Re: [PATCH v2 8/8] rust: workqueue: add examples

Alice Ryhl
2023-06-02T09:39:42Z

Gary Guo <gary@garyguo.net> writes:
> On Thu, 1 Jun 2023 13:49:46 +0000
> Alice Ryhl <aliceryhl@google.com> wrote:
>> This adds two examples of how to use the workqueue. The first example
>> shows how to use it when you only have one `work_struct` field, and the
>> second example shows how to use it when you have multiple `work_struct`
>> fields.
>>
>> Signed-off-by: Alice Ryhl <aliceryhl@google.com>
>> ---
>> rust/kernel/workqueue.rs | 104 +++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 104 insertions(+)
>>
>> diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
>> index c302e8b8624b..cefcf43ff40e 100644
>> --- a/rust/kernel/workqueue.rs
>> +++ b/rust/kernel/workqueue.rs
>> @@ -26,6 +26,110 @@
>> //! * 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};
>> +//!
>> +//! #[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 <- Work::new(),
>> +//! }))
>> +//! }
>> +//! }
>> +//!
>> +//! 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};
>> +//!
>> +//! #[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 <- Work::new(),
>> +//! work_2 <- Work::new(),
>> +//! }))
>> +//! }
>> +//! }
>> +//!
>> +//! 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);
>
> Nothing bad about explicit, but I just want to confirm that you could
> write
>
> let _ = workqueue::system().enqueue::<_, 1>(val);
>
> here, right?

Yes, you can also do that.