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 <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 12 insertions, 5 deletions

diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
index c3f6f1e311ea..090a1ba0abb6 100644
--- a/drivers/hid/hid-sensor-hub.c
+++ b/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;
diff --git a/include/linux/hid-sensor-hub.h b/include/linux/hid-sensor-hub.h
index 0408421d885f..0042bf330b99 100644
--- a/include/linux/hid-sensor-hub.h
+++ b/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;
 };