linux-stable.git/rust/helpers/atomic_ext.c, branch master Linux kernel stable tree rust: sync: atomic: Add Atomic<*{mut,const} T> support 2026-03-08T10:06:49+00:00 Boqun Feng boqun.feng@gmail.com 2026-03-03T20:16:55+00:00 ac8f06ade38a49f7725cc219fc6e90d1d4708d2b 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 
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
rust: helpers: Generify the definitions of rust_helper_*_cmpxchg* 2026-03-08T10:06:48+00:00 Boqun Feng boqun.feng@gmail.com 2026-03-03T20:16:53+00:00 a92236bf239cc01fd40d9cbe98fc8b9924c42a82 To support atomic pointers, more cmpxchg helpers will be introduced, hence define macros to generate these helpers to ease the introduction of the future helpers. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260117122243.24404-4-boqun.feng@gmail.com Link: https://patch.msgid.link/20260303201701.12204-6-boqun@kernel.org 
To support atomic pointers, more cmpxchg helpers will be introduced,
hence define macros to generate these helpers to ease the introduction
of the future helpers.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260117122243.24404-4-boqun.feng@gmail.com
Link: https://patch.msgid.link/20260303201701.12204-6-boqun@kernel.org
rust: helpers: Generify the definitions of rust_helper_*_xchg* 2026-03-08T10:06:48+00:00 Boqun Feng boqun.feng@gmail.com 2026-03-03T20:16:52+00:00 f92d22b00e3f75fad2efd965b20d49b4e763b792 To support atomic pointers, more xchg helpers will be introduced, hence define macros to generate these helpers to ease the introduction of the future helpers. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260117122243.24404-3-boqun.feng@gmail.com Link: https://patch.msgid.link/20260303201701.12204-5-boqun@kernel.org 
To support atomic pointers, more xchg helpers will be introduced, hence
define macros to generate these helpers to ease the introduction of the
future helpers.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260117122243.24404-3-boqun.feng@gmail.com
Link: https://patch.msgid.link/20260303201701.12204-5-boqun@kernel.org
rust: helpers: Generify the definitions of rust_helper_*_{read,set}* 2026-03-08T10:06:48+00:00 Boqun Feng boqun.feng@gmail.com 2026-03-03T20:16:51+00:00 ecc8e9fbaac35c8e5cced26f740f846506c4737b To support atomic pointers, more {read,set} helpers will be introduced, hence define macros to generate these helpers to ease the introduction of the future helpers. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260117122243.24404-2-boqun.feng@gmail.com Link: https://patch.msgid.link/20260303201701.12204-4-boqun@kernel.org 
To support atomic pointers, more {read,set} helpers will be introduced,
hence define macros to generate these helpers to ease the introduction
of the future helpers.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260117122243.24404-2-boqun.feng@gmail.com
Link: https://patch.msgid.link/20260303201701.12204-4-boqun@kernel.org
rust: helpers: Add i8/i16 atomic try_cmpxchg_relaxed helpers 2026-01-09T11:01:41+00:00 FUJITA Tomonori fujita.tomonori@gmail.com 2025-12-27T11:59:51+00:00 8de731a6c75547602601a5d219b5cf259ce2b38b Add i8/i16 atomic try_cmpxchg_relaxed helpers that call try_cmpxchg_relaxed() macro implementing atomic try_cmpxchg_relaxed using architecture-specific instructions. [boqun: Use try_cmpxchg_relaxed() instead of raw_try_cmpxchg_relaxed()] Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251227115951.1424458-5-fujita.tomonori@gmail.com 
Add i8/i16 atomic try_cmpxchg_relaxed helpers that call
try_cmpxchg_relaxed() macro implementing atomic try_cmpxchg_relaxed
using architecture-specific instructions.

[boqun: Use try_cmpxchg_relaxed() instead of raw_try_cmpxchg_relaxed()]

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251227115951.1424458-5-fujita.tomonori@gmail.com
rust: helpers: Add i8/i16 atomic try_cmpxchg_release helpers 2026-01-09T11:01:41+00:00 FUJITA Tomonori fujita.tomonori@gmail.com 2025-12-27T11:59:50+00:00 b5992f07a9736ab6279181c848f42227af9945bf Add i8/i16 atomic try_cmpxchg_release helpers that call try_cmpxchg_release() macro implementing atomic try_cmpxchg_release using architecture-specific instructions. [boqun: Use try_cmpxchg_release() instead of raw_try_cmpxchg_release()] Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251227115951.1424458-4-fujita.tomonori@gmail.com 
Add i8/i16 atomic try_cmpxchg_release helpers that call
try_cmpxchg_release() macro implementing atomic try_cmpxchg_release
using architecture-specific instructions.

