diff options
Diffstat (limited to 'rust/kernel/workqueue.rs')
| -rw-r--r-- | rust/kernel/workqueue.rs | 473 |
1 files changed, 406 insertions, 67 deletions
diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs index 553a5cba2adc..706e833e9702 100644 --- a/rust/kernel/workqueue.rs +++ b/rust/kernel/workqueue.rs @@ -26,7 +26,7 @@ //! * The [`WorkItemPointer`] trait is implemented for the pointer type that points at a something //! that implements [`WorkItem`]. //! -//! ## Example +//! ## Examples //! //! This example defines a struct that holds an integer and can be scheduled on the workqueue. When //! the struct is executed, it will print the integer. Since there is only one `work_struct` field, @@ -60,7 +60,7 @@ //! type Pointer = Arc<MyStruct>; //! //! fn run(this: Arc<MyStruct>) { -//! pr_info!("The value is: {}", this.value); +//! pr_info!("The value is: {}\n", this.value); //! } //! } //! @@ -69,6 +69,7 @@ //! fn print_later(val: Arc<MyStruct>) { //! let _ = workqueue::system().enqueue(val); //! } +//! # print_later(MyStruct::new(42).unwrap()); //! ``` //! //! The following example shows how multiple `work_struct` fields can be used: @@ -107,7 +108,7 @@ //! type Pointer = Arc<MyStruct>; //! //! fn run(this: Arc<MyStruct>) { -//! pr_info!("The value is: {}", this.value_1); +//! pr_info!("The value is: {}\n", this.value_1); //! } //! } //! @@ -115,7 +116,7 @@ //! type Pointer = Arc<MyStruct>; //! //! fn run(this: Arc<MyStruct>) { -//! pr_info!("The second value is: {}", this.value_2); +//! pr_info!("The second value is: {}\n", this.value_2); //! } //! } //! @@ -126,12 +127,73 @@ //! fn print_2_later(val: Arc<MyStruct>) { //! let _ = workqueue::system().enqueue::<Arc<MyStruct>, 2>(val); //! } +//! # print_1_later(MyStruct::new(24, 25).unwrap()); +//! # print_2_later(MyStruct::new(41, 42).unwrap()); +//! ``` +//! +//! This example shows how you can schedule delayed work items: +//! +//! ``` +//! use kernel::sync::Arc; +//! use kernel::workqueue::{self, impl_has_delayed_work, new_delayed_work, DelayedWork, WorkItem}; +//! +//! #[pin_data] +//! struct MyStruct { +//! value: i32, +//! #[pin] +//! work: DelayedWork<MyStruct>, +//! } +//! +//! impl_has_delayed_work! { +//! impl HasDelayedWork<Self> for MyStruct { self.work } +//! } +//! +//! impl MyStruct { +//! fn new(value: i32) -> Result<Arc<Self>> { +//! Arc::pin_init( +//! pin_init!(MyStruct { +//! value, +//! work <- new_delayed_work!("MyStruct::work"), +//! }), +//! GFP_KERNEL, +//! ) +//! } +//! } +//! +//! impl WorkItem for MyStruct { +//! type Pointer = Arc<MyStruct>; +//! +//! fn run(this: Arc<MyStruct>) { +//! pr_info!("The value is: {}\n", this.value); +//! } +//! } +//! +//! /// This method will enqueue the struct for execution on the system workqueue, where its value +//! /// will be printed 12 jiffies later. +//! fn print_later(val: Arc<MyStruct>) { +//! let _ = workqueue::system().enqueue_delayed(val, 12); +//! } +//! +//! /// It is also possible to use the ordinary `enqueue` method together with `DelayedWork`. This +//! /// is equivalent to calling `enqueue_delayed` with a delay of zero. +//! fn print_now(val: Arc<MyStruct>) { +//! let _ = workqueue::system().enqueue(val); +//! } +//! # print_later(MyStruct::new(42).unwrap()); +//! # print_now(MyStruct::new(42).unwrap()); //! ``` //! //! C header: [`include/linux/workqueue.h`](srctree/include/linux/workqueue.h) -use crate::alloc::{AllocError, Flags}; -use crate::{prelude::*, sync::Arc, sync::LockClassKey, types::Opaque}; +use crate::{ + alloc::{AllocError, Flags}, + container_of, + prelude::*, + sync::Arc, + sync::LockClassKey, + time::Jiffies, + types::Opaque, +}; use core::marker::PhantomData; /// Creates a [`Work`] initialiser with the given name and a newly-created lock class. @@ -143,6 +205,33 @@ macro_rules! new_work { } pub use new_work; +/// Creates a [`DelayedWork`] initialiser with the given name and a newly-created lock class. +#[macro_export] +macro_rules! new_delayed_work { + () => { + $crate::workqueue::DelayedWork::new( + $crate::optional_name!