Date: Tue, 21 Jul 2026 07:50:33 +0000
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Subject: Re: [PATCH v2] rust: irq: make Registration compatible with
 lifetime-bound drivers
From: Alice Ryhl <aliceryhl@google.com>
To: Danilo Krummrich <dakr@kernel.org>
Cc: daniel.almeida@collabora.com, ojeda@kernel.org, boqun@kernel.org, 
	gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, 
	a.hindborg@kernel.org, tmgross@umich.edu, tamird@kernel.org, 
	acourbot@nvidia.com, work@onurozkan.dev, bhelgaas@google.com, 
	kwilczynski@kernel.org, gregkh@linuxfoundation.org, rafael@kernel.org, 
	mhi@mailbox.org, driver-core@lists.linux.dev, rust-for-linux@vger.kernel.org, 
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
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On Sun, Jul 19, 2026 at 05:36:05PM +0200, Danilo Krummrich wrote:
> Adapt the IRQ registration to work with the Higher-Ranked Lifetime Types
> (HRT) device driver architecture introduced in commit 2c7c65933600
> ("Merge patch series "rust: device: Higher-Ranked Lifetime Types for
> device drivers"").
> 
> With HRT, driver structs carry a lifetime parameter tied to the device
> binding scope, allowing device resources such as pci::Bar<'bar> to be
> held directly rather than through Devres indirection. However, the IRQ
> abstraction required Handler: Sync + 'static, preventing handlers from
> embedding lifetime-parameterized resources.
> 
> Remove the 'static bound from Handler and ThreadedHandler and replace
> the Devres<RegistrationInner> indirection with direct request_irq() /
> free_irq() calls in the constructor and PinnedDrop.  Registration<'a, T>
> stores the IrqRequest<'a>, which structurally ties it to the device
> binding scope.
> 
> Also remove the &Device<Bound> parameter from the handler callbacks,
> since handlers that need device access can embed it in their own type.
> 
> IRQ handlers can now directly own device resources:
> 
> 	struct IrqHandler<'irq> {
> 	    bar: pci::Bar<'irq, BAR_SIZE>,
> 	}
> 
> 	impl irq::Handler for IrqHandler<'_> {
> 	    fn handle(&self) -> IrqReturn {
> 	        let stat = self.bar.read(regs::STAT);
> 	        ...
> 	    }
> 	}
> 
> This eliminates the indirection previously required for IRQ handlers to
> access device resources and aligns with the broader goal of expressing
> every registration scoped to a driver binding through compile-time
> lifetime bounds.
> 
> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>