[PATCH 4/4] Input: preallocate memory to hold event values

@@ -112,9 +112,6 @@ static void input_pass_values(struct input_dev *dev,
 
 	lockdep_assert_held(&dev->event_lock);
 
-	if (!count)
-		return;
-
 	rcu_read_lock();
 
 	handle = rcu_dereference(dev->grab);

@@ -320,9 +317,6 @@ static void input_event_dispose(struct input_dev *dev, int disposition,
 	if ((disposition & INPUT_PASS_TO_DEVICE) && dev->event)
 		dev->event(dev, type, code, value);
 
-	if (!dev->vals)
-		return;
-
 	if (disposition & INPUT_PASS_TO_HANDLERS) {
 		struct input_value *v;
 

@@ -1979,22 +1973,41 @@ struct input_dev *input_allocate_device(void)
 	struct input_dev *dev;
 
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
-	if (dev) {
-		dev->dev.type = &input_dev_type;
-		dev->dev.class = &input_class;
-		device_initialize(&dev->dev);
-		mutex_init(&dev->mutex);
-		spin_lock_init(&dev->event_lock);
-		timer_setup(&dev->timer, NULL, 0);
-		INIT_LIST_HEAD(&dev->h_list);
-		INIT_LIST_HEAD(&dev->node);
-
-		dev_set_name(&dev->dev, "input%lu",
-			     (unsigned long)atomic_inc_return(&input_no));
-
-		__module_get(THIS_MODULE);
+	if (!dev)
+		return NULL;
+
+	/*
+	 * Start with space for SYN_REPORT + 7 EV_KEY/EV_MSC events + 2 spare,
+	 * see input_estimate_events_per_packet(). We will tune the number
+	 * when we register the device.
+	 */
+	dev->max_vals = 10;
+	dev->vals = kcalloc(dev->max_vals, sizeof(*dev->vals), GFP_KERNEL);
+	if (!dev->vals) {
+		kfree(dev);
+		return NULL;
 	}
 
+	mutex_init(&dev->mutex);
+	spin_lock_init(&dev->event_lock);
+	timer_setup(&dev->timer, NULL, 0);
+	INIT_LIST_HEAD(&dev->h_list);
+	INIT_LIST_HEAD(&dev->node);
+
+	dev->dev.type = &input_dev_type;
+	dev->dev.class = &input_class;
+	device_initialize(&dev->dev);
+	/*
+	 * From this point on we can no longer simply "kfree(dev)", we need
+	 * to use input_free_device() so that device core properly frees its
+	 * resources associated with the input device.
+	 */
+
+	dev_set_name(&dev->dev, "input%lu",
+		     (unsigned long)atomic_inc_return(&input_no));
+
+	__module_get(THIS_MODULE);
+
 	return dev;
 }
 EXPORT_SYMBOL(input_allocate_device);

@@ -2334,6 +2347,34 @@ bool input_device_enabled(struct input_dev *dev)
 }
 EXPORT_SYMBOL_GPL(input_device_enabled);
 
+static int input_device_tune_vals(struct input_dev *dev)
+{
+	struct input_value *vals;
+	unsigned int packet_size;
+	unsigned int max_vals;
+
+	packet_size = input_estimate_events_per_packet(dev);
+	if (dev->hint_events_per_packet < packet_size)
+		dev->hint_events_per_packet = packet_size;
+
+	max_vals = dev->hint_events_per_packet + 2;
+	if (dev->max_vals >= max_vals)
+		return 0;
+
+	vals = kcalloc(max_vals, sizeof(*vals), GFP_KERNEL);
+	if (!vals)
+		return -ENOMEM;
+
+	spin_lock_irq(&dev->event_lock);
+	dev->max_vals = max_vals;
+	swap(dev->vals, vals);
+	spin_unlock_irq(&dev->event_lock);
+
+	kfree(vals);
+
+	return 0;
+}
+
 /**
  * input_register_device - register device with input core
  * @dev: device to be registered

@@ -2361,7 +2402,6 @@ int input_register_device(struct input_dev *dev)
 {
 	struct input_devres *devres = NULL;
 	struct input_handler *handler;
-	unsigned int packet_size;
 	const char *path;
 	int error;
 

@@ -2389,16 +2429,9 @@ int input_register_device(struct input_dev *dev)
 	/* Make sure that bitmasks not mentioned in dev->evbit are clean. */
 	input_cleanse_bitmasks(dev);
 
-	packet_size = input_estimate_events_per_packet(dev);
-	if (dev->hint_events_per_packet < packet_size)
-		dev->hint_events_per_packet = packet_size;
-
-	dev->max_vals = dev->hint_events_per_packet + 2;
-	dev->vals = kcalloc(dev->max_vals, sizeof(*dev->vals), GFP_KERNEL);
-	if (!dev->vals) {
-		error = -ENOMEM;
+	error = input_device_tune_vals(dev);
+	if (error)
 		goto err_devres_free;
-	}
 
 	/*
 	 * If delay and period are pre-set by the driver, then autorepeating

@@ -2418,7 +2451,7 @@ int input_register_device(struct input_dev *dev)
 
 	error = device_add(&dev->dev);
 	if (error)
-		goto err_free_vals;
+		goto err_devres_free;
 
 	path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
 	pr_info("%s as %s\n",

@@ -2448,9 +2481,6 @@ int input_register_device(struct input_dev *dev)
 
 err_device_del:
 	device_del(&dev->dev);
-err_free_vals:
-	kfree(dev->vals);
-	dev->vals = NULL;
 err_devres_free:
 	devres_free(devres);
 	return error;