177 Commits
Author SHA1 Message Date
Boqun FengandPeter Zijlstra 29c32c405e rust: sync: atomic: Add generic atomics
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/
2025-09-15 09:38:33 +02:00
Boqun FengandPeter Zijlstra b638c9bc47 rust: sync: atomic: Add ordering annotation types
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/
2025-09-15 09:38:33 +02:00
Boqun FengandPeter Zijlstra 2387fb2a9b rust: sync: Add basic atomic operation mapping framework
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/
2025-09-15 09:38:32 +02:00
Benno LossinandMiguel Ojeda a15d12c24f rust: sync: extend module documentation of aref
Commit 07dad44aa9 ("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>
2025-09-15 00:02:22 +02:00
Shankari AnandandMiguel Ojeda 8a7c11af8e rust: sync: Update ARef and AlwaysRefCounted imports from sync::aref
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>
2025-09-08 00:11:19 +02:00
Alice RyhlandDanilo Krummrich bb9749f32a rust: alloc: take the allocator into account for FOREIGN_ALIGN
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>
2025-08-15 20:55:16 +02:00
Linus Torvalds 352af6a011 Merge tag 'rust-6.17' of 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
  ...
2025-08-03 13:49:10 -07:00
Linus Torvalds 72b8944f14 Merge tag 'locking-core-2025-07-29' of 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
2025-07-29 18:11:32 -07:00
Linus Torvalds bf76f23aa1 Merge tag 'sched-core-2025-07-28' of 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
  ...
2025-07-29 17:42:52 -07:00
Linus Torvalds add07519ea Merge tag 'vfs-6.17-rc1.rust' of 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
2025-07-28 14:44:43 -07:00
Shankari AnandandMiguel Ojeda 07dad44aa9 rust: kernel: move ARef and AlwaysRefCounted to sync::aref
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>
2025-07-22 13:52:14 +02:00
Andreas HindborgandMiguel Ojeda 12717ebeff rust: types: add FOREIGN_ALIGN to ForeignOwnable
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>
2025-07-14 23:55:24 +02:00
Peter Zijlstra 8f2146159b Merge branch 'tip/sched/urgent'
Avoid merge conflicts

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
2025-07-14 17:16:28 +02:00
Alice RyhlandChristian Brauner de747bd023 poll: rust: allow poll_table ptrs to be null
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>
2025-07-14 14:12:24 +02:00
Jason DeversandBoqun Feng 99214efede rust: sync: Add #[must_use] to Lock::try_lock()
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
2025-07-11 15:11:54 -07:00
Alexandre CourbotandMiguel Ojeda 2009a2d569 rust: sync: implement Borrow and BorrowMut for Arc types
Implement `Borrow<T>` and `BorrowMut<T>` for `UniqueArc<T>`, and
`Borrow<T>` for `Arc<T>`. This allows these containers to be used in
generic APIs asking for types implementing those traits. `T` and `&mut
T` also implement those traits allowing users to use either owned,
shared or borrowed values.

`ForeignOwnable` makes a call to its own `borrow` method which must be
disambiguated.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250616-borrow_impls-v4-2-36f9beb3fe6a@nvidia.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-07-03 20:46:29 +02:00
Kunwu ChanandBoqun Feng 11867144ff rust: sync: Mark PollCondVar::drop() inline
When building the kernel using the llvm-18.1.3-rust-1.85.0-x86_64
with ARCH=arm64, the following symbols are generated:

$nm vmlinux | grep ' _R'.*PollCondVar  | rustfilt
... T <kernel::sync::poll::PollCondVar as kernel::init::PinnedDrop>::drop
...

This Rust symbol is trivial wrappers around the C functions
__wake_up_pollfree() and synchronize_rcu(). It doesn't make sense to go
through a trivial wrapper for its functions, so mark it inline.

[boqun: Reword the commit title and re-format the commit log per tip
tree's requirement, remove unnecessary information from "nm vmlinux"
result.]

Link: https://github.com/Rust-for-Linux/linux/issues/1145
Suggested-by: Alice Ryhl <aliceryhl@google.com>
Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20250317025205.2366518-1-kunwu.chan@linux.dev
2025-06-24 10:23:48 -07:00
Kunwu ChanandBoqun Feng 3f9ebeba98 rust: sync: Mark CondVar::notify_*() inline
When build the kernel using the llvm-18.1.3-rust-1.85.0-x86_64
with ARCH=arm64, the following symbols are generated:

$nm vmlinux | grep ' _R'.*CondVar | rustfilt
... T <kernel::sync::condvar::CondVar>::notify_all
... T <kernel::sync::condvar::CondVar>::notify_one
... T <kernel::sync::condvar::CondVar>::notify_sync
...