(), + $crate::static_lock_class!(), + $crate::c_str!(::core::concat!( + ::core::file!(), + ":", + ::core::line!(), + "_timer" + )), + $crate::static_lock_class!(), + ) + }; + ($name:literal) => { + $crate::workqueue::DelayedWork::new( + $crate::c_str!($name), + $crate::static_lock_class!(), + $crate::c_str!(::core::concat!($name, "_timer")), + $crate::static_lock_class!(), + ) + }; +} +pub use new_delayed_work; + /// A kernel work queue. /// /// Wraps the kernel's C `struct workqueue_struct`. @@ -167,7 +256,7 @@ impl Queue { pub unsafe fn from_raw<'a>(ptr: *const bindings::workqueue_struct) -> &'a Queue { // SAFETY: The `Queue` type is `#[repr(transparent)]`, so the pointer cast is valid. The // caller promises that the pointer is not dangling. - unsafe { &*(ptr as *const Queue) } + unsafe { &*ptr.cast::<Queue>() } } /// Enqueues a work item. @@ -195,7 +284,7 @@ impl Queue { unsafe { w.__enqueue(move |work_ptr| { bindings::queue_work_on( - bindings::wq_misc_consts_WORK_CPU_UNBOUND as _, + bindings::wq_misc_consts_WORK_CPU_UNBOUND as ffi::c_int, queue_ptr, work_ptr, ) @@ -203,6 +292,42 @@ impl Queue { } } + /// Enqueues a delayed work item. + /// + /// This may fail if the work item is already enqueued in a workqueue. + /// + /// The work item will be submitted using `WORK_CPU_UNBOUND`. + pub fn enqueue_delayed<W, const ID: u64>(&self, w: W, delay: Jiffies) -> W::EnqueueOutput + where + W: RawDelayedWorkItem<ID> + Send + 'static, + { + let queue_ptr = self.0.get(); + + // SAFETY: We only return `false` if the `work_struct` is already in a workqueue. The other + // `__enqueue` requirements are not relevant since `W` is `Send` and static. + // + // The call to `bindings::queue_delayed_work_on` will dereference the provided raw pointer, + // which is ok because `__enqueue` guarantees that the pointer is valid for the duration of + // this closure, and the safety requirements of `RawDelayedWorkItem` expands this + // requirement to apply to the entire `delayed_work`. + // + // Furthermore, if the C workqueue code accesses the pointer after this call to + // `__enqueue`, then the work item was successfully enqueued, and + // `bindings::queue_delayed_work_on` will have returned true. In this case, `__enqueue` + // promises that the raw pointer will stay valid until we call the function pointer in the + // `work_struct`, so the access is ok. + unsafe { + w.__enqueue(move |work_ptr| { + bindings::queue_delayed_work_on( + bindings::wq_misc_consts_WORK_CPU_UNBOUND as ffi::c_int, + queue_ptr, + container_of!(work_ptr, bindings::delayed_work, work), + delay, + ) + }) + } + } + /// Tries to spawn the given function or closure as a work item. /// /// This method can fail because it allocates memory to store the work item. @@ -216,7 +341,7 @@ impl Queue { func: Some(func), }); - self.enqueue(Box::pin_init(init, flags).map_err(|_| AllocError)?); + self.enqueue(KBox::pin_init(init, flags).map_err(|_| AllocError)?); Ok(()) } } @@ -231,18 +356,11 @@ struct ClosureWork<T> { func: Option<T>, } -impl<T> ClosureWork<T> { - fn project(self: Pin<&mut Self>) -> &mut Option<T> { - // SAFETY: The `func` field is not structurally pinned. - unsafe { &mut self.get_unchecked_mut().func } - } -} - impl<T: FnOnce()> WorkItem for ClosureWork<T> { - type Pointer = Pin<Box<Self>>; + type Pointer = Pin<KBox<Self>>; - fn run(mut this: Pin<Box<Self>>) { - if let Some(func) = this.as_mut().project().take() { + fn run(mut this: Pin<KBox<Self>>) { + if let Some(func) = this.as_mut().project().func.take() { (func)() } } @@ -295,9 +413,19 @@ pub unsafe trait RawWorkItem<const ID: u64> { F: FnOnce(*mut bindings::work_struct) -> bool; } +/// A raw delayed work item. +/// +/// # Safety +/// +/// If the `__enqueue` method in the `RawWorkItem` implementation calls the closure, then the +/// provided pointer must point at the `work` field of a valid `delayed_work`, and the guarantees +/// that `__enqueue` provides about accessing the `work_struct` must also apply to the rest of the +/// `delayed_work` struct. +pub unsafe trait RawDelayedWorkItem<const ID: u64>: RawWorkItem<ID> {} + /// Defines the method that should be called directly when a work item is executed. /// -/// This trait is implemented by `Pin<Box<T>>` and [`Arc<T>`], and is mainly intended to be +/// This trait is implemented by `Pin<KBox<T>>` and [`Arc<T>`], and is mainly intended to be /// implemented for smart pointer types. For your own structs, you would implement [`WorkItem`] /// instead. The [`run`] method on this trait will usually just perform the appropriate /// `container_of` translation and then call into the [`run`][WorkItem::run] method from the @@ -329,7 +457,7 @@ pub unsafe trait WorkItemPointer<const ID: u64>: RawWorkItem<ID> { /// This trait is used when the `work_struct` field is defined using the [`Work`] helper. pub trait WorkItem<const ID: u64 = 0> { /// The pointer type that this struct is wrapped in. This will typically be `Arc<Self>` or - /// `Pin<Box<Self>>`. + /// `Pin<KBox<Self>>`. type Pointer: WorkItemPointer<ID>; /// The method that should be called when this work item is executed. @@ -366,8 +494,7 @@ unsafe impl<T: ?Sized, const ID: u64> Sync for Work<T, ID> {} impl<T: ?Sized, const ID: u64> Work<T, ID> { /// Creates a new instance of [`Work`]. #[inline] - #[allow(clippy::new_ret_no_self)] - pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self> + pub fn new(name: &'static CStr, key: Pin<&'static LockClassKey>) -> impl PinInit<Self> where T: WorkItem<ID>, { @@ -401,11 +528,11 @@ impl<T: ?Sized, const ID: u64> Work<T, ID> { // // A pointer cast would also be ok due to `#[repr(transparent)]`. We use `addr_of!` so that // the compiler does not complain that the `work` field is unused. - unsafe { Opaque::raw_get(core::ptr::addr_of!((*ptr).work)) } + unsafe { Opaque::cast_into(core::ptr::addr_of!((*ptr).work)) } } } -/// Declares that a type has a [`Work<T, ID>`] field. +/// Declares that a type contains a [`Work<T, ID>`]. /// /// The intended way of using this trait is via the [`impl_has_work!`] macro. You can use the macro /// like this: @@ -427,51 +554,28 @@ impl<T: ?Sized, const ID: u64> Work<T, ID> { /// /// # Safety /// -/// The [`OFFSET`] constant must be the offset of a field in `Self` of type [`Work<T, ID>`]. The -/// methods on this trait must have exactly the behavior that the definitions given below have. +/// The methods [`raw_get_work`] and [`work_container_of`] must return valid pointers and must be +/// true inverses of each other; that is, they must satisfy the following invariants: +/// - `work_container_of(raw_get_work(ptr)) == ptr` for any `ptr: *mut Self`. +/// - `raw_get_work(work_container_of(ptr)) == ptr` for any `ptr: *mut Work<T, ID>`. /// /// [`impl_has_work!