> +static void usb_host_cleanup(struct Notifier* n)
> +{
> +    struct USBHostDevice *s;
> +
> +    QTAILQ_FOREACH(s,&hostdevs, next) {
> +        if (s->fd != -1) {
> +            ioctl(s->fd, USBDEVFS_RESET);
> +        }
> +    }
> +}

Well.  The point of exit notifiers is that you don't need global 
variables for your cleanup work because the notifier function gets 
passed in a handle to your state data.

In that specific case the global hostdevs is needed anyway for other 
reasons.  Nevertheless I don't want usb-linux.c set a bad example, but 
provide a good reference implementation for others to look at.

Patch attached (untested).

cheers,
   Gerd