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git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux
Pull Rust updates from Miguel Ojeda:
"Toolchain and infrastructure:
- Update vendored 'zerocopy' crate to v0.8.62 (released 2026-10-08).
This update advances 8 releases, with 3 of them carrying most of
the changes. It contains new features as well as fixes. However,
almost nothing has changed that requires updates on our side (a
move of our non-ASCII change and the addition of an SPDX license
identifier).
- Generate Rust KUnit test suites for doctests reusing the
'#[kunit_tests]' and '#[test]' attributes instead of C FFI
functions, which allows to remove the generated C glue file.
Relatedly, simplify 'kunit_assert!' by using 'file!()' and
'line!()' inside (which doctests override as needed), which allows
to remove the 'file' helper and 'CONFIG_RUSTC_HAS_SPAN_FILE'.
- Trim the function names in doctests generated by 'rustdoc' < 1.95.0
when building with 'O=', which were not reproducible.
- Fix the 'VM_MAYSHARE' value in the generated bindings and its
blocklist entry, due to typos.
- Build 'core' with '--cfg no_io_statics' to ensure 'core' does not
introduce any use of 'core::sync::atomic' into the kernel image
since upstream Rust is moving 'std::io::Error' into 'core', which
uses a global atomic pointer.
Upstream Rust merged a PR to add a test checking that builds of
'core' are warning-free with that 'cfg' enabled.
- Enable the unstable 'proc_macro_span' feature in 'proc-macro2',
which provides 'Span::join' and thus improves the quality of the
diagnostics of all our procedural macros, notably 'pin-init'. This
is only used for producing diagnostics, thus there is no hard
reliance on the feature.
- Globally allow 'clippy::comparison_chain', since its suggestions
are not always ideal and upstream downgraded it to 'pedantic' too.
'kernel' crate:
- New 'mem' module: add the 'Align<N>' zero-sized type so that
alignment can be specified via const generics ('repr(align(...))'
only works with integer literals), e.g.:
const N: usize = 128;
struct S {
_align: Align<N>,
}
assert_eq!(align_of::<S>(), N);
- New 'ratelimit' module: add the 'Ratelimit' abstraction for 'struct
ratelimit_state' and, based on it, the 'pr_*_ratelimited!' printing
macros, which can be used for printing that may be triggered by
userspace.
In addition, convert Rust Binder to use them.
- 'sync' module: to construct a global 'struct ratelimit_state', add
a 'const' constructor for 'raw_spinlock_t'.
In addition, move the lockdep types into a new 'sync::lockdep'
submodule, since there were starting to be too many of them.
- 'num' module: add the 'cv!' macro to create constant values ("cv")
from an integer constant expression, with validity checked at
compile time, inferring the target type from the context. It works
for any type that implements the new 'FromConst' trait, e.g.:
let a: Alignment = cv!(4096);
let b: Bounded<u32, 4> = cv!(15);
// Any integer constant expression works, not only literals.
let m: NonZero<usize> = cv!(usize::MAX);
// Checked narrowing, including in `const` items.
const SMALL: u8 = cv!(200u32);
// The target type can be given explicitly.
let e = cv!(200u32 => u8);
// With an explicit primitive target, the expression can use
// generic parameters.
const fn as_u64<const KEY: u16>() -> u64 {
cv!(KEY => u64)
}
This avoids the verbose turbofish syntax which disincentivized
using these types at interface boundaries (e.g.
'Alignment::new::<8>()').
- 'alloc' module:
- Allow different error types in 'KBox::pin_slice()', enabling use
of infallible initializers.
- Add 'NumaNode::id()' accessor to retrieve the underlying NUMA
node identifier.
- 'time' module:
- Add 'Delta::to_jiffies_timeout()' for use in timeout arguments.
- Add 'Delta::as_jiffies_unsigned()'.
- Make 'Delta::ZERO' generic over the time unit.
- Warn and assert when passing out-of-range inputs to 'fsleep' and
'udelay'.
- Rename 'ClockSource' to 'ClockId' to better align with naming
conventions in C kernel.
- Make 'CONFIG_HZ' value available as 'bindings::HZ'.
- Add implementation detail documentation for 'HrTimer'.
- 'bitmap' module:
- Add contiguous area operations ('next_zero_area{,_off}', 'set'
and 'clear'), with extra checks compared to the underlying C
code, plus additional ones under 'CONFIG_RUST_BITMAP_HARDENED'.
