Re: [PATCH net-next v4 3/6] rust: net::phy implement AsRef<kernel::device::Device> trait

[Benno Lossin <benno.lossin@proton.me>]

On 17.08.24 07:19, FUJITA Tomonori wrote:
> Implement AsRef<kernel::device::Device> trait for Device. A PHY driver
> needs a reference to device::Device to call the firmware API.
> 
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
> ---
>  rust/kernel/net/phy.rs | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
> index 5e8137a1972f..569dd3beef9c 100644
> --- a/rust/kernel/net/phy.rs
> +++ b/rust/kernel/net/phy.rs
> @@ -7,8 +7,7 @@
>  //! C headers: [`include/linux/phy.h`](srctree/include/linux/phy.h).
> 
>  use crate::{error::*, prelude::*, types::Opaque};
> -
> -use core::marker::PhantomData;
> +use core::{marker::PhantomData, ptr::addr_of_mut};
> 
>  /// PHY state machine states.
>  ///
> @@ -302,6 +301,15 @@ pub fn genphy_read_abilities(&mut self) -> Result {
>      }
>  }
> 
> +impl AsRef<kernel::device::Device> for Device {
> +    fn as_ref(&self) -> &kernel::device::Device {
> +        let phydev = self.0.get();
> +        // SAFETY: The struct invariant ensures that we may access
> +        // this field without additional synchronization.

I don't see this invariant on `phy::Device`.

---
Cheers,
Benno

> +        unsafe { kernel::device::Device::as_ref(addr_of_mut!((*phydev).mdio.dev)) }
> +    }
> +}
> +
>  /// Defines certain other features this PHY supports (like interrupts).
>  ///
>  /// These flag values are used in [`Driver::FLAGS`].
> --
> 2.34.1
>