[ Upstream commit a58b8764aed9648357b1c5b6368c9943ba33b7f9 ]

`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 <lossin@kernel.org>
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 <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Allow writing `_: { /* any number of statements */ }` in initializers to
run arbitrary code during initialization.

    try_init!(MyStruct {
        _: {
            if check_something() {
                return Err(MyError);
            }
        },
        foo: Foo::new(val),
        _: {
            println!("successfully initialized `MyStruct`");
        },
    })

Tested-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Benno Lossin <lossin@kernel.org>

The next commit makes the `#[pin_data]` attribute generate a `project`
function that would collide with any existing ones.

Signed-off-by: Benno Lossin <lossin@kernel.org>

Pull pin-init updates from Benno Lossin:
 "Added:

   - 'impl<T, E> [Pin]Init<T, E> for Result<T, E>', so results are now
     (pin-)initializers.

   - 'Zeroable::init_zeroed()' delegating to 'init_zeroed()'.

   - New 'zeroed()', a safe version of 'mem::zeroed()' and also provide
     it via 'Zeroable::zeroed()'.

   - Implement 'Zeroable' for 'Option<&T>' and 'Option<&mut T>'.

   - Implement 'Zeroable' for 'Option<[unsafe] [extern "abi"]
     fn(...args...) -> ret>' for '"Rust"' and '"C"' ABIs and up to 20
     arguments.

  Changed:

   - Blanket impls of 'Init' and 'PinInit' from 'impl<T, E>
     [Pin]Init<T, E> for T' to 'impl<T> [Pin]Init<T> for T'.

   - Renamed 'zeroed()' to 'init_zeroed()'.

  Upstream dev news:

   - More CI improvements to deny warnings, use '--all-targets'. Also
     check the synchronization status of the two '-next' branches in
     upstream and the kernel."

Acked-by: Andreas Hindborg <a.hindborg@kernel.org>

* tag 'pin-init-v6.17' of https://github.com/Rust-for-Linux/linux:
  rust: pin-init: examples, tests: use `ignore` instead of conditionally compiling tests
  rust: init: remove doctest's `Error::from_errno` workaround
  rust: init: re-enable doctests
  rust: pin-init: implement `ZeroableOption` for function pointers with up to 20 arguments
  rust: pin-init: change `impl Zeroable for Option<NonNull<T>>` to `ZeroableOption for NonNull<T>`
  rust: pin-init: implement `ZeroableOption` for `&T` and `&mut T`
  rust: pin-init: add `zeroed()` & `Zeroable::zeroed()` functions
  rust: pin-init: add `Zeroable::init_zeroed`
  rust: pin-init: rename `zeroed` to `init_zeroed`
  rust: pin-init: feature-gate the `stack_init_reuse` test on the `std` feature
  rust: pin-init: examples: pthread_mutex: disable the main test for miri
  rust: pin-init: examples, tests: add conditional compilation in order to compile under any feature combination
  rust: pin-init: change blanket impls for `[Pin]Init` and add one for `Result<T, E>`
  rust: pin-init: improve safety documentation for `impl<T> [Pin]Init<T> for T`

Use a consistent `# Examples` heading in rustdoc across the codebase.

Some modules previously used `## Examples` (even when they should be
available as top-level headers), while others used `# Example`, which
deviates from the preferred `# Examples` style.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Benno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/ddd5ce0ac20c99a72a4f1e4322d3de3911056922.1749545815.git.viresh.kumar@linaro.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

`Option<[unsafe] [extern "abi"] fn(...args...) -> ret>` is documented
[1] to also have the `None` variant equal all zeroes.

Link: https://doc.rust-lang.org/stable/std/option/index.html#representation [1]
Link: https://github.com/Rust-for-Linux/pin-init/pull/56/commits/b6c1ab4fb3699765f81ae512ecac5a2f032d8d51
Link: https://lore.kernel.org/all/20250523145125.523275-7-lossin@kernel.org
Signed-off-by: Benno Lossin <lossin@kernel.org>

This brings it in line with references. It too is listed in [1].

Link: https://doc.rust-lang.org/stable/std/option/index.html#representation
Link: https://github.com/Rust-for-Linux/pin-init/pull/56/commits/8e52bf56ddc2190ce901d2f7c008ab8a64f653a9
Link: https://lore.kernel.org/all/20250523145125.523275-6-lossin@kernel.org
Signed-off-by: Benno Lossin <lossin@kernel.org>

`Option<&T>` and `Option<&mut T>` are documented [1] to have the `None`
variant be all zeroes.

Link: https://doc.rust-lang.org/stable/std/option/index.html#representation [1]
Link: https://github.com/Rust-for-Linux/pin-init/pull/56/commits/5ef1638c79e019d3dc0c62db5905601644c2e60a
Link: https://lore.kernel.org/all/20250523145125.523275-5-lossin@kernel.org
Signed-off-by: Benno Lossin <lossin@kernel.org>

`zeroed()` returns a zeroed out value of a sized type implementing
`Zeroable`.

The function is added as a free standing function, in addition to an
associated function on `Zeroable`, because then it can be marked `const`
(functions in traits can't be const at the moment).

Link: https://github.com/Rust-for-Linux/pin-init/pull/56/commits/809e4ec160579c1601dce5d78b432a5b6c8e4e40
Link: https://lore.kernel.org/all/20250523145125.523275-4-lossin@kernel.org
Signed-off-by: Benno Lossin <lossin@kernel.org>

The trait function delegates to the already existing `init_zeroed`
function that returns a zeroing initializer for `Self`.

The syntax `..Zeroable::init_zeroed()` is already used by the
initialization macros to initialize all fields that are not mentioned in
the initializer with zero. Therefore it is expected that the function
also exists on the trait.

Link: https://github.com/Rust-for-Linux/pin-init/pull/56/commits/a424a6c9af5a4418a8e5e986a3db26a4432e2f1a
Link: https://lore.kernel.org/all/20250523145125.523275-3-lossin@kernel.org
Signed-off-by: Benno Lossin <lossin@kernel.org>