It includes tests demonstrating the edge cases.
- Restrict bitmap length to at most 'i32::MAX', matching
'BitmapVec::MAX_LEN' and simplifying a few things. This also
fixes 'u32' casts truncating in 'copy_and_extend', which could
otherwise lead to OOB writes.
- 'bug' module:
- Fix 'warn_on!' on UML which called 'warn_slowpath_fmt()' with
the wrong arguments; and fix its '// SAFETY:' comment too.
- Add a KUnit test for 'warn_on!'.
- 'id_pool' module: add contiguous ID reservation via the new
'reserve_ids' and 'release_ids' methods, built on top of the new
bitmap area operations.
- 'sizes' module: add the sub-1K size constants ('SZ_1' to 'SZ_512')
and implement 'SizeConstants' for 'Alignment', so that one can
write e.g. 'Alignment::SZ_8'.
'macros' crate:
- Add '#[optional]' attribute for optional methods in '#[vtable]' to
replace the 'build_error!(VTABLE_DEFAULT_ERROR)' boilerplate, e.g.:
#[vtable]
pub trait Operations: Sized {
#[optional]
fn f(&self) -> Result;
}
In addition, apply it to miscdevice and hide generated 'HAS_'
constants for required methods.
- Allow non-ASCII characters in the 'authors' field of the 'module!'
macro, which was unintentionally restricted when multiple authors
support was introduced.
'pin-init' crate:
[ Extra context from Gary's pull request:
"This is a cycle packed with feature updates. Two of the most
anticipated features, tuple struct support and safe self
reference creation, has been included in this pull request.
Safe self reference is a big one and is pushed a bit late in the
cycle. The initial plan was to include a minimum subset for this
cycle because I was worried about potential soundness issues;
however during Plumbers it was agreed that the features should be
upstreamed at once. This is because the initial users (Nova,
JobQueue) would all need the advanced features, so it is better
to ensure that the feature get put into use for real, and it can
iterate with users, rather than being fully designed on paper.
The existing safety checks are already very comprehensive, and
Benno and I are confident that if new ones are discovered, it
wouldn't affect the overall design.
That said, the the usage of the advanced features (invariance,
existential lifetime) shall be limited to the pre-agreed users
only, so even in case where the feature needs to be reworked, the
blast radius is limited.
Another theme in this cycle is to improve the developer
experience when things are used wrongly. A lot of work has been
done to use proper spans from user-provided tokens so error
message point to things that cause them. Many common misuse
scenarios also gain additional custom diagnostics." ]
- User visible changes:
- Support tuple structs.
- Allow safe creation of self references.
- Vastly improve diagnostics for common misuse scenarios.
- Other changes:
- Use 'mixed_site' hygiene consistently.
'MAINTAINERS':
- Add 'RUST [BUG]' entry for the Rust 'bug' module (i.e. 'warn_on!'),
which will be maintained by FUJITA Tomonori -- thank you!
- Add Alice Ryhl as co-maintainer for 'Rust [ALLOC]'.
And some other fixes, cleanups and improvements.
* tag 'rust-7.4' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (91 commits)
rust: zerocopy: update to v0.8.62
rust: zerocopy: fix link to upstream `README.md`
rust: id_pool: add contiguous ID reservation
rust: bitmap: add contiguous area operations
rust: sizes: implement SizeConstants for Alignment
rust: sizes: add sub-1K size constants
rust: bitmap: restrict bitmap length to at most i32::MAX
rust: bitmap: use function-level cfg on kunit test
rust: num: add cv! macro to create values from constant expressions
rust: bug: update the SAFETY comment for warn_slowpath_fmt() on UML
rust: time: add Delta::as_jiffies_unsigned()
rust: time: make Delta::ZERO generic over the time unit
rust_binder: use pr_*_ratelimited! for printing
rust: add pr_*_ratelimited! macros for printing
rust: sync: add const constructor for raw_spinlock_t
rust: sync: move lockdep types to rust/kernel/sync/lockdep.rs
rust: pin-init: internal: suppress `explicit_outlives_requirements`
MAINTAINERS: add entry for the Rust `bug` module
rust: pin-init: internal: pin_data: support existential lifetimes
rust: pin-init: internal: pin_data: support shared projection
...
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