Re: [PATCH v4 6/6] rust: pci: add irq accessors

[Danilo Krummrich <dakr@kernel.org>]

On Sun, Jun 08, 2025 at 07:51:11PM -0300, Daniel Almeida wrote:
> These accessors can be used to retrieve a irq::Registration or a
> irq::ThreadedRegistration from a pci device.
> 
> These accessors ensure that only valid IRQ lines can ever be registered.
> 
> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
> ---
>  rust/kernel/pci.rs | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
> index 8435f8132e38129ccc3495e7c4d3237fcaa97ad9..c690fa1c739c937324e902e61e68df238dbd733b 100644
> --- a/rust/kernel/pci.rs
> +++ b/rust/kernel/pci.rs
> @@ -395,6 +395,32 @@ pub fn resource_len(&self, bar: u32) -> Result<bindings::resource_size_t> {
>      }
>  }
>  
> +macro_rules! gen_irq_accessor {
> +    ($(#[$meta:meta])* $fn_name:ident, $reg_type:ident, $handler_trait:ident) => {
> +        $(#[$meta])*
> +        pub fn $fn_name<T: crate::irq::$handler_trait + 'static>(
> +            &self,
> +            index: u32,
> +            flags: crate::irq::flags::Flags,
> +            name: &'static crate::str::CStr,
> +            handler: T,
> +        ) -> Result<impl PinInit<crate::irq::$reg_type<T>, crate::error::Error> + '_> {
> +            // SAFETY: `self.as_raw` returns a valid pointer to a `struct pci_dev`.
> +            let irq = unsafe { crate::bindings::pci_irq_vector(self.as_raw(), index) };
> +            if irq < 0 {
> +                return Err(crate::error::Error::from_errno(irq));
> +            }
> +            Ok(crate::irq::$reg_type::<T>::register(
> +                self.as_ref(),
> +                irq as u32,
> +                flags,
> +                name,
> +                handler,
> +            ))
> +        }
> +    };
> +}

Given that we only have two invocations below, please implement them in-place. I
don't think it's worth having the macro indirection.

>  impl Device<device::Bound> {
>      /// Mapps an entire PCI-BAR after performing a region-request on it. I/O operation bound checks
>      /// can be performed on compile time for offsets (plus the requested type size) < SIZE.
> @@ -413,6 +439,15 @@ pub fn iomap_region_sized<const SIZE: usize>(
>      pub fn iomap_region(&self, bar: u32, name: &CStr) -> Result<Devres<Bar>> {
>          self.iomap_region_sized::<0>(bar, name)
>      }
> +
> +    gen_irq_accessor!(
> +        /// Returns a [`kernel::irq::Registration`] for the IRQ vector at the given index.
> +        irq_by_index, Registration, Handler
> +    );
> +    gen_irq_accessor!(
> +        /// Returns a [`kernel::irq::ThreadedRegistration`] for the IRQ vector at the given index.
> +        threaded_irq_by_index, ThreadedRegistration, ThreadedHandler
> +    );
>  }
>  
>  impl Device<device::Core> {
> 
> -- 
> 2.49.0
>