Re: [PATCH v2] rust: kernel: device: Add devm_of_platform_populate/depopulate

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Apr 29, 2025 at 04:31:52PM +0200, Danilo Krummrich wrote:
> On Tue, Apr 29, 2025 at 05:09:26PM +0530, Ayush Singh wrote:
> > +    /// Remove devices populated from device tree
> > +    pub fn devm_of_platform_depopulate(&self) {
> > +        // SAFETY: self is valid bound Device reference
> > +        unsafe { bindings::devm_of_platform_depopulate(self.as_raw()) }
> > +    }
> > +}
> 
> One additional question regarding devm_of_platform_depopulate(). This function
> is only used once throughout the whole kernel (in [1]), and at a first glance
> the usage there seems unnecessary.
> 
> In your upcoming driver you call devm_of_platform_depopulate() from a fallible
> path [2].
> 
> So, I think we should change devm_of_platform_depopulate() to return an error
> instead of WARN(ret).
> 
> If [1] needs it for some subtle reason I don't see, then I think we can still
> call it from there as
> 
> 	WARN(devm_of_platform_depopulate())
> 
> [1] https://elixir.bootlin.com/linux/v6.15-rc4/source/drivers/soc/ti/pruss.c#L558
> [2] https://github.com/Ayush1325/linux/commit/cdb1322b7166532445c54b601ad0a252866e574d#diff-7b9e3179e36732d5f3a681034d70c2fda4ff57745c79ad4a656f328c91e54b77R71

Ugh, no, we should just delete this function entirely if only one driver
is using it.  That implies it's not really needed at all.

And we should NEVER have a WARN() call, that's just an excuse to reboot
the box and assign a CVE...

thanks,

greg k-h