`]: crate::impl_has_work -/// [`OFFSET`]: HasWork::OFFSET +/// [`raw_get_work`]: HasWork::raw_get_work +/// [`work_container_of`]: HasWork::work_container_of pub unsafe trait HasWork<T, const ID: u64 = 0> { - /// The offset of the [`Work<T, ID>`] field. - const OFFSET: usize; - - /// Returns the offset of the [`Work<T, ID>`] field. - /// - /// This method exists because the [`OFFSET`] constant cannot be accessed if the type is not - /// [`Sized`]. - /// - /// [`OFFSET`]: HasWork::OFFSET - #[inline] - fn get_work_offset(&self) -> usize { - Self::OFFSET - } - /// Returns a pointer to the [`Work<T, ID>`] field. /// /// # Safety /// /// The provided pointer must point at a valid struct of type `Self`. - #[inline] - unsafe fn raw_get_work(ptr: *mut Self) -> *mut Work<T, ID> { - // SAFETY: The caller promises that the pointer is valid. - unsafe { (ptr as *mut u8).add(Self::OFFSET) as *mut Work<T, ID> } - } + unsafe fn raw_get_work(ptr: *mut Self) -> *mut Work<T, ID>; /// Returns a pointer to the struct containing the [`Work<T, ID>`] field. /// /// # Safety /// /// The pointer must point at a [`Work<T, ID>`] field in a struct of type `Self`. - #[inline] - unsafe fn work_container_of(ptr: *mut Work<T, ID>) -> *mut Self - where - Self: Sized, - { - // SAFETY: The caller promises that the pointer points at a field of the right type in the - // right kind of struct. - unsafe { (ptr as *mut u8).sub(Self::OFFSET) as *mut Self } - } + unsafe fn work_container_of(ptr: *mut Work<T, ID>) -> *mut Self; } /// Used to safely implement the [`HasWork<T, ID>`] trait. @@ -502,8 +606,6 @@ macro_rules! impl_has_work { // SAFETY: The implementation of `raw_get_work` only compiles if the field has the right // type. unsafe impl$(<$($generics)+>)? $crate::workqueue::HasWork<$work_type $(, $id)?> for $self { - const OFFSET: usize = ::core::mem::offset_of!(Self, $field) as usize; - #[inline] unsafe fn raw_get_work(ptr: *mut Self) -> *mut $crate::workqueue::Work<$work_type $(, $id)?> { // SAFETY: The caller promises that the pointer is not dangling. @@ -511,6 +613,15 @@ macro_rules! impl_has_work { ::core::ptr::addr_of_mut!((*ptr).$field) } } + + #[inline] + unsafe fn work_container_of( + ptr: *mut $crate::workqueue::Work<$work_type $(, $id)?>, + ) -> *mut Self { + // SAFETY: The caller promises that the pointer points at a field of the right type + // in the right kind of struct. + unsafe { $crate::container_of!(ptr, Self, $field) } + } } )*}; } @@ -520,14 +631,195 @@ impl_has_work! { impl{T} HasWork<Self> for ClosureWork<T> { self.work } } +/// Links for a delayed work item. +/// +/// This struct contains a function pointer to the [`run`] function from the [`WorkItemPointer`] +/// trait, and defines the linked list pointers necessary to enqueue a work item in a workqueue in +/// a delayed manner. +/// +/// Wraps the kernel's C `struct delayed_work`. +/// +/// This is a helper type used to associate a `delayed_work` with the [`WorkItem`] that uses it. +/// +/// [`run`]: WorkItemPointer::run +#[pin_data] +#[repr(transparent)] +pub struct DelayedWork<T: ?Sized, const ID: u64 = 0> { + #[pin] + dwork: Opaque<bindings::delayed_work>, + _inner: PhantomData<T>, +} + +// SAFETY: Kernel work items are usable from any thread. +// +// We do not need to constrain `T` since the work item does not actually contain a `T`. +unsafe impl<T: ?Sized, const ID: u64> Send for DelayedWork<T, ID> {} +// SAFETY: Kernel work items are usable from any thread. +// +// We do not need to constrain `T` since the work item does not actually contain a `T`. +unsafe impl<T: ?Sized, const ID: u64> Sync for DelayedWork<T, ID> {} + +impl<T: ?Sized, const ID: u64> DelayedWork<T, ID> { + /// Creates a new instance of [`DelayedWork`]. + #[inline] + pub fn new( + work_name: &'static CStr, + work_key: Pin<&'static LockClassKey>, + timer_name: &'static CStr, + timer_key: Pin<&'static LockClassKey>, + ) -> impl PinInit<Self> + where + T: WorkItem<ID>, + { + pin_init!