From: Greg KH <gregkh@linuxfoundation.org>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>,
Badhri Jagan Sridharan <badhri@google.com>,
Oliver Neukum <oneukum@suse.com>,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: [PATCHv11 2/3] usb: USB Type-C connector class
Date: Mon, 21 Nov 2016 15:45:06 +0100 [thread overview]
Message-ID: <20161121144506.GA28410@kroah.com> (raw)
In-Reply-To: <20161121131103.GA18501@kuha.fi.intel.com>
On Mon, Nov 21, 2016 at 03:11:03PM +0200, Heikki Krogerus wrote:
> Hi Greg,
>
> On Mon, Nov 21, 2016 at 11:35:28AM +0100, Greg KH wrote:
> > > +static void typec_partner_release(struct device *dev)
> > > +{
> > > + struct typec_port *port = to_typec_port(dev->parent);
> > > +
> > > + typec_unregister_altmodes(dev);
> > > + port->partner = NULL;
> > > +}
> >
> > This doesn't feel right, why are you both exporting
> > typec_unregister_altmodes() and also calling it from release callbacks?
> > That implies there is two way to clean stuff up, so what is a driver
> > writer to use? Please simplify and force it to be one way or the other.
>
> OK.
>
> > Also typec_unregister_altmodes() doesn't free memory, which release is
> > supposed to be doing, which also implies that the reference counting
> > logic is all wrong here. Please fix, like I asked you to previously.
>
> There is nothing wrong with the reference counting, and nothing has
> been allocated so there is nothing to free.
The device structure itself that this release call is for needs to
be freed, right? If not, something is really wrong...
> Please note that the partner device is meant to just represent the
> partner in user space and not to be actually used for anything. And
> please also note that there can only be one partner for a port at a
> time.
Ok, but these are still reference counted devices, you need to handle
that properly.
> We could allocate an extra structure for the partner when
> typec_connect() is called, but we would do that just for the sake of
> having something to free in the release hook. It would not be useful
> for anything. It would not help us increase/decrease the reference
> count of the device, and the port driver would still have to provide
> details about the partner capabilities the moment it tells us the
> partner was connected.
Again, free the device for which this release function is being called
for, that is why it is there.
thanks,
greg k-h
next prev parent reply other threads:[~2016-11-21 14:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-17 10:50 [PATCHv11 0/3] USB Type-C Connector class Heikki Krogerus
2016-11-17 10:50 ` [PATCHv11 1/3] lib/string: add sysfs_match_string helper Heikki Krogerus
2016-11-17 10:50 ` [PATCHv11 2/3] usb: USB Type-C connector class Heikki Krogerus
2016-11-21 10:33 ` Greg KH
2016-11-21 13:27 ` Heikki Krogerus
2016-11-21 14:46 ` Greg KH
2016-11-22 7:58 ` Heikki Krogerus
2016-11-22 8:19 ` Greg KH
2016-11-21 10:35 ` Greg KH
2016-11-21 13:11 ` Heikki Krogerus
2016-11-21 14:23 ` Heikki Krogerus
2016-11-21 15:33 ` Guenter Roeck
2016-11-22 8:52 ` Heikki Krogerus
2016-11-21 14:45 ` Greg KH [this message]
2016-11-22 10:51 ` Heikki Krogerus
2016-11-22 13:37 ` Heikki Krogerus
2016-11-22 13:45 ` Heikki Krogerus
2016-11-17 10:50 ` [PATCHv11 3/3] usb: typec: add driver for Intel Whiskey Cove PMIC USB Type-C PHY Heikki Krogerus
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