1 files changed, 125 insertions, 107 deletions

diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index f42d3f737a33..c7a8f453919e 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -48,59 +48,49 @@
  * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
  * held, taken with _irqsave.  One lock to rule them all
  */
-struct pm_qos_request_list {
-	struct list_head list;
-	union {
-		s32 value;
-		s32 usec;
-		s32 kbps;
-	};
-	int pm_qos_class;
+enum pm_qos_type {
+	PM_QOS_MAX,		/* return the largest value */
+	PM_QOS_MIN		/* return the smallest value */
 };
 
-static s32 max_compare(s32 v1, s32 v2);
-static s32 min_compare(s32 v1, s32 v2);
-
 struct pm_qos_object {
-	struct pm_qos_request_list requests;
+	struct plist_head requests;
 	struct blocking_notifier_head *notifiers;
 	struct miscdevice pm_qos_power_miscdev;
 	char *name;
 	s32 default_value;
-	atomic_t target_value;
-	s32 (*comparitor)(s32, s32);
+	enum pm_qos_type type;
 };
 
+static DEFINE_SPINLOCK(pm_qos_lock);
+
 static struct pm_qos_object null_pm_qos;
 static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
 static struct pm_qos_object cpu_dma_pm_qos = {
-	.requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)},
+	.requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests, pm_qos_lock),
 	.notifiers = &cpu_dma_lat_notifier,
 	.name = "cpu_dma_latency",
 	.default_value = 2000 * USEC_PER_SEC,
-	.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
-	.comparitor = min_compare
+	.type = PM_QOS_MIN,
 };
 
 static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
 static struct pm_qos_object network_lat_pm_qos = {
-	.requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)},
+	.requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests, pm_qos_lock),
 	.notifiers = &network_lat_notifier,
 	.name = "network_latency",
 	.default_value = 2000 * USEC_PER_SEC,
-	.target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
-	.comparitor = min_compare
+	.type = PM_QOS_MIN
 };
 
 
 static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
 static struct pm_qos_object network_throughput_pm_qos = {
-	.requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)},
+	.requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock),
 	.notifiers = &network_throughput_notifier,
 	.name = "network_throughput",
 	.default_value = 0,
-	.target_value = ATOMIC_INIT(0),
-	.comparitor = max_compare
+	.type = PM_QOS_MAX,
 };
 
 
@@ -111,8 +101,6 @@ static struct pm_qos_object *pm_qos_array[] = {
 	&network_throughput_pm_qos
 };
 
-static DEFINE_SPINLOCK(pm_qos_lock);
-
 static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
 		size_t count, loff_t *f_pos);
 static int pm_qos_power_open(struct inode *inode, struct file *filp);
@@ -122,48 +110,58 @@ static const struct file_operations pm_qos_power_fops = {
 	.write = pm_qos_power_write,
 	.open = pm_qos_power_open,
 	.release = pm_qos_power_release,
+	.llseek = noop_llseek,
 };
 
-/* static helper functions */
-static s32 max_compare(s32 v1, s32 v2)
+/* unlocked internal variant */
+static inline int pm_qos_get_value(struct pm_qos_object *o)
 {
-	return max(v1, v2);
-}
+	if (plist_head_empty(&o->requests))
+		return o->default_value;
 
-static s32 min_compare(s32 v1, s32 v2)
-{
-	return min(v1, v2);
-}
+	switch (o->type) {
+	case PM_QOS_MIN:
+		return plist_last(&o->requests)->prio;
+
+	case PM_QOS_MAX:
+		return plist_first(&o->requests)->prio;
 
+	default:
+		/* runtime check for not using enum */
+		BUG();
+	}
+}
 
-static void update_target(int pm_qos_class)
+static void update_target(struct pm_qos_object *o, struct plist_node *node,
+			  int del, int value)
 {
-	s32 extreme_value;
-	struct pm_qos_request_list *node;
 	unsigned long flags;
-	int call_notifier = 0;
+	int prev_value, curr_value;
 
