// SPDX-License-Identifier: GPL-2.0 //! 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`.//!//! ## Example//!//! 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::prelude::*;//! use kernel::sync::Arc;//! use kernel::workqueue::{self, Work, WorkItem};//! use kernel::{impl_has_work, new_work};//!//! #[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"),//! }))//! }//! }//!//! impl WorkItem for MyStruct {//! type Pointer = Arc<MyStruct>;//!//! fn run(this: Arc<MyStruct>) {//! pr_info!("The value is: {}", 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);//! }//! ```//!//! The following example shows how multiple `work_struct` fields can be used://!//! ```//! use kernel::prelude::*;//! use kernel::sync::Arc;//! use kernel::workqueue::{self, Work, WorkItem};//! use kernel::{impl_has_work, new_work};//!//! #[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"),//! }))//! }//! }//!//! impl WorkItem<1> for MyStruct {//! type Pointer = Arc<MyStruct>;//!//! fn run(this: Arc<MyStruct>) {//! pr_info!("The value is: {}", this.value_1);//! }//! }//!//! impl WorkItem<2> for MyStruct {//! type Pointer = Arc<MyStruct>;//!//! fn run(this: Arc<MyStruct>) {//! pr_info!("The second value is: {}", 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);//! }//! ```//!//! C header: [`include/linux/workqueue.h`](../../../../include/linux/workqueue.h) use crate::{bindings, prelude::*, sync::Arc, sync::LockClassKey, types::Opaque};use alloc::alloc::AllocError;use alloc::boxed::Box;use core::marker::PhantomData;use core::pin::Pin; /// 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!()) };} /// 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 as *const 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::WORK_CPU_UNBOUND as _, queue_ptr, work_ptr) }) } } /// 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, func: T) -> Result<(), AllocError> { let init = pin_init!(ClosureWork { work <- new_work!("Queue::try_spawn"), func: Some(func), }); self.enqueue(Box::pin_init(init).map_err(|_| AllocError)?); Ok(()) }} /// A helper type used in `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<Box<Self>>; fn run(mut this: Pin<Box<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 wont 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`.pub 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;} /// 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/// 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` 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. 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<Box<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.#[repr(transparent)]pub struct Work<T: ?Sized, const ID: u64 = 0> { 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] #[allow(clippy::new_ret_no_self)] pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self> where T: WorkItem<ID>, { // SAFETY: The `WorkItemPointer` implementation promises that `run` can be used as the work // item function. unsafe { kernel::init::pin_init_from_closure(move |slot| { let slot = Self::raw_get(slot); bindings::init_work_with_key( slot, Some(T::Pointer::run), false, name.as_char_ptr(), key.as_ptr(), ); Ok(()) }) } } /// 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::raw_get(core::ptr::addr_of!((*ptr).work)) } }} /// Declares that a type has a [`Work<T, ID>`] field.////// 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::impl_has_work;/// use kernel::prelude::*;/// use kernel::workqueue::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 [`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.////// [`Work<T, ID>`]: Work/// [`impl_has_work!`]: crate::impl_has_work/// [`OFFSET`]: HasWork::OFFSETpub unsafe trait HasWork<T, const ID: u64 = 0> { /// The offset of the [`Work<T, ID>`] field. /// /// [`Work<T, ID>`]: Work 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. /// /// [`Work<T, ID>`]: Work /// [`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`. /// /// [`Work<T, ID>`]: Work #[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> } } /// 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`. /// /// [`Work<T, ID>`]: Work #[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 } }} /// Used to safely implement the [`HasWork<T, ID>`] trait.////// # Examples////// ```/// use kernel::impl_has_work;/// use kernel::sync::Arc;/// use kernel::workqueue::{self, Work};////// struct MyStruct {/// work_field: Work<MyStruct, 17>,/// }////// impl_has_work! {/// impl HasWork<MyStruct, 17> for MyStruct { self.work_field }/// }/// ```////// [`HasWork<T, ID>`]: HasWork#[macro_export]macro_rules! impl_has_work { ($(impl$(<$($implarg:ident),*>)? HasWork<$work_type:ty $(, $id:tt)?> for $self:ident $(<$($selfarg:ident),*>)? { self.$field:ident } )*) => {$( // SAFETY: The implementation of `raw_get_work` only compiles if the field has the right // type. unsafe impl$(<$($implarg),*>)? $crate::workqueue::HasWork<$work_type $(, $id)?> for $self $(<$($selfarg),*>)? { const OFFSET: usize = ::core::mem::offset_of!(Self, $field) as usize;Lines 1–500 of 679. Load more
