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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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//! Work queues.//!//! This file has two components: The raw work item API, and the safe work item API.//!//! One pattern that is used in both APIs is the `ID` const generic, which exists to allow a single//! type to define multiple `work_struct` fields. This is done by choosing an id for each field,//! and using that id to specify which field you wish to use. (The actual value doesn't matter, as//! long as you use different values for different fields of the same struct.) Since these IDs are//! generic, they are used only at compile-time, so they shouldn't exist in the final binary.//!//! # The raw API//!//! The raw API consists of the [`RawWorkItem`] trait, where the work item needs to provide an//! arbitrary function that knows how to enqueue the work item. It should usually not be used//! directly, but if you want to, you can use it without using the pieces from the safe API.//!//! # The safe API//!//! The safe API is used via the [`Work`] struct and [`WorkItem`] traits. Furthermore, it also//! includes a trait called [`WorkItemPointer`], which is usually not used directly by the user.//!//! * The [`Work`] struct is the Rust wrapper for the C `work_struct` type.//! * The [`WorkItem`] trait is implemented for structs that can be enqueued to a workqueue.//! * The [`WorkItemPointer`] trait is implemented for the pointer type that points at a something//! that implements [`WorkItem`].//!//! ## 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,//! we do not need to specify ids for the fields.//!//! ```//! use kernel::sync::Arc;//! use kernel::workqueue::{self, impl_has_work, new_work, Work, WorkItem};//!//! #[pin_data]//! struct MyStruct {//! value: i32,//! #[pin]//! work: Work<MyStruct>,//! }//!//! impl_has_work! {//! impl HasWork<Self> for MyStruct { self.work }//! }//!//! impl MyStruct {//! fn new(value: i32) -> Result<Arc<Self>> {//! Arc::pin_init(pin_init!(MyStruct {//! value,//! work <- new_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.//! 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://!//! ```//! use kernel::sync::Arc;//! use kernel::workqueue::{self, impl_has_work, new_work, Work, WorkItem};//!//! #[pin_data]//! struct MyStruct {//! value_1: i32,//! value_2: i32,//! #[pin]//! work_1: Work<MyStruct, 1>,//! #[pin]//! work_2: Work<MyStruct, 2>,//! }//!//! impl_has_work! {//! impl HasWork<Self, 1> for MyStruct { self.work_1 }//! impl HasWork<Self, 2> for MyStruct { self.work_2 }//! }//!//! impl MyStruct {//! fn new(value_1: i32, value_2: i32) -> Result<Arc<Self>> {//! Arc::pin_init(pin_init!(MyStruct {//! value_1,//! value_2,//! work_1 <- new_work!("MyStruct::work_1"),//! work_2 <- new_work!("MyStruct::work_2"),//! }), GFP_KERNEL)//! }//! }//!//! impl WorkItem<1> for MyStruct {//! type Pointer = Arc<MyStruct>;//!//! fn run(this: Arc<MyStruct>) {//! pr_info!("The value is: {}\n", this.value_1);//! }//! }//!//! impl WorkItem<2> for MyStruct {//! type Pointer = Arc<MyStruct>;//!//! fn run(this: Arc<MyStruct>) {//! pr_info!("The second value is: {}\n", this.value_2);//! }//! }//!//! fn print_1_later(val: Arc<MyStruct>) {//! let _ = workqueue::system().enqueue::<Arc<MyStruct>, 1>(val);//! }//!//! 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}, 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.#[macro_export]macro_rules! new_work { ($($name:literal)?) => { $crate::workqueue::Work::new($crate::optional_name!($($name)?), $crate::static_lock_class!()) };}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`.////// It allows work items to be queued to run on thread pools managed by the kernel. Several are/// always available, for example, `system`, `system_highpri`, `system_long`, etc.#[repr(transparent)]pub struct Queue(Opaque<bindings::workqueue_struct>);
// SAFETY: Accesses to workqueues used by [`Queue`] are thread-safe.unsafe impl Send for Queue {}// SAFETY: Accesses to workqueues used by [`Queue`] are thread-safe.unsafe impl Sync for Queue {}
