HID: hid-sensor-hub: Fix debug lock warning

When CONFIG_DEBUG_LOCK_ALLOC is defined, mutex magic is compared and
warned for (l->magic != l), here l is the address of mutex pointer.
In hid-sensor-hub as part of hsdev creation, a per hsdev mutex is
initialized during MFD cell creation. This hsdev, which contains, mutex
is part of platform data for the a cell. But platform_data is copied
in platform_device_add_data() in platform.c. This copy will copy the
whole hsdev structure including mutex. But once copied the magic
will no longer match. So when client driver call
sensor_hub_input_attr_get_raw_value, this will trigger mutex warning.
So to avoid this allocate mutex dynamically. This will be same even
after copy.

Signed-off-by: Srinivas Pandruvada <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

Author: spandruvada

drivers/hid/hid-sensor-hub.c

@@ -294,7 +294,7 @@ int sensor_hub_input_attr_get_raw_value(struct hid_sensor_hub_device *hsdev,
 	if (!report)
 		return -EINVAL;
 
-	mutex_lock(&hsdev->mutex);
+	mutex_lock(hsdev->mutex_ptr);
 	if (flag == SENSOR_HUB_SYNC) {
 		memset(&hsdev->pending, 0, sizeof(hsdev->pending));
 		init_completion(&hsdev->pending.ready);
@@ -328,7 +328,7 @@ int sensor_hub_input_attr_get_raw_value(struct hid_sensor_hub_device *hsdev,
 		kfree(hsdev->pending.raw_data);
 		hsdev->pending.status = false;
 	}
-	mutex_unlock(&hsdev->mutex);
+	mutex_unlock(hsdev->mutex_ptr);
 
 	return ret_val;
 }
@@ -667,7 +667,14 @@ static int sensor_hub_probe(struct hid_device *hdev,
 			hsdev->vendor_id = hdev->vendor;
 			hsdev->product_id = hdev->product;
 			hsdev->usage = collection->usage;
-			mutex_init(&hsdev->mutex);
+			hsdev->mutex_ptr = devm_kzalloc(&hdev->dev,
+							sizeof(struct mutex),
+							GFP_KERNEL);
+			if (!hsdev->mutex_ptr) {
+				ret = -ENOMEM;
+				goto err_stop_hw;
+			}
+			mutex_init(hsdev->mutex_ptr);
 			hsdev->start_collection_index = i;
 			if (last_hsdev)
 				last_hsdev->end_collection_index = i;

include/linux/hid-sensor-hub.h

@@ -74,7 +74,7 @@ struct sensor_hub_pending {
  * @usage:		Usage id for this hub device instance.
  * @start_collection_index: Starting index for a phy type collection
  * @end_collection_index: Last index for a phy type collection
- * @mutex:		synchronizing mutex.
+ * @mutex_ptr:		synchronizing mutex pointer.
  * @pending:		Holds information of pending sync read request.
  */
 struct hid_sensor_hub_device {
@@ -84,7 +84,7 @@ struct hid_sensor_hub_device {
 	u32 usage;
 	int start_collection_index;
 	int end_collection_index;
-	struct mutex mutex;
+	struct mutex *mutex_ptr;
 	struct sensor_hub_pending pending;
 };