From: FUJITA Tomonori Date: Tue, 10 Jun 2025 13:28:22 +0000 (+0900) Subject: rust: time: Make HasHrTimer generic over HrTimerMode X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e0c0ab04f6785abaa71b9b8dc252cb1a2072c225;p=thirdparty%2Fkernel%2Flinux.git rust: time: Make HasHrTimer generic over HrTimerMode Add a `TimerMode` associated type to the `HasHrTimer` trait to represent the operational mode of the timer, such as absolute or relative expiration. This new type must implement the `HrTimerMode` trait, which defines how expiration values are interpreted. Update the `start()` method to accept an `expires` parameter of type `::Expires` instead of the fixed `Ktime`. This enables different timer modes to provide strongly typed expiration values, such as `Instant` or `Delta`. The `impl_has_hr_timer` macro is also extended to allow specifying the `HrTimerMode`. In the following example, it guarantees that the `start()` method for `Foo` only accepts `Instant`. Using a `Delta` or an `Instant` with a different clock source will result in a compile-time error: struct Foo { #[pin] timer: HrTimer, } impl_has_hr_timer! { impl HasHrTimer for Foo { mode : AbsoluteMode, field : self.timer } } This design eliminates runtime mismatches between expires types and clock sources, and enables stronger type-level guarantees throughout hrtimer. Signed-off-by: FUJITA Tomonori Reviewed-by: Andreas Hindborg Link: https://lore.kernel.org/r/20250610132823.3457263-5-fujita.tomonori@gmail.com [ changed conversion method names to `as_*` - Andreas ] Signed-off-by: Andreas Hindborg --- diff --git a/rust/kernel/time/hrtimer.rs b/rust/kernel/time/hrtimer.rs index cae7aad6e46d8..8b15eb374db01 100644 --- a/rust/kernel/time/hrtimer.rs +++ b/rust/kernel/time/hrtimer.rs @@ -98,7 +98,6 @@ impl Ktime { pub struct HrTimer { #[pin] timer: Opaque, - mode: bindings::hrtimer_mode, _t: PhantomData, } @@ -112,9 +111,10 @@ unsafe impl Sync for HrTimer {} impl HrTimer { /// Return an initializer for a new timer instance. - pub fn new() -> impl PinInit + pub fn new() -> impl PinInit where T: HrTimerCallback, + T: HasHrTimer, { pin_init!(Self { // INVARIANT: We initialize `timer` with `hrtimer_setup` below. @@ -126,12 +126,11 @@ impl HrTimer { bindings::hrtimer_setup( place, Some(T::Pointer::run), - U::ID, - M::C_MODE, + <>::TimerMode as HrTimerMode>::Clock::ID, + >::TimerMode::C_MODE, ); } }), - mode: M::C_MODE, _t: PhantomData, }) } @@ -193,6 +192,11 @@ impl HrTimer { /// exist. A timer can be manipulated through any of the handles, and a handle /// may represent a cancelled timer. pub trait HrTimerPointer: Sync + Sized { + /// The operational mode associated with this timer. + /// + /// This defines how the expiration value is interpreted. + type TimerMode: HrTimerMode; + /// A handle representing a started or restarted timer. /// /// If the timer is running or if the timer callback is executing when the @@ -205,7 +209,7 @@ pub trait HrTimerPointer: Sync + Sized { /// Start the timer with expiry after `expires` time units. If the timer was /// already running, it is restarted with the new expiry time. - fn start(self, expires: Ktime) -> Self::TimerHandle; + fn start(self, expires: ::Expires) -> Self::TimerHandle; } /// Unsafe version of [`HrTimerPointer`] for situations where leaking the @@ -220,6 +224,11 @@ pub trait HrTimerPointer: Sync + Sized { /// [`UnsafeHrTimerPointer`] outlives