mirror of https://github.com/torvalds/linux.git
21 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Danilo Krummrich
|
75a7b151e8 |
rust: devres: fix leaking call to devm_add_action()
When the data argument of Devres::new() is Err(), we leak the preceding
call to devm_add_action().
In order to fix this, call devm_add_action() in a unit type initializer in
try_pin_init!() after the initializers of all other fields.
Fixes:
|
|
Linus Torvalds
|
352af6a011 |
Rust changes for v6.17
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.
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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
...
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Danilo Krummrich
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85aa5b16fe |
rust: devres: provide an accessor for the device
Provide an accessor for the Device a Devres instance has been created with. For instance, this is useful when registrations want to provide a &Device<Bound> for a scope that is protected by Devres. Suggested-by: Benno Lossin <lossin@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Benno Lossin <lossin@kernel.org> Link: https://lore.kernel.org/r/20250713182737.64448-1-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org> |
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Danilo Krummrich
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91ae26b06a |
rust: devres: initialize Devres::inner::data last
Users may want to access the Devres object from callbacks registered through the initialization of Devres::inner::data. For those accesses to be valid, Devres::inner::data must be initialized last [1]. Credit to Boqun for spotting this [2]. Link: https://lore.kernel.org/lkml/DBBPHO26CPBS.2OVI1OERCB2J5@kernel.org/ [1] Link: https://lore.kernel.org/lkml/aHSmxWeIy3L-AKIV@Mac.home/ [2] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20250714113712.22158-1-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org> |
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Tamir Duberstein
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6d16cd5769 |
rust: devres: remove unused import
As far as I can tell, `c_str` was never used, hence remove it. Signed-off-by: Tamir Duberstein <tamird@gmail.com> Link: https://lore.kernel.org/r/20250704-cstr-include-devres-v1-1-4ee9e56fca09@gmail.com Signed-off-by: Danilo Krummrich <dakr@kernel.org> |
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Danilo Krummrich
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f5d3ef25d2 |
rust: devres: get rid of Devres' inner Arc
So far Devres uses an inner memory allocation and reference count, i.e. an inner Arc, in order to ensure that the devres callback can't run into a use-after-free in case where the Devres object is dropped while the devres callback runs concurrently. Instead, use a completion in order to avoid a potential UAF: In Devres::drop(), if we detect that we can't remove the devres action anymore, we wait for the completion that is completed from the devres callback. If, in turn, we were able to successfully remove the devres action, we can just go ahead. This, again, allows us to get rid of the internal Arc, and instead let Devres consume an `impl PinInit<T, E>` in order to return an `impl PinInit<Devres<T>, E>`, which enables us to get away with less memory allocations. Additionally, having the resulting explicit synchronization in Devres::drop() prevents potential subtle undesired side effects of the devres callback dropping the final Arc reference asynchronously within the devres callback. Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20250626200054.243480-4-dakr@kernel.org [ Move '# Invariants' below '# Examples'. - Danilo ] Signed-off-by: Danilo Krummrich <dakr@kernel.org> |
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Danilo Krummrich
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46ae8fd738 |
rust: devres: replace Devres::new_foreign_owned()
Replace Devres::new_foreign_owned() with devres::register(). The current implementation of Devres::new_foreign_owned() creates a full Devres container instance, including the internal Revocable and completion. However, none of that is necessary for the intended use of giving full ownership of an object to devres and getting it dropped once the given device is unbound. Hence, implement devres::register(), which is limited to consume the given data, wrap it in a KBox and drop the KBox once the given device is unbound, without any other synchronization. Cc: Dave Airlie <airlied@redhat.com> Cc: Simona Vetter <simona.vetter@ffwll.ch> Cc: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20250626200054.243480-3-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org> |
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Danilo Krummrich
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ce7c22b2e1 |
rust: revocable: support fallible PinInit types
Currently, Revocable::new() only supports infallible PinInit implementations, i.e. impl PinInit<T, Infallible>. This has been sufficient so far, since users such as Devres do not support fallibility. Since this is about to change, make Revocable::new() generic over the error type E. Reviewed-by: Benno Lossin <lossin@kernel.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Miguel Ojeda <ojeda@kernel.org> Link: https://lore.kernel.org/r/20250626200054.243480-2-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org> |
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Danilo Krummrich
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0dab138d0f |
rust: devres: require T: Send for Devres
Due to calling Revocable::revoke() from Devres::devres_callback() T may
be dropped from Devres::devres_callback() and hence must be Send.
Fix this by adding the corresponding bound to Devres and DevresInner.
