mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2024-12-28 16:53:49 +00:00
8373147ce4
Now that we got the kernel `Box` type in place, convert all existing `Box` users to make use of it. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-13-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
689 lines
25 KiB
Rust
689 lines
25 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Work queues.
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//!
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//! This file has two components: The raw work item API, and the safe work item API.
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//!
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//! One pattern that is used in both APIs is the `ID` const generic, which exists to allow a single
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//! type to define multiple `work_struct` fields. This is done by choosing an id for each field,
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//! and using that id to specify which field you wish to use. (The actual value doesn't matter, as
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//! long as you use different values for different fields of the same struct.) Since these IDs are
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//! generic, they are used only at compile-time, so they shouldn't exist in the final binary.
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//!
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//! # The raw API
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//!
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//! The raw API consists of the [`RawWorkItem`] trait, where the work item needs to provide an
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//! arbitrary function that knows how to enqueue the work item. It should usually not be used
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//! directly, but if you want to, you can use it without using the pieces from the safe API.
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//!
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//! # The safe API
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//!
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//! The safe API is used via the [`Work`] struct and [`WorkItem`] traits. Furthermore, it also
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//! includes a trait called [`WorkItemPointer`], which is usually not used directly by the user.
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//!
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//! * The [`Work`] struct is the Rust wrapper for the C `work_struct` type.
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//! * The [`WorkItem`] trait is implemented for structs that can be enqueued to a workqueue.
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//! * The [`WorkItemPointer`] trait is implemented for the pointer type that points at a something
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//! that implements [`WorkItem`].
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//!
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//! ## Example
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//!
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//! This example defines a struct that holds an integer and can be scheduled on the workqueue. When
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//! the struct is executed, it will print the integer. Since there is only one `work_struct` field,
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//! we do not need to specify ids for the fields.
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//!
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//! ```
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//! use kernel::sync::Arc;
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//! use kernel::workqueue::{self, impl_has_work, new_work, Work, WorkItem};
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//!
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//! #[pin_data]
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//! struct MyStruct {
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//! value: i32,
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//! #[pin]
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//! work: Work<MyStruct>,
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//! }
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//!
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//! impl_has_work! {
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//! impl HasWork<Self> for MyStruct { self.work }
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//! }
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//!
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//! impl MyStruct {
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//! fn new(value: i32) -> Result<Arc<Self>> {
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//! Arc::pin_init(pin_init!(MyStruct {
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//! value,
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//! work <- new_work!("MyStruct::work"),
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//! }), GFP_KERNEL)
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//! }
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//! }
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//!
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//! impl WorkItem for MyStruct {
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//! type Pointer = Arc<MyStruct>;
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//!
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//! fn run(this: Arc<MyStruct>) {
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//! pr_info!("The value is: {}", this.value);
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//! }
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//! }
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//!
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//! /// This method will enqueue the struct for execution on the system workqueue, where its value
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//! /// will be printed.
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//! fn print_later(val: Arc<MyStruct>) {
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//! let _ = workqueue::system().enqueue(val);
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//! }
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//! ```
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//!
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//! The following example shows how multiple `work_struct` fields can be used:
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//!
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//! ```
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//! use kernel::sync::Arc;
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//! use kernel::workqueue::{self, impl_has_work, new_work, Work, WorkItem};
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//!
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//! #[pin_data]
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//! struct MyStruct {
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//! value_1: i32,
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//! value_2: i32,
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//! #[pin]
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//! work_1: Work<MyStruct, 1>,
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//! #[pin]
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//! work_2: Work<MyStruct, 2>,
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//! }
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//!
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//! impl_has_work! {
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//! impl HasWork<Self, 1> for MyStruct { self.work_1 }
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//! impl HasWork<Self, 2> for MyStruct { self.work_2 }
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//! }
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//!
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//! impl MyStruct {
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//! fn new(value_1: i32, value_2: i32) -> Result<Arc<Self>> {
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//! Arc::pin_init(pin_init!(MyStruct {
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//! value_1,
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//! value_2,
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//! work_1 <- new_work!("MyStruct::work_1"),
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//! work_2 <- new_work!("MyStruct::work_2"),
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//! }), GFP_KERNEL)
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//! }
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//! }
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//!
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//! impl WorkItem<1> for MyStruct {
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//! type Pointer = Arc<MyStruct>;
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//!
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//! fn run(this: Arc<MyStruct>) {
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//! pr_info!("The value is: {}", this.value_1);
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//! }
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//! }
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//!
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//! impl WorkItem<2> for MyStruct {
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//! type Pointer = Arc<MyStruct>;
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//!
