On Thu, 29 Mar 2012, Lan Tianyu wrote:
> >> @@ -1475,11 +1477,12 @@ bool usb_device_is_owned(struct usb_device *udev)
> >>
> >> static void recursively_mark_NOTATTACHED(struct usb_device *udev)
> >> {
> >> + struct usb_hub *hub = hdev_to_hub(udev);
> >
> > I'm not sure this is good. You are calling hdev_to_hub without knowing
> > beforehand that udev really is a hub -- in fact, most of the time udev
> > won't be a hub. The routine wasn't meant to be used that way. Have
> > you checked that hdev_to_hub won't crash when the argument isn't a hub?
> > What happens if the active configuration has no interfaces?
> About this, I have an idea to add a check of hdev->maxchild. I have
> verified that hdev->maxchild only is set in the hub_configure() and
> hub_disconnect(). So we can identify whether the udev is a usb hub or
> not through hdev->maxchild. Does this make sense?
Yes, okay. If you add such a check to hdev_to_hub() then it will work
properly. Unless somebody markets a hub with no ports -- but we don't
need to worry about that! :-)
Alan Stern
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