[boqun: Use try_cmpxchg_release() instead of raw_try_cmpxchg_release()]

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251227115951.1424458-4-fujita.tomonori@gmail.com
rust: helpers: Add i8/i16 atomic try_cmpxchg_acquire helpers 2026-01-09T11:01:41+00:00 FUJITA Tomonori fujita.tomonori@gmail.com 2025-12-27T11:59:49+00:00 fed6aaa392c301721144303d64b7c68575d9d5ef Add i8/i16 atomic try_cmpxchg_acquire helpers that call try_cmpxchg_acquire() macro implementing atomic try_cmpxchg_acquire using architecture-specific instructions. [boqun: Use try_cmpxchg_acquire() instead of raw_try_cmpxchg_acquire()] Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251227115951.1424458-3-fujita.tomonori@gmail.com 
Add i8/i16 atomic try_cmpxchg_acquire helpers that call
try_cmpxchg_acquire() macro implementing atomic try_cmpxchg_acquire
using architecture-specific instructions.

[boqun: Use try_cmpxchg_acquire() instead of raw_try_cmpxchg_acquire()]

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251227115951.1424458-3-fujita.tomonori@gmail.com
rust: helpers: Add i8/i16 atomic try_cmpxchg helpers 2026-01-09T11:01:41+00:00 FUJITA Tomonori fujita.tomonori@gmail.com 2025-12-27T11:59:48+00:00 164e4b5600b32b4ddeac58bb5b37bc1490a1dce4 Add i8/i16 atomic try_cmpxchg helpers that call try_cmpxchg() macro implementing atomic try_cmpxchg using architecture-specific instructions. [boqun: Add comments explaining CONFIG_ARCH_SUPPORTS_ATOMIC_RMW and use try_cmpxchg() instead of raw_try_cmpxchg()] Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20251227115951.1424458-2-fujita.tomonori@gmail.com 
Add i8/i16 atomic try_cmpxchg helpers that call try_cmpxchg() macro
implementing atomic try_cmpxchg using architecture-specific
instructions.

[boqun: Add comments explaining CONFIG_ARCH_SUPPORTS_ATOMIC_RMW and use
try_cmpxchg() instead of raw_try_cmpxchg()]

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251227115951.1424458-2-fujita.tomonori@gmail.com
rust: helpers: Add i8/i16 atomic xchg_relaxed helpers 2026-01-09T11:01:41+00:00 FUJITA Tomonori fujita.tomonori@gmail.com 2025-12-23T06:21:40+00:00 910cbddc416cc30d83966baf378f44e59f3dc5d7 Add i8/i16 atomic xchg_relaxed helpers that call xchg_relaxed() macro implementing atomic xchg_relaxed using architecture-specific instructions. [boqun: Use xchg_relaxed() instead of raw_xchg_relaxed()] Reviewed-by: Alice Ryhl <aliceryhl@google.com> 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/20251223062140.938325-5-fujita.tomonori@gmail.com 
Add i8/i16 atomic xchg_relaxed helpers that call xchg_relaxed() macro
implementing atomic xchg_relaxed using architecture-specific
instructions.

[boqun: Use xchg_relaxed() instead of raw_xchg_relaxed()]

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
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/20251223062140.938325-5-fujita.tomonori@gmail.com
rust: helpers: Add i8/i16 atomic xchg_release helpers 2026-01-09T11:01:40+00:00 FUJITA Tomonori fujita.tomonori@gmail.com 2025-12-23T06:21:39+00:00 1bfca1e7e845a55fa82046727666f713d24ebdad Add i8/i16 atomic xchg_release helpers that call xchg_release() macro implementing atomic xchg_release using architecture-specific instructions. [boqun: Use xchg_release() instead of raw_xchg_release()] Reviewed-by: Alice Ryhl <aliceryhl@google.com> 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/20251223062140.938325-4-fujita.tomonori@gmail.com 
Add i8/i16 atomic xchg_release helpers that call xchg_release() macro
implementing atomic xchg_release using architecture-specific
instructions.

[boqun: Use xchg_release() instead of raw_xchg_release()]

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
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/20251223062140.938325-4-fujita.tomonori@gmail.com