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//! fn run(this: Arc<MyStruct>) {
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//! pr_info!("The second value is: {}", this.value_2);
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//! }
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//! }
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//!
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//! fn print_1_later(val: Arc<MyStruct>) {
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//! let _ = workqueue::system().enqueue::<Arc<MyStruct>, 1>(val);
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//! }
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//!
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//! fn print_2_later(val: Arc<MyStruct>) {
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//! let _ = workqueue::system().enqueue::<Arc<MyStruct>, 2>(val);
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//! }
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//! ```
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//!
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//! C header: [`include/linux/workqueue.h`](srctree/include/linux/workqueue.h)
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use crate::alloc::{AllocError, Flags};
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use crate::{prelude::*, sync::Arc, sync::LockClassKey, types::Opaque};
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use core::marker::PhantomData;
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/// Creates a [`Work`] initialiser with the given name and a newly-created lock class.
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#[macro_export]
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macro_rules! new_work {
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($($name:literal)?) => {
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$crate::workqueue::Work::new($crate::optional_name!($($name)?), $crate::static_lock_class!())
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};
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}
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pub use new_work;
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/// A kernel work queue.
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///
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/// Wraps the kernel's C `struct workqueue_struct`.
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///
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/// It allows work items to be queued to run on thread pools managed by the kernel. Several are
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/// always available, for example, `system`, `system_highpri`, `system_long`, etc.
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#[repr(transparent)]
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pub struct Queue(Opaque<bindings::workqueue_struct>);
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// SAFETY: Accesses to workqueues used by [`Queue`] are thread-safe.
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unsafe impl Send for Queue {}
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// SAFETY: Accesses to workqueues used by [`Queue`] are thread-safe.
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unsafe impl Sync for Queue {}
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impl Queue {
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/// Use the provided `struct workqueue_struct` with Rust.
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///
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/// # Safety
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///
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/// The caller must ensure that the provided raw pointer is not dangling, that it points at a
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/// valid workqueue, and that it remains valid until the end of `'a`.
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pub unsafe fn from_raw<'a>(ptr: *const bindings::workqueue_struct) -> &'a Queue {
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// SAFETY: The `Queue` type is `#[repr(transparent)]`, so the pointer cast is valid. The
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// caller promises that the pointer is not dangling.
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unsafe { &*(ptr as *const Queue) }
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}
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/// Enqueues a work item.
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///
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/// This may fail if the work item is already enqueued in a workqueue.
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///
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/// The work item will be submitted using `WORK_CPU_UNBOUND`.
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pub fn enqueue<W, const ID: u64>(&self, w: W) -> W::EnqueueOutput
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where
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W: RawWorkItem<ID> + Send + 'static,
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{
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let queue_ptr = self.0.get();
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// SAFETY: We only return `false` if the `work_struct` is already in a workqueue. The other
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// `__enqueue` requirements are not relevant since `W` is `Send` and static.
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//
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// The call to `bindings::queue_work_on` will dereference the provided raw pointer, which
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// is ok because `__enqueue` guarantees that the pointer is valid for the duration of this
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// closure.
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//
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// Furthermore, if the C workqueue code accesses the pointer after this call to
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// `__enqueue`, then the work item was successfully enqueued, and `bindings::queue_work_on`
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// will have returned true. In this case, `__enqueue` promises that the raw pointer will
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// stay valid until we call the function pointer in the `work_struct`, so the access is ok.
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unsafe {
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w.__enqueue(move |work_ptr| {
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bindings::queue_work_on(
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bindings::wq_misc_consts_WORK_CPU_UNBOUND as _,
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queue_ptr,
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work_ptr,
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)
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})
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}
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}
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/// Tries to spawn the given function or closure as a work item.
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///
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/// This method can fail because it allocates memory to store the work item.
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pub fn try_spawn<T: 'static + Send + FnOnce()>(
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&self,
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flags: Flags,
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func: T,
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) -> Result<(), AllocError> {
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let init = pin_init!(ClosureWork {
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work <- new_work!("Queue::try_spawn"),
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func: Some(func),
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});
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self.enqueue(KBox::pin_init(init, flags).map_err(|_| AllocError)?);
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Ok(())
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}
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}
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/// A helper type used in [`try_spawn`].
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///
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/// [`try_spawn`]: Queue::try_spawn
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#[pin_data]
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struct ClosureWork<T> {
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#[pin]
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work: Work<ClosureWork<T>>,
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func: Option<T>,
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}
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impl<T> ClosureWork<T> {
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fn project(self: Pin<&mut Self>) -> &mut Option<T> {
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// SAFETY: The `func` field is not structurally pinned.
