On Tue, 5 May 2015, Srinivas Pandruvada wrote: > 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 use mutex pointer, which points to the original > mutex structure, and use this. This will be same even after copy. > > Signed-off-by: Srinivas Pandruvada <[email protected]> > --- > drivers/hid/hid-sensor-hub.c | 5 +++-- > include/linux/hid-sensor-hub.h | 2 ++ > 2 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c > index 5eb338d..2ee6a3f8 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; > } > @@ -668,6 +668,7 @@ static int sensor_hub_probe(struct hid_device *hdev, > hsdev->product_id = hdev->product; > hsdev->usage = collection->usage; > mutex_init(&hsdev->mutex); > + hsdev->mutex_ptr = &hsdev->mutex; > 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 d48e91f..6f27c6e 100644 > --- a/include/linux/hid-sensor-hub.h > +++ b/include/linux/hid-sensor-hub.h > @@ -75,6 +75,7 @@ struct sensor_hub_pending { > * @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: Pointer to the above synchronizing mutex. > * @pending: Holds information of pending sync read request. > */ > struct hid_sensor_hub_device { > @@ -85,6 +86,7 @@ struct hid_sensor_hub_device { > int start_collection_index; > int end_collection_index; > struct mutex mutex; > + struct mutex *mutex_ptr;
This is quite ugly, isn't it? Is there any reason why you can't just have a pointer in the struct, and allocate the mutex dynamically at the same time you are allocating the struct? -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