impl Queue { /// Use the provided `struct workqueue_struct` with Rust. /// /// # Safety /// /// The caller must ensure that the provided raw pointer is not dangling, that it points at a /// valid workqueue, and that it remains valid until the end of `'a`. 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.cast::<Queue>() } }
/// Enqueues a 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<W, const ID: u64>(&self, w: W) -> W::EnqueueOutput where W: RawWorkItem<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_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. // // Furthermore, if the C workqueue code accesses the pointer after this call to // `__enqueue`, then the work item was successfully enqueued, and `bindings::queue_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_work_on( bindings::wq_misc_consts_WORK_CPU_UNBOUND as ffi::c_int, queue_ptr, work_ptr, ) }) } }
/// 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. pub fn try_spawn<T: 'static + Send + FnOnce()>( &self, flags: Flags, func: T, ) -> Result<(), AllocError> { let init = pin_init!(ClosureWork { work <- new_work!("Queue::try_spawn"), func: Some(func), });
self.enqueue(KBox::pin_init(init, flags).map_err(|_| AllocError)?); Ok(()) }}
/// A helper type used in [`try_spawn`].////// [`try_spawn`]: Queue::try_spawn#[pin_data]struct ClosureWork<T> { #[pin] work: Work<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<KBox<Self>>;
fn run(mut this: Pin<KBox<Self>>) { if let Some(func) = this.as_mut().project().take() { (func)() } }}
/// A raw work item.////// This is the low-level trait that is designed for being as general as possible.////// The `ID` parameter to this trait exists so that a single type can provide multiple/// implementations of this trait. For example, if a struct has multiple `work_struct` fields, then/// you will implement this trait once for each field, using a different id for each field. The/// actual value of the id is not important as long as you use different ids for different fields/// of the same struct. (Fields of different structs need not use different ids.)////// Note that the id is used only to select the right method to call during compilation. It won't be/// part of the final executable.////// # Safety////// Implementers must ensure that any pointers passed to a `queue_work_on` closure by [`__enqueue`]/// remain valid for the duration specified in the guarantees section of the documentation for/// [`__enqueue`].////// [`__enqueue`]: RawWorkItem::__enqueuepub unsafe trait RawWorkItem<const ID: u64> { /// The return type of [`Queue::enqueue`]. type EnqueueOutput;
/// Enqueues this work item on a queue using the provided `queue_work_on` method. /// /// # Guarantees /// /// If this method calls the provided closure, then the raw pointer is guaranteed to point at a /// valid `work_struct` for the duration of the call to the closure. If the closure returns /// true, then it is further guaranteed that the pointer remains valid until someone calls the /// function pointer stored in the `work_struct`. /// /// # Safety /// /// The provided closure may only return `false` if the `work_struct` is already in a workqueue. /// /// If the work item type is annotated with any lifetimes, then you must not call the function /// pointer after any such lifetime expires. (Never calling the function pointer is okay.) /// /// If the work item type is not [`Send`], then the function pointer must be called on the same /// thread as the call to `__enqueue`. unsafe fn __enqueue<F>(self, queue_work_on: F) -> Self::EnqueueOutput where 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<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/// [`WorkItem`] trait.////// This trait is used when the `work_struct` field is defined using the [`Work`] helper.////// # Safety////// Implementers must ensure that [`__enqueue`] uses a `work_struct` initialized with the [`run`]/// method of this trait as the function pointer.////// [`__enqueue`]: RawWorkItem::__enqueue/// [`run`]: WorkItemPointer::runpub unsafe trait WorkItemPointer<const ID: u64>: RawWorkItem<ID> { /// Run this work item. /// /// # Safety /// /// The provided `work_struct` pointer must originate from a previous call to [`__enqueue`] /// where the `queue_work_on` closure returned true, and the pointer must still be valid. /// /// [`__enqueue`]: RawWorkItem::__enqueue unsafe extern "C" fn run(ptr: *mut bindings::work_struct);}