any associated [`HrTimerPointer::TimerHandle`] /// instances. pub unsafe trait UnsafeHrTimerPointer: Sync + Sized { + /// The operational mode associated with this timer. + /// + /// This defines how the expiration value is interpreted. + type TimerMode: HrTimerMode; + /// A handle representing a running timer. /// /// # Safety @@ -236,7 +245,7 @@ pub unsafe trait UnsafeHrTimerPointer: Sync + Sized { /// /// Caller promises keep the timer structure alive until the timer is dead. /// Caller can ensure this by not leaking the returned [`Self::TimerHandle`]. - unsafe fn start(self, expires: Ktime) -> Self::TimerHandle; + unsafe fn start(self, expires: ::Expires) -> Self::TimerHandle; } /// A trait for stack allocated timers. @@ -246,9 +255,14 @@ pub unsafe trait UnsafeHrTimerPointer: Sync + Sized { /// Implementers must ensure that `start_scoped` does not return until the /// timer is dead and the timer handler is not running. pub unsafe trait ScopedHrTimerPointer { + /// The operational mode associated with this timer. + /// + /// This defines how the expiration value is interpreted. + type TimerMode: HrTimerMode; + /// Start the timer to run after `expires` time units and immediately /// after call `f`. When `f` returns, the timer is cancelled. - fn start_scoped(self, expires: Ktime, f: F) -> T + fn start_scoped(self, expires: ::Expires, f: F) -> T where F: FnOnce() -> T; } @@ -260,7 +274,13 @@ unsafe impl ScopedHrTimerPointer for T where T: UnsafeHrTimerPointer, { - fn start_scoped(self, expires: Ktime, f: F) -> U + type TimerMode = T::TimerMode; + + fn start_scoped( + self, + expires: <::TimerMode as HrTimerMode>::Expires, + f: F, + ) -> U where F: FnOnce() -> U, { @@ -335,6 +355,11 @@ pub unsafe trait HrTimerHandle { /// their documentation. All the methods of this trait must operate on the same /// field. pub unsafe trait HasHrTimer { + /// The operational mode associated with this timer. + /// + /// This defines how the expiration value is interpreted. + type TimerMode: HrTimerMode; + /// Return a pointer to the [`HrTimer`] within `Self`. /// /// This function is useful to get access to the value without creating @@ -382,14 +407,14 @@ pub unsafe trait HasHrTimer { /// - `this` must point to a valid `Self`. /// - Caller must ensure that the pointee of `this` lives until the timer /// fires or is canceled. - unsafe fn start(this: *const Self, expires: Ktime) { + unsafe fn start(this: *const Self, expires: ::Expires) { // SAFETY: By function safety requirement, `this` is a valid `Self`. unsafe { bindings::hrtimer_start_range_ns( Self::c_timer_ptr(this).cast_mut(), - expires.to_ns(), + expires.as_nanos(), 0, - (*Self::raw_get_timer(this)).mode, + ::Clock::ID as u32, ); } } @@ -568,12 +593,16 @@ macro_rules! impl_has_hr_timer { impl$({$($generics:tt)*})? HasHrTimer<$timer_type:ty> for $self:ty - { self.$field:ident } + { + mode : $mode:ty, + field : self.