| b91d5d4b | 03-Mar-2026 |
Andreas Hindborg <a.hindborg@kernel.org> |
rust: atomic: Update a safety comment in impl of `fetch_add()`
The safety comment used in the implementation of `fetch_add()` could be
read as just saying something it is true without justifying it.
rust: atomic: Update a safety comment in impl of `fetch_add()`
The safety comment used in the implementation of `fetch_add()` could be
read as just saying something it is true without justifying it. Update
the safety comment to include justification.
Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260220-atomic-sub-v3-3-e63cbed1d2aa@kernel.org
Link: https://patch.msgid.link/20260303201701.12204-14-boqun@kernel.org
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| 0b864375 | 03-Mar-2026 |
Andreas Hindborg <a.hindborg@kernel.org> |
rust: sync: atomic: Update documentation for `fetch_add()`
The documentation for `fetch_add()` does not indicate that the original
value is returned by `fetch_add()`. Update the documentation so thi
rust: sync: atomic: Update documentation for `fetch_add()`
The documentation for `fetch_add()` does not indicate that the original
value is returned by `fetch_add()`. Update the documentation so this is
clear.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260220-atomic-sub-v3-2-e63cbed1d2aa@kernel.org
Link: https://patch.msgid.link/20260303201701.12204-13-boqun@kernel.org
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| c49cf341 | 03-Mar-2026 |
Andreas Hindborg <a.hindborg@kernel.org> |
rust: sync: atomic: Add fetch_sub()
Add `Atomic::fetch_sub()` with implementation and documentation in line
with existing `Atomic::fetch_add()` implementation.
Signed-off-by: Andreas Hindborg <a.hi
rust: sync: atomic: Add fetch_sub()
Add `Atomic::fetch_sub()` with implementation and documentation in line
with existing `Atomic::fetch_add()` implementation.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260220-atomic-sub-v3-1-e63cbed1d2aa@kernel.org
Link: https://patch.msgid.link/20260303201701.12204-12-boqun@kernel.org
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| e2f9c86f | 03-Mar-2026 |
Boqun Feng <boqun.feng@gmail.com> |
rust: sync: atomic: Add atomic operation helpers over raw pointers
In order to synchronize with C or external memory, atomic operations
over raw pointers are need. Although there is already an
`Atom
rust: sync: atomic: Add atomic operation helpers over raw pointers
In order to synchronize with C or external memory, atomic operations
over raw pointers are need. Although there is already an
`Atomic::from_ptr()` to provide a `&Atomic<T>`, it's more convenient to
have helpers that directly perform atomic operations on raw pointers.
Hence a few are added, which are basically an `Atomic::from_ptr().op()`
wrapper.
Note: for naming, since `atomic_xchg()` and `atomic_cmpxchg()` have a
conflict naming to 32bit C atomic xchg/cmpxchg, hence the helpers are
just named as `xchg()` and `cmpxchg()`. For `atomic_load()` and
`atomic_store()`, their 32bit C counterparts are `atomic_read()` and
`atomic_set()`, so keep the `atomic_` prefix.
[boqun: Fix typo spotted by Alice and fix broken sentence spotted by
Gary]
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: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260120115207.55318-3-boqun.feng@gmail.com
Link: https://patch.msgid.link/20260303201701.12204-11-boqun@kernel.org
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|
| ec6fc66a | 03-Mar-2026 |
FUJITA Tomonori <fujita.tomonori@gmail.com> |
rust: sync: atomic: Add performance-optimal Flag type for atomic booleans
Add AtomicFlag type for boolean flags.
Document when AtomicFlag is generally preferable to Atomic<bool>: in
particular, whe
rust: sync: atomic: Add performance-optimal Flag type for atomic booleans
Add AtomicFlag type for boolean flags.
Document when AtomicFlag is generally preferable to Atomic<bool>: in
particular, when RMW operations such as xchg()/cmpxchg() may be used
and minimizing memory usage is not the top priority. On some
architectures without byte-sized RMW instructions, Atomic<bool> can be
slower for RMW operations.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260129122622.3896144-2-tomo@aliasing.net
Link: https://patch.msgid.link/20260303201701.12204-9-boqun@kernel.org
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|
| ac8f06ad | 03-Mar-2026 |
Boqun Feng <boqun.feng@gmail.com> |
rust: sync: atomic: Add Atomic<*{mut,const} T> support
Atomic pointer support is an important piece of synchronization
algorithm, e.g. RCU, hence provide the support for that.
Note that instead of
rust: sync: atomic: Add Atomic<*{mut,const} T> support
Atomic pointer support is an important piece of synchronization
algorithm, e.g. RCU, hence provide the support for that.
