Commit 115c95e9 authored by Alice Ryhl's avatar Alice Ryhl Committed by Tejun Heo
Browse files

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: default avatarGary Guo <gary@garyguo.net>
Signed-off-by: default avatarGary Guo <gary@garyguo.net>
Signed-off-by: default avatarAlice Ryhl <aliceryhl@google.com>
Reviewed-by: default avatarMartin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: default avatar"Andreas Hindborg (Samsung)" <nmi@metaspace.dk>
Reviewed-by: default avatarBenno Lossin <benno.lossin@proton.me>
Reviewed-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 47f0dbe8

rust/kernel/workqueue.rs

+43 −0
Original line number Diff line number Diff line
@@ -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>,