Re: [PATCH v5 01/20] rust: io: add dynamically-sized `Region` type
"Alexandre Courbot" <[email protected]>
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On Fri Jun 26, 2026 at 11:45 PM JST, Gary Guo wrote:
<...>
> diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs
> index fcc7678fd9e3..d1c5f0121994 100644
> --- a/rust/kernel/io.rs
> +++ b/rust/kernel/io.rs
> @@ -6,7 +6,11 @@
>
> use crate::{
> bindings,
> - prelude::*, //
> + prelude::*,
> + ptr::{
> + Alignment,
> + KnownSize, //
> + }, //
> };
>
> pub mod mem;
> @@ -31,6 +35,57 @@
> /// `CONFIG_PHYS_ADDR_T_64BIT`, and it can be a u64 even on 32-bit architectures.
> pub type ResourceSize = bindings::resource_size_t;
>
> +/// Untyped I/O region.
> +///
> +/// This type can be used when an I/O region without known type information has a compile-time known
> +/// minimum size (and a runtime known actual size).
> +///
> +/// # Invariants
> +///
> +/// - Size of the region is at least as large as the `SIZE` generic parameter.
> +/// - Size of the region is multiple of 4.
> +#[repr(C, align(4))]
> +pub struct Region<const SIZE: usize = 0> {
> + inner: [u8],
> +}
> +
> +impl<const SIZE: usize> Region<SIZE> {
> + /// Create a raw mutable pointer from given base address and size.
> + ///
> + /// `size` should be at least as large as the minimum size `SIZE`, and `base` and `size` should
> + /// be 4-byte aligned to uphold the type invariant.
The second part of my comment on v4 was not relevant [1], but how about the
"should -> must" proposal?
Regardless:
Reviewed-by: Alexandre Courbot <[email protected]>
[1] https://lore.kernel.org/all/[email protected]/