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3 daysMerge tag 'locking-core-2026-02-08' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "Lock debugging: - Implement compiler-driven static analysis locking context checking, using the upcoming Clang 22 compiler's context analysis features (Marco Elver) We removed Sparse context analysis support, because prior to removal even a defconfig kernel produced 1,700+ context tracking Sparse warnings, the overwhelming majority of which are false positives. On an allmodconfig kernel the number of false positive context tracking Sparse warnings grows to over 5,200... On the plus side of the balance actual locking bugs found by Sparse context analysis is also rather ... sparse: I found only 3 such commits in the last 3 years. So the rate of false positives and the maintenance overhead is rather high and there appears to be no active policy in place to achieve a zero-warnings baseline to move the annotations & fixers to developers who introduce new code. Clang context analysis is more complete and more aggressive in trying to find bugs, at least in principle. Plus it has a different model to enabling it: it's enabled subsystem by subsystem, which results in zero warnings on all relevant kernel builds (as far as our testing managed to cover it). Which allowed us to enable it by default, similar to other compiler warnings, with the expectation that there are no warnings going forward. This enforces a zero-warnings baseline on clang-22+ builds (Which are still limited in distribution, admittedly) Hopefully the Clang approach can lead to a more maintainable zero-warnings status quo and policy, with more and more subsystems and drivers enabling the feature. Context tracking can be enabled for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y (default disabled), but this will generate a lot of false positives. ( Having said that, Sparse support could still be added back, if anyone is interested - the removal patch is still relatively straightforward to revert at this stage. ) Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng) - Add support for Atomic<i8/i16/bool> and replace most Rust native AtomicBool usages with Atomic<bool> - Clean up LockClassKey and improve its documentation - Add missing Send and Sync trait implementation for SetOnce - Make ARef Unpin as it is supposed to be - Add __rust_helper to a few Rust helpers as a preparation for helper LTO - Inline various lock related functions to avoid additional function calls WW mutexes: - Extend ww_mutex tests and other test-ww_mutex updates (John Stultz) Misc fixes and cleanups: - rcu: Mark lockdep_assert_rcu_helper() __always_inline (Arnd Bergmann) - locking/local_lock: Include more missing headers (Peter Zijlstra) - seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap) - rust: sync: Replace `kernel::c_str!` with C-Strings (Tamir Duberstein)" * tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits) locking/rwlock: Fix write_trylock_irqsave() with CONFIG_INLINE_WRITE_TRYLOCK rcu: Mark lockdep_assert_rcu_helper() __always_inline compiler-context-analysis: Remove __assume_ctx_lock from initializers tomoyo: Use scoped init guard crypto: Use scoped init guard kcov: Use scoped init guard compiler-context-analysis: Introduce scoped init guards cleanup: Make __DEFINE_LOCK_GUARD handle commas in initializers seqlock: fix scoped_seqlock_read kernel-doc tools: Update context analysis macros in compiler_types.h rust: sync: Replace `kernel::c_str!` with C-Strings rust: sync: Inline various lock related methods rust: helpers: Move #define __rust_helper out of atomic.c rust: wait: Add __rust_helper to helpers rust: time: Add __rust_helper to helpers rust: task: Add __rust_helper to helpers rust: sync: Add __rust_helper to helpers rust: refcount: Add __rust_helper to helpers rust: rcu: Add __rust_helper to helpers rust: processor: Add __rust_helper to helpers ...
2026-01-26rust: sync: atomic: Provide stub for `rusttest` 32-bit hostsMiguel Ojeda
For arm32, on a x86_64 builder, running the `rusttest` target yields: error[E0080]: evaluation of constant value failed --> rust/kernel/static_assert.rs:37:23 | 37 | const _: () = ::core::assert!($condition $(,$arg)?); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'assertion failed: size_of::<isize>() == size_of::<isize_atomic_repr>()', rust/kernel/sync/atomic/predefine.rs:68:1 | ::: rust/kernel/sync/atomic/predefine.rs:68:1 | 68 | static_assert!(size_of::<isize>() == size_of::<isize_atomic_repr>()); | -------------------------------------------------------------------- in this macro invocation | = note: this error originates in the macro `::core::assert` which comes from the expansion of the macro `static_assert` (in Nightly builds, run with -Z macro-backtrace for more info) The reason is that `rusttest` runs on the host, so for e.g. a x86_64 builder `isize` is 64 bits but it is not a `CONFIG_64BIT` build. Fix it by providing a stub for `rusttest` as usual. Fixes: 84c6d36bcaf9 ("rust: sync: atomic: Add Atomic<{usize,isize}>") Cc: stable@vger.kernel.org Reviewed-by: Onur Özkan <work@onurozkan.dev> Acked-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20260123233432.22703-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-01-18rust: sync: refcount: always inline functions using build_assert with argumentsAlexandre Courbot
`build_assert` relies on the compiler to optimize out its error path. Functions using it with its arguments must thus always be inlined, otherwise the error path of `build_assert` might not be optimized out, triggering a build error. Cc: stable@vger.kernel.org Fixes: bb38f35b35f9 ("rust: implement `kernel::sync::Refcount`") Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251208-io-build-assert-v3-5-98aded02c1ea@nvidia.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-01-10rust: sync: Inline various lock related methodsAlice Ryhl
While debugging a different issue [1], the following relocation was noticed in the rust_binder.ko file: R_AARCH64_CALL26 _RNvXNtNtNtCsdfZWD8DztAw_6kernel4sync4lock8spinlockNtB2_15SpinLockBackendNtB4_7Backend6unlock This relocation (and a similar one for lock) occurred many times throughout the module. That is not really useful because all this function does is call spin_unlock(), so what we actually want here is that a call to spin_unlock() dirctly is generated in favor of this wrapper method. Thus, mark these methods inline. [boqun: Reword the commit message a bit] Link: https://lore.kernel.org/p/20251111-binder-fix-list-remove-v1-0-8ed14a0da63d@google.com Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251218-inline-lock-unlock-v2-1-fbadac8bd61b@google.com
2026-01-09rust: sync: atomic: Add atomic bool testsFUJITA Tomonori
Add tests for Atomic<bool> operations. Atomic<bool> does not fit into the existing u8/16/32/64 tests so introduce a dedicated test for it. Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20260101034922.2020334-3-fujita.tomonori@gmail.com
2026-01-09rust: sync: atomic: Add atomic bool support via i8 representationFUJITA Tomonori
