Re: [PATCH v4 3/6] rust: irq: add support for non-threaded IRQs and handlers

["Benno Lossin" <lossin@kernel.org>]

On Tue Jun 24, 2025 at 2:31 PM CEST, Daniel Almeida wrote:
> On 23 Jun 2025, at 16:28, Benno Lossin <lossin@kernel.org> wrote:
>> On Mon Jun 23, 2025 at 9:18 PM CEST, Boqun Feng wrote:
>>>    try_pin_init!(&this in Self {
>>>        handler,
>>>        inner: Devres::new(
>>>            dev,
>>>            RegistrationInner {
>>>                // Needs to use `handler` address as cookie, same for
>>>                // request_irq().
>>>                cookie: &raw (*(this.as_ptr().cast()).handler),
>>>                irq: {
>>>                     to_result(unsafe { bindings::request_irq(...) })?;
>>>  irq
>>> }
>>>             },
>>>             GFP_KERNEL,
>>>        )?,
>>>        _pin: PhantomPinned
>>>    })
>> 
>> Well yes and no, with the Devres changes, the `cookie` can just be the
>> address of the `RegistrationInner` & we can do it this way :)
>> 
>> ---
>> Cheers,
>> Benno
>
>
> No, we need this to be the address of the the whole thing (i.e.
> Registration<T>), otherwise you can’t access the handler in the irq
> callback.

Gotcha, so you keep the cookie field, but you should still be able to
use `try_pin_init` & the devres improvements to avoid the use of
`pin_init_from_closure`.

---
Cheers,
Benno