linux-kernel - Re: [PATCH v1 1/1] i2c: core: Do not dereference fwnode in struct device

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Message-ID: <YbHVpwl5uGpV+Lei@smile.fi.intel.com>
Date:   Thu, 9 Dec 2021 12:08:39 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Wolfram Sang <wsa+renesas@...g-engineering.com>,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/1] i2c: core: Do not dereference fwnode in struct
 device

On Thu, Dec 09, 2021 at 09:44:49AM +0100, Wolfram Sang wrote:
> 
> >  	client->dev.parent = &client->adapter->dev;
> >  	client->dev.bus = &i2c_bus_type;
> >  	client->dev.type = &i2c_client_type;
> > -	client->dev.of_node = of_node_get(info->of_node);
> > -	client->dev.fwnode = info->fwnode;
> >  
> >  	device_enable_async_suspend(&client->dev);
> >  	i2c_dev_set_name(adap, client, info);
> >  
> > +	device_set_node(&client->dev, info->fwnode);
> > +	client->dev.of_node = of_node_get(info->of_node);
> > +
> 
> I am basically OK with this change. I'd just move the code block a
> little to have the same behaviour as before. Something like this
> (hand-edited preview version):

And this is exactly what have been done.

> >  	client->dev.bus = &i2c_bus_type;
> >  	client->dev.type = &i2c_client_type;
> >  	client->dev.of_node = of_node_get(info->of_node);
> > -	client->dev.fwnode = info->fwnode;
> >  
> > +	device_set_node(&client->dev, info->fwnode);
> >  	device_enable_async_suspend(&client->dev);
> >  	i2c_dev_set_name(adap, client, info);
> 
> Are you okay with that?

It will be broken in this case. There is subtle detail about device_set_node(),
it sets both fwnode and of_node at once. More thinking about this, I admit that
the best strategy now is to drop this change for now.

-- 
With Best Regards,
Andy Shevchenko