linux.git/rust/pin-init, branch master

rust: pin-init: replace `addr_of_mut!` with `&raw mut`

2026-03-25T09:57:53+00:00

`feature(raw_ref_op)` became stable in Rust 1.82.0 which is the current
MSRV of pin-init with no default features. Earlier Rust versions will
now need to enable `raw_ref_op` to continue to work with pin-init.

This reduces visual complexity and improves consistency with existing
reference syntax.

Suggested-by: Benno Lossin 
Link: https://github.com/Rust-for-Linux/linux/issues/1148
Closes: https://github.com/Rust-for-Linux/pin-init/issues/99
Signed-off-by: Antonio Hickey 
Link: https://github.com/Rust-for-Linux/pin-init/commit/e27763004e2f6616b089437fbe9b3719cd72bd5c
[ Reworded commit message. - Benno ]
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260319093542.3756606-6-lossin@kernel.org
Signed-off-by: Benno Lossin

rust: pin-init: implement ZeroableOption for NonZero* integer types

2026-03-25T09:57:33+00:00

Add a macro for implementing `ZeroableOption` for `NonZero*` types.

`Option` now automatically implements `Zeroable` trait  by
implementing `ZeroableOption` for `NonZero*` types, which serves as a
blanket impl.

Closes: https://github.com/Rust-for-Linux/pin-init/issues/95
Signed-off-by: Hamdan-Khan 
Link: https://github.com/Rust-for-Linux/pin-init/commit/74f772641cd9670848fa360f4ebfd20fdb40bf78
[ Fixed a typo in the commit message. - Benno ]
Link: https://patch.msgid.link/20260319093542.3756606-5-lossin@kernel.org
Signed-off-by: Benno Lossin

rust: pin-init: doc: de-clutter documentation with fake-variadics

2026-03-25T09:57:16+00:00

Currently the doc for `Zeroable` and `ZeroableOption` are filled with the
generated impl of tuples and fn pointers. Use the internal
"fake_variadics" feature to improve the rendered quality.

This makes use of an internal feature, however this is of minimal risk as
it's for documentation only, not activated during normal build, gated
behind `USE_RUSTC_FEATURES`, and can be removed at any time. This feature
is already used by serde and bevy to improve documentation quality.

For compilers that cannot use this feature, we still hide most generated
impls, and the existence of them are hinted by doc comments on the single
non-hidden impl.

Signed-off-by: Gary Guo 
Link: https://github.com/Rust-for-Linux/pin-init/commit/530c4eb79a449599e219821f9397f03250cc2aa4
[ Reordered `#[doc]` attributes and safety comments to avoid errors in
  older versions of clippy. - Benno ]
Link: https://patch.msgid.link/20260319093542.3756606-4-lossin@kernel.org
Signed-off-by: Benno Lossin

rust: pin-init: properly document let binding workaround

2026-03-25T09:56:53+00:00

The three let bindings (in the bodies of `cast_init`, `cast_pin_init`
and the `init!` macro) are used to avoid the following compiler error in
Rust 1.78.0, 1.79.0, 1.80.0, 1.80.1, and 1.81.0 (just showing the one
for `cast_init`, the others are similar):

    error[E0391]: cycle detected when computing type of opaque `cast_init::{opaque#0}`
        --> src/lib.rs:1160:66
         |
    1160 | pub const unsafe fn cast_init(init: impl Init) -> impl Init {
         |                                                                  ^^^^^^^^^^^^^^^
         |
    note: ...which requires borrow-checking `cast_init`...
        --> src/lib.rs:1160:1
         |
    1160 | pub const unsafe fn cast_init(init: impl Init) -> impl Init {
         | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    note: ...which requires const checking `cast_init`...
        --> src/lib.rs:1160:1
         |
    1160 | pub const unsafe fn cast_init(init: impl Init) -> impl Init {
         | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
         = note: ...which requires computing whether `cast_init::{opaque#0}` is freeze...
         = note: ...which requires evaluating trait selection obligation `cast_init::{opaque#0}: core::marker::Freeze`...
         = note: ...which again requires computing type of opaque `cast_init::{opaque#0}`, completing the cycle
    note: cycle used when computing type of `cast_init::{opaque#0}`
        --> src/lib.rs:1160:66
         |
    1160 | pub const unsafe fn cast_init(init: impl Init) -> impl Init {
         |                                                                  ^^^^^^^^^^^^^^^
         = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information

Once we raise the nightly-MSRV above 1.81, we can remove this
workaround.

Link: https://github.com/Rust-for-Linux/pin-init/commit/bb3e96f3e9a4f5fca80a22af883c7e5aa90f0893
[ Moved this commit after the previous one to avoid a build failure due
  to unstable features. Changed the cfg to use `USE_RUSTC_FEAUTURES`.
  - Benno ]
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260319093542.3756606-3-lossin@kernel.org
Signed-off-by: Benno Lossin

rust: pin-init: build: simplify use of nightly features

2026-03-25T09:56:16+00:00

We use some features that are already stable in later versions of Rust,
but only available as unstable features in older Rust versions that the
kernel needs to support.

Instead of checking if a feature is already stable, simply enable them
and allow the warning if the feature is already stable. This avoids the
need of hardcoding whether a feature has been stabilized at a given
version.

`#[feature(...)]` is used when cfg `USE_RUSTC_FEATURES` is enabled. The
build script automatically does this when a nightly compiler is detected
or `RUSTC_BOOTSTRAP` is set.

Signed-off-by: Gary Guo 
Link: https://github.com/Rust-for-Linux/pin-init/commit/885c5d83d7eb778a796d4a17380a0898b0d0a571
[ Added kernel build system changes to always enable USE_RUSTC_FEATURES.
  Moved this commit earlier (swapped with the next one) to avoid a build
  error. - Benno ]
Link: https://patch.msgid.link/20260319093542.3756606-2-lossin@kernel.org
Signed-off-by: Benno Lossin

rust: pin-init: replace shadowed return token by `unsafe`-to-create token

2026-03-12T07:46:17+00:00

We use a unit struct `__InitOk` in the closure generated by the
initializer macros as the return value. We shadow it by creating a
struct with the same name again inside of the closure, preventing early
returns of `Ok` in the initializer (before all fields have been
initialized).

In the face of Type Alias Impl Trait (TAIT) and the next trait solver,
this solution no longer works [1]. The shadowed struct can be named
through type inference. In addition, there is an RFC proposing to add
the feature of path inference to Rust, which would similarly allow [2].

Thus remove the shadowed token and replace it with an `unsafe` to create
token.

The reason we initially used the shadowing solution was because an
alternative solution used a builder pattern. Gary writes [3]:

    In the early builder-pattern based InitOk, having a single InitOk
    type for token is unsound because one can launder an InitOk token
    used for one place to another initializer. I used a branded lifetime
    solution, and then you figured out that using a shadowed type would
    work better because nobody could construct it at all.

The laundering issue does not apply to the approach we ended up with
today.

With this change, the example by Tim Chirananthavat in [1] no longer
compiles and results in this error:

    error: cannot construct `pin_init::__internal::InitOk` with struct literal syntax due to private fields
      --> src/main.rs:26:17
       |
    26 |                 InferredType {}
       |                 ^^^^^^^^^^^^
       |
       = note: private field `0` that was not provided
    help: you might have meant to use the `new` associated function
       |
    26 -                 InferredType {}
    26 +                 InferredType::new()
       |

Applying the suggestion of using the `::new()` function, results in
another expected error:

    error[E0133]: call to unsafe function `pin_init::__internal::InitOk::new` is unsafe and requires unsafe block
      --> src/main.rs:26:17
       |
    26 |                 InferredType::new()
       |                 ^^^^^^^^^^^^^^^^^^^ call to unsafe function
       |
       = note: consult the function's documentation for information on how to avoid undefined behavior

Reported-by: Tim Chirananthavat 
Link: https://github.com/rust-lang/rust/issues/153535 [1]
Link: https://github.com/rust-lang/rfcs/pull/3444#issuecomment-4016145373 [2]
Link: https://github.com/rust-lang/rust/issues/153535#issuecomment-4017620804 [3]
Fixes: fc6c6baa1f40 ("rust: init: add initialization macros")
Cc: stable@vger.kernel.org
Signed-off-by: Benno Lossin 
Reviewed-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260311105056.1425041-1-lossin@kernel.org
[ Added period as mentioned. - Miguel ]
Signed-off-by: Miguel Ojeda

rust: pin-init: internal: init: document load-bearing fact of field accessors

2026-03-06T01:05:46+00:00

The functions `[Pin]Init::__[pinned_]init` and `ptr::write` called from
the `init!` macro require the passed pointer to be aligned. This fact is
ensured by the creation of field accessors to previously initialized
fields.

Since we missed this very important fact from the beginning [1],
document it in the code.