(Self { + dwork <- Opaque::ffi_init(|slot: *mut bindings::delayed_work| { + // SAFETY: The `WorkItemPointer` implementation promises that `run` can be used as + // the work item function. + unsafe { + bindings::init_work_with_key( + core::ptr::addr_of_mut!((*slot).work), + Some(T::Pointer::run), + false, + work_name.as_char_ptr(), + work_key.as_ptr(), + ) + } + + // SAFETY: The `delayed_work_timer_fn` function pointer can be used here because + // the timer is embedded in a `struct delayed_work`, and only ever scheduled via + // the core workqueue code, and configured to run in irqsafe context. + unsafe { + bindings::timer_init_key( + core::ptr::addr_of_mut!((*slot).timer), + Some(bindings::delayed_work_timer_fn), + bindings::TIMER_IRQSAFE, + timer_name.as_char_ptr(), + timer_key.as_ptr(), + ) + } + }), + _inner: PhantomData, + }) + } + + /// Get a pointer to the inner `delayed_work`. + /// + /// # Safety + /// + /// The provided pointer must not be dangling and must be properly aligned. (But the memory + /// need not be initialized.) + #[inline] + pub unsafe fn raw_as_work(ptr: *const Self) -> *mut Work<T, ID> { + // SAFETY: The caller promises that the pointer is aligned and not dangling. + let dw: *mut bindings::delayed_work = + unsafe { Opaque::cast_into(core::ptr::addr_of!((*ptr).dwork)) }; + // SAFETY: The caller promises that the pointer is aligned and not dangling. + let wrk: *mut bindings::work_struct = unsafe { core::ptr::addr_of_mut!((*dw).work) }; + // CAST: Work and work_struct have compatible layouts. + wrk.cast() + } +} + +/// Declares that a type contains a [`DelayedWork<T, ID>`]. +/// +/// # Safety +/// +/// The `HasWork<T, ID>` implementation must return a `work_struct` that is stored in the `work` +/// field of a `delayed_work` with the same access rules as the `work_struct`. +pub unsafe trait HasDelayedWork<T, const ID: u64 = 0>: HasWork<T, ID> {} + +/// Used to safely implement the [`HasDelayedWork<T, ID>`] trait. +/// +/// This macro also implements the [`HasWork`] trait, so you do not need to use [`impl_has_work!`] +/// when using this macro. +/// +/// # Examples +/// +/// ``` +/// use kernel::sync::Arc; +/// use kernel::workqueue::{self, impl_has_delayed_work, DelayedWork}; +/// +/// struct MyStruct<'a, T, const N: usize> { +/// work_field: DelayedWork<MyStruct<'a, T, N>, 17>, +/// f: fn(&'a [T; N]), +/// } +/// +/// impl_has_delayed_work! { +/// impl{'a, T, const N: usize} HasDelayedWork<MyStruct<'a, T, N>, 17> +/// for MyStruct<'a, T, N> { self.work_field } +/// } +/// ``` +#[macro_export] +macro_rules! impl_has_delayed_work { + ($(impl$({$($generics:tt)*})? + HasDelayedWork<$work_type:ty $(, $id:tt)?> + for $self:ty + { self.$field:ident } + )*) => {$( + // SAFETY: The implementation of `raw_get_work` only compiles if the field has the right + // type. + unsafe impl$(<$($generics)+>)? + $crate::workqueue::HasDelayedWork<$work_type $(, $id)?> for $self {} + + // SAFETY: The implementation of `raw_get_work` only compiles if the field has the right + // type. + unsafe impl$(<$($generics)+>)? $crate::workqueue::HasWork<$work_type $(, $id)?