Re: [PATCH v4 2/7] rust: pci: rework device enabling API

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] rust: pci: missing #[inline] on DeviceEnableGuard::drop()
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commit 74e19693f9a2d2ce6a2ed986dc5fdc9a88535014
Author: Maurice Hieronymus <mhi@mailbox.org>

rust: pci: rework device enabling API

This commit replaces Device::enable_device_mem() with
Device::enable_device(), returning a DeviceEnableGuard<'a> that calls
pci_disable_device() on drop to keep the PCI device enable count balanced.
It also updates the nova-core driver to store the guard in NovaCore.

Link: https://lore.kernel.org/rust-for-linux/DJOEYVBS17MJ.1YD3TNGQBWHNK@kernel.org

> diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
> index 769d01d234296..75efd5c5ee97f 100644
> --- a/rust/kernel/pci.rs
> +++ b/rust/kernel/pci.rs
> @@ -469,6 +469,25 @@ pub fn pci_class(&self) -> Class {
>      }
>  }
>  
> +/// A guard that keeps the device's I/O and memory resources enabled.
> +///
> +/// # Invariants
> +///
> +/// The device's enable count was incremented once for this guard; dropping the guard decrements
> +/// it again.
> +#[must_use = "if unused, the device will be immediately disabled"]
> +pub struct DeviceEnableGuard<'a> {
> +    dev: &'a Device<device::Bound>,
> +}
> +
> +impl Drop for DeviceEnableGuard<'_> {
> +    fn drop(&mut self) {
> +        // SAFETY: `self.dev.as_raw()` is a valid pointer to a `struct pci_dev`, and by the type
> +        // invariant this guard holds one increment of the device's enable count.
> +        unsafe { bindings::pci_disable_device(self.dev.as_raw()) };
> +    }
> +}

[Severity: Low]
This isn't a bug, but since DeviceEnableGuard::drop() in rust/kernel/pci.rs
is a small non-generic abstraction method in the kernel crate that forwards
directly to bindings::pci_disable_device() when a DeviceEnableGuard is
dropped on driver unbind or probe error unwind, should it be marked with
#[inline] to allow cross-crate inlining into drivers (matching
Device::enable_device() below and IrqVectorRegistration::drop() in
rust/kernel/pci/irq.rs)?

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Sashiko AI review · https://sashiko.dev/#/patchset/20261105-b4-rust-pci-edu-driver-v4-0-20ef027bb707@mailbox.org?part=2