Add `bool` support, `Atomic<bool>` by using `i8` as its underlying representation. Rust specifies that `bool` has size 1 and alignment 1 [1], so it matches `i8` on layout; keep `static_assert!()` checks to enforce this assumption at build time. [boqun: Remove the unnecessary impl AtomicImpl for bool] Link: https://doc.rust-lang.org/reference/types/boolean.html [1] Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20260101034922.2020334-2-fujita.tomonori@gmail.com
2026-01-09rust: sync: atomic: Add i8/i16 xchg and cmpxchg supportFUJITA Tomonori
Add atomic xchg and cmpxchg operation support for i8 and i16 types with tests. Note that since the current implementation of Atomic::<{i8,i16}>::{load,store}() is READ_ONCE()/WRITE_ONCE()-based. The atomicity between load/store and xchg/cmpxchg is only guaranteed if the architecture has native RmW support, hence i8/i16 is currently AtomicImpl only when CONFIG_ARCH_SUPPORTS_ATOMIC_RWM=y. [boqun: Make i8/i16 AtomicImpl only when CONFIG_ARCH_SUPPORTS_ATOMIC_RWM=y] Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251228120546.1602275-4-fujita.tomonori@gmail.com
2026-01-09rust: sync: atomic: Add store_release/load_acquire testsFUJITA Tomonori
Add minimum store_release/load_acquire tests. Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251211113826.1299077-5-fujita.tomonori@gmail.com
2026-01-09rust: sync: atomic: Add i8/i16 load and store supportFUJITA Tomonori
Add atomic operation support for i8 and i16 types using volatile read/write and smp_load_acquire/smp_store_release helpers. [boqun: Adjust [1] to avoid introduction of impl_atomic_only_load_and_store_ops!() in the middle] Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com> Link: https://lore.kernel.org/all/20251228120546.1602275-1-fujita.tomonori@gmail.com/ [1] Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251211113826.1299077-4-fujita.tomonori@gmail.com
2026-01-09rust: sync: atomic: Prepare AtomicOps macros for i8/i16 supportFUJITA Tomonori
Rework the internal AtomicOps macro plumbing to generate per-type implementations from a mapping list. Capture the trait definition once and reuse it for both declaration and per-type impl expansion to reduce duplication and keep future extensions simple. This is a preparatory refactor for enabling i8/i16 atomics cleanly. Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251228120546.1602275-2-fujita.tomonori@gmail.com
2026-01-09rust: sync: Implement Unpin for ARefAlice Ryhl
The default implementation of Unpin for ARef<T> is conditional on T being Unpin due to its PhantomData<T> field. However, this is overly strict as pointers to T are legal to move even if T itself cannot move. Since commit 66f1ea83d9f8 ("rust: lock: Add a Pin<&mut T> accessor") this causes build failures when combined with a Mutex that contains an field ARef<T>, because almost any type that ARef is used with is !Unpin. Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251218-unpin-for-aref-v2-1-30d77129cbc6@google.com
2026-01-09rust: sync: set_once: Implement Send and SyncFUJITA Tomonori
Implement Send and Sync for SetOnce<T> to allow it to be used across thread boundaries. Send: SetOnce<T> can be transferred across threads when T: Send, as the contained value is also transferred and will be dropped on the destination thread. Sync: SetOnce<T> can be shared across threads when T: Sync, as as_ref() provides shared references &T and atomic operations ensure proper synchronization. Since the inner T may be dropped on any thread, we also require T: Send. Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251216000901.221375-1-fujita.tomonori@gmail.com
2025-12-06rust: sync: atomic: separate import "blocks"Miguel Ojeda
Commit 14e9a18b07ec ("rust: sync: atomic: Make Atomic*Ops pub(crate)") added a `pub(crate)` import in the same "block" as the `pub` one, without running `rustfmt`, which would sort them differently. Instead of running `rustfmt` as-is, add a newline to keep the import "blocks" with different visibilities separate. Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2025-12-06Merge tag 'modules-6.19-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux Pull module updates from Daniel Gomez: "Rust module parameter support: - Add Rust module parameter support, enabling Rust kernel modules to declare and use module parameters. The rust_minimal sample module demonstrates this, and the rust null block driver will be the first to use it in the next cycle. This also adds the Rust module files under the modules subsystem as agreed between the Rust and modules maintainers. Hardening: - Add compile-time check for embedded NUL characters in MODULE_*() macros. This module metadata was once used (and maybe still) to bypass license enforcement (LWN article from 2003): https://lwn.net/Articles/82305/ [1] MAINTAINERS: - Add Aaron Tomlin as reviewer for the Modules subsystem" * tag 'modules-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux: MAINTAINERS: Add myself as reviewer for module support module: Add compile-time check for embedded NUL characters media: radio: si470x: Fix DRIVER_AUTHOR macro definition media: dvb-usb-v2: lmedm04: Fix firmware macro definitions modules: add rust modules files to MAINTAINERS rust: samples: add a module parameter to the rust_minimal sample rust: module: update the module macro with module parameter support rust: module: use a reference in macros::module::module rust: introduce module_param module rust: str: add radix prefixed integer parsing functions rust: sync: add `SetOnce`
2025-12-03Merge tag 'rust-6.19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux Pull Rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Add support for 'syn'. Syn is a parsing library for parsing a stream of Rust tokens into a syntax tree of Rust source code. Currently this library is geared toward use in Rust procedural macros, but contains some APIs that may be useful more generally. 'syn' allows us to greatly simplify writing complex macros such as 'pin-init' (Benno has already prepared the 'syn'-based version). We will use it in the 'macros' crate too. 'syn' is the most downloaded Rust crate (according to crates.io), and it is also used by the Rust compiler itself. While the amount of code is substantial, there should not be many updates needed for these crates, and even if there are, they should not be too big, e.g. +7k -3k lines across the 3 crates in the last year. 'syn' requires two smaller dependencies: 'quote' and 'proc-macro2'. I only modified their code to remove a third dependency ('unicode-ident') and to add the SPDX identifiers. The code can be easily verified to exactly match upstream with the provided scripts. They are all licensed under "Apache-2.0 OR MIT", like the other vendored 'alloc' crate we had for a while. Please see the merge commit with the cover letter for more context. - Allow 'unreachable_pub' and 'clippy::disallowed_names' for doctests. Examples (i.e. doctests) may want to do things like show public items and use names such as 'foo'. Nevertheless, we still try to keep examples as close to real code as possible (this is part of why running Clippy on doctests is important for us, e.g. for safety comments, which userspace Rust does not support yet but we are stricter). 