Re: [PATCH 1/4] rust: device: support `dev_printk` on all devices

["Danilo Krummrich" <dakr@kernel.org>]

On Tue Jan 20, 2026 at 7:11 PM CET, Gary Guo wrote:
> diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
> index c7b5db9dcca1..94e0548e7687 100644
> --- a/rust/kernel/device.rs
> +++ b/rust/kernel/device.rs
> @@ -601,6 +601,13 @@ impl DeviceContext for Core {}
>  impl DeviceContext for CoreInternal {}
>  impl DeviceContext for Normal {}
>  
> +impl<Ctx: DeviceContext> AsRef<Device<Ctx>> for Device<Ctx> {
> +    #[inline]
> +    fn as_ref(&self) -> &Device<Ctx> {
> +        self
> +    }
> +}
> +
>  /// Convert device references to bus device references.
>  ///
>  /// Bus devices can implement this trait to allow abstractions to provide the bus device in
> @@ -720,7 +727,7 @@ macro_rules! impl_device_context_into_aref {
>  macro_rules! dev_printk {
>      ($method:ident, $dev:expr, $($f:tt)*) => {
>          {
> -            ($dev).$method($crate::prelude::fmt!($($f)*));
> +            $crate::device::Device::$method($dev.as_ref(), $crate::prelude::fmt!($($f)*))

At a first glance I wasn't sure if we really want to rely on AsRef when hide it
in the macro. But on the other hand, if someone would implement AsRef on a class
or bus device to return some other (unrelated) &Device it would be wrong
anyways. So I think using AsRef is fine.

I think a lot of people will be very happy about this patch. :)

I will pick up patches 1 and 2 this cycle, patch 3 and 4 can go through the
corresponding subsystem tree next cycle.

> diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
> index bea76ca9c3da..3946ca919332 100644
> --- a/rust/kernel/pci.rs
> +++ b/rust/kernel/pci.rs
> @@ -351,7 +351,7 @@ impl Device {
>      ///     // Get an instance of `Vendor`.
>      ///     let vendor = pdev.vendor_id();
>      ///     dev_info!(
> -    ///         pdev.as_ref(),
> +    ///         pdev,
>      ///         "Device: Vendor={}, Device=0x{:x}\n",
>      ///         vendor,
>      ///         pdev.device_id()
> diff --git a/rust/kernel/pci/id.rs b/rust/kernel/pci/id.rs
> index c09125946d9e..e2d9e8804347 100644
> --- a/rust/kernel/pci/id.rs
> +++ b/rust/kernel/pci/id.rs
> @@ -22,7 +22,7 @@
>  /// fn probe_device(pdev: &pci::Device<Core>) -> Result {
>  ///     let pci_class = pdev.pci_class();
>  ///     dev_info!(
> -///         pdev.as_ref(),
> +///         pdev,
>  ///         "Detected PCI class: {}\n",
>  ///         pci_class
>  ///     );

Can you please send a separate patch for those?