[media] media: v4l2-dev: fix video device index assignment

mszyprow · mchehab · commit 6c3df5da67f1 · 2014-01-27T21:42:42.000-02:00
The side effect of commit 1056e43 ("v4l2-dev: Fix race condition on __video_register_device") is the increased number of index value assigned on video_device registration. Before that commit video_devices were numbered from 0, after it, the indexes starts from 1, because get_index() always count the device, which is being registered. Some device drivers rely on video_device index number for internal purposes, i.e. s5p-mfc driver stopped working after that patch. This patch restores the old method of numbering the video_device indexes. Cc: stable@vger.kernel.org # for v3.12 Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Acked-by: Ricardo Ribalda <ricardo.ribalda@gmail.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
@@ -872,8 +872,8 @@ int __video_register_device(struct video_device *vdev, int type, int nr,
 
 	/* Should not happen since we thought this minor was free */
 	WARN_ON(video_device[vdev->minor] != NULL);
-	video_device[vdev->minor] = vdev;
 	vdev->index = get_index(vdev);
+	video_device[vdev->minor] = vdev;
 	mutex_unlock(&videodev_lock);
 
 	if (vdev->ioctl_ops)
