<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/rust/kernel/list/arc.rs, branch v7.1-rc4</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'locking-core-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2026-04-14T19:36:25+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-04-14T19:36:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7393febcb1b2082c0484952729cbebfe4dc508d5'/>
<id>7393febcb1b2082c0484952729cbebfe4dc508d5</id>
<content type='text'>
Pull locking updates from Ingo Molnar:
 "Mutexes:

   - Add killable flavor to guard definitions (Davidlohr Bueso)

   - Remove the list_head from struct mutex (Matthew Wilcox)

   - Rename mutex_init_lockep() (Davidlohr Bueso)

  rwsems:

   - Remove the list_head from struct rw_semaphore and
     replace it with a single pointer (Matthew Wilcox)

   - Fix logic error in rwsem_del_waiter() (Andrei Vagin)

  Semaphores:

   - Remove the list_head from struct semaphore (Matthew Wilcox)

  Jump labels:

   - Use ATOMIC_INIT() for initialization of .enabled (Thomas Weißschuh)

   - Remove workaround for old compilers in initializations
     (Thomas Weißschuh)

  Lock context analysis changes and improvements:

   - Add context analysis for rwsems (Peter Zijlstra)

   - Fix rwlock and spinlock lock context annotations (Bart Van Assche)

   - Fix rwlock support in &lt;linux/spinlock_up.h&gt; (Bart Van Assche)

   - Add lock context annotations in the spinlock implementation
     (Bart Van Assche)

   - signal: Fix the lock_task_sighand() annotation (Bart Van Assche)

   - ww-mutex: Fix the ww_acquire_ctx function annotations
     (Bart Van Assche)

   - Add lock context support in do_raw_{read,write}_trylock()
     (Bart Van Assche)

   - arm64, compiler-context-analysis: Permit alias analysis through
     __READ_ONCE() with CONFIG_LTO=y (Marco Elver)

   - Add __cond_releases() (Peter Zijlstra)

   - Add context analysis for mutexes (Peter Zijlstra)

   - Add context analysis for rtmutexes (Peter Zijlstra)

   - Convert futexes to compiler context analysis (Peter Zijlstra)

  Rust integration updates:

   - Add atomic fetch_sub() implementation (Andreas Hindborg)

   - Refactor various rust_helper_ methods for expansion (Boqun Feng)

   - Add Atomic&lt;*{mut,const} T&gt; support (Boqun Feng)

   - Add atomic operation helpers over raw pointers (Boqun Feng)

   - Add performance-optimal Flag type for atomic booleans, to avoid
     slow byte-sized RMWs on architectures that don't support them.
     (FUJITA Tomonori)

   - Misc cleanups and fixes (Andreas Hindborg, Boqun Feng, FUJITA
     Tomonori)

  LTO support updates:

   - arm64: Optimize __READ_ONCE() with CONFIG_LTO=y (Marco Elver)

   - compiler: Simplify generic RELOC_HIDE() (Marco Elver)

  Miscellaneous fixes and cleanups by Peter Zijlstra, Randy Dunlap,
  Thomas Weißschuh, Davidlohr Bueso and Mikhail Gavrilov"

* tag 'locking-core-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits)
  compiler: Simplify generic RELOC_HIDE()
  locking: Add lock context annotations in the spinlock implementation
  locking: Add lock context support in do_raw_{read,write}_trylock()
  locking: Fix rwlock support in &lt;linux/spinlock_up.h&gt;
  lockdep: Raise default stack trace limits when KASAN is enabled
  cleanup: Optimize guards
  jump_label: remove workaround for old compilers in initializations
  jump_label: use ATOMIC_INIT() for initialization of .enabled
  futex: Convert to compiler context analysis
  locking/rwsem: Fix logic error in rwsem_del_waiter()
  locking/rwsem: Add context analysis
  locking/rtmutex: Add context analysis
  locking/mutex: Add context analysis
  compiler-context-analysys: Add __cond_releases()
  locking/mutex: Remove the list_head from struct mutex
  locking/semaphore: Remove the list_head from struct semaphore
  locking/rwsem: Remove the list_head from struct rw_semaphore
  rust: atomic: Update a safety comment in impl of `fetch_add()`
  rust: sync: atomic: Update documentation for `fetch_add()`
  rust: sync: atomic: Add fetch_sub()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull locking updates from Ingo Molnar:
 "Mutexes:

   - Add killable flavor to guard definitions (Davidlohr Bueso)

   - Remove the list_head from struct mutex (Matthew Wilcox)

   - Rename mutex_init_lockep() (Davidlohr Bueso)

  rwsems:

   - Remove the list_head from struct rw_semaphore and
     replace it with a single pointer (Matthew Wilcox)

   - Fix logic error in rwsem_del_waiter() (Andrei Vagin)

  Semaphores:

   - Remove the list_head from struct semaphore (Matthew Wilcox)

  Jump labels:

   - Use ATOMIC_INIT() for initialization of .enabled (Thomas Weißschuh)

   - Remove workaround for old compilers in initializations
     (Thomas Weißschuh)

  Lock context analysis changes and improvements:

   - Add context analysis for rwsems (Peter Zijlstra)

   - Fix rwlock and spinlock lock context annotations (Bart Van Assche)

   - Fix rwlock support in &lt;linux/spinlock_up.h&gt; (Bart Van Assche)

   - Add lock context annotations in the spinlock implementation
     (Bart Van Assche)

   - signal: Fix the lock_task_sighand() annotation (Bart Van Assche)

   - ww-mutex: Fix the ww_acquire_ctx function annotations
     (Bart Van Assche)

   - Add lock context support in do_raw_{read,write}_trylock()
     (Bart Van Assche)

   - arm64, compiler-context-analysis: Permit alias analysis through
     __READ_ONCE() with CONFIG_LTO=y (Marco Elver)

   - Add __cond_releases() (Peter Zijlstra)

   - Add context analysis for mutexes (Peter Zijlstra)

   - Add context analysis for rtmutexes (Peter Zijlstra)

   - Convert futexes to compiler context analysis (Peter Zijlstra)

  Rust integration updates:

   - Add atomic fetch_sub() implementation (Andreas Hindborg)

   - Refactor various rust_helper_ methods for expansion (Boqun Feng)

   - Add Atomic&lt;*{mut,const} T&gt; support (Boqun Feng)

   - Add atomic operation helpers over raw pointers (Boqun Feng)

   - Add performance-optimal Flag type for atomic booleans, to avoid
     slow byte-sized RMWs on architectures that don't support them.
     (FUJITA Tomonori)

   - Misc cleanups and fixes (Andreas Hindborg, Boqun Feng, FUJITA
     Tomonori)

  LTO support updates:

   - arm64: Optimize __READ_ONCE() with CONFIG_LTO=y (Marco Elver)

   - compiler: Simplify generic RELOC_HIDE() (Marco Elver)

  Miscellaneous fixes and cleanups by Peter Zijlstra, Randy Dunlap,
  Thomas Weißschuh, Davidlohr Bueso and Mikhail Gavrilov"