These notify_*() symbols are trivial wrappers around the C functions
__wake_up() and __wake_up_sync(). It doesn't make sense to go through
a trivial wrapper for these functions, so mark them inline.

[boqun: Reword the commit title for consistency and reformat the commit
log.]

Suggested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://github.com/Rust-for-Linux/linux/issues/1145
Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20250324061835.1693125-1-kunwu.chan@linux.dev
2025-06-24 10:23:48 -07:00
Tamir DubersteinandMiguel Ojeda fcad9bbf9e rust: enable clippy::ptr_as_ptr lint
In Rust 1.51.0, Clippy introduced the `ptr_as_ptr` lint [1]:

> Though `as` casts between raw pointers are not terrible,
> `pointer::cast` is safer because it cannot accidentally change the
> pointer's mutability, nor cast the pointer to other types like `usize`.

There are a few classes of changes required:
- Modules generated by bindgen are marked
  `#[allow(clippy::ptr_as_ptr)]`.
- Inferred casts (` as _`) are replaced with `.cast()`.
- Ascribed casts (` as *... T`) are replaced with `.cast::<T>()`.
- Multistep casts from references (` as *const _ as *const T`) are
  replaced with `core::ptr::from_ref(&x).cast()` with or without `::<T>`
  according to the previous rules. The `core::ptr::from_ref` call is
  required because `(x as *const _).cast::<T>()` results in inference
  failure.
- Native literal C strings are replaced with `c_str!().as_char_ptr()`.
- `*mut *mut T as _` is replaced with `let *mut *const T = (*mut *mut
  T)`.cast();` since pointer to pointer can be confusing.

Apply these changes and enable the lint -- no functional change
intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-1-f43b024581e8@gmail.com
[ Added `.cast()` for `opp`. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-06-22 23:08:42 +02:00
Danilo Krummrich 1b56e765bf rust: completion: implement initial abstraction
Implement a minimal abstraction for the completion synchronization
primitive.

This initial abstraction only adds complete_all() and
wait_for_completion(), since that is what is required for the subsequent
Devres patch.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250612121817.1621-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-06-13 23:46:56 +02:00
Linus Torvalds ec7714e494 Merge tag 'rust-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux
Pull Rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - KUnit '#[test]'s:

      - Support KUnit-mapped 'assert!' macros.

        The support that landed last cycle was very basic, and the
        'assert!' macros panicked since they were the standard library
        ones. Now, they are mapped to the KUnit ones in a similar way to
        how is done for doctests, reusing the infrastructure there.

        With this, a failing test like:

            #[test]
            fn my_first_test() {
                assert_eq!(42, 43);
            }

        will report:

            # my_first_test: ASSERTION FAILED at rust/kernel/lib.rs:251
            Expected 42 == 43 to be true, but is false
            # my_first_test.speed: normal
            not ok 1 my_first_test

      - Support tests with checked 'Result' return types.

        The return value of test functions that return a 'Result' will
        be checked, thus one can now easily catch errors when e.g. using
        the '?' operator in tests.

        With this, a failing test like:

            #[test]
            fn my_test() -> Result {
                f()?;
                Ok(())
            }

        will report:

            # my_test: ASSERTION FAILED at rust/kernel/lib.rs:321
            Expected is_test_result_ok(my_test()) to be true, but is false
            # my_test.speed: normal
            not ok 1 my_test

      - Add 'kunit_tests' to the prelude.

   - Clarify the remaining language unstable features in use.

   - Compile 'core' with edition 2024 for Rust >= 1.87.

   - Workaround 'bindgen' issue with forward references to 'enum' types.

   - objtool: relax slice condition to cover more 'noreturn' functions.

   - Use absolute paths in macros referencing 'core' and 'kernel'
     crates.

   - Skip '-mno-fdpic' flag for bindgen in GCC 32-bit arm builds.

   - Clean some 'doc_markdown' lint hits -- we may enable it later on.

  'kernel' crate:

   - 'alloc' module:

      - 'Box': support for type coercion, e.g. 'Box<T>' to 'Box<dyn U>'
        if 'T' implements 'U'.

      - 'Vec': implement new methods (prerequisites for nova-core and
        binder): 'truncate', 'resize', 'clear', 'pop',
        'push_within_capacity' (with new error type 'PushError'),
        'drain_all', 'retain', 'remove' (with new error type
        'RemoveError'), insert_within_capacity' (with new error type
        'InsertError').