'kernel' crate: - Replace our custom 'CStr' type with 'core::ffi::CStr'. Using the standard library type reduces our custom code footprint, and we retain needed custom functionality through an extension trait and a new 'fmt!' macro which replaces the previous 'core' import. This started in 6.17 and continued in 6.18, and we finally land the replacement now. This required quite some stamina from Tamir, who split the changes in steps to prepare for the flag day change here. - Replace 'kernel::c_str!' with C string literals. C string literals were added in Rust 1.77, which produce '&CStr's (the 'core' one), so now we can write: c"hi" instead of: c_str!("hi") - Add 'num' module for numerical features. It includes the 'Integer' trait, implemented for all primitive integer types. It also includes the 'Bounded' integer wrapping type: an integer value that requires only the 'N' least significant bits of the wrapped type to be encoded: // An unsigned 8-bit integer, of which only the 4 LSBs are used. let v = Bounded::<u8, 4>::new::<15>(); assert_eq!(v.get(), 15); 'Bounded' is useful to e.g. enforce guarantees when working with bitfields that have an arbitrary number of bits. Values can also be constructed from simple non-constant expressions or, for more complex ones, validated at runtime. 'Bounded' also comes with comparison and arithmetic operations (with both their backing type and other 'Bounded's with a compatible backing type), casts to change the backing type, extending/shrinking and infallible/fallible conversions from/to primitives as applicable. - 'rbtree' module: add immutable cursor ('Cursor'). It enables to use just an immutable tree reference where appropriate. The existing fully-featured mutable cursor is renamed to 'CursorMut'. kallsyms: - Fix wrong "big" kernel symbol type read from procfs. 'pin-init' crate: - A couple minor fixes (Benno asked me to pick these patches up for him this cycle). Documentation: - Quick Start guide: add Debian 13 (Trixie). Debian Stable is now able to build Linux, since Debian 13 (released 2025-08-09) packages Rust 1.85.0, which is recent enough. We are planning to propose that the minimum supported Rust version in Linux follows Debian Stable releases, with Debian 13 being the first one we upgrade to, i.e. Rust 1.85. MAINTAINERS: - Add entry for the new 'num' module. - Remove Alex as Rust maintainer: he hasn't had the time to contribute for a few years now, so it is a no-op change in practice. And a few other cleanups and improvements" * tag 'rust-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (53 commits) rust: macros: support `proc-macro2`, `quote` and `syn` rust: syn: enable support in kbuild rust: syn: add `README.md` rust: syn: remove `unicode-ident` dependency rust: syn: add SPDX License Identifiers rust: syn: import crate rust: quote: enable support in kbuild rust: quote: add `README.md` rust: quote: add SPDX License Identifiers rust: quote: import crate rust: proc-macro2: enable support in kbuild rust: proc-macro2: add `README.md` rust: proc-macro2: remove `unicode_ident` dependency rust: proc-macro2: add SPDX License Identifiers rust: proc-macro2: import crate rust: kbuild: support using libraries in `rustc_procmacro` rust: kbuild: support skipping flags in `rustc_test_library` rust: kbuild: add proc macro library support rust: kbuild: simplify `--cfg` handling rust: kbuild: introduce `core-flags` and `core-skip_flags` ...
2025-12-01Merge tag 'locking-core-2025-12-01' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "Mutexes: - Redo __mutex_init() to reduce generated code size (Sebastian Andrzej Siewior) Seqlocks: - Introduce scoped_seqlock_read() (Peter Zijlstra) - Change thread_group_cputime() to use scoped_seqlock_read() (Oleg Nesterov) - Change do_task_stat() to use scoped_seqlock_read() (Oleg Nesterov) - Change do_io_accounting() to use scoped_seqlock_read() (Oleg Nesterov) - Fix the incorrect documentation of read_seqbegin_or_lock() / need_seqretry() (Oleg Nesterov) - Allow KASAN to fail optimizing (Peter Zijlstra) Local lock updates: - Fix all kernel-doc warnings (Randy Dunlap) - Add the <linux/local_lock*.h> headers to MAINTAINERS (Sebastian Andrzej Siewior) - Reduce the risk of shadowing via s/l/__l/ and s/tl/__tl/ (Vincent Mailhol) Lock debugging: - spinlock/debug: Fix data-race in do_raw_write_lock (Alexander Sverdlin) Atomic primitives infrastructure: - atomic: Skip alignment check for try_cmpxchg() old arg (Arnd Bergmann) Rust runtime integration: - sync: atomic: Enable generated Atomic<T> usage (Boqun Feng) - sync: atomic: Implement Debug for Atomic<Debug> (Boqun Feng) - debugfs: Remove Rust native atomics and replace them with Linux versions (Boqun Feng) - debugfs: Implement Reader for Mutex<T> only when T is Unpin (Boqun Feng) - lock: guard: Add T: Unpin bound to DerefMut (Daniel Almeida) - lock: Pin the inner data (Daniel Almeida) - lock: Add a Pin<&mut T> accessor (Daniel Almeida)" * tag 'locking-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/local_lock: Fix all kernel-doc warnings locking/local_lock: s/l/__l/ and s/tl/__tl/ to reduce the risk of shadowing locking/local_lock: Add the <linux/local_lock*.h> headers to MAINTAINERS locking/mutex: Redo __mutex_init() to reduce generated code size rust: debugfs: Replace the usage of Rust native atomics rust: sync: atomic: Implement Debug for Atomic<Debug> rust: sync: atomic: Make Atomic*Ops pub(crate) seqlock: Allow KASAN to fail optimizing rust: debugfs: Implement Reader for Mutex<T> only when T is Unpin seqlock: Change do_io_accounting() to use scoped_seqlock_read() seqlock: Change do_task_stat() to use scoped_seqlock_read() seqlock: Change thread_group_cputime() to use scoped_seqlock_read() seqlock: Introduce scoped_seqlock_read() documentation: seqlock: fix the wrong documentation of read_seqbegin_or_lock/need_seqretry atomic: Skip alignment check for try_cmpxchg() old arg rust: lock: Add a Pin<&mut T> accessor rust: lock: Pin the inner data rust: lock: guard: Add T: Unpin bound to DerefMut locking/spinlock/debug: Fix data-race in do_raw_write_lock
2025-11-12rust: sync: atomic: Implement Debug for Atomic<Debug>Boqun Feng
If `Atomic<T>` is `Debug` then it's a `debugfs::Writer`, therefore make it so since 1) debugfs needs to support `Atomic<T>` and 2) it's rather trivial to implement `Debug` for `Atomic<Debug>`. Tested-by: David Gow <davidgow@google.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251022035324.70785-3-boqun.feng@gmail.com
2025-11-12rust: sync: atomic: Make Atomic*Ops pub(crate)Boqun Feng
In order to write code over a generate Atomic<T> we need to make Atomic*Ops public so that functions like `.load()` and `.store()` are available. Make these pub(crate) at the beginning so the usage in kernel crate is supported. Tested-by: David Gow <davidgow@google.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251022035324.70785-2-boqun.feng@gmail.com
2025-11-03rust: sync: add `SetOnce`Andreas Hindborg
Introduce the `SetOnce` type, a container that can only be written once. The container uses an internal atomic to synchronize writes to the internal value. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org> Tested-by: Daniel Gomez <da.gomez@samsung.com> Signed-off-by: Daniel Gomez <da.gomez@kernel.org>
2025-11-02rust: condvar: fix broken intra-doc linkMiguel Ojeda
The future move of pin-init to `syn` uncovers the following broken intra-doc link: error: unresolved link to `crate::pin_init` --> rust/kernel/sync/condvar.rs:39:40 | 39 | /// instances is with the [`pin_init`](crate::pin_init!) and [`new_condvar`] macros. | ^^^^^^^^^^^^^^^^ no item named `pin_init` in module `kernel` | = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(rustdoc::broken_intra_doc_links)]` Currently, when rendered, the link points to a literal `crate::pin_init!` URL. Thus fix it. Cc: stable@vger.kernel.org Fixes: 129e97be8e28 ("rust: pin-init: fix documentation links") Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20251029073344.349341-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-10-22rust: replace `CStr` with `core::ffi::CStr`Tamir Duberstein
`kernel::ffi::CStr` was introduced in commit d126d2380131 ("rust: str: add `CStr` type") in November 2022 as an upstreaming of earlier work that was done in May 2021[0]. That earlier work, having predated the inclusion of `CStr` in `core`, largely duplicated the implementation of `std::ffi::CStr`. `std::ffi::CStr` was moved to `core::ffi::CStr` in Rust 1.64 in September 2022. Hence replace `kernel::str::CStr` with `core::ffi::CStr` to reduce our custom code footprint, and retain needed custom functionality through an extension trait. Add `CStr` to `ffi` and the kernel prelude. Link: https://github.com/Rust-for-Linux/linux/commit/faa3cbcca03d0dec8f8e43f1d8d5c0860d98a23f [0] Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Danilo Krummrich <dakr@kernel.org> Reviewed-by: Benno Lossin <lossin@kernel.org> Signed-off-by: Tamir Duberstein <tamird@gmail.com> Link: https://patch.msgid.link/20251018-cstr-core-v18-16-9378a54385f8@gmail.com [ Removed assert that would now depend on the Rust version. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-10-21rust: lock: Add a Pin<&mut T> accessorDaniel Almeida
In order for callers to be able to access the inner T safely if T: !Unpin, there needs to be a way to get a Pin<&mut T>. Add this accessor and a corresponding example to tell users how it works. This requires the pin projection functionality [1] for better ergonomic. [boqun: Apply Daniel's fix to the code example, add the reference to pin projection patch and remove out-of-date part in the commit log] Suggested-by: Benno Lossin <lossin@kernel.org> Suggested-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1181 Link: https://lore.kernel.org/rust-for-linux/20250912174148.373530-1-lossin@kernel.org/ [1]
2025-10-21rust: lock: Pin the inner dataDaniel Almeida
In preparation to support Lock<T> where T is pinned, the first thing that needs to be done is to structurally pin the 'data' member. This switches the 't' parameter in Lock<T>::new() to take in an impl PinInit<T> instead of a plain T. This in turn uses the blanket implementation "impl PinInit<T> for T". Subsequent patches will touch on Guard<T>. Suggested-by: Benno Lossin <lossin@kernel.org> Suggested-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://github.com/Rust-for-Linux/linux/issues/1181
2025-10-21rust: lock: guard: Add T: Unpin bound to DerefMutDaniel Almeida
A core property of pinned types is not handing a mutable reference to the inner data in safe code, as this trivially allows that data to be moved. Enforce this condition by adding a bound on lock::Guard's DerefMut implementation, so that it's only implemented for pinning-agnostic types. Suggested-by: Benno Lossin <lossin@kernel.org> Suggested-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://github.com/Rust-for-Linux/linux/issues/1181
2025-09-30Merge tag 'rust-6.18' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux Pull rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Derive 'Zeroable' for all structs and unions generated by 'bindgen' where possible and corresponding cleanups. To do so, add the 'pin-init' crate as a dependency to 'bindings' and 'uapi'. It also includes its first use in the 'cpufreq' module, with more to come in the next cycle. - Add warning to the 'rustdoc' target to detect broken 'srctree/' links and fix existing cases. - Remove support for unused (since v6.16) host '#[test]'s, simplifying the 'rusttest' target. Tests should generally run within KUnit. 'kernel' crate: - Add 'ptr' module with a new 'Alignment' type, which is always a power of two and is used to validate that a given value is a valid alignment and to perform masking and alignment operations: // Checked at build time. assert_eq!(Alignment::new::<16>().as_usize(), 16); // Checked at runtime. assert_eq!(Alignment::new_checked(15), None); assert_eq!(Alignment::of::<u8>().log2(), 0); assert_eq!(0x25u8.align_down(Alignment::new::<0x10>()), 0x20); assert_eq!(0x5u8.align_up(Alignment::new::<0x10>()), Some(0x10)); assert_eq!(u8::MAX.align_up(Alignment::new::<0x10>()), None); It also includes its first use in Nova. - Add 'core::mem::{align,size}_of{,_val}' to the prelude, matching Rust 1.80.0. - Keep going with the steps on our migration to the standard library 'core::ffi::CStr' type (use 'kernel::{fmt, prelude::fmt!}' and use upstream method names). - 'error' module: improve 'Error::from_errno' and 'to_result' documentation, including examples/tests. - 'sync' module: extend 'aref' submodule documentation now that it exists, and more updates to complete the ongoing move of 'ARef' and 'AlwaysRefCounted' to 'sync::aref'. - 'list' module: add an example/test for 'ListLinksSelfPtr' usage. - 'alloc' module: - Implement 'Box::pin_slice()', which constructs a pinned slice of elements. - Provide information about the minimum alignment guarantees of 'Kmalloc', 'Vmalloc' and 'KVmalloc'. - Take minimum alignment guarantees of allocators for 'ForeignOwnable' into account. - Remove the 'allocator_test' (including 'Cmalloc'). - Add doctest for 'Vec::as_slice()'. - Constify various methods. - 'time' module: - Add methods on 'HrTimer' that can only be called with exclusive access to an unarmed timer, or from timer callback context. - Add arithmetic operations to 'Instant' and 'Delta'. - Add a few convenience and access methods to 'HrTimer' and 'Instant'. 'macros' crate: - Reduce collections in 'quote!' macro. And a few other cleanups and improvements" * tag 'rust-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (58 commits) gpu: nova-core: use Alignment for alignment-related operations rust: add `Alignment` type rust: macros: reduce collections in `quote!` macro rust: acpi: use `core::ffi::CStr` method names rust: of: use `core::ffi::CStr` method names rust: net: use `core::ffi::CStr` method names rust: miscdevice: use `core::ffi::CStr` method names rust: kunit: use `core::ffi::CStr` method names rust: firmware: use `core::ffi::CStr` method names rust: drm: use `core::ffi::CStr` method names rust: cpufreq: use `core::ffi::CStr` method names rust: configfs: use `core::ffi::CStr` method names rust: auxiliary: use `core::ffi::CStr` method names drm/panic: use `core::ffi::CStr` method names rust: device: use `kernel::{fmt,prelude::fmt!}` rust: sync: use `kernel::{fmt,prelude::fmt!}` rust: seq_file: use `kernel::{fmt,prelude::fmt!}` rust: kunit: use `kernel::{fmt,prelude::fmt!}` rust: file: use `kernel::{fmt,prelude::fmt!}` rust: device: use `kernel::{fmt,prelude::fmt!}` ...
2025-09-16rust: sync: use `kernel::{fmt,prelude::fmt!}`Tamir Duberstein
Reduce coupling to implementation details of the formatting machinery by avoiding direct use for `core`'s formatting traits and macros. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Signed-off-by: Tamir Duberstein <tamird@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-09-15rust: block: convert `block::mq` to use `Refcount`Gary Guo
Currently there's a custom reference counting in `block::mq`, which uses `AtomicU64` Rust atomics, and this type doesn't exist on some 32-bit architectures. We cannot just change it to use 32-bit atomics, because doing so will make it vulnerable to refcount overflow. So switch it to use the kernel refcount `kernel::sync::Refcount` instead. There is an operation needed by `block::mq`, atomically decreasing refcount from 2 to 0, which is not available through refcount.h, so I exposed `Refcount::as_atomic` which allows accessing the refcount directly. [boqun: Adopt the LKMM atomic API] Signed-off-by: Gary Guo <gary@garyguo.net> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Acked-by: Andreas Hindborg <a.hindborg@kernel.org> Tested-by: David Gow <davidgow@google.com> Link: https://lore.kernel.org/r/20250723233312.3304339-5-gary@kernel.org
2025-09-15rust: convert `Arc` to use `Refcount`Gary Guo
With `Refcount` type created, `Arc` can use `Refcount` instead of calling into FFI directly. Signed-off-by: Gary Guo <gary@garyguo.net> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/r/20250723233312.3304339-4-gary@kernel.org
2025-09-15rust: make `Arc::into_unique_or_drop` associated functionGary Guo
Make `Arc::into_unique_or_drop` to become a mere associated function instead of a method (i.e. removing the `self` receiver). It's a general convention for Rust smart pointers to avoid having methods defined on them, because if the pointee type has a method of the same name, then it is shadowed. This is normally for avoiding semver breakage, which isn't an issue for kernel codebase, but it's still generally a good practice to follow this rule, so that `ptr.foo()` would always be calling a method on the pointee type. Signed-off-by: Gary Guo <gary@garyguo.net> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/r/20250723233312.3304339-3-gary@kernel.org
2025-09-15rust: implement `kernel::sync::Refcount`Gary Guo
This is a wrapping layer of `include/linux/refcount.h`. Currently the kernel refcount has already been used in `Arc`, however it calls into FFI directly. [boqun: Add the missing <> for the link in comment] Signed-off-by: Gary Guo <gary@garyguo.net> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Fiona Behrens <me@kloenk.dev> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/r/20250723233312.3304339-2-gary@kernel.org
2025-09-15rust: sync: Add memory barriersBoqun Feng
Memory barriers are building blocks for concurrent code, hence provide a minimal set of them. The compiler barrier, barrier(), is implemented in inline asm instead of using core::sync::atomic::compiler_fence() because memory models are different: kernel's atomics are implemented in inline asm therefore the compiler barrier should be implemented in inline asm as well. Also it's currently only public to the kernel crate until there's a reasonable driver usage. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/all/20250719030827.61357-10-boqun.feng@gmail.com/
2025-09-15rust: sync: atomic: Add Atomic<{usize,isize}>Boqun Feng
Add generic atomic support for `usize` and `isize`. Note that instead of mapping directly to `atomic_long_t`, the represention type (`AtomicType::Repr`) is selected based on CONFIG_64BIT. This reduces the necessity of creating `atomic_long_*` helpers, which could save the binary size of kernel if inline helpers are not available. To do so, an internal type `isize_atomic_repr` is defined, it's `i32` in 32bit kernel and `i64` in 64bit kernel. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/all/20250719030827.61357-9-boqun.feng@gmail.com/
2025-09-15rust: sync: atomic: Add Atomic<u{32,64}>Boqun Feng
Add generic atomic support for basic unsigned types that have an `AtomicImpl` with the same size and alignment. Unit tests are added including Atomic<i32> and Atomic<i64>. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/all/20250719030827.61357-8-boqun.feng@gmail.com/
2025-09-15rust: sync: atomic: Add the framework of arithmetic operationsBoqun Feng
One important set of atomic operations is the arithmetic operations, i.e. add(), sub(), fetch_add(), add_return(), etc. However it may not make senses for all the types that `AtomicType` to have arithmetic operations, for example a `Foo(u32)` may not have a reasonable add() or sub(), plus subword types (`u8` and `u16`) currently don't have atomic arithmetic operations even on C side and might not have them in the future in Rust (because they are usually suboptimal on a few architecures). Therefore the plan is to add a few subtraits of `AtomicType` describing which types have and can do atomic arithemtic operations. One trait `AtomicAdd` is added, and only add() and fetch_add() are added. The rest will be added in the future. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/all/20250719030827.61357-7-boqun.feng@gmail.com/
2025-09-15rust: sync: atomic: Add atomic {cmp,}xchg operationsBoqun Feng
xchg() and cmpxchg() are basic operations on atomic. Provide these based on C APIs. Note that cmpxchg() use the similar function signature as compare_exchange() in Rust std: returning a `Result`, `Ok(old)` means the operation succeeds and `Err(old)` means the operation fails. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/all/20250719030827.61357-6-boqun.feng@gmail.com/
2025-09-15rust: sync: atomic: Add generic atomicsBoqun Feng
To provide using LKMM atomics for Rust code, a generic `Atomic<T>` is added, currently `T` needs to be Send + Copy because these are the straightforward usages and all basic types support this. Implement `AtomicType` for `i32` and `i64`, and so far only basic operations load() and store() are introduced. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/all/20250719030827.61357-5-boqun.feng@gmail.com/
2025-09-15rust: sync: atomic: Add ordering annotation typesBoqun Feng