$field:ident $(,)? + } $($rest:tt)* ) => { // SAFETY: This implementation of `raw_get_timer` only compiles if the // field has the right type. unsafe impl$(<$($generics)*>)? $crate::time::hrtimer::HasHrTimer<$timer_type> for $self { + type TimerMode = $mode; #[inline] unsafe fn raw_get_timer( diff --git a/rust/kernel/time/hrtimer/arc.rs b/rust/kernel/time/hrtimer/arc.rs index ccf1e66e5b2d5..ed490a7a89503 100644 --- a/rust/kernel/time/hrtimer/arc.rs +++ b/rust/kernel/time/hrtimer/arc.rs @@ -4,8 +4,8 @@ use super::HasHrTimer; use super::HrTimer; use super::HrTimerCallback; use super::HrTimerHandle; +use super::HrTimerMode; use super::HrTimerPointer; -use super::Ktime; use super::RawHrTimerCallback; use crate::sync::Arc; use crate::sync::ArcBorrow; @@ -54,9 +54,13 @@ where T: HasHrTimer, T: for<'a> HrTimerCallback = Self>, { + type TimerMode = >::TimerMode; type TimerHandle = ArcHrTimerHandle; - fn start(self, expires: Ktime) -> ArcHrTimerHandle { + fn start( + self, + expires: <>::TimerMode as HrTimerMode>::Expires, + ) -> ArcHrTimerHandle { // SAFETY: // - We keep `self` alive by wrapping it in a handle below. // - Since we generate the pointer passed to `start` from a valid diff --git a/rust/kernel/time/hrtimer/pin.rs b/rust/kernel/time/hrtimer/pin.rs index 293ca9cf058ce..550aad28d987c 100644 --- a/rust/kernel/time/hrtimer/pin.rs +++ b/rust/kernel/time/hrtimer/pin.rs @@ -4,7 +4,7 @@ use super::HasHrTimer; use super::HrTimer; use super::HrTimerCallback; use super::HrTimerHandle; -use super::Ktime; +use super::HrTimerMode; use super::RawHrTimerCallback; use super::UnsafeHrTimerPointer; use core::pin::Pin; @@ -54,9 +54,13 @@ where T: HasHrTimer, T: HrTimerCallback = Self>, { + type TimerMode = >::TimerMode; type TimerHandle = PinHrTimerHandle<'a, T>; - unsafe fn start(self, expires: Ktime) -> Self::TimerHandle { + unsafe fn start( + self, + expires: <>::TimerMode as HrTimerMode>::Expires, + ) -> Self::TimerHandle { // Cast to pointer let self_ptr: *const T = self.get_ref(); diff --git a/rust/kernel/time/hrtimer/pin_mut.rs b/rust/kernel/time/hrtimer/pin_mut.rs index 6033572d35ad7..bacd3d5d972a3 100644 --- a/rust/kernel/time/hrtimer/pin_mut.rs +++ b/rust/kernel/time/hrtimer/pin_mut.rs @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 use super::{ - HasHrTimer, HrTimer, HrTimerCallback, HrTimerHandle, Ktime, RawHrTimerCallback, + HasHrTimer, HrTimer, HrTimerCallback, HrTimerHandle, HrTimerMode, RawHrTimerCallback, UnsafeHrTimerPointer, }; use core::{marker::PhantomData, pin::Pin, ptr::NonNull}; @@ -52,9 +52,13 @@ where T: HasHrTimer, T: HrTimerCallback = Self>, { + type TimerMode = >::TimerMode; type TimerHandle = PinMutHrTimerHandle<'a, T>; - unsafe fn start(mut self, expires: Ktime) -> Self::TimerHandle { + unsafe fn start( + mut self, + expires: <>::TimerMode as HrTimerMode>::Expires, + ) -> Self::TimerHandle { // SAFETY: // - We promise not to move out of `self`. We only pass `self` // back to the caller as a `Pin<&mut self>`. diff --git a/rust/kernel/time/hrtimer/tbox.rs b/rust/kernel/time/hrtimer/tbox.rs index 29526a5da2037..ec08303315f28 100644 --- a/rust/kernel/time/hrtimer/tbox.rs +++ b/rust/kernel/time/hrtimer/tbox.rs @@ -4,8 +4,8 @@ use super::HasHrTimer; use super::HrTimer; use super::HrTimerCallback; use super::HrTimerHandle; +use super::HrTimerMode; use super::HrTimerPointer; -use super::Ktime; use super::RawHrTimerCallback; use crate::prelude::*; use core::ptr::NonNull; @@ -64,9 +64,13 @@ where T: for<'a> HrTimerCallback = Pin>>, A: crate::alloc::Allocator, { + type TimerMode = >::TimerMode; type TimerHandle = BoxHrTimerHandle; - fn start(self, expires: Ktime) -> Self::TimerHandle { + fn start( + self, + expires: <>::TimerMode as HrTimerMode>::Expires, + ) -> Self::TimerHandle { // SAFETY: // - We will not move out of this box during timer callback (we pass an // immutable reference to the callback).