Re: [PATCH v2] rust: device: allow `Device<DeviceContext>::parent()`

[Danilo Krummrich <dakr@kernel.org>]

On Tue, Apr 29, 2025 at 11:06:29PM +0200, Miguel Ojeda wrote:
> When `CONFIG_AUXILIARY_BUS` is disabled, `parent()` is still dead code:
> 
>     error: method `parent` is never used
>       --> rust/kernel/device.rs:71:19
>        |
>     64 | impl<Ctx: DeviceContext> Device<Ctx> {
>        | ------------------------------------ method in this implementation
>     ...
>     71 |     pub(crate) fn parent(&self) -> Option<&Self> {
>        |                   ^^^^^^
>        |
>        = note: `-D dead-code` implied by `-D warnings`
>        = help: to override `-D warnings` add `#[allow(dead_code)]`
> 
> Thus reintroduce the `expect`, but now as a conditional one. Do so as
> `dead_code` since that is narrower.
> 
> An `allow` would also be possible, but Danilo wants to catch new users
> in the future [1].
> 
> Link: https://lore.kernel.org/rust-for-linux/aBE8qQrpXOfru_K3@pollux/ [1]
> Fixes: ce735e73dd59 ("rust: auxiliary: add auxiliary device / driver abstractions")
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Applied to nova-next, thanks!

[ Adjust commit subject to "rust: device: conditionally expect
  `dead_code` for `parent()`". - Danilo ]