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

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

On 18.08.24 04:13, FUJITA Tomonori wrote:
> On Sat, 17 Aug 2024 13:30:15 +0000
> Benno Lossin <benno.lossin@proton.me> wrote:
> 
>>> +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`.
> 
> You meant that `phy::Device` Invariants says that all methods defined
> on this struct are safe to call; not about accessing a field so the
> above SAFETY comment isn't correct, right?

Correct.

>> ---
>> Cheers,
>> Benno
>>
>>> +        unsafe { kernel::device::Device::as_ref(addr_of_mut!((*phydev).mdio.dev)) }
>>> +    }
>>> +}
> 
> SAFETY: A valid `phy_device` always have a valid `mdio.dev`.
> 
> Better?

It would be nice if you could add this on the invariants on
`phy::Device` (you will also have to extend the INVAIRANTS comment that
creates a `&'a mut Device`)

---
Cheers,
Benno