Re: [PATCH v2 2/2] USB: misc: Add onboard_usb_hub driver

From: Alan Stern
Date: Mon Sep 21 2020 - 21:08:15 EST

On Mon, Sep 21, 2020 at 05:41:58PM -0700, Matthias Kaehlcke wrote:
> > > + put_device(hub->dev);
> >
> > Is there a matching get_device somewhere (like in _find_onboard_hub)?
> > If so, I didn't see it. And I don't see any reason for it.
> Yes, implicitly, of_find_device_by_node() "takes a reference to the
> embedded struct device which needs to be dropped after use."

Okay. In that case it probably would be better to do the put_device()
right away, at the end of _find_onboard_hub().

There would be no danger of the platform device getting freed too soon
if you make onboard_hub_remove unbind the associated USB hub devices.
But there would still be a danger of those devices somehow getting
rebound again at the wrong time; this suggests that you should add a
flag to the onboard_hub structure saying that the platform device is
about to go away.

Alan Stern