PM / QoS: Prepare struct dev_pm_qos_request for more request types

The subsequent patches will use struct dev_pm_qos_request for
representing both latency requests and flags requests.  To make that
easier, put the node member of struct dev_pm_qos_request (under the
name "pnode") into a union called "data" that will represent the
request's  value and list node depending on its type.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: mark gross <markgross@thegnar.org>

drivers/base/power/qos.c

@@ -90,7 +90,7 @@ static int apply_constraint(struct dev_pm_qos_request *req,
 	int ret, curr_value;
 
 	ret = pm_qos_update_target(&req->dev->power.qos->latency,
-				   &req->node, action, value);
+				   &req->data.pnode, action, value);
 
 	if (ret) {
 		/* Call the global callbacks if needed */
@@ -183,7 +183,7 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
 
 	c = &qos->latency;
 	/* Flush the constraints list for the device */
-	plist_for_each_entry_safe(req, tmp, &c->list, node) {
+	plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
 		/*
 		 * Update constraints list and call the notification
 		 * callbacks if needed
@@ -293,7 +293,7 @@ int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
 	mutex_lock(&dev_pm_qos_mtx);
 
 	if (req->dev->power.qos) {
-		if (new_value != req->node.prio)
+		if (new_value != req->data.pnode.prio)
 			ret = apply_constraint(req, PM_QOS_UPDATE_REQ,
 					       new_value);
 	} else {

drivers/base/power/sysfs.c

@@ -221,7 +221,7 @@ static DEVICE_ATTR(autosuspend_delay_ms, 0644, autosuspend_delay_ms_show,
 static ssize_t pm_qos_latency_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%d\n", dev->power.pq_req->node.prio);
+	return sprintf(buf, "%d\n", dev->power.pq_req->data.pnode.prio);
 }
 
 static ssize_t pm_qos_latency_store(struct device *dev,

include/linux/pm_qos.h

@@ -39,7 +39,9 @@ struct pm_qos_flags_request {
 };
 
 struct dev_pm_qos_request {
-	struct plist_node node;
+	union {
+		struct plist_node pnode;
+	} data;
 	struct device *dev;
 };