Re: [PATCH v3 2/8] rust: pci: add sriov_get_totalvfs() helper

[Alexandre Courbot]

On Wed Jul 1, 2026 at 3:26 PM JST, Zhi Wang wrote:
> Expose pci_sriov_get_totalvfs() to Rust PCI drivers so they can query
> how many SR-IOV VFs a device supports.
>
> Cc: Alexandre Courbot <acourbot@xxxxxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: David Laight <david.laight.linux@xxxxxxxxx>
> Cc: Gary Guo <gary@xxxxxxxxxxx>
> Cc: linux-pci@xxxxxxxxxxxxxxx
> Link: https://lore.kernel.org/all/DJHPRE4TGGT8.BUTMYOF5YE05@xxxxxxxxxx/
> Signed-off-by: Zhi Wang <zhiw@xxxxxxxxxx>
> ---
>  rust/kernel/pci.rs | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
> index 5071cae6543f..21c51981c02e 100644
> --- a/rust/kernel/pci.rs
> +++ b/rust/kernel/pci.rs
> @@ -450,6 +450,17 @@ pub fn pci_class(&self) -> Class {
>          // SAFETY: `self.as_raw` is a valid pointer to a `struct pci_dev`.
>          Class::from_raw(unsafe { (*self.as_raw()).class })
>      }
> +
> +    /// Returns the total number of VFs, or 0 if SR-IOV is not available.
> +    #[inline]
> +    pub fn sriov_get_totalvfs(&self) -> u16 {
> +        // SAFETY: `self.as_raw()` is a valid pointer to a `struct pci_dev`.
> +        let total_vfs = unsafe { bindings::pci_sriov_get_totalvfs(self.as_raw()) };
> +
> +        // CAST: The C helper returns `unsigned int`, but the value originates
> +        // from TotalVFs/driver_max_VFs, so this cast cannot truncate.

nit: "from TotalVFs/driver_max_VFs (which are defined as `u16`), ..."

With that,

Reviewed-by: Alexandre Courbot <acourbot@xxxxxxxxxx>