rust: workqueue: add try_spawn helper method

This adds a convenience method that lets you spawn a closure for
execution on a workqueue. This will be the most convenient way to use
workqueues, but it is fallible because it needs to allocate memory.

Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: "Andreas Hindborg (Samsung)" <nmi@metaspace.dk>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Alice Ryhl 2023-08-28 10:48:06 +00:00 committed by Tejun Heo
parent 47f0dbe8fd
commit 115c95e9e1

View File

@ -29,6 +29,7 @@
//! 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;
@ -96,6 +97,44 @@ impl Queue {
})
}
}
/// 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.
@ -365,6 +404,10 @@ macro_rules! impl_has_work {
)*};
}
impl_has_work! {
impl<T> HasWork<Self> for ClosureWork<T> { self.work }
}
unsafe impl<T, const ID: u64> WorkItemPointer<ID> for Arc<T>
where
T: WorkItem<ID, Pointer = Self>,