[media] v4l: Do not allow re-registering sub-devices

Albeit not prohibited explicitly, re-registering sub-devices generated a
big, loud warning which quite likely soon was followed by a crash. What
followed was re-initialising a media entity, driver's registered() callback
being called and re-adding a list entry to a list.

Prevent this by returning an error if a sub-device is already registered.

[mchehab@s-opensource.com: reorder logic to check if !sd before dereferencing it]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Sakari Ailus 2016-08-11 07:18:37 -03:00 committed by Mauro Carvalho Chehab
parent 6a21b72873
commit fc49071766

View File

@ -160,12 +160,9 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
int err;
/* Check for valid input */
if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0])
return -EINVAL;
/* Warn if we apparently re-register a subdev */
WARN_ON(sd->v4l2_dev != NULL);
/*
* The reason to acquire the module here is to avoid unloading
* a module of sub-device which is registered to a media