* tag 'locking-core-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits)
  compiler: Simplify generic RELOC_HIDE()
  locking: Add lock context annotations in the spinlock implementation
  locking: Add lock context support in do_raw_{read,write}_trylock()
  locking: Fix rwlock support in &lt;linux/spinlock_up.h&gt;
  lockdep: Raise default stack trace limits when KASAN is enabled
  cleanup: Optimize guards
  jump_label: remove workaround for old compilers in initializations
  jump_label: use ATOMIC_INIT() for initialization of .enabled
  futex: Convert to compiler context analysis
  locking/rwsem: Fix logic error in rwsem_del_waiter()
  locking/rwsem: Add context analysis
  locking/rtmutex: Add context analysis
  locking/mutex: Add context analysis
  compiler-context-analysys: Add __cond_releases()
  locking/mutex: Remove the list_head from struct mutex
  locking/semaphore: Remove the list_head from struct semaphore
  locking/rwsem: Remove the list_head from struct rw_semaphore
  rust: atomic: Update a safety comment in impl of `fetch_add()`
  rust: sync: atomic: Update documentation for `fetch_add()`
  rust: sync: atomic: Add fetch_sub()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: remove `RUSTC_HAS_COERCE_POINTEE` and simplify code</title>
<updated>2026-04-07T08:00:23+00:00</updated>
<author>
<name>Miguel Ojeda</name>
<email>ojeda@kernel.org</email>
</author>
<published>2026-04-05T23:52:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4ab22c543f18cfbcc2f8ae691dc5ec5cc0ac35fb'/>
<id>4ab22c543f18cfbcc2f8ae691dc5ec5cc0ac35fb</id>
<content type='text'>
With the Rust version bump in place, the `RUSTC_HAS_COERCE_POINTEE`
Kconfig (automatic) option is always true.

Thus remove the option and simplify the code.

In particular, this includes removing our use of the predecessor unstable
features we used with Rust &lt; 1.84.0 (`coerce_unsized`, `dispatch_from_dyn`
and `unsize`).

Reviewed-by: Tamir Duberstein &lt;tamird@kernel.org&gt;
Acked-by: Danilo Krummrich &lt;dakr@kernel.org&gt;
Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Link: https://patch.msgid.link/20260405235309.418950-11-ojeda@kernel.org
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
With the Rust version bump in place, the `RUSTC_HAS_COERCE_POINTEE`
Kconfig (automatic) option is always true.

Thus remove the option and simplify the code.

In particular, this includes removing our use of the predecessor unstable
features we used with Rust &lt; 1.84.0 (`coerce_unsized`, `dispatch_from_dyn`
and `unsize`).

Reviewed-by: Tamir Duberstein &lt;tamird@kernel.org&gt;
Acked-by: Danilo Krummrich &lt;dakr@kernel.org&gt;
Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Link: https://patch.msgid.link/20260405235309.418950-11-ojeda@kernel.org
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: list: hide macros from top-level kernel doc</title>
<updated>2026-03-27T11:15:47+00:00</updated>
<author>
<name>Gary Guo</name>
<email>gary@garyguo.net</email>
</author>
<published>2026-03-12T17:46:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d58f0f146a6e3fe3c6fcf6db1e0d385414bc8713'/>
<id>d58f0f146a6e3fe3c6fcf6db1e0d385414bc8713</id>
<content type='text'>
Due to Rust macro scoping rules, all macros defined in a crate using
`#[macro_export]` end up in the top-level. For the list macros, we
re-export them inside the list module, and expect users to use
`kernel::list::macro_name!()`.

Use `#[doc(hidden)]` on the macro definition, and use `#[doc(inline)]` on
the re-export to make the macro appear to be defined at module-level inside
documentation.

The other exported types are already automatically `#[doc(inline)]` because
they are defined in a non-public module, so there is no need to split the
macro re-exports out.

Signed-off-by: Gary Guo &lt;gary@garyguo.net&gt;
Link: https://patch.msgid.link/20260312174700.4016015-1-gary@kernel.org
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Due to Rust macro scoping rules, all macros defined in a crate using
`#[macro_export]` end up in the top-level. For the list macros, we
re-export them inside the list module, and expect users to use
`kernel::list::macro_name!()`.

Use `#[doc(hidden)]` on the macro definition, and use `#[doc(inline)]` on
the re-export to make the macro appear to be defined at module-level inside
documentation.

The other exported types are already automatically `#[doc(inline)]` because
they are defined in a non-public module, so there is no need to split the
macro re-exports out.

