Re: [PATCH 0/8] I/O type generalization and projection

["Alexandre Courbot" <acourbot@nvidia.com>]

On Tue Mar 24, 2026 at 12:37 AM JST, Gary Guo wrote:
> From: Gary Guo <gary@garyguo.net>
>
> This series generalize `Mmio`/`MmioRaw` type from just an untyped region
> to typed representations (so `MmioRaw<T>` is `__iomem *T`). This allows
> us to remove the `IoKnownSize` trait; the information is sourced from
> just the pointer from the `KnownSize` trait instead.
>
> This enables us to implement `Io` trait for `Coherent<T>`, enabling
> unified handling of MMIO and DMA coherent memory. It also paves the way
> to uniformly support shared system memory, which Tyr will likely need
> [1].
>
> Built on this generalization, this series also add a `io::View` type
> which represents a subview of a bigger I/O region, and a `io_project!()`
> macro that provides a safe way to perform this. Some Nova code has been
> converted in this series to demonstrate cleanups possible with this
> addition.
>
> This series depend on the Coherent API rework series [2].
>
> Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089-General/topic/Generic.20I.2FO.20backends/near/572377073 [1]
> Link: https://lore.kernel.org/rust-for-linux/DH87CCNRR5EC.2SK3IT6N6Q8V5@nvidia.com/ [2]

I'm getting quite a few clippy warnings when applying this series:

    warning: lint `clippy::invalid_null_ptr_usage` has been renamed to `invalid_null_arguments`
      --> ../rust/kernel/pci/io.rs:78:9
      |
    78 |         clippy::invalid_null_ptr_usage,
      |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_null_arguments`
      |
      = note: `#[warn(renamed_and_removed_lints)]` on by default

    warning: lint `clippy::invalid_null_ptr_usage` has been renamed to `invalid_null_arguments`
      --> ../rust/kernel/pci/io.rs:94:9
      |
    94 |         clippy::invalid_null_ptr_usage,
      |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_null_arguments`

    warning: macro has unnecessary safety comment
        --> ../rust/kernel/io.rs:1045:1
        |
    1045 | macro_rules! io_project {
        | ^^^^^^^^^^^^^^^^^^^^^^^^^
        |
    help: consider removing the safety comment
        --> ../rust/kernel/io.rs:1034:8
        |
    1034 | /// // SAFETY: Instances of `MyStruct` have no uninitialized portions.
        |        ^^^^^^^
        = help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.94.0/index.html#unnecessary_safety_comment
        = note: requested on the command line with `-W clippy::unnecessary-safety-comment`

    warning: macro has unnecessary safety comment
        --> ../rust/kernel/io.rs:1086:1
        |
    1086 | macro_rules! io_read {
        | ^^^^^^^^^^^^^^^^^^^^^^
        |
    help: consider removing the safety comment
        --> ../rust/kernel/io.rs:1077:8
        |
    1077 | /// // SAFETY: Instances of `MyStruct` have no uninitialized portions.
        |        ^^^^^^^
        = help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.94.0/index.html#unnecessary_safety_comment

    warning: macro has unnecessary safety comment
        --> ../rust/kernel/io.rs:1118:1
        |
    1118 | macro_rules! io_write {
        | ^^^^^^^^^^^^^^^^^^^^^^^
        |
    help: consider removing the safety comment
        --> ../rust/kernel/io.rs:1109:8
        |
    1109 | /// // SAFETY: Instances of `MyStruct` have no uninitialized portions.
        |        ^^^^^^^
        = help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.94.0/index.html#unnecessary_safety_comment

    warning: 5 warnings emitted