On Tue, Jun 24, 2025 at 07:42:05AM -0700, Boqun Feng wrote:
> On Tue, Jun 24, 2025 at 07:33:35AM -0700, Boqun Feng wrote:
> > On Tue, Jun 24, 2025 at 02:50:23PM +0100, Alice Ryhl wrote:
> > > On Tue, Jun 24, 2025 at 1:46 PM Benno Lossin <lossin@xxxxxxxxxx> wrote:
> > > >
> > > > On Tue Jun 24, 2025 at 2:31 PM CEST, Daniel Almeida wrote:
> > > > > On 23 Jun 2025, at 16:28, Benno Lossin <lossin@xxxxxxxxxx> 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.
> >
> > You only need the access of `handler` in the irq callback, right? I.e.
> > passing the address of `handler` would suffice (of course you need
> > to change the irq callback as well).
> >
> > > >
> > > > 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`.
> > >
> > > It sounds like this is getting too complicated and that
> > > `pin_init_from_closure` is the simpler way to go.
> >
> > Even if we use `pin_init_from_closure`, we still need the other
> > `try_pin_init` anyway for `Devres::new()` (or alternatively we can
> > implement a `RegistrationInner::new()`).
> >
> > Below is what would look like with the Devres changes in mind:
> >
> >
> > try_pin_init!(&this in Self {
> > handler,
> > inner: <- Devres::new(
> > dev,
> > try_pin_init!( RegistrationInner {
> > // Needs to use `handler` address as cookie, same for
> > // request_irq().
> > cookie: &raw (*(this.as_ptr().cast()).handler),
> > // @Benno, would this "this" work here?
> > irq: {
> > to_result(unsafe { bindings::request_irq(...) })?;
> > irq
> > }
> > }),
> > )?,
> > _pin: PhantomPinned
> > })
> >
> >
>
> Never mind, `dev` is a `Device<Bound>` so it cannot be unbounded during
> the call ;-)
We even know that `dev` won't be unbound as long as the returned
`impl PinInit<Self, Error> + 'a` lives. :)