Signed-off-by: Gary Guo &lt;gary@garyguo.net&gt;
Link: https://patch.msgid.link/20260312174700.4016015-1-gary@kernel.org
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: list: Use AtomicFlag in AtomicTracker</title>
<updated>2026-03-08T10:06:50+00:00</updated>
<author>
<name>FUJITA Tomonori</name>
<email>fujita.tomonori@gmail.com</email>
</author>
<published>2026-03-03T20:16:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=282866207020b15c2afc4d43b1ca0c5d96c9032d'/>
<id>282866207020b15c2afc4d43b1ca0c5d96c9032d</id>
<content type='text'>
Make AtomicTracker use AtomicFlag instead of Atomic&lt;bool&gt; to avoid
slow byte-sized RMWs on architectures that don't support them.

Signed-off-by: FUJITA Tomonori &lt;fujita.tomonori@gmail.com&gt;
Signed-off-by: Boqun Feng &lt;boqun@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Link: https://patch.msgid.link/20260129122622.3896144-3-tomo@aliasing.net
Link: https://patch.msgid.link/20260303201701.12204-10-boqun@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Make AtomicTracker use AtomicFlag instead of Atomic&lt;bool&gt; to avoid
slow byte-sized RMWs on architectures that don't support them.

Signed-off-by: FUJITA Tomonori &lt;fujita.tomonori@gmail.com&gt;
Signed-off-by: Boqun Feng &lt;boqun@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Link: https://patch.msgid.link/20260129122622.3896144-3-tomo@aliasing.net
Link: https://patch.msgid.link/20260303201701.12204-10-boqun@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: list: Switch to kernel::sync atomic primitives</title>
<updated>2026-01-09T11:01:41+00:00</updated>
<author>
<name>FUJITA Tomonori</name>
<email>fujita.tomonori@gmail.com</email>
</author>
<published>2025-12-30T09:37:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=323e4bfcbe2dc6c6cac6e007dded0ba4f89a6458'/>
<id>323e4bfcbe2dc6c6cac6e007dded0ba4f89a6458</id>
<content type='text'>
Convert uses of `AtomicBool` to `Atomic&lt;bool&gt;`.

Note that the compare_exchange migration simplifies to
`try_cmpxchg()`, since `try_cmpxchg()` provides relaxed ordering on
failure, making the explicit failure ordering unnecessary.

Signed-off-by: FUJITA Tomonori &lt;fujita.tomonori@gmail.com&gt;
Reviewed-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Signed-off-by: Boqun Feng &lt;boqun.feng@gmail.com&gt;
Link: https://patch.msgid.link/20251230093718.1852322-3-fujita.tomonori@gmail.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Convert uses of `AtomicBool` to `Atomic&lt;bool&gt;`.

Note that the compare_exchange migration simplifies to
`try_cmpxchg()`, since `try_cmpxchg()` provides relaxed ordering on
failure, making the explicit failure ordering unnecessary.

Signed-off-by: FUJITA Tomonori &lt;fujita.tomonori@gmail.com&gt;
Reviewed-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Signed-off-by: Boqun Feng &lt;boqun.feng@gmail.com&gt;
Link: https://patch.msgid.link/20251230093718.1852322-3-fujita.tomonori@gmail.com
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: list: Fix typo `much` in arc.rs</title>
<updated>2025-05-29T21:35:44+00:00</updated>
<author>
<name>Sylvan Smit</name>
<email>sylvan@sylvansmit.com</email>
</author>
<published>2025-05-29T16:29:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7a17bbc1d952057898cb0739e60665908fbb8c72'/>
<id>7a17bbc1d952057898cb0739e60665908fbb8c72</id>
<content type='text'>
Correct the typo (s/much/must) in the ListArc documentation.

Reported-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Closes: https://github.com/Rust-for-Linux/linux/issues/1166
Fixes: a48026315cd7 ("rust: list: add tracking for ListArc")
Signed-off-by: Sylvan Smit &lt;sylvan@sylvansmit.com&gt;
Reviewed-by: Benno Lossin &lt;lossin@kernel.org&gt;
Link: https://lore.kernel.org/r/20250529162923.434978-1-sylvan@sylvansmit.com
[ Changed tag to "Reported-by" and sorted. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Correct the typo (s/much/must) in the ListArc documentation.

