linux.git/rust/pin-init/src/lib.rs, branch v7.1-rc4

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

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

rust: pin-init: Implement `InPlaceWrite` for `&'static mut MaybeUninit`

2026-01-17T09:53:28+00:00

This feature allows users to use `&'static mut MaybeUninit` as a
place to initialize the value. It mirrors an existing implemetation
for `Box`, but enables users to use external allocation
mechanisms such as `static_cell` [1].

Signed-off-by: Oleksandr Babak 
Link: https://crates.io/crates/static_cell [1]
[ Added link to `static_cell` - Benno ]
Signed-off-by: Benno Lossin

rust: pin-init: rewrite the initializer macros using `syn`

2026-01-17T09:51:42+00:00

Rewrite the initializer macros `[pin_]init!` using `syn`. No functional
changes intended aside from improved error messages on syntactic and
semantical errors. For example if one forgets to use `<-` with an
initializer (and instead uses `:`):

    impl Bar {
        fn new() -> impl PinInit { ... }
    }

    impl Foo {
        fn new() -> impl PinInit {
            pin_init!(Self { bar: Bar::new() })
        }
    }

Then the declarative macro would report:

    error[E0308]: mismatched types
      --> tests/ui/compile-fail/init/colon_instead_of_arrow.rs:21:9
       |
    14 |     fn new() -> impl PinInit {
       |                 ------------------ the found opaque type
    ...
    21 |         pin_init!(Self { bar: Bar::new() })
       |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
       |         |
       |         expected `Bar`, found opaque type
       |         arguments to this function are incorrect
       |
       = note:   expected struct `Bar`
               found opaque type `impl pin_init::PinInit`
    note: function defined here
      --> $RUST/core/src/ptr/mod.rs
       |
       | pub const unsafe fn write(dst: *mut T, src: T) {
       |                     ^^^^^
       = note: this error originates in the macro `$crate::__init_internal` which comes from the expansion of the macro `pin_init` (in Nightly builds, run with -Z macro-backtrace for more info)

And the new error is:

    error[E0308]: mismatched types
      --> tests/ui/compile-fail/init/colon_instead_of_arrow.rs:21:31
       |
    14 |     fn new() -> impl PinInit {
       |                 ------------------ the found opaque type
    ...
    21 |         pin_init!(Self { bar: Bar::new() })
       |                          ---  ^^^^^^^^^^ expected `Bar`, found opaque type
       |                          |
       |                          arguments to this function are incorrect
       |
       = note:   expected struct `Bar`
               found opaque type `impl pin_init::PinInit`
    note: function defined here
      --> $RUST/core/src/ptr/mod.rs
       |
       | pub const unsafe fn write(dst: *mut T, src: T) {
       |                     ^^^^^

Importantly, this error gives much more accurate span locations,
pointing to the offending field, rather than the entire macro
invocation.

Tested-by: Andreas Hindborg 
Reviewed-by: Gary Guo 
Signed-off-by: Benno Lossin

rust: pin-init: allow the crate to refer to itself as `pin-init` in doc tests

2026-01-17T09:49:31+00:00

The `syn` approach requires use of `::pin_init::...` instead of the
`$crate::...` construct available to declarative macros. To be able to
use the `pin_init` crate from itself (which includes doc tests), we have
to declare it as such.

Reviewed-by: Gary Guo 
Tested-by: Andreas Hindborg 
Signed-off-by: Benno Lossin