> for $self { + #[inline] + unsafe fn raw_get_work( + ptr: *mut Self + ) -> *mut $crate::workqueue::Work<$work_type $(, $id)?> { + // SAFETY: The caller promises that the pointer is not dangling. + let ptr: *mut $crate::workqueue::DelayedWork<$work_type $(, $id)?> = unsafe { + ::core::ptr::addr_of_mut!((*ptr).$field) + }; + + // SAFETY: The caller promises that the pointer is not dangling. + unsafe { $crate::workqueue::DelayedWork::raw_as_work(ptr) } + } + + #[inline] + unsafe fn work_container_of( + ptr: *mut $crate::workqueue::Work<$work_type $(, $id)?>, + ) -> *mut Self { + // SAFETY: The caller promises that the pointer points at a field of the right type + // in the right kind of struct. + let ptr = unsafe { $crate::workqueue::Work::raw_get(ptr) }; + + // SAFETY: The caller promises that the pointer points at a field of the right type + // in the right kind of struct. + let delayed_work = unsafe { + $crate::container_of!(ptr, $crate::bindings::delayed_work, work) + }; + + let delayed_work: *mut $crate::workqueue::DelayedWork<$work_type $(, $id)?> = + delayed_work.cast(); + + // SAFETY: The caller promises that the pointer points at a field of the right type + // in the right kind of struct. + unsafe { $crate::container_of!(delayed_work, Self, $field) } + } + } + )*}; +} +pub use impl_has_delayed_work; + +// SAFETY: The `__enqueue` implementation in RawWorkItem uses a `work_struct` initialized with the +// `run` method of this trait as the function pointer because: +// - `__enqueue` gets the `work_struct` from the `Work` field, using `T::raw_get_work`. +// - The only safe way to create a `Work` object is through `Work::new`. +// - `Work::new` makes sure that `T::Pointer::run` is passed to `init_work_with_key`. +// - Finally `Work` and `RawWorkItem` guarantee that the correct `Work` field +// will be used because of the ID const generic bound. This makes sure that `T::raw_get_work` +// uses the correct offset for the `Work` field, and `Work::new` picks the correct +// implementation of `WorkItemPointer` for `Arc<T>`. unsafe impl<T, const ID: u64> WorkItemPointer<ID> for Arc<T> where T: WorkItem<ID, Pointer = Self>, T: HasWork<T, ID>, { unsafe extern "C" fn run(ptr: *mut bindings::work_struct) { - // SAFETY: The `__enqueue` method always uses a `work_struct` stored in a `Work<T, ID>`. - let ptr = ptr as *mut Work<T, ID>; + // The `__enqueue` method always uses a `work_struct` stored in a `Work<T, ID>`. + let ptr = ptr.cast::<Work<T, ID>>(); // SAFETY: This computes the pointer that `__enqueue` got from `Arc::into_raw`. let ptr = unsafe { T::work_container_of(ptr) }; // SAFETY: This pointer comes from `Arc::into_raw` and we've been given back ownership. @@ -537,6 +829,13 @@ where } } +// SAFETY: The `work_struct` raw pointer is guaranteed to be valid for the duration of the call to +// the closure because we get it from an `Arc`, which means that the ref count will be at least 1, +// and we don't drop the `Arc` ourselves. If `queue_work_on` returns true, it is further guaranteed +// to be valid until a call to the function pointer in `work_struct` because we leak the memory it +// points to, and only reclaim it if the closure returns false, or in `WorkItemPointer::run`, which +// is what the function pointer in the `work_struct` must be pointing to, according to the safety +// requirements of `WorkItemPointer`. unsafe impl<T, const ID: u64> RawWorkItem<ID> for Arc<T> where T: WorkItem<ID, Pointer = Self>, @@ -565,18 +864,29 @@ where } } -unsafe impl<T, const ID: u64> WorkItemPointer<ID> for Pin<Box<T>> +// SAFETY: By the safety requirements of `HasDelayedWork`, the `work_struct` returned