Re: [PATCH v4 5/5] rust: devres: implement register_release()

["Benno Lossin" <lossin@kernel.org>]

On Sat Jun 28, 2025 at 11:58 AM CEST, Danilo Krummrich wrote:
> On Sat, Jun 28, 2025 at 09:53:06AM +0200, Benno Lossin wrote:
>> Hmm @Danilo, do you have any use-cases in mind or already done?
>
> There may be other use-cases, but the one that I could forsee is very specific:
>
> A Registration type that carries additional reference-counted data, where the
> Registration should be released exactly when the device is unbound, independent
> of the lifetime of the data.
>
> Obviously, this implies that the ForeignOwnable is an Arc.
>
> With KBox, Release and Drop are pretty much identical, so using
> devres::release() instead, is much simpler and hence what we do for all simple
> class device registrations.
>
> Besides that, the use-case described above can also be covered by Devres with
> the pin-init rework, by having the Registration  embed a Devres<Inner>, which
> is what irq::Registration does and I also do in the MiscDeviceRegistration
> patches.
>
> Hence, I already considered dropping this patch -- and I think we should do this
> for now.

Sounds good! We can always pick it up again when needed.

---
Cheers,
Benno