 	spin_lock_irqsave(&pm_qos_lock, flags);
-	extreme_value = pm_qos_array[pm_qos_class]->default_value;
-	list_for_each_entry(node,
-			&pm_qos_array[pm_qos_class]->requests.list, list) {
-		extreme_value = pm_qos_array[pm_qos_class]->comparitor(
-				extreme_value, node->value);
-	}
-	if (atomic_read(&pm_qos_array[pm_qos_class]->target_value) !=
-			extreme_value) {
-		call_notifier = 1;
-		atomic_set(&pm_qos_array[pm_qos_class]->target_value,
-				extreme_value);
-		pr_debug(KERN_ERR "new target for qos %d is %d\n", pm_qos_class,
-			atomic_read(&pm_qos_array[pm_qos_class]->target_value));
+	prev_value = pm_qos_get_value(o);
+	/* PM_QOS_DEFAULT_VALUE is a signal that the value is unchanged */
+	if (value != PM_QOS_DEFAULT_VALUE) {
+		/*
+		 * to change the list, we atomically remove, reinit
+		 * with new value and add, then see if the extremal
+		 * changed
+		 */
+		plist_del(node, &o->requests);
+		plist_node_init(node, value);
+		plist_add(node, &o->requests);
+	} else if (del) {
+		plist_del(node, &o->requests);
+	} else {
+		plist_add(node, &o->requests);
 	}
+	curr_value = pm_qos_get_value(o);
 	spin_unlock_irqrestore(&pm_qos_lock, flags);
 
-	if (call_notifier)
-		blocking_notifier_call_chain(
-				pm_qos_array[pm_qos_class]->notifiers,
-					(unsigned long) extreme_value, NULL);
+	if (prev_value != curr_value)
+		blocking_notifier_call_chain(o->notifiers,
+					     (unsigned long)curr_value,
+					     NULL);
 }
 
 static int register_pm_qos_misc(struct pm_qos_object *qos)
@@ -196,42 +194,53 @@ static int find_pm_qos_object_by_minor(int minor)
  */
 int pm_qos_request(int pm_qos_class)
 {
-	return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
+	unsigned long flags;
+	int value;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	value = pm_qos_get_value(pm_qos_array[pm_qos_class]);
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	return value;
 }
 EXPORT_SYMBOL_GPL(pm_qos_request);
 
+int pm_qos_request_active(struct pm_qos_request_list *req)
+{
+	return req->pm_qos_class != 0;
+}
+EXPORT_SYMBOL_GPL(pm_qos_request_active);
+
 /**
  * pm_qos_add_request - inserts new qos request into the list
- * @pm_qos_class: identifies which list of qos request to us
+ * @dep: pointer to a preallocated handle
+ * @pm_qos_class: identifies which list of qos request to use
  * @value: defines the qos request
  *
  * This function inserts a new entry in the pm_qos_class list of requested qos
  * performance characteristics.  It recomputes the aggregate QoS expectations
- * for the pm_qos_class of parameters, and returns the pm_qos_request list
- * element as a handle for use in updating and removal.  Call needs to save
- * this handle for later use.
+ * for the pm_qos_class of parameters and initializes the pm_qos_request_list
+ * handle.  Caller needs to save this handle for later use in updates and
+ * removal.
  */
-struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value)
+
+void pm_qos_add_request(struct pm_qos_request_list *dep,
+			int pm_qos_class, s32 value)
 {
-	struct pm_qos_request_list *dep;
-	unsigned long flags;
+	struct pm_qos_object *o =  pm_qos_array[pm_qos_class];
+	int new_value;
 
-	dep = kzalloc(sizeof(struct pm_qos_request_list), GFP_KERNEL);
-	if (dep) {
-		if (value == PM_QOS_DEFAULT_VALUE)
-			dep->value = pm_qos_array[pm_qos_class]->default_value;
-		else
-			dep->value = value;
-		dep->pm_qos_class = pm_qos_class;
-
-		spin_lock_irqsave(&pm_qos_lock, flags);
-		list_add(&dep->list,
-			&pm_qos_array[pm_qos_class]->requests.list);
-		spin_unlock_irqrestore(&pm_qos_lock, flags);
-		update_target(pm_qos_class);
+	if (pm_qos_request_active(dep)) {
+		WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n");
+		return;
 	}
-
-	return dep;
+	if (value == PM_QOS_DEFAULT_VALUE)
+		new_value = o->default_value;
+	else
+		new_value = value;
+	plist_node_init(&dep->list, new_value);
+	dep->pm_qos_class = pm_qos_class;
+	update_target(o, &dep->list, 0, PM_QOS_DEFAULT_VALUE);
 }
 EXPORT_SYMBOL_GPL(pm_qos_add_request);
 
