1 files changed, 29 insertions, 3 deletions

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index f48a00e49794..fecdba85ab27 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -883,17 +883,42 @@ static void uvc_free(struct usb_function *f)
 	kfree(uvc);
 }
 
-static void uvc_unbind(struct usb_configuration *c, struct usb_function *f)
+static void uvc_function_unbind(struct usb_configuration *c,
+				struct usb_function *f)
 {
 	struct usb_composite_dev *cdev = c->cdev;
 	struct uvc_device *uvc = to_uvc(f);
+	long wait_ret = 1;
 
-	uvcg_info(f, "%s\n", __func__);
+	uvcg_info(f, "%s()\n", __func__);
+
+	/* If we know we're connected via v4l2, then there should be a cleanup
+	 * of the device from userspace either via UVC_EVENT_DISCONNECT or
+	 * though the video device removal uevent. Allow some time for the
+	 * application to close out before things get deleted.
+	 */
+	if (uvc->func_connected) {
+		uvcg_dbg(f, "waiting for clean disconnect\n");
+		wait_ret = wait_event_interruptible_timeout(uvc->func_connected_queue,
+				uvc->func_connected == false, msecs_to_jiffies(500));
+		uvcg_dbg(f, "done waiting with ret: %ld\n", wait_ret);
+	}
 
 	device_remove_file(&uvc->vdev.dev, &dev_attr_function_name);
 	video_unregister_device(&uvc->vdev);
 	v4l2_device_unregister(&uvc->v4l2_dev);
 
+	if (uvc->func_connected) {
+		/* Wait for the release to occur to ensure there are no longer any
+		 * pending operations that may cause panics when resources are cleaned
+		 * up.
+		 */
+		uvcg_warn(f, "%s no clean disconnect, wait for release\n", __func__);
+		wait_ret = wait_event_interruptible_timeout(uvc->func_connected_queue,
+				uvc->func_connected == false, msecs_to_jiffies(1000));
+		uvcg_dbg(f, "done waiting for release with ret: %ld\n", wait_ret);
+	}
+
 	usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
 	kfree(uvc->control_buf);
 
@@ -912,6 +937,7 @@ static struct usb_function *uvc_alloc(struct usb_function_instance *fi)
 
 	mutex_init(&uvc->video.mutex);
 	uvc->state = UVC_STATE_DISCONNECTED;
+	init_waitqueue_head(&uvc->func_connected_queue);
 	opts = fi_to_f_uvc_opts(fi);
 
 	mutex_lock(&opts->lock);
@@ -942,7 +968,7 @@ static struct usb_function *uvc_alloc(struct usb_function_instance *fi)
 	/* Register the function. */
 	uvc->func.name = "uvc";
 	uvc->func.bind = uvc_function_bind;
-	uvc->func.unbind = uvc_unbind;
+	uvc->func.unbind = uvc_function_unbind;
 	uvc->func.get_alt = uvc_function_get_alt;
 	uvc->func.set_alt = uvc_function_set_alt;
 	uvc->func.disable = uvc_function_disable;