by methods in +// `HasWork` provides a `work_struct` that is the `work` field of a `delayed_work`, and the rest of +// the `delayed_work` has the same access rules as its `work` field. +unsafe impl<T, const ID: u64> RawDelayedWorkItem<ID> for Arc<T> +where + T: WorkItem<ID, Pointer = Self>, + T: HasDelayedWork<T, ID>, +{ +} + +// SAFETY: TODO. +unsafe impl<T, const ID: u64> WorkItemPointer<ID> for Pin<KBox<T>> where T: WorkItem<ID, Pointer = Self>, T: HasWork<T, ID>, { unsafe extern "C" fn run(ptr: *mut bindings::work_struct) { - // SAFETY: The `__enqueue` method always uses a `work_struct` stored in a `Work<T, ID>`. - let ptr = ptr as *mut Work<T, ID>; + // The `__enqueue` method always uses a `work_struct` stored in a `Work<T, ID>`. + let ptr = ptr.cast::<Work<T, ID>>(); // SAFETY: This computes the pointer that `__enqueue` got from `Arc::into_raw`. let ptr = unsafe { T::work_container_of(ptr) }; // SAFETY: This pointer comes from `Arc::into_raw` and we've been given back ownership. - let boxed = unsafe { Box::from_raw(ptr) }; + let boxed = unsafe { KBox::from_raw(ptr) }; // SAFETY: The box was already pinned when it was enqueued. let pinned = unsafe { Pin::new_unchecked(boxed) }; @@ -584,7 +894,8 @@ where } } -unsafe impl<T, const ID: u64> RawWorkItem<ID> for Pin<Box<T>> +// SAFETY: TODO. +unsafe impl<T, const ID: u64> RawWorkItem<ID> for Pin<KBox<T>> where T: WorkItem<ID, Pointer = Self>, T: HasWork<T, ID>, @@ -598,9 +909,9 @@ where // SAFETY: We're not going to move `self` or any of its fields, so its okay to temporarily // remove the `Pin` wrapper. let boxed = unsafe { Pin::into_inner_unchecked(self) }; - let ptr = Box::into_raw(boxed); + let ptr = KBox::into_raw(boxed); - // SAFETY: Pointers into a `Box` point at a valid value. + // SAFETY: Pointers into a `KBox` point at a valid value. let work_ptr = unsafe { T::raw_get_work(ptr) }; // SAFETY: `raw_get_work` returns a pointer to a valid value. let work_ptr = unsafe { Work::raw_get(work_ptr) }; @@ -613,6 +924,16 @@ where } } +// SAFETY: By the safety requirements of `HasDelayedWork`, the `work_struct` returned by methods in +// `HasWork` provides a `work_struct` that is the `work` field of a `delayed_work`, and the rest of +// the `delayed_work` has the same access rules as its `work` field. +unsafe impl<T, const ID: u64> RawDelayedWorkItem<ID> for Pin<KBox<T>> +where + T: WorkItem<ID, Pointer = Self>, + T: HasDelayedWork<T, ID>, +{ +} + /// Returns the system work queue (`system_wq`). /// /// It is the one used by `schedule[_delayed]_work[_on]()`. Multi-CPU multi-threaded. There are @@ -683,3 +1004,21 @@ pub fn system_freezable_power_efficient() -> &'static Queue { // SAFETY: `system_freezable_power_efficient_wq` is a C global, always available. unsafe { Queue::from_raw(bindings::system_freezable_power_efficient_wq) } } + +/// Returns the system bottom halves work queue (`system_bh_wq`). +/// +/// It is similar to the one returned by [`system`] but for work items which +/// need to run from a softirq context. +pub fn system_bh() -> &'static Queue { + // SAFETY: `system_bh_wq` is a C global, always available. + unsafe { Queue::from_raw(bindings::system_bh_wq) } +} + +/// Returns the system bottom halves high-priority work queue (`system_bh_highpri_wq`). +/// +/// It is similar to the one returned by [`system_bh`] but for work items which +/// require higher scheduling priority. +pub fn system_bh_highpri() -> &'static Queue { + // SAFETY: `system_bh_highpri_wq` is a C global, always available. + unsafe { Queue::from_raw(bindings::system_bh_highpri_wq) } +} |