Reported-by: Boqun Feng <boqun.feng@gmail.com>
Closes: https://lore.kernel.org/lkml/aFzI5L__OcB9hqdG@Mac.home/
Fixes:
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Viresh Kumar
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b6985083be |
rust: Use consistent "# Examples" heading style in rustdoc
Use a consistent `# Examples` heading in rustdoc across the codebase. Some modules previously used `## Examples` (even when they should be available as top-level headers), while others used `# Example`, which deviates from the preferred `# Examples` style. Suggested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Benno Lossin <lossin@kernel.org> Link: https://lore.kernel.org/r/ddd5ce0ac20c99a72a4f1e4322d3de3911056922.1749545815.git.viresh.kumar@linaro.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org> |
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Tamir Duberstein
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5e30550558 |
rust: enable `clippy::as_underscore` lint
In Rust 1.63.0, Clippy introduced the `as_underscore` lint [1]: > The conversion might include lossy conversion or a dangerous cast that > might go undetected due to the type being inferred. > > The lint is allowed by default as using `_` is less wordy than always > specifying the type. Always specifying the type is especially helpful in function call contexts where the inferred type may change at a distance. Specifying the type also allows Clippy to spot more cases of `useless_conversion`. The primary downside is the need to specify the type in trivial getters. There are 4 such functions: 3 have become slightly less ergonomic, 1 was revealed to be a `useless_conversion`. While this doesn't eliminate unchecked `as` conversions, it makes such conversions easier to scrutinize. It also has the slight benefit of removing a degree of freedom on which to bikeshed. Thus apply the changes and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_underscore [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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-4-f43b024581e8@gmail.com [ Changed `isize` to `c_long`. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org> |
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Tamir Duberstein
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23773bd8da |
rust: enable `clippy::as_ptr_cast_mut` lint
In Rust 1.66.0, Clippy introduced the `as_ptr_cast_mut` lint [1]: > Since `as_ptr` takes a `&self`, the pointer won’t have write > permissions unless interior mutability is used, making it unlikely > that having it as a mutable pointer is correct. There is only one affected callsite, and the change amounts to replacing `as _` with `.cast_mut().cast()`. This doesn't change the semantics, but is more descriptive of what's going on. Apply this change and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_ptr_cast_mut [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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-3-f43b024581e8@gmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org> |
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Tamir Duberstein
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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> |
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Danilo Krummrich
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20c96ed278 |
rust: devres: do not dereference to the internal Revocable
We can't expose direct access to the internal Revocable, since this
allows users to directly revoke the internal Revocable without Devres
having the chance to synchronize with the devres callback -- we have to
guarantee that the internal Revocable has been fully revoked before
the device is fully unbound.
Hence, remove the corresponding Deref implementation and, instead,
provide indirect accessors for the internal Revocable.
Note that we can still support Devres::revoke() by implementing the
required synchronization (which would be almost identical to the
synchronization in Devres::drop()).
Fixes:
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Danilo Krummrich
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f744201c61 |
rust: devres: fix race in Devres::drop()
In Devres::drop() we first remove the devres action and then drop the wrapped device resource. The design goal is to give the owner of a Devres object control over when the device resource is dropped, but limit the overall scope to the corresponding device being bound to a driver. However, there's a race that was introduced with commit |
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Miguel Ojeda
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42055939a3 |
rust: devres: fix doctest build under `!CONFIG_PCI`
The doctest requires `CONFIG_PCI`:
error[E0432]: unresolved import `kernel::pci`
--> rust/doctests_kernel_generated.rs:2689:44
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2689 | use kernel::{device::Core, devres::Devres, pci};
| ^^^ no `pci` in the root
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note: found an item that was configured out
--> rust/kernel/lib.rs:96:9
note: the item is gated here
--> rust/kernel/lib.rs:95:1
Thus conditionally compile it (which still checks the syntax).
Fixes:
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Danilo Krummrich
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f301cb978c |
rust: devres: implement Devres::access()
Implement a direct accessor for the data stored within the Devres for cases where we can prove that we own a reference to a Device<Bound> (i.e. a bound device) of the same device that was used to create the corresponding Devres container. Usually, when accessing the data stored within a Devres container, it is not clear whether the data has been revoked already due to the device being unbound and, hence, we have to try whether the access is possible and subsequently keep holding the RCU read lock for the duration of the access. However, when we can prove that we hold a reference to Device<Bound> matching the device the Devres container has been created with, we can guarantee that the device is not unbound for the duration of the lifetime of the Device<Bound> reference and, hence, it is not possible for the data within the Devres container to be revoked. Therefore, in this case, we can bypass the atomic check and the RCU read lock, which is a great optimization and simplification for drivers. Reviewed-by: Christian Schrefl <chrisi.schrefl@gmail.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com> Link: https://lore.kernel.org/r/20250428140137.468709-3-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org> |
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Danilo Krummrich
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f720efda2d |
rust: devres: require a bound device
Require the Bound device context to be able to a new Devres container. This ensures that we can't register devres callbacks for unbound devices. Link: https://lore.kernel.org/r/20250413173758.12068-9-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org> |
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Fiona Behrens
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040b17ae0e |
rust: io: fix devres test with new io accessor functions
Fix doctest of `Devres` which still used `writeb` instead of `write8`.
Fixes:
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Danilo Krummrich
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8ff656643d |
rust: devres: remove action in `Devres::drop`
So far `DevresInner` is kept alive, even if `Devres` is dropped until the devres callback is executed to avoid a WARN() when the action has been released already. With the introduction of devm_remove_action_nowarn() we can remove the action in `Devres::drop`, handle the case where the action has been released already and hence also free `DevresInner`. Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20250107122609.8135-2-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Danilo Krummrich
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76c01ded72 |
rust: add devres abstraction
Add a Rust abstraction for the kernel's devres (device resource management) implementation. The Devres type acts as a container to manage the lifetime and accessibility of device bound resources. Therefore it registers a devres callback and revokes access to the resource on invocation. Users of the Devres abstraction can simply free the corresponding resources in their Drop implementation, which is invoked when either the Devres instance goes out of scope or the devres callback leads to the resource being revoked, which implies a call to drop_in_place(). Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Link: https://lore.kernel.org/r/20241219170425.12036-9-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |