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rust: driver: simplify IdArray::new_without_index

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This method can very easily construct the `IdArray` on its own without
delegating to `Self::build`. Doing so also simplifies the phy device table
macro because it does not need to construct tuples anymore.

This also allows simplification of `new` and `build` which removes the
`unsafe`.

Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260629-id_info-v2-2-56fccbe9c5ef@garyguo.net
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Gary Guo 2026-06-29 13:39:36 +01:00 committed by Danilo Krummrich
parent 3474bbba4d
commit e49f626ef5
2 changed files with 28 additions and 38 deletions
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64
rust/kernel/device_id.rs
View File

@ -73,19 +73,11 @@ pub struct IdArray<T: RawDeviceId, U, const N: usize> {
id_infos: [U; N],
}
impl<T: RawDeviceId, U, const N: usize> IdArray<T, U, N> {
impl<T: RawDeviceId + RawDeviceIdIndex, U, const N: usize> IdArray<T, U, N> {
/// Creates a new instance of the array.
///
/// The contents are derived from the given identifiers and context information.
///
/// # Safety
///
/// `data_offset` as `None` is always safe.
/// If `data_offset` is `Some(data_offset)`, then:
/// - `data_offset` must be the correct offset (in bytes) to the context/data field
/// (e.g., the `driver_data` field) within the raw device ID structure.
/// - The field at `data_offset` must be correctly sized to hold a `usize`.
const unsafe fn build(ids: [(T, U); N], data_offset: Option<usize>) -> Self {
pub const fn new(ids: [(T, U); N]) -> Self {
let mut raw_ids = [const { MaybeUninit::<T::RawType>::uninit() }; N];
let mut infos = [const { MaybeUninit::uninit() }; N];
@ -94,16 +86,14 @@ impl<T: RawDeviceId, U, const N: usize> IdArray<T, U, N> {
// SAFETY: by the safety requirement of `RawDeviceId`, we're guaranteed that `T` is
// layout-wise compatible with `RawType`.
raw_ids[i] = unsafe { core::mem::transmute_copy(&ids[i].0) };
if let Some(data_offset) = data_offset {
// SAFETY: by the safety requirement of this function, this would be effectively
// `raw_ids[i].driver_data = i;`.
unsafe {
raw_ids[i]
.as_mut_ptr()
.byte_add(data_offset)
.cast::<usize>()
.write(i);
}
// SAFETY: by the safety requirement of `RawDeviceIdIndex`, this would be effectively
// `raw_ids[i].driver_data = i;`.
unsafe {
raw_ids[i]
.as_mut_ptr()
.byte_add(T::DRIVER_DATA_OFFSET)
.cast::<usize>()
.write(i);
}
// SAFETY: this is effectively a move: `infos[i] = ids[i].1`. We make a copy here but
@ -127,32 +117,32 @@ impl<T: RawDeviceId, U, const N: usize> IdArray<T, U, N> {
id_infos: unsafe { core::mem::transmute_copy(&infos) },
}
}
}
/// Creates a new instance of the array without writing index values.
///
/// The contents are derived from the given identifiers and context information.
/// If the device implements [`RawDeviceIdIndex`], consider using [`IdArray::new`] instead.
pub const fn new_without_index(ids: [(T, U); N]) -> Self {
// SAFETY: Calling `Self::build` with `offset = None` is always safe,
// because no raw memory writes are performed in this case.
unsafe { Self::build(ids, None) }
}
impl<T: RawDeviceId, U, const N: usize> IdArray<T, U, N> {
/// Reference to the contained [`RawIdArray`].
pub const fn raw_ids(&self) -> &RawIdArray<T, N> {
&self.raw_ids
}
}
impl<T: RawDeviceId + RawDeviceIdIndex, U, const N: usize> IdArray<T, U, N> {
/// Creates a new instance of the array.
impl<T: RawDeviceId, const N: usize> IdArray<T, (), N> {
/// Creates a new instance of the array without writing index values.
///
/// The contents are derived from the given identifiers and context information.
pub const fn new(ids: [(T, U); N]) -> Self {
// SAFETY: by the safety requirement of `RawDeviceIdIndex`,
// `T::DRIVER_DATA_OFFSET` is guaranteed to be the correct offset (in bytes) to
// a field within `T::RawType`.
unsafe { Self::build(ids, Some(T::DRIVER_DATA_OFFSET)) }
/// If the device implements [`RawDeviceIdIndex`], consider using [`IdArray::new`] instead.
pub const fn new_without_index(ids: [T; N]) -> Self {
// SAFETY: `T` is layout-wise compatible with `T::RawType`, so is the array of them.
let raw_ids: [T::RawType; N] = unsafe { core::mem::transmute_copy(&ids) };
core::mem::forget(ids);
Self {
raw_ids: RawIdArray {
ids: raw_ids,
sentinel: MaybeUninit::zeroed(),
},
id_infos: [(); N],
}
}
}

2
rust/kernel/net/phy.rs
View File

@ -868,7 +868,7 @@ macro_rules! module_phy_driver {
const N: usize = $crate::module_phy_driver!(@count_devices $($dev),+);
const TABLE: $crate::device_id::IdArray<$crate::net::phy::DeviceId, (), N> =
$crate::device_id::IdArray::new_without_index([ $(($dev,())),+, ]);
$crate::device_id::IdArray::new_without_index([ $($dev),+, ]);
$crate::module_device_table!("mdio", phydev, TABLE);
};