Re: [PATCH v2 0/4] i2c: provide and use i2c_adapter_dev()

[Andy Shevchenko]

On Mon, Feb 23, 2026 at 10:02:48AM +0100, Bartosz Golaszewski wrote:
> It's been another year of discussing the object life-time problems at
> conferences. I2C is one of the offenders and its problems are more
> complex than those of some other subsystems. It seems the revocable[1]
> API may make its way into the kernel this year but even with it in
> place, I2C won't be able to use it as there's currently nothing to
> *revoke*. The struct device is embedded within the i2c_adapter struct
> whose lifetime is tied to the provider device being bound to its driver.
> 
> Fixing this won't be fast and easy but nothing's going to happen if we
> don't start chipping away at it. The ultimate goal in order to be able
> to use an SRCU-based solution (revocable or otherwise) is to convert the
> embedded struct device in struct i2c_adapter into an __rcu pointer that
> can be *revoked*. To that end we need to hide all dereferences of
> adap->dev in drivers.
> 
> Other series address more generic problems - like printk helpers and
> parent/of_node setting - but there are still some more specific
> use-cases of drivers dereferencing the internal struct device of
> i2c_adapters. We need to hide the fact that the device is embedded in
> i2c_adapter before we can move it out so provide a helper that provides
> the address of struct device without showing how it's stored and use it
> in some drivers.

LGTM, and I follow the evolution of these two series for a while,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
for this one.

-- 
With Best Regards,
Andy Shevchenko