On Mon, Jun 23, 2025 at 4:23 PM Danilo Krummrich <dakr@xxxxxxxxxx> wrote:
>
> On Mon, Jun 23, 2025 at 04:10:50PM +0100, Alice Ryhl wrote:
> > On Mon, Jun 9, 2025 at 12:47 PM Danilo Krummrich <dakr@xxxxxxxxxx> wrote:
> > >
> > > On Sun, Jun 08, 2025 at 07:51:08PM -0300, Daniel Almeida wrote:
> > > > + dev: &'a Device<Bound>,
> > > > + irq: u32,
> > > > + flags: Flags,
> > > > + name: &'static CStr,
> > > > + handler: T,
> > > > + ) -> impl PinInit<Self, Error> + 'a {
> > > > + let closure = move |slot: *mut Self| {
> > > > + // SAFETY: The slot passed to pin initializer is valid for writing.
> > > > + unsafe {
> > > > + slot.write(Self {
> > > > + inner: Devres::new(
> > > > + dev,
> > > > + RegistrationInner {
> > > > + irq,
> > > > + cookie: slot.cast(),
> > > > + },
> > > > + GFP_KERNEL,
> > > > + )?,
> > > > + handler,
> > > > + _pin: PhantomPinned,
> > > > + })
> > > > + };
> > > > +
> > > > + // SAFETY:
> > > > + // - The callbacks are valid for use with request_irq.
> > > > + // - If this succeeds, the slot is guaranteed to be valid until the
> > > > + // destructor of Self runs, which will deregister the callbacks
> > > > + // before the memory location becomes invalid.
> > > > + let res = to_result(unsafe {
> > > > + bindings::request_irq(
> > > > + irq,
> > > > + Some(handle_irq_callback::<T>),
> > > > + flags.into_inner() as usize,
> > > > + name.as_char_ptr(),
> > > > + slot.cast(),
> > > > + )
> > > > + });
> > > > +
> > > > + if res.is_err() {
> > > > + // SAFETY: We are returning an error, so we can destroy the slot.
> > > > + unsafe { core::ptr::drop_in_place(&raw mut (*slot).handler) };
> > > > + }
> > > > +
> > > > + res
> > > > + };
> > > > +
> > > > + // SAFETY:
> > > > + // - if this returns Ok, then every field of `slot` is fully
> > > > + // initialized.
> > > > + // - if this returns an error, then the slot does not need to remain
> > > > + // valid.
> > > > + unsafe { pin_init_from_closure(closure) }
> > >
> > > Can't we use try_pin_init!() instead, move request_irq() into the initializer of
> > > RegistrationInner and initialize inner last?
> >
> > We need a pointer to the entire struct when calling
> > bindings::request_irq. I'm not sure this allows you to easily get one?
> > I don't think using container_of! here is worth it.
>
> Would `try_pin_init!(&this in Self { ...` work?
Ah, could be. If that works, then that's fine with me.
Alice
