 val);
 
+#ifdef CONFIG_CPU_IDLE
 s32 cpu_latency_qos_limit(void);
 bool cpu_latency_qos_request_active(struct pm_qos_request *req);
 void cpu_latency_qos_add_request(struct pm_qos_request *req, s32 value);
 void cpu_latency_qos_update_request(struct pm_qos_request *req, s32 new_value);
 void cpu_latency_qos_remove_request(struct pm_qos_request *req);
+#else
+static inline s32 cpu_latency_qos_limit(void) { return INT_MAX; }
+static inline bool cpu_latency_qos_request_active(struct pm_qos_request *req)
+{
+	return false;
+}
+static inline void cpu_latency_qos_add_request(struct pm_qos_request *req,
+					       s32 value) {}
+static inline void cpu_latency_qos_update_request(struct pm_qos_request *req,
+						  s32 new_value) {}
+static inline void cpu_latency_qos_remove_request(struct pm_qos_request *req) {}
+#endif
 
 #ifdef CONFIG_PM
 enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask);

kernel/power/qos.c

@@ -209,6 +209,7 @@ bool pm_qos_update_flags(struct pm_qos_flags *pqf,
 	return prev_value != curr_value;
 }
 
+#ifdef CONFIG_CPU_IDLE
 /* Definitions related to the CPU latency QoS. */
 
 static struct pm_qos_constraints cpu_latency_constraints = {
@@ -421,6 +422,7 @@ static int __init cpu_latency_qos_init(void)
 	return ret;
 }
 late_initcall(cpu_latency_qos_init);
+#endif /* CONFIG_CPU_IDLE */
 
 /* Definitions related to the frequency QoS below. */