Reported-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Closes: https://github.com/Rust-for-Linux/linux/issues/1166
Fixes: a48026315cd7 ("rust: list: add tracking for ListArc")
Signed-off-by: Sylvan Smit &lt;sylvan@sylvansmit.com&gt;
Reviewed-by: Benno Lossin &lt;lossin@kernel.org&gt;
Link: https://lore.kernel.org/r/20250529162923.434978-1-sylvan@sylvansmit.com
[ Changed tag to "Reported-by" and sorted. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: make section names plural</title>
<updated>2025-05-26T16:03:09+00:00</updated>
<author>
<name>Patrick Miller</name>
<email>paddymills@proton.me</email>
</author>
<published>2024-10-02T02:28:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4bf7b97eb390f0a0730572101e0ce3367d31a770'/>
<id>4bf7b97eb390f0a0730572101e0ce3367d31a770</id>
<content type='text'>
Clean Rust documentation section headers to use plural names.

Suggested-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Link: https://github.com/Rust-for-Linux/linux/issues/1110
Signed-off-by: Patrick Miller &lt;paddymills@proton.me&gt;
Link: https://lore.kernel.org/r/20241002022749.390836-1-paddymills@proton.me
[ Removed the `init` one that doesn't apply anymore and
  reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Clean Rust documentation section headers to use plural names.

Suggested-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Link: https://github.com/Rust-for-Linux/linux/issues/1110
Signed-off-by: Patrick Miller &lt;paddymills@proton.me&gt;
Link: https://lore.kernel.org/r/20241002022749.390836-1-paddymills@proton.me
[ Removed the `init` one that doesn't apply anymore and
  reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: list: fix path of `assert_pinned!`</title>
<updated>2025-05-26T15:43:53+00:00</updated>
<author>
<name>Benno Lossin</name>
<email>lossin@kernel.org</email>
</author>
<published>2025-05-25T17:34:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=eb71feaacaaca227ae8f91c8578cf831553c5ab5'/>
<id>eb71feaacaaca227ae8f91c8578cf831553c5ab5</id>
<content type='text'>
Commit dbd5058ba60c ("rust: make pin-init its own crate") moved all
items from pin-init into the pin-init crate, including the
`assert_pinned!` macro.

Thus fix the path of the sole user of the `assert_pinned!` macro.

This occurrence was missed in the commit above, since it is in a macro
rule that has no current users (although binder is a future user).

Cc: stable@kernel.org
Fixes: dbd5058ba60c ("rust: make pin-init its own crate")
Signed-off-by: Benno Lossin &lt;lossin@kernel.org&gt;
Link: https://lore.kernel.org/r/20250525173450.853413-1-lossin@kernel.org
[ Reworded slightly as discussed in the list. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit dbd5058ba60c ("rust: make pin-init its own crate") moved all
items from pin-init into the pin-init crate, including the
`assert_pinned!` macro.

Thus fix the path of the sole user of the `assert_pinned!` macro.

This occurrence was missed in the commit above, since it is in a macro
rule that has no current users (although binder is a future user).

Cc: stable@kernel.org
Fixes: dbd5058ba60c ("rust: make pin-init its own crate")
Signed-off-by: Benno Lossin &lt;lossin@kernel.org&gt;
Link: https://lore.kernel.org/r/20250525173450.853413-1-lossin@kernel.org
[ Reworded slightly as discussed in the list. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: use derive(CoercePointee) on rustc &gt;= 1.84.0</title>
<updated>2025-01-13T22:45:30+00:00</updated>
<author>
<name>Xiangfei Ding</name>
<email>dingxiangfei2009@gmail.com</email>
</author>
<published>2024-12-03T20:47:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=47cb6bf7860ce33bdd000198f8b65cf9fb3324b4'/>
<id>47cb6bf7860ce33bdd000198f8b65cf9fb3324b4</id>
<content type='text'>
The `kernel` crate relies on both `coerce_unsized` and `dispatch_from_dyn`
unstable features.

