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media: uvcvideo: Fix driver reference counting 

kref_init initializes the reference count to 1, not 0. This additional
reference is never released since the conversion to reference counters.
As a result, uvc_delete is not called anymore when UVC cameras are
disconnected.
Fix this by adding an additional kref_put in uvc_disconnect and in the
probe error path. This also allows to remove the temporary additional
reference in uvc_unregister_video.

Fixes: 9d15cd958c ("media: uvcvideo: Convert from using an atomic variable to a reference count")

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Philipp Zabel 2018-05-21 06:24:58 -04:00 committed by Mauro Carvalho Chehab
parent 6c0e931c74
commit f9ffcb0a21
1 changed files with 2 additions and 9 deletions
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11
drivers/media/usb/uvc/uvc_driver.c
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@ -1871,13 +1871,6 @@ static void uvc_unregister_video(struct uvc_device *dev)
{
struct uvc_streaming *stream;
/* Unregistering all video devices might result in uvc_delete() being
* called from inside the loop if there's no open file handle. To avoid
* that, increment the refcount before iterating over the streams and
* decrement it when done.
*/
kref_get(&dev->ref);
list_for_each_entry(stream, &dev->streams, list) {
if (!video_is_registered(&stream->vdev))
continue;
@ -1887,8 +1880,6 @@ static void uvc_unregister_video(struct uvc_device *dev)
uvc_debugfs_cleanup_stream(stream);
}
kref_put(&dev->ref, uvc_delete);
}
int uvc_register_video_device(struct uvc_device *dev,
@ -2184,6 +2175,7 @@ static int uvc_probe(struct usb_interface *intf,
error:
uvc_unregister_video(dev);
kref_put(&dev->ref, uvc_delete);
return -ENODEV;
}
@ -2201,6 +2193,7 @@ static void uvc_disconnect(struct usb_interface *intf)
return;
uvc_unregister_video(dev);
kref_put(&dev->ref, uvc_delete);
}
static int uvc_suspend(struct usb_interface *intf, pm_message_t message)