[PATCH 1/2] [media] media-device: check before unregister if mdev was registered

From: Javier Martinez Canillas
Date: Thu Sep 10 2015 - 09:04:20 EST


Most media functions that unregister, check if the corresponding register
function succeed before. So these functions can safely be called even if a
registration was never made or the component as already been unregistered.

Add the same check to media_device_unregister() function for consistency.

This will also allow to split the media_device_register() function in an
initialization and registration functions without the need to change the
generic cleanup functions and error code paths for all the media drivers.

Suggested-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Signed-off-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx>
---

drivers/media/media-device.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 1312e93ebd6e..745defb34b33 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -574,6 +574,8 @@ EXPORT_SYMBOL_GPL(__media_device_register);
* media_device_unregister - unregister a media device
* @mdev: The media device
*
+ * If the media device has never been registered this function will
+ * return immediately.
*/
void media_device_unregister(struct media_device *mdev)
{
@@ -582,6 +584,10 @@ void media_device_unregister(struct media_device *mdev)
struct media_link *link, *tmp_link;
struct media_interface *intf, *tmp_intf;

+ /* Check if mdev was ever registered at all */
+ if (!media_devnode_is_registered(&mdev->devnode))
+ return;
+
/* Remove interface links from the media device */
list_for_each_entry_safe(link, tmp_link, &mdev->links,
graph_obj.list) {
--
2.4.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/