Alice Ryhl has proposed [1] the introduction of the unstable macro
`SmartPointer` to reduce such dependence, along with a RFC patch [2].
Since Rust 1.81.0 this macro, later renamed to `CoercePointee` in
Rust 1.84.0 [3], has been fully implemented with the naming discussion
resolved.

This feature is now on track to stabilization in the language.
In order to do so, we shall start using this macro in the `kernel` crate
to prove the functionality and utility of the macro as the justification
of its stabilization.

This patch makes this switch in such a way that the crate remains
backward compatible with older Rust compiler versions,
via the new Kconfig option `RUSTC_HAS_COERCE_POINTEE`.

A minimal demonstration example is added to the
`samples/rust/rust_print_main.rs` module.

Link: https://rust-lang.github.io/rfcs/3621-derive-smart-pointer.html [1]
Link: https://lore.kernel.org/all/20240823-derive-smart-pointer-v1-1-53769cd37239@google.com/ [2]
Link: https://github.com/rust-lang/rust/pull/131284 [3]
Signed-off-by: Xiangfei Ding &lt;dingxiangfei2009@gmail.com&gt;
Reviewed-by: Fiona Behrens &lt;me@kloenk.dev&gt;
Reviewed-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Link: https://lore.kernel.org/r/20241203205050.679106-2-dingxiangfei2009@gmail.com
[ Fixed version to 1.84. Renamed option to `RUSTC_HAS_COERCE_POINTEE`
  to match `CC_HAS_*` ones. Moved up new config option, closer to the
  `CC_HAS_*` ones. Simplified Kconfig line. Fixed typos and slightly
  reworded example and commit. Added Link to PR. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The `kernel` crate relies on both `coerce_unsized` and `dispatch_from_dyn`
unstable features.

Alice Ryhl has proposed [1] the introduction of the unstable macro
`SmartPointer` to reduce such dependence, along with a RFC patch [2].
Since Rust 1.81.0 this macro, later renamed to `CoercePointee` in
Rust 1.84.0 [3], has been fully implemented with the naming discussion
resolved.

This feature is now on track to stabilization in the language.
In order to do so, we shall start using this macro in the `kernel` crate
to prove the functionality and utility of the macro as the justification
of its stabilization.

This patch makes this switch in such a way that the crate remains
backward compatible with older Rust compiler versions,
via the new Kconfig option `RUSTC_HAS_COERCE_POINTEE`.

A minimal demonstration example is added to the
`samples/rust/rust_print_main.rs` module.

Link: https://rust-lang.github.io/rfcs/3621-derive-smart-pointer.html [1]
Link: https://lore.kernel.org/all/20240823-derive-smart-pointer-v1-1-53769cd37239@google.com/ [2]
Link: https://github.com/rust-lang/rust/pull/131284 [3]
Signed-off-by: Xiangfei Ding &lt;dingxiangfei2009@gmail.com&gt;
Reviewed-by: Fiona Behrens &lt;me@kloenk.dev&gt;
Reviewed-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Link: https://lore.kernel.org/r/20241203205050.679106-2-dingxiangfei2009@gmail.com
[ Fixed version to 1.84. Renamed option to `RUSTC_HAS_COERCE_POINTEE`
  to match `CC_HAS_*` ones. Moved up new config option, closer to the
  `CC_HAS_*` ones. Simplified Kconfig line. Fixed typos and slightly
  reworded example and commit. Added Link to PR. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: enable arbitrary_self_types and remove `Receiver`</title>
<updated>2024-10-07T19:39:57+00:00</updated>
<author>
<name>Gary Guo</name>
<email>gary@garyguo.net</email>
</author>
<published>2024-09-15T13:26:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c95bbb59a9b22f9b838b15d28319185c1c884329'/>
<id>c95bbb59a9b22f9b838b15d28319185c1c884329</id>
<content type='text'>
The term "receiver" means that a type can be used as the type of `self`,
and thus enables method call syntax `foo.bar()` instead of
`Foo::bar(foo)`. Stable Rust as of today (1.81) enables a limited
selection of types (primitives and types in std, e.g. `Box` and `Arc`)
to be used as receivers, while custom types cannot.

