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Commit 9e882e3b authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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[media] v4l2-device: check if already unregistered 



It was possible to unregister an already unregistered v4l2_device struct.
Add a check whether that already happened and just return if that was
the case.
Also refuse to register a v4l2_device if both the dev and name fields are
empty. A warning was already produced in that case, but since the name field
is now used to detect whether or not the v4l2_device was already unregistered
this particular combination should be rejected.

Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 7feeb148

drivers/media/v4l2-core/v4l2-device.c

+7 −2
Original line number Diff line number Diff line
@@ -44,7 +44,8 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev) 
	v4l2_dev->dev = dev;

	if (dev == NULL) {

		/* If dev == NULL, then name must be filled in by the caller */

		WARN_ON(!v4l2_dev->name[0]);

		if (WARN_ON(!v4l2_dev->name[0]))

			return -EINVAL;

		return 0;

	}
@@ -105,7 +106,9 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev) 
{

	struct v4l2_subdev *sd, *next;



	if (v4l2_dev == NULL)

	/* Just return if v4l2_dev is NULL or if it was already

	 * unregistered before. */

	if (v4l2_dev == NULL || !v4l2_dev->name[0])

		return;

	v4l2_device_disconnect(v4l2_dev);
@@ -135,6 +138,8 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev) 
		}

#endif

	}

	/* Mark as unregistered, thus preventing duplicate unregistrations */

	v4l2_dev->name[0] = '\0';

}

EXPORT_SYMBOL_GPL(v4l2_device_unregister);