Re: [PATCH v2 2/4] rust: device: implement device context marker

Boqun Feng
2025-03-14T17:22:05Z

On Fri, Mar 14, 2025 at 05:09:05PM +0100, Danilo Krummrich wrote:
> Some bus device functions should only be called from bus callbacks,
> such as probe(), remove(), resume(), suspend(), etc.
>
> To ensure this add device context marker structs, that can be used as
> generics for bus device implementations.
>
> Reviewed-by: Benno Lossin <benno.lossin@proton.me>
> Suggested-by: Benno Lossin <benno.lossin@proton.me>

Try chronological order for the tags? It was suggested first and then
reviewed.

Regards,
Boqun

> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
> ---
> rust/kernel/device.rs | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
> index db2d9658ba47..21b343a1dc4d 100644
> --- a/rust/kernel/device.rs
> +++ b/rust/kernel/device.rs
> @@ -209,6 +209,32 @@ unsafe impl Send for Device {}
> // synchronization in `struct device`.
> unsafe impl Sync for Device {}
>
> +/// Marker trait for the context of a bus specific device.
> +///
> +/// Some functions of a bus specific device should only be called from a certain context, i.e. bus
> +/// callbacks, such as `probe()`.
> +///
> +/// This is the marker trait for structures representing the context of a bus specific device.
> +pub trait DeviceContext: private::Sealed {}
> +
> +/// The [`Normal`] context is the context of a bus specific device when it is not an argument of
> +/// any bus callback.
> +pub struct Normal;
> +
> +/// The [`Core`] context is the context of a bus specific device when it is supplied as argument of
> +/// any of the bus callbacks, such as `probe()`.
> +pub struct Core;
> +
> +mod private {
> + pub trait Sealed {}
> +
> + impl Sealed for super::Core {}
> + impl Sealed for super::Normal {}
> +}
> +
> +impl DeviceContext for Core {}
> +impl DeviceContext for Normal {}
> +
> #[doc(hidden)]
> #[macro_export]
> macro_rules! dev_printk {
> --
> 2.48.1
>