On 01/28/2016 10:05 AM, Mauro Carvalho Chehab wrote:

Em Wed,  6 Jan 2016 13:27:20 -0700
Shuah Khan [off-list ref] escreveu:

quoted

Change au0828_unregister_media_device() to check media
device media device unregister is in progress and avoid
calling media_device_unregister() and other cleanup done
in au0828_unregister_media_device().

Signed-off-by: Shuah Khan <redacted>
---
 drivers/media/usb/au0828/au0828-core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/au0828/au0828-core.c b/drivers/media/usb/au0828/au0828-core.c
index 886fb28..de357a2 100644
--- a/drivers/media/usb/au0828/au0828-core.c
+++ b/drivers/media/usb/au0828/au0828-core.c

@@ -136,7 +136,9 @@ static void au0828_unregister_media_device(struct au0828_dev *dev)
 
 #ifdef CONFIG_MEDIA_CONTROLLER
 	if (dev->media_dev &&
-		media_devnode_is_registered(&dev->media_dev->devnode)) {
+		media_devnode_is_registered(&dev->media_dev->devnode) &&
+		!media_device_is_unregister_in_progress(dev->media_dev)) {
+

A kref would likely work better here.

Hope you saw my response to[PATCH 29/31] on why ensuring
two drivers don't get into unregister is necessary.

Could you please elaborate on kref. Are you saying adding
kref to struct media_device?

thanks,
-- Shuah

quoted

 		media_device_unregister(dev->media_dev);
 		media_device_cleanup(dev->media_dev);
 		dev->media_dev = NULL;

-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org | (970) 217-8978