Preparation for atomic primitives. Instead of a suffix like _acquire, a method parameter along with the corresponding generic parameter will be used to specify the ordering of an atomic operations. For example, atomic load() can be defined as: impl<T: ...> Atomic<T> { pub fn load<O: AcquireOrRelaxed>(&self, _o: O) -> T { ... } } and acquire users would do: let r = x.load(Acquire); relaxed users: let r = x.load(Relaxed); doing the following: let r = x.load(Release); will cause a compiler error. Compared to suffixes, it's easier to tell what ordering variants an operation has, and it also make it easier to unify the implementation of all ordering variants in one method via generic. The `TYPE` associate const is for generic function to pick up the particular implementation specified by an ordering annotation. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/all/20250719030827.61357-4-boqun.feng@gmail.com/
2025-09-15rust: sync: Add basic atomic operation mapping frameworkBoqun Feng
Preparation for generic atomic implementation. To unify the implementation of a generic method over `i32` and `i64`, the C side atomic methods need to be grouped so that in a generic method, they can be referred as <type>::<method>, otherwise their parameters and return value are different between `i32` and `i64`, which would require using `transmute()` to unify the type into a `T`. Introduce `AtomicImpl` to represent a basic type in Rust that has the direct mapping to an atomic implementation from C. Use a sealed trait to restrict `AtomicImpl` to only support `i32` and `i64` for now. Further, different methods are put into different `*Ops` trait groups, and this is for the future when smaller types like `i8`/`i16` are supported but only with a limited set of API (e.g. only set(), load(), xchg() and cmpxchg(), no add() or sub() etc). While the atomic mod is introduced, documentation is also added for memory models and data races. Also bump my role to the maintainer of ATOMIC INFRASTRUCTURE to reflect my responsibility on the Rust atomic mod. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev> Link: https://lore.kernel.org/all/20250719030827.61357-3-boqun.feng@gmail.com/
2025-09-15rust: sync: extend module documentation of arefBenno Lossin
Commit 07dad44aa9a9 ("rust: kernel: move ARef and AlwaysRefCounted to sync::aref") moved `ARef` and `AlwaysRefCounted` into their own module. In that process only a short, single line description of the module was added. Extend the description by explaining what is meant by "internal reference counting", the two items in the trait & the difference to `Arc`. Signed-off-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-09-08rust: sync: Update ARef and AlwaysRefCounted imports from sync::arefShankari Anand
Update the in-file reference of sync/aref.rs to import `ARef` and `AlwaysRefCounted` from `sync::aref` instead of `types`. This aligns with the ongoing effort to move `ARef` and `AlwaysRefCounted` to sync. Suggested-by: Benno Lossin <lossin@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1173 Signed-off-by: Shankari Anand <shankari.ak0208@gmail.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-08-15rust: alloc: take the allocator into account for FOREIGN_ALIGNAlice Ryhl
When converting a Box<T> into a void pointer, the allocator might guarantee a higher alignment than the type itself does, and in that case it is guaranteed that the void pointer has that higher alignment. This is quite useful when combined with the XArray, which you can only create using a ForeignOwnable whose FOREIGN_ALIGN is at least 4. This means that you can now always use a Box<T> with the XArray no matter the alignment of T. Reviewed-by: Benno Lossin <lossin@kernel.org> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org> Link: https://lore.kernel.org/r/20250811-align-min-allocator-v2-2-3386cc94f4fc@google.com Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-08-03Merge tag 'rust-6.17' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux Pull Rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Enable a set of Clippy lints: 'ptr_as_ptr', 'ptr_cast_constness', 'as_ptr_cast_mut', 'as_underscore', 'cast_lossless' and 'ref_as_ptr' These are intended to avoid type casts with the 'as' operator, which are quite powerful, into restricted variants that are less powerful and thus should help to avoid mistakes - Remove the 'author' key now that most instances were moved to the plural one in the previous cycle 'kernel' crate: - New 'bug' module: add 'warn_on!' macro which reuses the existing 'BUG'/'WARN' infrastructure, i.e. it respects the usual sysctls and kernel parameters: warn_on!(value == 42); To avoid duplicating the assembly code, the same strategy is followed as for the static branch code in order to share the assembly between both C and Rust This required a few rearrangements on C arch headers -- the existing C macros should still generate the same outputs, thus no functional change expected there - 'workqueue' module: add delayed work items, including a 'DelayedWork' struct, a 'impl_has_delayed_work!' macro and an 'enqueue_delayed' method, e.g.: /// Enqueue the struct for execution on the system workqueue, /// where its value will be printed 42 jiffies later. fn print_later(value: Arc<MyStruct>) { let _ = workqueue::system().enqueue_delayed(value, 42); } - New 'bits' module: add support for 'bit' and 'genmask' functions, with runtime- and compile-time variants, e.g.: static_assert!(0b00010000 == bit_u8(4)); static_assert!(0b00011110 == genmask_u8(1..=4)); assert!(checked_bit_u32(u32::BITS).is_none()); - 'uaccess' module: add 'UserSliceReader::strcpy_into_buf', which reads NUL-terminated strings from userspace into a '&CStr' Introduce 'UserPtr' newtype, similar in purpose to '__user' in C, to minimize mistakes handling userspace pointers, including mixing them up with integers and leaking them via the 'Debug' trait. Add it to the prelude, too - Start preparations for the replacement of our custom 'CStr' type with the analogous type in the 'core' standard library. This will take place across several cycles to make it easier. For this one, it includes a new 'fmt' module, using upstream method names and some other cleanups Replace 'fmt!' with a re-export, which helps Clippy lint properly, and clean up the found 'uninlined-format-args' instances - 'dma' module: - Clarify wording and be consistent in 'coherent' nomenclature - Convert the 'read!()' and 'write!