@@ -246,27 +255,28 @@ EXPORT_SYMBOL_GPL(pm_qos_add_request);
  * Attempts are made to make this code callable on hot code paths.
  */
 void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
-		s32 new_value)
+			   s32 new_value)
 {
-	unsigned long flags;
-	int pending_update = 0;
 	s32 temp;
+	struct pm_qos_object *o;
+
+	if (!pm_qos_req) /*guard against callers passing in null */
+		return;
 
-	if (pm_qos_req) { /*guard against callers passing in null */
-		spin_lock_irqsave(&pm_qos_lock, flags);
-		if (new_value == PM_QOS_DEFAULT_VALUE)
-			temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
-		else
-			temp = new_value;
-
-		if (temp != pm_qos_req->value) {
-			pending_update = 1;
-			pm_qos_req->value = temp;
-		}
-		spin_unlock_irqrestore(&pm_qos_lock, flags);
-		if (pending_update)
-			update_target(pm_qos_req->pm_qos_class);
+	if (!pm_qos_request_active(pm_qos_req)) {
+		WARN(1, KERN_ERR "pm_qos_update_request() called for unknown object\n");
+		return;
 	}
+
+	o = pm_qos_array[pm_qos_req->pm_qos_class];
+
+	if (new_value == PM_QOS_DEFAULT_VALUE)
+		temp = o->default_value;
+	else
+		temp = new_value;
+
+	if (temp != pm_qos_req->list.prio)
+		update_target(o, &pm_qos_req->list, 0, temp);
 }
 EXPORT_SYMBOL_GPL(pm_qos_update_request);
 
@@ -280,19 +290,20 @@ EXPORT_SYMBOL_GPL(pm_qos_update_request);
  */
 void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
 {
-	unsigned long flags;
-	int qos_class;
+	struct pm_qos_object *o;
 
 	if (pm_qos_req == NULL)
 		return;
 		/* silent return to keep pcm code cleaner */
 
-	qos_class = pm_qos_req->pm_qos_class;
-	spin_lock_irqsave(&pm_qos_lock, flags);
-	list_del(&pm_qos_req->list);
-	kfree(pm_qos_req);
-	spin_unlock_irqrestore(&pm_qos_lock, flags);
-	update_target(qos_class);
+	if (!pm_qos_request_active(pm_qos_req)) {
+		WARN(1, KERN_ERR "pm_qos_remove_request() called for unknown object\n");
+		return;
+	}
+
+	o = pm_qos_array[pm_qos_req->pm_qos_class];
+	update_target(o, &pm_qos_req->list, 1, PM_QOS_DEFAULT_VALUE);
+	memset(pm_qos_req, 0, sizeof(*pm_qos_req));
 }
 EXPORT_SYMBOL_GPL(pm_qos_remove_request);
 
@@ -340,8 +351,12 @@ static int pm_qos_power_open(struct inode *inode, struct file *filp)
 
 	pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
 	if (pm_qos_class >= 0) {
-		filp->private_data = (void *) pm_qos_add_request(pm_qos_class,
-				PM_QOS_DEFAULT_VALUE);
+               struct pm_qos_request_list *req = kzalloc(sizeof(*req), GFP_KERNEL);
+		if (!req)
+			return -ENOMEM;
+
+		pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE);
+		filp->private_data = req;
 
 		if (filp->private_data)
 			return 0;
@@ -353,8 +368,9 @@ static int pm_qos_power_release(struct inode *inode, struct file *filp)
 {
 	struct pm_qos_request_list *req;
 
-	req = (struct pm_qos_request_list *)filp->private_data;
+	req = filp->private_data;
 	pm_qos_remove_request(req);
+	kfree(req);
 
 	return 0;
 }
@@ -374,14 +390,16 @@ static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
 	} else if (count == 11) { /* len('0x12345678/0') */
 		if (copy_from_user(ascii_value, buf, 11))
 			return -EFAULT;
+		if (strlen(ascii_value) != 10)
+			return -EINVAL;
 		x = sscanf(ascii_value, "%x", &value);
 		if (x != 1)
 			return -EINVAL;
-		pr_debug(KERN_ERR "%s, %d, 0x%x\n", ascii_value, x, value);
+		pr_debug("%s, %d, 0x%x\n", ascii_value, x, value);
 	} else
 		return -EINVAL;
 
-	pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
+	pm_qos_req = filp->private_data;
 	pm_qos_update_request(pm_qos_req, value);
 
 	return count;