USB: usbip: fix stub_dev hub disconnect

If a hub is disconnected that has device(s) that's attached to the usbip layer
the disconnect function might fail because it tries to release the port
on an already disconnected hub.

Fixes: 6080cd0 ("staging: usbip: claim ports used by shared devices")
Signed-off-by: Jonas Blixt <jonas.blixt@actia.se>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20230615092810.1215490-1-jonas.blixt@actia.se
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/usbip/stub_dev.c

@@ -464,8 +464,13 @@ static void stub_disconnect(struct usb_device *udev)
 	/* release port */
 	rc = usb_hub_release_port(udev->parent, udev->portnum,
 				  (struct usb_dev_state *) udev);
-	if (rc) {
-		dev_dbg(&udev->dev, "unable to release port\n");
+	/*
+	 * NOTE: If a HUB disconnect triggered disconnect of the down stream
+	 * device usb_hub_release_port will return -ENODEV so we can safely ignore
+	 * that error here.
+	 */
+	if (rc && (rc != -ENODEV)) {
+		dev_dbg(&udev->dev, "unable to release port (%i)\n", rc);
 		return;
 	}