()' macros to return a 'Result' - Add 'as_slice()', 'write()' methods in 'CoherentAllocation' - Expose 'count()' and 'size()' in 'CoherentAllocation' and add the corresponding type invariants - Implement 'CoherentAllocation::dma_handle_with_offset()' - 'time' module: - Make 'Instant' generic over clock source. This allows the compiler to assert that arithmetic expressions involving the 'Instant' use 'Instants' based on the same clock source - Make 'HrTimer' generic over the timer mode. 'HrTimer' timers take a 'Duration' or an 'Instant' when setting the expiry time, depending on the timer mode. With this change, the compiler can check the type matches the timer mode - Add an abstraction for 'fsleep'. 'fsleep' is a flexible sleep function that will select an appropriate sleep method depending on the requested sleep time - Avoid 64-bit divisions on 32-bit hardware when calculating timestamps - Seal the 'HrTimerMode' trait. This prevents users of the 'HrTimerMode' from implementing the trait on their own types - Pass the correct timer mode ID to 'hrtimer_start_range_ns()' - 'list' module: remove 'OFFSET' constants, allowing to remove pointer arithmetic; now 'impl_list_item!' invokes 'impl_has_list_links!' or 'impl_has_list_links_self_ptr!'. Other simplifications too - 'types' module: remove 'ForeignOwnable::PointedTo' in favor of a constant, which avoids exposing the type of the opaque pointer, and require 'into_foreign' to return non-null Remove the 'Either<L, R>' type as well. It is unused, and we want to encourage the use of custom enums for concrete use cases - 'sync' module: implement 'Borrow' and 'BorrowMut' for 'Arc' types to allow them to be used in generic APIs - 'alloc' module: implement 'Borrow' and 'BorrowMut' for 'Box<T, A>'; and 'Borrow', 'BorrowMut' and 'Default' for 'Vec<T, A>' - 'Opaque' type: add 'cast_from' method to perform a restricted cast that cannot change the inner type and use it in callers of 'container_of!'. Rename 'raw_get' to 'cast_into' to match it - 'rbtree' module: add 'is_empty' method - 'sync' module: new 'aref' submodule to hold 'AlwaysRefCounted' and 'ARef', which are moved from the too general 'types' module which we want to reduce or eventually remove. Also fix a safety comment in 'static_lock_class' 'pin-init' crate: - Add 'impl<T, E> [Pin]Init<T, E> for Result<T, E>', so results are now (pin-)initializers - Add 'Zeroable::init_zeroed()' that delegates to 'init_zeroed()' - New 'zeroed()', a safe version of 'mem::zeroed()' and also provide it via 'Zeroable::zeroed()' - Implement 'Zeroable' for 'Option<&T>', 'Option<&mut T>' and 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: improve CI more to deny warnings, use '--all-targets'. Check the synchronization status of the two '-next' branches in upstream and the kernel MAINTAINERS: - Add Vlastimil Babka, Liam R. Howlett, Uladzislau Rezki and Lorenzo Stoakes as reviewers (thanks everyone) And a few other cleanups and improvements" * tag 'rust-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (76 commits) rust: Add warn_on macro arm64/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust riscv/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust x86/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust rust: kernel: move ARef and AlwaysRefCounted to sync::aref rust: sync: fix safety comment for `static_lock_class` rust: types: remove `Either<L, R>` rust: kernel: use `core::ffi::CStr` method names rust: str: add `CStr` methods matching `core::ffi::CStr` rust: str: remove unnecessary qualification rust: use `kernel::{fmt,prelude::fmt!}` rust: kernel: add `fmt` module rust: kernel: remove `fmt!`, fix clippy::uninlined-format-args scripts: rust: emit path candidates in panic message scripts: rust: replace length checks with match rust: list: remove nonexistent generic parameter in link rust: bits: add support for bits/genmask macros rust: list: remove OFFSET constants rust: list: add `impl_list_item!` examples rust: list: use fully qualified path ...
2025-07-29Merge tag 'locking-core-2025-07-29' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "Locking primitives: - Mark devm_mutex_init() as __must_check and fix drivers that didn't check the return code (Thomas Weißschuh) - Reorganize <linux/local_lock.h> to better expose the internal APIs to local variables (Sebastian Andrzej Siewior) - Remove OWNER_SPINNABLE in rwsem (Jinliang Zheng) - Remove redundant #ifdefs in the mutex code (Ran Xiaokai) Lockdep: - Avoid returning struct in lock_stats() (Arnd Bergmann) - Change `static const` into enum for LOCKF_*_IRQ_* (Arnd Bergmann) - Temporarily use synchronize_rcu_expedited() in lockdep_unregister_key() to speed things up. (Breno Leitao) Rust runtime: - Add #[must_use] to Lock::try_lock() (Jason Devers)" * tag 'locking-core-2025-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: lockdep: Speed up lockdep_unregister_key() with expedited RCU synchronization locking/mutex: Remove redundant #ifdefs locking/lockdep: Change 'static const' variables to enum values locking/lockdep: Avoid struct return in lock_stats() locking/rwsem: Use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE rust: sync: Add #[must_use] to Lock::try_lock() locking/mutex: Mark devm_mutex_init() as __must_check leds: lp8860: Check return value of devm_mutex_init() spi: spi-nxp-fspi: Check return value of devm_mutex_init() local_lock: Move this_cpu_ptr() notation from internal to main header
2025-07-29Merge tag 'sched-core-2025-07-28' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "Core scheduler changes: - Better tracking of maximum lag of tasks in presence of different slices duration, for better handling of lag in the fair scheduler (Vincent Guittot) - Clean up and standardize #if/#else/#endif markers throughout the entire scheduler code base (Ingo Molnar) - Make SMP unconditional: build the SMP scheduler's data structures and logic on UP kernel too, even though they are not used, to simplify the scheduler and remove around 200 #ifdef/[#else]/#endif blocks from the scheduler (Ingo Molnar) - Reorganize cgroup bandwidth control interface handling for better interfacing with sched_ext (Tejun Heo) Balancing: - Bump sd->max_newidle_lb_cost when newidle balance fails (Chris Mason) - Remove sched_domain_topology_level::flags to simplify the code (Prateek Nayak) - Simplify and clean up build_sched_topology() (Li Chen) - Optimize build_sched_topology() on large machines (Li Chen) Real-time scheduling: - Add initial version of proxy execution: a mechanism for mutex-owning tasks to inherit the scheduling context of higher priority waiters. Currently limited to a single runqueue and conditional on