Re: [PATCH v2] rust: irq: add support for request_irq()

[Daniel Almeida <daniel.almeida@collabora.com>]

Hi Andreas,

I will address your other comments later this week, as I’m off for a few days.

> On 4 Mar 2025, at 10:43, Andreas Hindborg <a.hindborg@kernel.org> wrote:
> 
> "Daniel Almeida" <daniel.almeida@collabora.com> writes:
> 
>> Add support for registering IRQ handlers in Rust.
>> 
>> IRQ handlers are extensively used in drivers when some peripheral wants to
>> obtain the CPU attention. Registering a handler will make the system invoke the
>> passed-in function whenever the chosen IRQ line is triggered.
>> 
>> Both regular and threaded IRQ handlers are supported through a Handler (or
>> ThreadedHandler) trait that is meant to be implemented by a type that:
>> 
>> a) provides a function to be run by the system when the IRQ fires and,
>> 
>> b) holds the shared data (i.e.: `T`) between process and IRQ contexts.
>> 
>> The requirement that T is Sync derives from the fact that handlers might run
>> concurrently with other processes executing the same driver, creating the
>> potential for data races.
>> 
>> Ideally, some interior mutability must be in place if T is to be mutated. This
>> should usually be done through the in-flight SpinLockIrq type.
>> 
>> Co-developed-by: Alice Ryhl <aliceryhl@google.com>
>> Signed-off-by: Alice Ryhl <aliceryhl@google.com>
>> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
> 
> What is the base commit to apply this patch to? I am getting some
> compiler errors when trying it out:
> 
>   error[E0308]: mismatched types
>     --> /home/aeh/src/linux-rust/linux/rust/kernel/irq/request.rs:240:21
>       |
>   237 |                 bindings::request_irq(
>       |                 --------------------- arguments to this function are incorrect
>   ...
>   240 |                     flags.0,
>       |                     ^^^^^^^ expected `usize`, found `u64`
>       |
> 
> [...]

This patch needs a rebase. I’ve been waiting for Lyude & Boqun
new SpinLockIrq series, which just came out last week.

I’ll work on a v3 soon.