media: mc: mark the media devnode as registered from the, start

This is an automatic generated email to let you know that the following patch were queued:

Subject: media: mc: mark the media devnode as registered from the, start
Author:  Hans Verkuil <[email protected]>
Date:    Fri Feb 23 09:46:19 2024 +0100

First the media device node was created, and if successful it was marked as 'registered'. This leaves a small race condition where an application can open the device node and get an error back because the 'registered' flag was not yet set.

Change the order: first set the 'registered' flag, then actually register the media device node. If that fails, then clear the flag.

 drivers/media/mc/mc-devnode.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

---

index 7f67825c8757..318e267e798e 100644
@@ -245,15 +245,14 @@ int __must_check media_devnode_register(struct media_device *mdev,
 	kobject_set_name(&devnode->cdev.kobj, "media%d", devnode->minor);
 
 	/* Part 3: Add the media and char device */
+	set_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
 	ret = cdev_device_add(&devnode->cdev, &devnode->dev);
 	if (ret < 0) {
+		clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
 		pr_err("%s: cdev_device_add failed\n", __func__);
 		goto cdev_add_error;
 	}
 
-	/* Part 4: Activate this minor. The char device can now be used. */
-	set_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
-
 	return 0;
 
 cdev_add_error: