Re: [PATCH v3 09/10] rust: pci: add SR-IOV enable and disable callbacks

[Danilo Krummrich]

On Wed Sep 30, 2026 at 12:18 PM CEST, Zhi Wang wrote:
> +    #[cfg(CONFIG_PCI_IOV)]
> +    fn sriov_enable<'bound, 'callback>(

I'd just call it 'a.

> +        dev: &'bound Device<device::Core<'_>>,

This is the same lifetime, as the token stores Device<Core<'_>>, so I'd also
make it 'a.

> +        this: Pin<&Self::Data<'bound>>,

Let's call this 'data', unbind() has 'this' for historical reasons.

> +        token: SriovEnable<'callback>,
> +    ) -> Result<SriovEnabled<'callback>> {
> +        let _ = (dev, this, token);
> +        build_error!(crate::error::VTABLE_DEFAULT_ERROR)
> +    }

<snip>

> +    #[cfg(CONFIG_PCI_IOV)]
> +    fn sriov_disable<'bound>(
> +        dev: &'bound Device<device::Core<'_>>,
> +        this: Pin<&Self::Data<'bound>>,
> +        token: SriovDisable<'_>,
> +    ) -> Result {
> +        let _ = (dev, this, token);
> +        build_error!(crate::error::VTABLE_DEFAULT_ERROR)
> +    }
>  }

<snip>

> +impl<T: Driver> Adapter<T> {
> +    pub(super) extern "C" fn sriov_configure_callback(
> +        pdev: *mut bindings::pci_dev,
> +        nr_virtfn: c_int,
> +    ) -> c_int {
> +        // SAFETY: The PCI bus only ever calls the sriov_configure callback with a valid pointer to
> +        // a `struct pci_dev`.
> +        //
> +        // INVARIANT: `pdev` is valid for the duration of `sriov_configure_callback()`.
> +        let pdev = unsafe { &*pdev.cast::<Device<device::CoreInternal<'_>>>() };
> +
> +        // SAFETY: `sriov_configure` is called only after a successful probe and before unbind, so
> +        // the stored pointer has type `T::Data<'_>` and remains valid throughout this callback.
> +        let data = unsafe { pdev.as_ref().drvdata_borrow::<T::Data<'_>>() };
> +
> +        from_result(|| {
> +            if !pdev.is_physfn() {
> +                return Err(ENODEV);
> +            }

I don't think this can ever happen.

> +            if nr_virtfn == 0 {
> +                T::sriov_disable(pdev, data, SriovDisable { pdev })?;
> +                if pdev.num_vf() != 0 {
> +                    return Err(EBUSY);
> +                }
> +                Ok(0)
> +            } else {
> +                let num_vfs = u16::try_from(nr_virtfn).map_err(|_| EINVAL)?;
> +                let enabled = T::sriov_enable(
> +                    pdev,
> +                    data,
> +                    SriovEnable {
> +                        pdev,
> +                        num_vfs: u32::from(num_vfs),
> +                    },
> +                )?;
> +                Ok(enabled.disarm())
> +            }
> +        })
> +    }
> +}