Link: https://rust-for-linux.zulipchat.com/#narrow/channel/561532-pin-init/topic/initialized.20field.20accessor.20detection/with/576210658 [1]
Fixes: 90e53c5e70a6 ("rust: add pin-init API core")
Cc:  # 6.6.y, 6.12.y: 42415d163e5d: rust: pin-init: add references to previously initialized fields
Cc:  # 6.6.y, 6.12.y, 6.18.y, 6.19.y
Signed-off-by: Benno Lossin 
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260302140424.4097655-2-lossin@kernel.org
[ Updated Cc: stable@ tags as discussed. - Miguel ]
Signed-off-by: Miguel Ojeda

rust: pin-init: internal: init: remove `#[disable_initialized_field_access]`

2026-03-06T01:04:09+00:00

Gary noticed [1] that the initializer macros as well as the `[Pin]Init`
traits cannot support unaligned fields, since they use operations that
require aligned pointers. This means that any code using structs with
unaligned fields in pin-init is unsound.

By default, the `init!` macro generates references to initialized fields,
which makes the compiler check that those fields are aligned. However,
we added the `#[disable_initialized_field_access]` attribute to avoid
this behavior in commit ceca298c53f9 ("rust: pin-init: internal: init:
add escape hatch for referencing initialized fields"). Thus remove the
`#[disable_initialized_field_access]` attribute from `init!`, which is
the only safe way to create an initializer handling unaligned fields.

If support for in-place initializing structs with unaligned fields is
required in the future, we could figure out a solution. This is tracked
in [2].

Reported-by: Gary Guo
Closes: https://rust-for-linux.zulipchat.com/#narrow/channel/561532-pin-init/topic/initialized.20field.20accessor.20detection/with/576210658 [1]
Link: https://github.com/Rust-for-Linux/pin-init/issues/112 [2]
Fixes: ceca298c53f9 ("rust: pin-init: internal: init: add escape hatch for referencing initialized fields")
Signed-off-by: Benno Lossin
Acked-by: Janne Grunau
Reviewed-by: Gary Guo
Reviewed-by: Alice Ryhl
Link: https://patch.msgid.link/20260302140424.4097655-1-lossin@kernel.org
[ Adjusted tags and reworded as discussed. - Miguel ]
Signed-off-by: Miguel Ojeda

Merge tag 'rust-fixes-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

2026-02-22T16:43:31+00:00

Pull rust fixes from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Pass '-Zunstable-options' flag required by the future Rust 1.95.0

   - Fix 'objtool' warning for Rust 1.84.0

  'kernel' crate:

   - 'irq' module: add missing bound detected by the future Rust 1.95.0

   - 'list' module: add missing 'unsafe' blocks and placeholder safety
     comments to macros (an issue for future callers within the crate)

  'pin-init' crate:

   - Clean Clippy warning that changed behavior in the future Rust
     1.95.0"

* tag 'rust-fixes-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
  rust: list: Add unsafe blocks for container_of and safety comments
  rust: pin-init: replace clippy `expect` with `allow`
  rust: irq: add `'static` bounds to irq callbacks
  objtool/rust: add one more `noreturn` Rust function
  rust: kbuild: pass `-Zunstable-options` for Rust 1.95.0

rust: pin-init: replace clippy `expect` with `allow`

2026-02-19T08:33:43+00:00

`clippy` has changed behavior in [1] (Rust 1.95) where it no longer
warns about the `let_and_return` lint when a comment is placed between
the let binding and the return expression. Nightly thus fails to build,
because the expectation is no longer fulfilled.

Thus replace the expectation with an `allow`.

[ The errors were:

      error: this lint expectation is unfulfilled
          --> rust/pin-init/src/lib.rs:1279:10
           |
      1279 | #[expect(clippy::let_and_return)]
           |          ^^^^^^^^^^^^^^^^^^^^^^
           |
           = note: `-D unfulfilled-lint-expectations` implied by `-D warnings`
           = help: to override `-D warnings` add `#[allow(unfulfilled_lint_expectations)]`

      error: this lint expectation is unfulfilled
          --> rust/pin-init/src/lib.rs:1295:10
           |
      1295 | #[expect(clippy::let_and_return)]
           |          ^^^^^^^^^^^^^^^^^^^^^^

    - Miguel ]

Link: https://github.com/rust-lang/rust-clippy/pull/16461 [1]
Signed-off-by: Benno Lossin 
Cc: stable@vger.kernel.org # Needed in 6.18.y and later.
Link: https://patch.msgid.link/20260215132232.1549861-1-lossin@kernel.org
Signed-off-by: Miguel Ojeda