/// Defines the method that should be called when this work item is executed.////// 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<KBox<Self>>`. type Pointer: WorkItemPointer<ID>;
/// The method that should be called when this work item is executed. fn run(this: Self::Pointer);}
/// Links for a 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.////// Wraps the kernel's C `struct work_struct`.////// This is a helper type used to associate a `work_struct` with the [`WorkItem`] that uses it.////// [`run`]: WorkItemPointer::run#[pin_data]#[repr(transparent)]pub struct Work<T: ?Sized, const ID: u64 = 0> { #[pin] work: Opaque<bindings::work_struct>, _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 Work<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 Work<T, ID> {}
impl<T: ?Sized, const ID: u64> Work<T, ID> { /// Creates a new instance of [`Work`]. #[inline] pub fn new(name: &'static CStr, key: Pin<&'static LockClassKey>) -> impl PinInit<Self> where T: WorkItem<ID>, { pin_init!(Self { work <- Opaque::ffi_init(|slot| { // SAFETY: The `WorkItemPointer` implementation promises that `run` can be used as // the work item function. unsafe { bindings::init_work_with_key( slot, Some(T::Pointer::run), false, name.as_char_ptr(), key.as_ptr(), ) } }), _inner: PhantomData, }) }
/// Get a pointer to the inner `work_struct`. /// /// # 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_get(ptr: *const Self) -> *mut bindings::work_struct { // SAFETY: The caller promises that the pointer is aligned and not dangling. // // 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::cast_into(core::ptr::addr_of!((*ptr).work)) } }}
/// 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:////// ```no_run/// use kernel::workqueue::{impl_has_work, Work};////// struct MyWorkItem {/// work_field: Work<MyWorkItem, 1>,/// }////// impl_has_work! {/// impl HasWork<MyWorkItem, 1> for MyWorkItem { self.work_field }/// }/// ```////// Note that since the [`Work`] type is annotated with an id, you can have several `work_struct`/// fields by using a different id for each one.////// # Safety////// 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/// [`raw_get_work`]: HasWork::raw_get_work/// [`work_container_of`]: HasWork::work_container_ofpub unsafe trait HasWork<T, const ID: u64 = 0> { /// Returns a pointer to the [`Work<T, ID>`] field. /// /// # Safety /// /// The provided pointer must point at a valid struct of type `Self`. 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`. unsafe fn work_container_of(ptr: *mut Work<T, ID>) -> *mut Self;}
/// Used to safely implement the [`HasWork<T, ID>`] trait.////// # Examples////// ```/// use kernel::sync::Arc;/// use kernel::workqueue::{self, impl_has_work, Work};////// struct MyStruct<'a, T, const N: usize> {/// work_field: Work<MyStruct<'a, T, N>, 17>,/// f: fn(&'a [T; N]),/// }////// impl_has_work! {/// impl{'a, T, const N: usize} HasWork<MyStruct<'a, T, N>, 17>/// for MyStruct<'a, T, N> { self.work_field }/// }/// ```#[macro_export]macro_rules! impl_has_work { ($(impl$({$($generics:tt)*})? HasWork<$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)+>)? $crate::workqueue::HasWork<$work_type $(, $id)?> for $self { #[inline] unsafe fn raw_get_work(ptr: *mut Self) -> *mut $crate::workqueue::Work<$work_type $(, $id)?> { // SAFETY: The caller promises that the pointer is not dangling. unsafe { ::core::ptr::addr_of_mut!((*ptr).$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) } } } )*};}pub use impl_has_work;
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) { // 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 arc = unsafe { Arc::from_raw(ptr) };
T::run(arc) }}
// 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>, T: HasWork<T, ID>,{ type EnqueueOutput = Result<(), Self>;
unsafe fn __enqueue<F>(self, queue_work_on: F) -> Self::EnqueueOutput where F: FnOnce(*mut bindings::work_struct) -> bool, { // Casting between const and mut is not a problem as long as the pointer is a raw pointer. let ptr = Arc::into_raw(self).cast_mut();