        In addition, simplify 'push' using 'spare_capacity_mut', split
        'set_len' into 'inc_len' and 'dec_len', add type invariant 'len
        <= capacity' and simplify 'truncate' using 'dec_len'.

   - 'time' module:

      - Morph the Rust hrtimer subsystem into the Rust timekeeping
        subsystem, covering delay, sleep, timekeeping, timers. This new
        subsystem has all the relevant timekeeping C maintainers listed
        in the entry.

      - Replace 'Ktime' with 'Delta' and 'Instant' types to represent a
        duration of time and a point in time.

      - Temporarily add 'Ktime' to 'hrtimer' module to allow 'hrtimer'
        to delay converting to 'Instant' and 'Delta'.

   - 'xarray' module:

      - Add a Rust abstraction for the 'xarray' data structure. This
        abstraction allows Rust code to leverage the 'xarray' to store
        types that implement 'ForeignOwnable'. This support is a
        dependency for memory backing feature of the Rust null block
        driver, which is waiting to be merged.

      - Set up an entry in 'MAINTAINERS' for the XArray Rust support.
        Patches will go to the new Rust XArray tree and then via the
        Rust subsystem tree for now.

      - Allow 'ForeignOwnable' to carry information about the pointed-to
        type. This helps asserting alignment requirements for the
        pointer passed to the foreign language.

   - 'container_of!': retain pointer mut-ness and add a compile-time
     check of the type of the first parameter ('$field_ptr').

   - Support optional message in 'static_assert!'.

   - Add C FFI types (e.g. 'c_int') to the prelude.

   - 'str' module: simplify KUnit tests 'format!' macro, convert
     'rusttest' tests into KUnit, take advantage of the '-> Result'
     support in KUnit '#[test]'s.

   - 'list' module: add examples for 'List', fix path of
     'assert_pinned!' (so far unused macro rule).

   - 'workqueue' module: remove 'HasWork::OFFSET'.

   - 'page' module: add 'inline' attribute.

  'macros' crate:

   - 'module' macro: place 'cleanup_module()' in '.exit.text' section.

  'pin-init' crate:

   - Add 'Wrapper<T>' trait for creating pin-initializers for wrapper
     structs with a structurally pinned value such as 'UnsafeCell<T>' or
     'MaybeUninit<T>'.

   - Add 'MaybeZeroable' derive macro to try to derive 'Zeroable', but
     not error if not all fields implement it. This is needed to derive
     'Zeroable' for all bindgen-generated structs.

   - Add 'unsafe fn cast_[pin_]init()' functions to unsafely change the
     initialized type of an initializer. These are utilized by the
     'Wrapper<T>' implementations.

   - Add support for visibility in 'Zeroable' derive macro.

   - Add support for 'union's in 'Zeroable' derive macro.

   - Upstream dev news: streamline CI, fix some bugs. Add new workflows
     to check if the user-space version and the one in the kernel tree
     have diverged. Use the issues tab [1] to track them, which should
     help folks report and diagnose issues w.r.t. 'pin-init' better.

       [1] https://github.com/rust-for-linux/pin-init/issues

  Documentation:

   - Testing: add docs on the new KUnit '#[test]' tests.

   - Coding guidelines: explain that '///' vs. '//' applies to private
     items too. Add section on C FFI types.

   - Quick Start guide: update Ubuntu instructions and split them into
     "25.04" and "24.04 LTS and older".

  And a few other cleanups and improvements"

* tag 'rust-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (78 commits)
  rust: list: Fix typo `much` in arc.rs
  rust: check type of `$ptr` in `container_of!`
  rust: workqueue: remove HasWork::OFFSET
  rust: retain pointer mut-ness in `container_of!`
  Documentation: rust: testing: add docs on the new KUnit `#[test]` tests
  Documentation: rust: rename `#[test]`s to "`rusttest` host tests"
  rust: str: take advantage of the `-> Result` support in KUnit `#[test]`'s
  rust: str: simplify KUnit tests `format!` macro
  rust: str: convert `rusttest` tests into KUnit
  rust: add `kunit_tests` to the prelude
  rust: kunit: support checked `-> Result`s in KUnit `#[test]`s
  rust: kunit: support KUnit-mapped `assert!` macros in `#[test]`s
  rust: make section names plural
  rust: list: fix path of `assert_pinned!`
  rust: compile libcore with edition 2024 for 1.87+
  rust: dma: add missing Markdown code span
  rust: task: add missing Markdown code spans and intra-doc links
  rust: pci: fix docs related to missing Markdown code spans
  rust: alloc: add missing Markdown code span
  rust: alloc: add missing Markdown code spans
  ...
2025-06-04 21:18:37 -07:00
Patrick MillerandMiguel Ojeda 4bf7b97eb3 rust: make section names plural
Clean Rust documentation section headers to use plural names.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1110
Signed-off-by: Patrick Miller <paddymills@proton.me>
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 <ojeda@kernel.org>
2025-05-26 18:03:09 +02:00
Miguel Ojeda 06ff274f25 Merge tag 'rust-xarray-for-v6.16' of https://github.com/Rust-for-Linux/linux into rust-next
Pull XArray updates from Andreas Hindborg:
 "Introduce Rust support for the 'xarray' data structure:

   - Add a Rust abstraction for the 'xarray' data structure. This
     abstraction allows Rust code to leverage the 'xarray' to store
     types that implement 'ForeignOwnable'. This support is a dependency
     for memory backing feature of the Rust null block driver, which is
     waiting to be merged.

   - Set up an entry in MAINTAINERS for the XArray Rust support. Patches
     will go to the new Rust XArray tree and then via the Rust subsystem
     tree for now.

  'kernel' crate:

   - Allow 'ForeignOwnable' to carry information about the pointed-to
     type. This helps asserting alignment requirements for the pointer
     passed to the foreign language."

* tag 'rust-xarray-for-v6.16' of https://github.com/Rust-for-Linux/linux:
  MAINTAINERS: add entry for Rust XArray API
  rust: xarray: Add an abstraction for XArray
  rust: types: add `ForeignOwnable::PointedTo`
2025-05-18 20:36:56 +02:00
I Hsin ChengandJoel Fernandes 9520371e3d rust: sync: rcu: Mark Guard methods as inline
Currently the implementation of "Guard" methods are basically wrappers
around rcu's function within kernel. Building the kernel with llvm
18.1.8 on x86_64 machine will generate the following symbols:

$ nm vmlinux | grep ' _R'.*Guard | rustfilt
ffffffff817b6c90 T <kernel::sync::rcu::Guard>::new
ffffffff817b6cb0 T <kernel::sync::rcu::Guard>::unlock
ffffffff817b6cd0 T <kernel::sync::rcu::Guard as core::ops::drop::Drop>::drop
ffffffff817b6c90 T <kernel::sync::rcu::Guard as core::default::Default>::default

These Rust symbols are basically wrappers around functions
"rcu_read_lock" and "rcu_read_unlock". Marking them as inline can
reduce the generation of these symbols, and saves the size of code
generation for 132 bytes.

$ ./scripts/bloat-o-meter vmlinux_old vmlinux_new
(Output is demangled for readability)

add/remove: 0/10 grow/shrink: 0/1 up/down: 0/-132 (-132)
Function                                     old     new   delta
rust_driver_pci::SampleDriver::probe        1041    1034      -7
kernel::sync::rcu::Guard::default             9       -      -9
kernel::sync::rcu::Guard::drop                9       -      -9
kernel::sync::rcu::read_lock                  9       -      -9
kernel::sync::rcu::Guard::unlock              9       -      -9
kernel::sync::rcu::Guard::new                 9       -      -9
__pfx__kernel::sync::rcu::Guard::default     16       -     -16
__pfx__kernel::sync::rcu::Guard::drop        16       -     -16
__pfx__kernel::sync::rcu::read_lock          16       -     -16
__pfx__kernel::sync::rcu::Guard::unlock      16       -     -16
__pfx__kernel::sync::rcu::Guard::new         16       -     -16
Total: Before=23365955, After=23365823, chg -0.00%

Link: https://github.com/Rust-for-Linux/linux/issues/1145
Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Charalampos Mitrodimas <charmitro@posteo.net>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
2025-05-16 09:00:54 -04:00
Xizhe YinandMiguel Ojeda 86d990c7b6 rust: convert raw URLs to Markdown autolinks in comments
Some comments in Rust files use raw URLs (http://example.com) rather
than Markdown autolinks <URL>. This inconsistency makes the
documentation less uniform and harder to maintain.

This patch converts all remaining raw URLs in Rust code comments to use
the Markdown autolink format, maintaining consistency with the rest of
the codebase which already uses this style.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1153
Signed-off-by: Xizhe Yin <xizheyin@smail.nju.edu.cn>
Link: https://lore.kernel.org/r/509F0B66E3C1575D+20250407033441.5567-1-xizheyin@smail.nju.edu.cn
[ Used From form for Signed-off-by. Sorted tags. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-05-12 00:20:25 +02:00