V4L/DVB: hdpvr: fix disconnect sequence

Disconnecting the HDPVR caused a kernel oops if lockdep was enabled.
In addition, if an app still had video0 open and attempted to call ioctl
when the device was already disconnected the system would crash.

Move the freeing and cleanup code to the release function: that is the
right place for it since you know when you get there that nobody is
using the device.

Also removed usb_set_intfdata: v4l2_device_register sets this already
to v4l2_dev.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/hdpvr/hdpvr-core.c

@@ -373,9 +373,6 @@ static int hdpvr_probe(struct usb_interface *interface,
 	}
 #endif /* CONFIG_I2C */
 
-	/* save our data pointer in this interface device */
-	usb_set_intfdata(interface, dev);
-
 	/* let the user know what node this device is now attached to */
 	v4l2_info(&dev->v4l2_dev, "device now attached to %s\n",
 		  video_device_node_name(dev->video_dev));
@@ -391,44 +388,24 @@ error:
 
 static void hdpvr_disconnect(struct usb_interface *interface)
 {
-	struct hdpvr_device *dev;
-
-	dev = usb_get_intfdata(interface);
-	usb_set_intfdata(interface, NULL);
+	struct hdpvr_device *dev = to_hdpvr_dev(usb_get_intfdata(interface));
 
+	v4l2_info(&dev->v4l2_dev, "device %s disconnected\n",
+		  video_device_node_name(dev->video_dev));
 	/* prevent more I/O from starting and stop any ongoing */
 	mutex_lock(&dev->io_mutex);
 	dev->status = STATUS_DISCONNECTED;
-	v4l2_device_disconnect(&dev->v4l2_dev);
-	video_unregister_device(dev->video_dev);
 	wake_up_interruptible(&dev->wait_data);
 	wake_up_interruptible(&dev->wait_buffer);
 	mutex_unlock(&dev->io_mutex);
+	v4l2_device_disconnect(&dev->v4l2_dev);
 	msleep(100);
 	flush_workqueue(dev->workqueue);
 	mutex_lock(&dev->io_mutex);
 	hdpvr_cancel_queue(dev);
-	destroy_workqueue(dev->workqueue);
 	mutex_unlock(&dev->io_mutex);
-
-	/* deregister I2C adapter */
-#ifdef CONFIG_I2C
-	mutex_lock(&dev->i2c_mutex);
-	if (dev->i2c_adapter)
-		i2c_del_adapter(dev->i2c_adapter);
-	kfree(dev->i2c_adapter);
-	dev->i2c_adapter = NULL;
-	mutex_unlock(&dev->i2c_mutex);
-#endif /* CONFIG_I2C */
-
+	video_unregister_device(dev->video_dev);
 	atomic_dec(&dev_nr);
-
-	v4l2_info(&dev->v4l2_dev, "device %s disconnected\n",
-		  video_device_node_name(dev->video_dev));
-
-	v4l2_device_unregister(&dev->v4l2_dev);
-	kfree(dev->usbc_buf);
-	kfree(dev);
 }
 
 

drivers/media/video/hdpvr/hdpvr-video.c

@@ -1214,6 +1214,24 @@ static void hdpvr_device_release(struct video_device *vdev)
 	struct hdpvr_device *dev = video_get_drvdata(vdev);
 
 	hdpvr_delete(dev);
+	mutex_lock(&dev->io_mutex);
+	destroy_workqueue(dev->workqueue);
+	mutex_unlock(&dev->io_mutex);
+
+	v4l2_device_unregister(&dev->v4l2_dev);
+
+	/* deregister I2C adapter */
+#ifdef CONFIG_I2C
+	mutex_lock(&dev->i2c_mutex);
+	if (dev->i2c_adapter)
+		i2c_del_adapter(dev->i2c_adapter);
+	kfree(dev->i2c_adapter);
+	dev->i2c_adapter = NULL;
+	mutex_unlock(&dev->i2c_mutex);
+#endif /* CONFIG_I2C */
+
+	kfree(dev->usbc_buf);
+	kfree(dev);
 }
 
 static const struct video_device hdpvr_video_template = {

drivers/media/video/hdpvr/hdpvr.h

@@ -111,6 +111,11 @@ struct hdpvr_device {
 	u8			*usbc_buf;
 };
 
+static inline struct hdpvr_device *to_hdpvr_dev(struct v4l2_device *v4l2_dev)
+{
+	return container_of(v4l2_dev, struct hdpvr_device, v4l2_dev);
+}
+
 
 /* buffer one bulk urb of data */
 struct hdpvr_buffer {