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Message-ID: <20230828104807.1581592-7-aliceryhl@google.com>
Date: Mon, 28 Aug 2023 10:48:06 +0000
From: Alice Ryhl <aliceryhl@...gle.com>
To: rust-for-linux@...r.kernel.org, Tejun Heo <tj@...nel.org>,
Miguel Ojeda <ojeda@...nel.org>
Cc: Lai Jiangshan <jiangshanlai@...il.com>,
Wedson Almeida Filho <wedsonaf@...il.com>,
Alex Gaynor <alex.gaynor@...il.com>,
Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>,
"Björn Roy Baron" <bjorn3_gh@...tonmail.com>,
Benno Lossin <benno.lossin@...ton.me>,
Alice Ryhl <aliceryhl@...gle.com>,
linux-kernel@...r.kernel.org, patches@...ts.linux.dev,
Martin Rodriguez Reboredo <yakoyoku@...il.com>,
Andreas Hindborg <nmi@...aspace.dk>
Subject: [PATCH v4 6/7] 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@...yguo.net>
Signed-off-by: Gary Guo <gary@...yguo.net>
Signed-off-by: Alice Ryhl <aliceryhl@...gle.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@...il.com>
Reviewed-by: Andreas Hindborg (Samsung) <nmi@...aspace.dk>
Reviewed-by: Benno Lossin <benno.lossin@...ton.me>
---
v3 -> v4:
* Use new `new_work!` macro.
rust/kernel/workqueue.rs | 43 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
index c1334c48b96b..40ccc53f6e93 100644
--- a/rust/kernel/workqueue.rs
+++ b/rust/kernel/workqueue.rs
@@ -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 @@ pub fn enqueue<W, const ID: u64>(&self, w: W) -> W::EnqueueOutput
})
}
}
+
+ /// 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 @@ unsafe fn raw_get_work(ptr: *mut Self) -> *mut $crate::workqueue::Work<$work_typ
)*};
}
+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>,
--
2.42.0.rc1.204.g551eb34607-goog
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