Re: [PATCH v1] spi: Don't have controller clean up spi device before driver unbind

[Saravana Kannan <saravanak@xxxxxxxxxx>]

On Tue, May 4, 2021 at 10:48 PM Lukas Wunner <lukas@xxxxxxxxx> wrote:
>
> On Tue, May 04, 2021 at 08:14:16PM -0700, Saravana Kannan wrote:
> > @@ -415,6 +421,7 @@ static int spi_remove(struct device *dev)
> >                                ERR_PTR(ret));
> >       }
> >
> > +     spi_cleanup(to_spi_device(dev));
> >       dev_pm_domain_detach(dev, true);
> >
> >       return 0;
>
> Unfortunately this doesn't look right:  spi_remove() is run on
> driver unbind of the spi_device.  With the above change,
> ->setup is called on spi_device addition and ->cleanup is called
> on unbind, which is obviously assymetric.  What can happen
> here is that a slave-specific controller_state is allocated on
> spi_device addition, then on unbind that controller_state is freed
> and on a subsequent rebind it won't be recreated because ->setup
> isn't run on spi_device ->probe.

Good point!

>
> As I've written yesterday, calling spi_cleanup() in
> spi_unregister_device() should be fine if you move it to the end
> of the function, but before the final put_device().  For that,
> you need to open code the calls to device_del() and put_device()
> that happen in device_unregister() so far.

Yeah, I saw that email after I sent out this patch. I'll send out a v2.

-Saravana