Re: [net-next PATCH v10 7/7] rust: net::phy sync with match_phy_device C changes

[FUJITA Tomonori]

On Mon, 19 May 2025 14:51:55 +0200
"Benno Lossin" <lossin@xxxxxxxxxx> wrote:

> On Mon May 19, 2025 at 2:44 PM CEST, FUJITA Tomonori wrote:
>> On Mon, 19 May 2025 14:32:44 +0200
>> "Benno Lossin" <lossin@xxxxxxxxxx> wrote:
>>>>>> The other use case, as mentioned above, is when using the generic helper
>>>>>> function inside match_phy_device() callback. For example, the 4th
>>>>>> patch in this patchset adds genphy_match_phy_device():
>>>>>>
>>>>>> int genphy_match_phy_device(struct phy_device *phydev,
>>>>>>                            const struct phy_driver *phydrv)
>>>>>>
>>>>>> We could add a wrapper for this function as phy::Device's method like
>>>>>>
>>>>>> impl Device {
>>>>>>     ...
>>>>>>     pub fn genphy_match_phy_device(&self, drv: &phy::DriverVTable) -> i32 
>>>>> 
>>>>> Not sure why this returns an `i32`, but we probably could have such a
>>>>
>>>> Maybe a bool would be more appropriate here because the C's comment
>>>> says:
>>>>
>>>> Return: 1 if the PHY device matches the driver, 0 otherwise.
>>>>
>>>>> function as well (though I wouldn't use the vtable for that).
>>>>
>>>> What would you use instead?
>>> 
>>> The concept that I sketched above:
>>> 
>>>     impl Device {
>>>         fn genphy_match_phy_device<T: Driver>(&self) -> bool {
>>>             self.phy_id() == T::PHY_DEVICE_ID.id
>>>         }
>>>     }
>>
>> I think there might be a misunderstanding.
>>
>> Rust's genphy_match_phy_device() is supposed to be a wrapper for C's
>> genphy_match_phy_device():
>>
>> https://lore.kernel.org/rust-for-linux/20250517201353.5137-5-ansuelsmth@xxxxxxxxx/
> 
> Oh yeah you're right. But using `DriverVTable` for that doesn't sound
> nice...

Agreed. We initially assumed that DriverVTable would be internal to
driver registration and not something driver developers would use
directly. Now that this has changed, it might be a good idea to rename
it.