CONFIG_EXPERT, and other limitations (John Stultz, Peter Zijlstra, Valentin Schneider) - Deadline scheduler (Juri Lelli): - Fix dl_servers initialization order (Juri Lelli) - Fix DL scheduler's root domain reinitialization logic (Juri Lelli) - Fix accounting bugs after global limits change (Juri Lelli) - Fix scalability regression by implementing less agressive dl_server handling (Peter Zijlstra) PSI: - Improve scalability by optimizing psi_group_change() cpu_clock() usage (Peter Zijlstra) Rust changes: - Make Task, CondVar and PollCondVar methods inline to avoid unnecessary function calls (Kunwu Chan, Panagiotis Foliadis) - Add might_sleep() support for Rust code: Rust's "#[track_caller]" mechanism is used so that Rust's might_sleep() doesn't need to be defined as a macro (Fujita Tomonori) - Introduce file_from_location() (Boqun Feng) Debugging & instrumentation: - Make clangd usable with scheduler source code files again (Peter Zijlstra) - tools: Add root_domains_dump.py which dumps root domains info (Juri Lelli) - tools: Add dl_bw_dump.py for printing bandwidth accounting info (Juri Lelli) Misc cleanups & fixes: - Remove play_idle() (Feng Lee) - Fix check_preemption_disabled() (Sebastian Andrzej Siewior) - Do not call __put_task_struct() on RT if pi_blocked_on is set (Luis Claudio R. Goncalves) - Correct the comment in place_entity() (wang wei)" * tag 'sched-core-2025-07-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (84 commits) sched/idle: Remove play_idle() sched: Do not call __put_task_struct() on rt if pi_blocked_on is set sched: Start blocked_on chain processing in find_proxy_task() sched: Fix proxy/current (push,pull)ability sched: Add an initial sketch of the find_proxy_task() function sched: Fix runtime accounting w/ split exec & sched contexts sched: Move update_curr_task logic into update_curr_se locking/mutex: Add p->blocked_on wrappers for correctness checks locking/mutex: Rework task_struct::blocked_on sched: Add CONFIG_SCHED_PROXY_EXEC & boot argument to enable/disable sched/topology: Remove sched_domain_topology_level::flags x86/smpboot: avoid SMT domain attach/destroy if SMT is not enabled x86/smpboot: moves x86_topology to static initialize and truncate x86/smpboot: remove redundant CONFIG_SCHED_SMT smpboot: introduce SDTL_INIT() helper to tidy sched topology setup tools/sched: Add dl_bw_dump.py for printing bandwidth accounting info tools/sched: Add root_domains_dump.py which dumps root domains info sched/deadline: Fix accounting after global limits change sched/deadline: Reset extra_bw to max_bw when clearing root domains sched/deadline: Initialize dl_servers after SMP ...
2025-07-28Merge tag 'vfs-6.17-rc1.rust' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs rust updates from Christian Brauner: - Allow poll_table pointers to be NULL - Add Rust files to vfs MAINTAINERS entry * tag 'vfs-6.17-rc1.rust' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: vfs: add Rust files to MAINTAINERS poll: rust: allow poll_table ptrs to be null
2025-07-22rust: kernel: move ARef and AlwaysRefCounted to sync::arefShankari Anand
Move the definitions of `ARef` and `AlwaysRefCounted` from `types.rs` to a new file `sync/aref.rs`. Define the corresponding `aref` module under `rust/kernel/sync.rs`. These types are better grouped in `sync`. To avoid breaking existing imports, they are re-exported from `types.rs`. Drop unused imports `mem::ManuallyDrop`, `ptr::NonNull` from `types.rs`, they are now only used in `sync/aref.rs`, where they are already imported. Suggested-by: Benno Lossin <lossin@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1173 Signed-off-by: Shankari Anand <shankari.ak0208@gmail.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Link: https://lore.kernel.org/r/20250715110423.334744-1-shankari.ak0208@gmail.com [ Added missing `///`. Changed module title. Reworded slightly. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-07-14rust: types: add FOREIGN_ALIGN to ForeignOwnableAndreas Hindborg
The current implementation of `ForeignOwnable` is leaking the type of the opaque pointer to consumers of the API. This allows consumers of the opaque pointer to rely on the information that can be extracted from the pointer type. To prevent this, change the API to the version suggested by Maira Canal (link below): Remove `ForeignOwnable::PointedTo` in favor of a constant, which specifies the alignment of the pointers returned by `into_foreign`. With this change, `ArcInner` no longer needs `pub` visibility, so change it to private. Suggested-by: Alice Ryhl <aliceryhl@google.com> Suggested-by: Maíra Canal <mcanal@igalia.com> Link: https://lore.kernel.org/r/20240309235927.168915-3-mcanal@igalia.com Acked-by: Danilo Krummrich <dakr@kernel.org> Reviewed-by: Benno Lossin <lossin@kernel.org> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20250612-pointed-to-v3-1-b009006d86a1@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-07-14Merge branch 'tip/sched/urgent'Peter Zijlstra
Avoid merge conflicts Signed-off-by: Peter Zijlstra <peterz@infradead.org>
2025-07-14poll: rust: allow poll_table ptrs to be nullAlice Ryhl
It's possible for a poll_table to be null. This can happen if an end-user just wants to know if a resource has events right now without registering a waiter for when events become available. Furthermore, these null pointers should be handled transparently by the API, so we should not change `from_ptr` to return an `Option`. Thus, change `PollTable` to wrap a raw pointer rather than use a reference so that you can pass null. Comments mentioning `struct poll_table` are changed to just `poll_table` since `poll_table` is a typedef. (It's a typedef because it's supposed to be opaque.) Reviewed-by: Benno Lossin <lossin@kernel.org> Signed-off-by: Alice Ryhl <aliceryhl@google.com>
2025-07-11rust: sync: Add #[must_use] to Lock::try_lock()Jason Devers
The `Lock::try_lock()` function returns an `Option<Guard<...>>`, but it currently does not issue a warning if the return value is unused. To avoid potential bugs, the `#[must_use]` annotation is added to ensure proper usage. Note that `T` is `#[must_use]` but `Option<T>` is not. For more context, see: https://github.com/rust-lang/rust/issues/71368. Suggested-by: Alice Ryhl <aliceryhl@google.com> Link: https://github.com/Rust-for-Linux/linux/issues/1133 Signed-off-by: Jason Devers <dev.json2@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20241212154753.139563-1-dev.json2@gmail.com