// SPDX-License-Identifier: GPL-2.0 //! 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`. //! //! ## Example //! //! 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::prelude::*; //! use kernel::sync::Arc; //! use kernel::workqueue::{self, Work, WorkItem}; //! use kernel::{impl_has_work, new_work}; //! //! #[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"), //! })) //! } //! } //! //! impl WorkItem for MyStruct { //! type Pointer = Arc<MyStruct>; //! //! fn run(this: Arc<MyStruct>) { //! pr_info!("The value is: {}", 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); //! } //! ``` //! //! The following example shows how multiple `work_struct` fields can be used: //! //! ``` //! use kernel::prelude::*; //! use kernel::sync::Arc; //! use kernel::workqueue::{self, Work, WorkItem}; //! use kernel::{impl_has_work, new_work}; //! //! #[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"), //! })) //! } //! } //! //! impl WorkItem<1> for MyStruct { //! type Pointer = Arc<MyStruct>; //! //! fn run(this: Arc<MyStruct>) { //! pr_info!("The value is: {}", this.value_1); //! } //! } //! //! impl WorkItem<2> for MyStruct { //! type Pointer = Arc<MyStruct>; //! //! fn run(this: Arc<MyStruct>) { //! pr_info!("The second value is: {}", 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); //! } //! ``` //! //! C header: [`include/linux/workqueue.h`](../../../../include/linux/workqueue.h) use crate::{bindings, prelude::*, sync::Arc, sync::LockClassKey, types::Opaque}; use alloc::alloc::AllocError; use alloc::boxed::Box; use core::marker::PhantomData; use core::pin::Pin; /// 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!()) }; } /// 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 as *const 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::WORK_CPU_UNBOUND as _, queue_ptr, work_ptr) }) } } /// 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, func: T) -> Result<(), AllocError> { let init = pin_init!(ClosureWork { work <- new_work!("Queue::try_spawn"), func: Some(func), }); self.enqueue(Box::pin_init(init).map_err(|_| AllocError)?); Ok(()) } } /// A helper type used in `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<Box<Self>>; fn run(mut this: Pin<Box<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 wont 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`. pub 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; } /// 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 /// 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` 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::run pub 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. 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<Box<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. #[repr(transparent)] pub struct Work<T: ?Sized, const ID: u64 = 0> { 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] #[allow(clippy::new_ret_no_self)] pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self> where T: WorkItem<ID>, { // SAFETY: The `WorkItemPointer` implementation promises that `run` can be used as the work // item function. unsafe { kernel::init::pin_init_from_closure(move |slot| { let slot = Self::raw_get(slot); bindings::init_work_with_key( slot, Some(T::Pointer::run), false, name.as_char_ptr(), key.as_ptr(), ); Ok(()) }) } } /// 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::raw_get(core::ptr::addr_of!((*ptr).work)) } } } /// Declares that a type has a [`Work<T, ID>`] field. /// /// 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::impl_has_work; /// use kernel::prelude::*; /// use kernel::workqueue::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 [`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. /// /// [`Work<T, ID>`]: Work /// [`impl_has_work!`]: crate::impl_has_work /// [`OFFSET`]: HasWork::OFFSET pub unsafe trait HasWork<T, const ID: u64 = 0> { /// The offset of the [`Work<T, ID>`] field. /// /// [`Work<T, ID>`]: Work 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. /// /// [`Work<T, ID>`]: Work /// [`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`. /// /// [`Work<T, ID>`]: Work #[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> } } /// 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`. /// /// [`Work<T, ID>`]: Work #[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 } } } /// Used to safely implement the [`HasWork<T, ID>`] trait. /// /// # Examples /// /// ``` /// use kernel::impl_has_work; /// use kernel::sync::Arc; /// use kernel::workqueue::{self, Work}; /// /// struct MyStruct { /// work_field: Work<MyStruct, 17>, /// } /// /// impl_has_work! { /// impl HasWork<MyStruct, 17> for MyStruct { self.work_field } /// } /// ``` /// /// [`HasWork<T, ID>`]: HasWork #[macro_export] macro_rules! impl_has_work { ($(impl$(<$($implarg:ident),*>)? HasWork<$work_type:ty $(, $id:tt)?> for $self:ident $(<$($selfarg:ident),*>)? { self.$field:ident } )*) => {$( // SAFETY: The implementation of `raw_get_work` only compiles if the field has the right // type. unsafe impl$(<$($implarg),*>)? $crate::workqueue::HasWork<$work_type $(, $id)?> for $self $(<$($selfarg),*>)? { const OFFSET: usize = ::core::mem::offset_of!(Self, $field) as usize;