Merge tag 'rust-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

Pull Rust updates from Miguel Ojeda:
"Toolchain and infrastructure:

- Bump the minimum Rust version to 1.85.0 (and 'bindgen' to 0.71.1).

As proposed in LPC 2025 and the Maintainers Summit [1], we are
going to follow Debian Stable's Rust versions as our minimum
versions.

Debian Trixie was released on 2025-08-09 with a Rust 1.85.0 and
'bindgen' 0.71.1 toolchain, which is a fair amount of time for e.g.
kernel developers to upgrade.

Other major distributions support a Rust version that is high
enough as well, including:

+ Arch Linux.
+ Fedora Linux.
+ Gentoo Linux.
+ Nix.
+ openSUSE Slowroll and openSUSE Tumbleweed.
+ Ubuntu 25.10 and 26.04 LTS. In addition, 24.04 LTS using
their versioned packages.

The merged patch series comes with the associated cleanups and
simplifications treewide that can be performed thanks to both
bumps, as well as documentation updates.

In addition, start using 'bindgen''s '--with-attribute-custom-enum'
feature to set the 'cfi_encoding' attribute for the 'lru_status'
enum used in Binder.

Link: https://lwn.net/Articles/1050174/ [1]

- Add experimental Kconfig option ('CONFIG_RUST_INLINE_HELPERS') that
inlines C helpers into Rust.

Essentially, it performs a step similar to LTO, but just for the
helpers, i.e. very local and fast.

It relies on 'llvm-link' and its '--internalize' flag, and requires
a compatible LLVM between Clang and 'rustc' (i.e. same major
version, 'CONFIG_RUSTC_CLANG_LLVM_COMPATIBLE'). It is only enabled
for two architectures for now.

The result is a measurable speedup in different workloads that
different users have tested. For instance, for the null block
driver, it amounts to a 2%.

- Support global per-version flags.

While we already have per-version flags in many places, we didn't
have a place to set global ones that depend on the compiler
version, i.e. in 'rust_common_flags', which sometimes is needed to
e.g. tweak the lints set per version.

Use that to allow the 'clippy::precedence' lint for Rust < 1.86.0,
since it had a change in behavior.

- Support overriding the crate name and apply it to Rust Binder,
which wanted the module to be called 'rust_binder'.

- Add the remaining '__rust_helper' annotations (started in the
previous cycle).

'kernel' crate:

- Introduce the 'const_assert!' macro: a more powerful version of
'static_assert!' that can refer to generics inside functions or
implementation bodies, e.g.:

fn f<const N: usize>() {
const_assert!(N > 1);
}

fn g<T>() {
const_assert!(size_of::<T>() > 0, "T cannot be ZST");
}

In addition, reorganize our set of build-time assertion macros
('{build,const,static_assert}!') to live in the 'build_assert'
module.

Finally, improve the docs as well to clarify how these are
different from one another and how to pick the right one to use,
and their equivalence (if any) to the existing C ones for extra
clarity.

- 'sizes' module: add 'SizeConstants' trait.

This gives us typed 'SZ_*' constants (avoiding casts) for use in
device address spaces where the address width depends on the
hardware (e.g. 32-bit MMIO windows, 64-bit GPU framebuffers, etc.),
e.g.:

let gpu_heap = 14 * u64::SZ_1M;
let mmio_window = u32::SZ_16M;

- 'clk' module: implement 'Send' and 'Sync' for 'Clk' and thus
simplify the users in Tyr and PWM.

- 'ptr' module: add 'const_align_up'.

- 'str' module: improve the documentation of the 'c_str!' macro to
explain that one should only use it for non-literal cases (for the
other case we instead use C string literals, e.g. 'c"abc"').

- Disallow the use of 'CStr::{as_ptr,from_ptr}' and clean one such
use in the 'task' module.

- 'sync' module: finish the move of 'ARef' and 'AlwaysRefCounted'
outside of the 'types' module, i.e. update the last remaining
instances and finally remove the re-exports.

- 'error' module: clarify that 'from_err_ptr' can return 'Ok(NULL)',
including runtime-tested examples.

The intention is to hopefully prevent UB that assumes the result of
the function is not 'NULL' if successful. This originated from a
case of UB I noticed in 'regulator' that created a 'NonNull' on it.

Timekeeping:

- Expand the example section in the 'HrTimer' documentation.

- Mark the 'ClockSource' trait as unsafe to ensure valid values for
'ktime_get()'.

- Add 'Delta::from_nanos()'.

'pin-init' crate:

- Replace the 'Zeroable' impls for 'Option<NonZero*>' with impls of
'ZeroableOption' for 'NonZero*'.

- Improve feature gate handling for unstable features.

- Declutter the documentation of implementations of 'Zeroable' for
tuples.

- Replace uses of 'addr_of[_mut]!' with '&raw [mut]'.

rust-analyzer:

- Add type annotations to 'generate_rust_analyzer.py'.

- Add support for scripts written in Rust ('generate_rust_target.rs',
'rustdoc_test_builder.rs', 'rustdoc_test_gen.rs').

- Refactor 'generate_rust_analyzer.py' to explicitly identify host
and target crates, improve readability, and reduce duplication.

And some other fixes, cleanups and improvements"

* tag 'rust-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (79 commits)
rust: sizes: add SizeConstants trait for device address space constants
rust: kernel: update `file_with_nul` comment
rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0
rust: kbuild: support global per-version flags
rust: declare cfi_encoding for lru_status
docs: rust: general-information: use real example
docs: rust: general-information: simplify Kconfig example
docs: rust: quick-start: remove GDB/Binutils mention
docs: rust: quick-start: remove Nix "unstable channel" note
docs: rust: quick-start: remove Gentoo "testing" note
docs: rust: quick-start: add Ubuntu 26.04 LTS and remove subsection title
docs: rust: quick-start: update minimum Ubuntu version
docs: rust: quick-start: update Ubuntu versioned packages
docs: rust: quick-start: openSUSE provides `rust-src` package nowadays
rust: kbuild: remove "dummy parameter" workaround for `bindgen` < 0.71.1
rust: kbuild: update `bindgen --rust-target` version and replace comment
rust: rust_is_available: remove warning for `bindgen` < 0.69.5 && libclang >= 19.1
rust: rust_is_available: remove warning for `bindgen` 0.66.[01]
rust: bump `bindgen` minimum supported version to 0.71.1 (Debian Trixie)
rust: block: update `const_refs_to_static` MSRV TODO comment
...