Note that instead of relying on atomic_long or the implementation of
`Atomic<usize>`, a new set of helpers (atomic_ptr_*) is introduced for
atomic pointer specifically, this is because ptr2int casting would
lose the provenance of a pointer and even though in theory there are a
few tricks the provenance can be restored, it'll still be a simpler
implementation if C could provide atomic pointers directly. The side
effects of this approach are: we don't have the arithmetic and logical
operations for pointers yet and the current implementation only works
on ARCH_SUPPORTS_ATOMIC_RMW architectures, but these are implementation
issues and can be added later.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Link: https://patch.msgid.link/20260120140503.62804-3-boqun.feng@gmail.com
Link: https://patch.msgid.link/20260303201701.12204-8-boqun@kernel.org
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| 553c02fb | 03-Mar-2026 |
Boqun Feng <boqun.feng@gmail.com> |
rust: sync: atomic: Clarify the need of CONFIG_ARCH_SUPPORTS_ATOMIC_RMW
Currently, since all the architectures that support Rust all have
CONFIG_ARCH_SUPPORTS_ATOMIC_RMW selected, the helpers of ato
rust: sync: atomic: Clarify the need of CONFIG_ARCH_SUPPORTS_ATOMIC_RMW
Currently, since all the architectures that support Rust all have
CONFIG_ARCH_SUPPORTS_ATOMIC_RMW selected, the helpers of atomic
load/store on i8 and i16 relies on CONFIG_ARCH_SUPPORTS_ATOMIC_RMW=y.
It's generally fine since most of architectures support that.
The plan for CONFIG_ARCH_SUPPORTS_ATOMIC_RMW=n architectures is adding
their (probably lock-based) atomic load/store for i8 and i16 as their
atomic_{read,set}() and atomic64_{read,set}() counterpart when they
plans to support Rust.
Hence use a statis_assert!() to check this and remind the future us the
need of the helpers. This is more clear than the #[cfg] on impl blocks
of i8 and i16.
Suggested-by: Dirk Behme <dirk.behme@gmail.com>
Suggested-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260120140503.62804-2-boqun.feng@gmail.com
Link: https://patch.msgid.link/20260303201701.12204-7-boqun@kernel.org
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|
| bebf7bdc | 03-Mar-2026 |
FUJITA Tomonori <fujita.tomonori@gmail.com> |
rust: sync: atomic: Add example for Atomic::get_mut()
Add an example for Atomic::get_mut(). No functional change.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: Boqun Fen
rust: sync: atomic: Add example for Atomic::get_mut()
Add an example for Atomic::get_mut(). No functional change.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260128123313.3850604-1-tomo@aliasing.net
Link: https://patch.msgid.link/20260303201701.12204-3-boqun@kernel.org
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|
| bd36f6e2 | 23-Jan-2026 |
Miguel Ojeda <ojeda@kernel.org> |
rust: sync: atomic: Provide stub for `rusttest` 32-bit hosts
For arm32, on a x86_64 builder, running the `rusttest` target yields:
error[E0080]: evaluation of constant value failed
--> ru
rust: sync: atomic: Provide stub for `rusttest` 32-bit hosts
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>
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|
| ccf9e070 | 18-Dec-2025 |
Alice Ryhl <aliceryhl@google.com> |
rust: sync: Inline various lock related methods
While debugging a different issue [1], the following relocation was
noticed in the rust_binder.ko file:
R_AARCH64_CALL26 _RNvXNtNtNtCsdfZWD8DztAw_6k
rust: sync: Inline various lock related methods
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
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|
| 4bac2872 | 01-Jan-2026 |
FUJITA Tomonori <fujita.tomonori@gmail.com> |
rust: sync: atomic: Add atomic bool tests
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:
rust: sync: atomic: Add atomic bool tests
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
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|
| 06bd0e52 | 01-Jan-2026 |
FUJITA Tomonori <fujita.tomonori@gmail.com> |
rust: sync: atomic: Add atomic bool support via i8 representation
Add `bool` support, `Atomic<bool>` by using `i8` as its underlying
representation.
Rust specifies that `bool` has size 1 and alignm
rust: sync: atomic: Add atomic bool support via i8 representation
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
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|
| 584f286f | 28-Dec-2025 |
FUJITA Tomonori <fujita.tomonori@gmail.com> |
rust: sync: atomic: Add i8/i16 xchg and cmpxchg support
Add atomic xchg and cmpxchg operation support for i8 and i16 types
with tests.
Note that since the current implementation of
Atomic::<{i8,i16
rust: sync: atomic: Add i8/i16 xchg and cmpxchg support
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
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|
| 7b001c97 | 11-Dec-2025 |
FUJITA Tomonori <fujita.tomonori@gmail.com> |
rust: sync: atomic: Add store_release/load_acquire tests
Add minimum store_release/load_acquire tests.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo
rust: sync: atomic: Add store_release/load_acquire tests
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
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|
| b33796d5 | 11-Dec-2025 |
FUJITA Tomonori <fujita.tomonori@gmail.com> |
rust: sync: atomic: Add i8/i16 load and store support
Add atomic operation support for i8 and i16 types using volatile
read/write and smp_load_acquire/smp_store_release helpers.
[boqun: Adjust [1]
rust: sync: atomic: Add i8/i16 load and store support
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
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|
| 2bb8c41e | 28-Dec-2025 |
FUJITA Tomonori <fujita.tomonori@gmail.com> |
rust: sync: atomic: Prepare AtomicOps macros for i8/i16 support
Rework the internal AtomicOps macro plumbing to generate per-type
implementations from a mapping list.
Capture the trait definition o
rust: sync: atomic: Prepare AtomicOps macros for i8/i16 support
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
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|
| 09248ed8 | 18-Dec-2025 |
Alice Ryhl <aliceryhl@google.com> |
rust: sync: Implement Unpin for ARef
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
rust: sync: Implement Unpin for ARef
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
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|