We want the kernel `Arc` type to have the same functionality as the Rust
std `Arc`, so we use the `Receiver` trait (gated behind `receiver_trait`
unstable feature) to gain the functionality.

The `arbitrary_self_types` RFC [1] (tracking issue [2]) is accepted and
it will allow all types that implement a new `Receiver` trait (different
from today's unstable trait) to be used as receivers. This trait will be
automatically implemented for all `Deref` types, which include our `Arc`
type, so we no longer have to opt-in to be used as receiver. To prepare
us for the change, remove the `Receiver` implementation and the
associated feature. To still allow `Arc` and others to be used as method
receivers, turn on `arbitrary_self_types` feature instead.

This feature gate is introduced in 1.23.0. It used to enable both
`Deref` types and raw pointer types to be used as receivers, but the
latter is now split into a different feature gate in Rust 1.83 nightly.
We do not need receivers on raw pointers so this change would not affect
us and usage of `arbitrary_self_types` feature would work for all Rust
versions that we support (&gt;=1.78).

Cc: Adrian Taylor &lt;ade@hohum.me.uk&gt;
Link: https://github.com/rust-lang/rfcs/pull/3519 [1]
Link: https://github.com/rust-lang/rust/issues/44874 [2]
Signed-off-by: Gary Guo &lt;gary@garyguo.net&gt;
Reviewed-by: Benno Lossin &lt;benno.lossin@proton.me&gt;
Reviewed-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Link: https://lore.kernel.org/r/20240915132734.1653004-1-gary@garyguo.net
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The term "receiver" means that a type can be used as the type of `self`,
and thus enables method call syntax `foo.bar()` instead of
`Foo::bar(foo)`. Stable Rust as of today (1.81) enables a limited
selection of types (primitives and types in std, e.g. `Box` and `Arc`)
to be used as receivers, while custom types cannot.

We want the kernel `Arc` type to have the same functionality as the Rust
std `Arc`, so we use the `Receiver` trait (gated behind `receiver_trait`
unstable feature) to gain the functionality.

The `arbitrary_self_types` RFC [1] (tracking issue [2]) is accepted and
it will allow all types that implement a new `Receiver` trait (different
from today's unstable trait) to be used as receivers. This trait will be
automatically implemented for all `Deref` types, which include our `Arc`
type, so we no longer have to opt-in to be used as receiver. To prepare
us for the change, remove the `Receiver` implementation and the
associated feature. To still allow `Arc` and others to be used as method
receivers, turn on `arbitrary_self_types` feature instead.

This feature gate is introduced in 1.23.0. It used to enable both
`Deref` types and raw pointer types to be used as receivers, but the
latter is now split into a different feature gate in Rust 1.83 nightly.
We do not need receivers on raw pointers so this change would not affect
us and usage of `arbitrary_self_types` feature would work for all Rust
versions that we support (&gt;=1.78).

Cc: Adrian Taylor &lt;ade@hohum.me.uk&gt;
Link: https://github.com/rust-lang/rfcs/pull/3519 [1]
Link: https://github.com/rust-lang/rust/issues/44874 [2]
Signed-off-by: Gary Guo &lt;gary@garyguo.net&gt;
Reviewed-by: Benno Lossin &lt;benno.lossin@proton.me&gt;
Reviewed-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Link: https://lore.kernel.org/r/20240915132734.1653004-1-gary@garyguo.net
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