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unsafe { &mut self.get_unchecked_mut().func }
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}
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}
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impl<T: FnOnce()> WorkItem for ClosureWork<T> {
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type Pointer = Pin<KBox<Self>>;
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fn run(mut this: Pin<KBox<Self>>) {
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if let Some(func) = this.as_mut().project().take() {
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(func)()
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}
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}
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}
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/// A raw work item.
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///
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/// This is the low-level trait that is designed for being as general as possible.
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///
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/// The `ID` parameter to this trait exists so that a single type can provide multiple
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/// implementations of this trait. For example, if a struct has multiple `work_struct` fields, then
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/// you will implement this trait once for each field, using a different id for each field. The
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/// actual value of the id is not important as long as you use different ids for different fields
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/// of the same struct. (Fields of different structs need not use different ids.)
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///
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/// Note that the id is used only to select the right method to call during compilation. It won't be
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/// part of the final executable.
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///
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/// # Safety
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///
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/// Implementers must ensure that any pointers passed to a `queue_work_on` closure by [`__enqueue`]
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/// remain valid for the duration specified in the guarantees section of the documentation for
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/// [`__enqueue`].
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///
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/// [`__enqueue`]: RawWorkItem::__enqueue
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pub unsafe trait RawWorkItem<const ID: u64> {
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/// The return type of [`Queue::enqueue`].
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type EnqueueOutput;
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/// Enqueues this work item on a queue using the provided `queue_work_on` method.
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///
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/// # Guarantees
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///
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/// If this method calls the provided closure, then the raw pointer is guaranteed to point at a
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/// valid `work_struct` for the duration of the call to the closure. If the closure returns
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/// true, then it is further guaranteed that the pointer remains valid until someone calls the
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/// function pointer stored in the `work_struct`.
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///
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/// # Safety
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///
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/// The provided closure may only return `false` if the `work_struct` is already in a workqueue.
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///
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/// If the work item type is annotated with any lifetimes, then you must not call the function
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/// pointer after any such lifetime expires. (Never calling the function pointer is okay.)
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///
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/// If the work item type is not [`Send`], then the function pointer must be called on the same
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/// thread as the call to `__enqueue`.
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unsafe fn __enqueue<F>(self, queue_work_on: F) -> Self::EnqueueOutput
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where
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F: FnOnce(*mut bindings::work_struct) -> bool;
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}
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/// Defines the method that should be called directly when a work item is executed.
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///
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/// This trait is implemented by `Pin<KBox<T>>` and [`Arc<T>`], and is mainly intended to be
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/// implemented for smart pointer types. For your own structs, you would implement [`WorkItem`]
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/// instead. The [`run`] method on this trait will usually just perform the appropriate
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/// `container_of` translation and then call into the [`run`][WorkItem::run] method from the
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/// [`WorkItem`] trait.
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///
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/// This trait is used when the `work_struct` field is defined using the [`Work`] helper.
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///
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/// # Safety
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///
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/// Implementers must ensure that [`__enqueue`] uses a `work_struct` initialized with the [`run`]
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/// method of this trait as the function pointer.
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///
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/// [`__enqueue`]: RawWorkItem::__enqueue
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/// [`run`]: WorkItemPointer::run
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pub unsafe trait WorkItemPointer<const ID: u64>: RawWorkItem<ID> {
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/// Run this work item.
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///
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/// # Safety
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///
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/// The provided `work_struct` pointer must originate from a previous call to [`__enqueue`]
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/// where the `queue_work_on` closure returned true, and the pointer must still be valid.
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///
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/// [`__enqueue`]: RawWorkItem::__enqueue
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unsafe extern "C" fn run(ptr: *mut bindings::work_struct);
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}
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/// Defines the method that should be called when this work item is executed.
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///
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/// This trait is used when the `work_struct` field is defined using the [`Work`] helper.
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pub trait WorkItem<const ID: u64 = 0> {
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/// The pointer type that this struct is wrapped in. This will typically be `Arc<Self>` or
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/// `Pin<KBox<Self>>`.
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type Pointer: WorkItemPointer<ID>;
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/// The method that should be called when this work item is executed.
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fn run(this: Self::Pointer);
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}
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/// Links for a work item.
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///
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/// This struct contains a function pointer to the [`run`] function from the [`WorkItemPointer`]
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/// trait, and defines the linked list pointers necessary to enqueue a work item in a workqueue.
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///
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/// Wraps the kernel's C `struct work_struct`.
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///
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/// This is a helper type used to associate a `work_struct` with the [`WorkItem`] that uses it.
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///
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/// [`run`]: WorkItemPointer::run
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#[pin_data]
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#[repr(transparent)]
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pub struct Work<T: ?Sized, const ID: u64 = 0> {
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#[pin]
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work: Opaque<bindings::work_struct>,
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_inner: PhantomData<T>,
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}
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// SAFETY: Kernel work items are usable from any thread.
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//
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// We do not need to constrain `T` since the work item does not actually contain a `T`.
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unsafe impl<T: ?Sized, const ID: u64> Send for Work<T, ID> {}
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// SAFETY: Kernel work items are usable from any thread.
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//
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// We do not need to constrain `T` since the work item does not actually contain a `T`.
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unsafe impl<T: ?Sized, const ID: u64> Sync for Work<T, ID> {}
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impl<T: ?Sized, const ID: u64> Work<T, ID> {
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/// Creates a new instance of [`Work`].
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#[inline]
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pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self>
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where
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T: WorkItem<ID>,
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{
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pin_init!(Self {
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work <- Opaque::ffi_init(|slot| {
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// SAFETY: The `WorkItemPointer` implementation promises that `run` can be used as
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// the work item function.
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unsafe {
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bindings::init_work_with_key(
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slot,
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Some(T::Pointer::run),
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false,
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name.as_char_ptr(),
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key.as_ptr(),
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)
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}
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}),
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_inner: PhantomData,
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})
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}
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/// Get a pointer to the inner `work_struct`.
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///
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/// # Safety
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///
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/// The provided pointer must not be dangling and must be properly aligned. (But the memory
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/// need not be initialized.)
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#[inline]
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pub unsafe fn raw_get(ptr: *const Self) -> *mut bindings::work_struct {
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// SAFETY: The caller promises that the pointer is aligned and not dangling.
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//
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// A pointer cast would also be ok due to `#[repr(transparent)]`. We use `addr_of!` so that
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// the compiler does not complain that the `work` field is unused.
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unsafe { Opaque::raw_get(core::ptr::addr_of!((*ptr).work)) }
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}
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}
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/// Declares that a type has a [`Work<T, ID>`] field.
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///
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/// The intended way of using this trait is via the [`impl_has_work!`] macro. You can use the macro
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/// like this:
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///
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/// ```no_run
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/// use kernel::workqueue::{impl_has_work, Work};
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///
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/// struct MyWorkItem {
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/// work_field: Work<MyWorkItem, 1>,
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/// }
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///
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/// impl_has_work! {
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/// impl HasWork<MyWorkItem, 1> for MyWorkItem { self.work_field }
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/// }
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/// ```
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///
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/// Note that since the [`Work`] type is annotated with an id, you can have several `work_struct`
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/// fields by using a different id for each one.
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///
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/// # Safety
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///
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/// The [`OFFSET`] constant must be the offset of a field in `Self` of type [`Work<T, ID>`]. The
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/// methods on this trait must have exactly the behavior that the definitions given below have.
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///
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/// [`impl_has_work!`]: crate::impl_has_work
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/// [`OFFSET`]: HasWork::OFFSET
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pub unsafe trait HasWork<T, const ID: u64 = 0> {
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/// The offset of the [`Work<T, ID>`] field.
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const OFFSET: usize;
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/// Returns the offset of the [`Work<T, ID>`] field.
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///
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/// This method exists because the [`OFFSET`] constant cannot be accessed if the type is not
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/// [`Sized`].
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///
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/// [`OFFSET`]: HasWork::OFFSET
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#[inline]
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fn get_work_offset(&self) -> usize {
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Self::OFFSET
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}
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/// Returns a pointer to the [`Work<T, ID>`] field.
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///
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/// # Safety
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///
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/// The provided pointer must point at a valid struct of type `Self`.
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#[inline]
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unsafe fn raw_get_work(ptr: *mut Self) -> *mut Work<T, ID> {
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// SAFETY: The caller promises that the pointer is valid.
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unsafe { (ptr as *mut u8).add(Self::OFFSET) as *mut Work<T, ID> }
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}
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/// Returns a pointer to the struct containing the [`Work<T, ID>`] field.
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///
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|
/// # 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 }
|
|
}
|
|
}
|
|
|
|
/// 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 {
|
|
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 $(, $id)?> {
|
|
// SAFETY: The caller promises that the pointer is not dangling.
|
|
unsafe {
|
|
::core::ptr::addr_of_mut!((*ptr).$field)
|
|
}
|
|
}
|
|
}
|
|
)*};
|
|
}
|
|
pub use impl_has_work;
|
|
|
|
impl_has_work! {
|
|
impl{T} HasWork<Self> for ClosureWork<T> { self.work }
|
|
}
|
|
|
|
// SAFETY: TODO.
|
|
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 as *mut 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: TODO.
|
|
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: 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 as *mut 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() }
|
|
}
|
|
}
|
|
}
|
|
|
|
/// 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) }
|
|
}
|