linux/rust/kernel/of.rs
Tamir Duberstein 5e30550558 rust: enable clippy::as_underscore lint
In Rust 1.63.0, Clippy introduced the `as_underscore` lint [1]:

> The conversion might include lossy conversion or a dangerous cast that
> might go undetected due to the type being inferred.
>
> The lint is allowed by default as using `_` is less wordy than always
> specifying the type.

Always specifying the type is especially helpful in function call
contexts where the inferred type may change at a distance. Specifying
the type also allows Clippy to spot more cases of `useless_conversion`.

The primary downside is the need to specify the type in trivial getters.
There are 4 such functions: 3 have become slightly less ergonomic, 1 was
revealed to be a `useless_conversion`.

While this doesn't eliminate unchecked `as` conversions, it makes such
conversions easier to scrutinize.  It also has the slight benefit of
removing a degree of freedom on which to bikeshed. Thus apply the
changes and enable the lint -- no functional change intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_underscore [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-4-f43b024581e8@gmail.com
[ Changed `isize` to `c_long`. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-22 23:09:17 +02:00

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1.9 KiB
Rust

// SPDX-License-Identifier: GPL-2.0
//! Device Tree / Open Firmware abstractions.
use crate::{bindings, device_id::RawDeviceId, prelude::*};
/// IdTable type for OF drivers.
pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;
/// An open firmware device id.
#[repr(transparent)]
#[derive(Clone, Copy)]
pub struct DeviceId(bindings::of_device_id);
// SAFETY:
// * `DeviceId` is a `#[repr(transparent)` wrapper of `struct of_device_id` and does not add
// additional invariants, so it's safe to transmute to `RawType`.
// * `DRIVER_DATA_OFFSET` is the offset to the `data` field.
unsafe impl RawDeviceId for DeviceId {
type RawType = bindings::of_device_id;
const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::of_device_id, data);
fn index(&self) -> usize {
self.0.data as usize
}
}
impl DeviceId {
/// Create a new device id from an OF 'compatible' string.
pub const fn new(compatible: &'static CStr) -> Self {
let src = compatible.as_bytes_with_nul();
// Replace with `bindings::of_device_id::default()` once stabilized for `const`.
// SAFETY: FFI type is valid to be zero-initialized.
let mut of: bindings::of_device_id = unsafe { core::mem::zeroed() };
// TODO: Use `copy_from_slice` once stabilized for `const`.
let mut i = 0;
while i < src.len() {
of.compatible[i] = src[i];
i += 1;
}
Self(of)
}
}
/// Create an OF `IdTable` with an "alias" for modpost.
#[macro_export]
macro_rules! of_device_table {
($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => {
const $table_name: $crate::device_id::IdArray<
$crate::of::DeviceId,
$id_info_type,
{ $table_data.len() },
> = $crate::device_id::IdArray::new($table_data);
$crate::module_device_table!("of", $module_table_name, $table_name);
};
}