// SAFETY: Pointers into an `Arc` 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) };
if queue_work_on(work_ptr) { Ok(()) } else { // SAFETY: The work queue has not taken ownership of the pointer. Err(unsafe { Arc::from_raw(ptr) }) } }}
// 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) { // 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 { KBox::from_raw(ptr) }; // SAFETY: The box was already pinned when it was enqueued. let pinned = unsafe { Pin::new_unchecked(boxed) };
T::run(pinned) }}
// SAFETY: TODO.unsafe impl<T, const ID: u64> RawWorkItem<ID> for Pin<KBox<T>>where T: WorkItem<ID, Pointer = Self>, T: HasWork<T, ID>,{ type EnqueueOutput = ();
unsafe fn __enqueue<F>(self, queue_work_on: F) -> Self::EnqueueOutput where F: FnOnce(*mut bindings::work_struct) -> bool, { // 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 = KBox::into_raw(boxed);
// 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) };
if !queue_work_on(work_ptr) { // SAFETY: This method requires exclusive ownership of the box, so it cannot be in a // workqueue. unsafe { ::core::hint::unreachable_unchecked() } } }}
// 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/// users which expect relatively short queue flush time.////// Callers shouldn't queue work items which can run for too long.pub fn system() -> &'static Queue { // SAFETY: `system_wq` is a C global, always available. unsafe { Queue::from_raw(bindings::system_wq) }}
/// Returns the system high-priority work queue (`system_highpri_wq`).////// It is similar to the one returned by [`system`] but for work items which require higher/// scheduling priority.pub fn system_highpri() -> &'static Queue { // SAFETY: `system_highpri_wq` is a C global, always available. unsafe { Queue::from_raw(bindings::system_highpri_wq) }}
/// Returns the system work queue for potentially long-running work items (`system_long_wq`).////// It is similar to the one returned by [`system`] but may host long running work items. Queue/// flushing might take relatively long.pub fn system_long() -> &'static Queue { // SAFETY: `system_long_wq` is a C global, always available. unsafe { Queue::from_raw(bindings::system_long_wq) }}
/// Returns the system unbound work queue (`system_unbound_wq`).////// Workers are not bound to any specific CPU, not concurrency managed, and all queued work items/// are executed immediately as long as `max_active` limit is not reached and resources are/// available.pub fn system_unbound() -> &'static Queue { // SAFETY: `system_unbound_wq` is a C global, always available. unsafe { Queue::from_raw(bindings::system_unbound_wq) }}
/// Returns the system freezable work queue (`system_freezable_wq`).////// It is equivalent to the one returned by [`system`] except that it's freezable.////// A freezable workqueue participates in the freeze phase of the system suspend operations. Work/// items on the workqueue are drained and no new work item starts execution until thawed.pub fn system_freezable() -> &'static Queue { // SAFETY: `system_freezable_wq` is a C global, always available. unsafe { Queue::from_raw(bindings::system_freezable_wq) }}
/// Returns the system power-efficient work queue (`system_power_efficient_wq`).////// It is inclined towards saving power and is converted to "unbound" variants if the/// `workqueue.power_efficient` kernel parameter is specified; otherwise, it is similar to the one/// returned by [`system`].pub fn system_power_efficient() -> &'static Queue { // SAFETY: `system_power_efficient_wq` is a C global, always available. unsafe { Queue::from_raw(bindings::system_power_efficient_wq) }}
/// Returns the system freezable power-efficient work queue (`system_freezable_power_efficient_wq`).////// It is similar to the one returned by [`system_power_efficient`] except that is freezable.////// A freezable workqueue participates in the freeze phase of the system suspend operations. Work/// items on the workqueue are drained and no new work item starts execution until thawed.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) }}