[PATCH v2 3/5] rust: pci: remove request_irq() and request_threaded_irq() from Device

[Danilo Krummrich <dakr@kernel.org>]

Remove the thin wrappers on Device<Bound> that only forwarded to
irq::Registration::new() and irq::ThreadedRegistration::new(). With
IrqVector embedding a resolved IrqRequest, the conversion is infallible
and drivers call irq::Registration::new(vector.into(), ...) directly.

Unlike the platform equivalents, which combine a fallible IRQ lookup
with handler registration, the PCI wrappers add no value beyond
namespacing. They also introduce a redundant device reference.
IrqVector already carries a device borrow through its embedded
IrqRequest, yet the wrappers required a second, potentially unrelated,
&self receiver.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 rust/kernel/pci/irq.rs | 50 ++++++------------------------------------
 1 file changed, 7 insertions(+), 43 deletions(-)

diff --git a/rust/kernel/pci/irq.rs b/rust/kernel/pci/irq.rs
index 305701440114..b3dce5b49d57 100644
--- a/rust/kernel/pci/irq.rs
+++ b/rust/kernel/pci/irq.rs
@@ -8,10 +8,7 @@
     device,
     device::Bound,
     error::to_result,
-    irq::{
-        self,
-        IrqRequest, //
-    },
+    irq::IrqRequest,
     prelude::*, //
 };
 use core::num::NonZero;
@@ -70,9 +67,10 @@ const fn as_raw(self) -> u32 {
 
 /// A resolved IRQ vector from a PCI interrupt vector allocation.
 ///
-/// Created by [`IrqVectorRegistration::vector`] and consumed by [`Device::request_irq`] or
-/// [`Device::request_threaded_irq`]. Borrows the [`IrqVectorRegistration`] it was derived from,
-/// so the allocation stays live until the handler is freed.
+/// Created by [`IrqVectorRegistration::vector`]. Convert to [`IrqRequest`] via [`From`] to register
+/// a handler with [`irq::Registration::new`](crate::irq::Registration::new). Borrows the
+/// [`IrqVectorRegistration`] it was derived from, so the allocation stays live until the handler is
+/// freed.
 pub struct IrqVector<'a> {
     request: IrqRequest<'a>,
     reg: &'a IrqVectorRegistration<'a>,
@@ -169,40 +167,6 @@ fn drop(&mut self) {
 }
 
 impl Device<device::Bound> {
-    /// Returns a [`kernel::irq::Registration`] for the given IRQ vector.
-    ///
-    /// # Safety
-    ///
-    /// Callers must not `mem::forget()` the resulting [`irq::Registration`] or otherwise prevent
-    /// its [`Drop`] implementation from running.
-    pub unsafe fn request_irq<'a, T: crate::irq::Handler + 'a>(
-        &'a self,
-        vector: IrqVector<'a>,
-        flags: irq::Flags,
-        name: &'static CStr,
-        handler: impl PinInit<T, Error> + 'a,
-    ) -> impl PinInit<irq::Registration<'a, T>, Error> + 'a {
-        // SAFETY: Caller guarantees the Registration will not be leaked.
-        unsafe { irq::Registration::<T>::new(vector.into(), flags, name, handler) }
-    }
-
-    /// Returns a [`kernel::irq::ThreadedRegistration`] for the given IRQ vector.
-    ///
-    /// # Safety
-    ///
-    /// Callers must not `mem::forget()` the resulting [`irq::ThreadedRegistration`] or otherwise
-    /// prevent its [`Drop`] implementation from running.
-    pub unsafe fn request_threaded_irq<'a, T: crate::irq::ThreadedHandler + 'a>(
-        &'a self,
-        vector: IrqVector<'a>,
-        flags: irq::Flags,
-        name: &'static CStr,
-        handler: impl PinInit<T, Error> + 'a,
-    ) -> impl PinInit<irq::ThreadedRegistration<'a, T>, Error> + 'a {
-        // SAFETY: Caller guarantees the Registration will not be leaked.
-        unsafe { irq::ThreadedRegistration::<T>::new(vector.into(), flags, name, handler) }
-    }
-
     /// Allocate IRQ vectors for this PCI device.
     ///
     /// Allocates between `min_vecs` and `max_vecs` interrupt vectors for the device.
@@ -211,8 +175,8 @@ pub unsafe fn request_threaded_irq<'a, T: crate::irq::ThreadedHandler + 'a>(
     /// will try them in order of preference: MSI-X first, then MSI, then INTx interrupts.
     ///
     /// The allocated vectors are freed when the returned [`IrqVectorRegistration`] is dropped.
-    /// IRQ handlers registered via [`Self::request_irq`] or [`Self::request_threaded_irq`]
-    /// borrow from the registration, so the compiler ensures they are freed first.
+    /// Use [`IrqVectorRegistration::vector`] to obtain an [`IrqVector`] for a given vector
+    /// index.
     ///
     /// # Arguments
     ///
-- 
2.55.0