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authorSakari Ailus <sakari.ailus@linux.intel.com>2013-12-12 09:36:46 -0300
committerMauro Carvalho Chehab <m.chehab@samsung.com>2014-05-13 13:41:44 -0300
commitb2a06aecb24329e16edc3108b8192d65ace8da75 (patch)
tree114ac342659d1e9fb598cb55bc93d158369b735b /drivers/media/v4l2-core/v4l2-device.c
parent85de721c46ba8ad9b283b2b3e307c9a3e8425042 (diff)
[media] v4l: Only get module if it's different than the driver for v4l2_dev
When the sub-device is registered, increment the use count of the sub-device owner only if it's different from the owner of the driver for the media device. This avoids increasing the use count by the module itself and thus making it possible to unload it when it's not in use. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Diffstat (limited to 'drivers/media/v4l2-core/v4l2-device.c')
-rw-r--r--drivers/media/v4l2-core/v4l2-device.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
index 02d1b6327117..015f92aab44a 100644
--- a/drivers/media/v4l2-core/v4l2-device.c
+++ b/drivers/media/v4l2-core/v4l2-device.c
@@ -158,7 +158,17 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
/* Warn if we apparently re-register a subdev */
WARN_ON(sd->v4l2_dev != NULL);
- if (!try_module_get(sd->owner))
+ /*
+ * The reason to acquire the module here is to avoid unloading
+ * a module of sub-device which is registered to a media
+ * device. To make it possible to unload modules for media
+ * devices that also register sub-devices, do not
+ * try_module_get() such sub-device owners.
+ */
+ sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
+ sd->owner == v4l2_dev->dev->driver->owner;
+
+ if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
return -ENODEV;
sd->v4l2_dev = v4l2_dev;
@@ -192,7 +202,8 @@ error_unregister:
if (sd->internal_ops && sd->internal_ops->unregistered)
sd->internal_ops->unregistered(sd);
error_module:
- module_put(sd->owner);
+ if (!sd->owner_v4l2_dev)
+ module_put(sd->owner);
sd->v4l2_dev = NULL;
return err;
}
@@ -280,6 +291,7 @@ void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
}
#endif
video_unregister_device(sd->devnode);
- module_put(sd->owner);
+ if (!sd->owner_v4l2_dev)
+ module_put(sd->owner);
}
EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);

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