[v2,8/8] rust: workqueue: add examples

  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(+)
  

On 6/1/23 10:49, Alice Ryhl 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>
> ---
> [...]

Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
  

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?

Reviewed-by: Gary Guo <gary@garyguo.net>

> +//! }
> +//!
> +//! fn print_2_later(val: Arc<MyStruct>) {
> +//!     let _ = workqueue::system().enqueue::<Arc<MyStruct>, 2>(val);
> +//! }
> +//! ```
> +//!
>  //! C header: [`include/linux/workqueue.h`](../../../../include/linux/workqueue.h)
>  
>  use crate::{bindings, prelude::*, sync::Arc, types::Opaque};
  

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.
  

Alice Ryhl <aliceryhl@google.com> writes:

> 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>

Reviewed-by: Andreas Hindborg (Samsung) <nmi@metaspace.dk>

> ---
>  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);
> +//! }
> +//!
> +//! fn print_2_later(val: Arc<MyStruct>) {
> +//!     let _ = workqueue::system().enqueue::<Arc<MyStruct>, 2>(val);
> +//! }
> +//! ```
> +//!
>  //! C header: [`include/linux/workqueue.h`](../../../../include/linux/workqueue.h)
>  
>  use crate::{bindings, prelude::*, sync::Arc, types::Opaque};
  

Alice Ryhl <aliceryhl@google.com> writes:

> 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>

Reviewed-by: Andreas Hindborg (Samsung) <nmi@metaspace.dk>

> ---
>  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);
> +//! }
> +//!
> +//! fn print_2_later(val: Arc<MyStruct>) {
> +//!     let _ = workqueue::system().enqueue::<Arc<MyStruct>, 2>(val);
> +//! }
> +//! ```
> +//!
>  //! C header: [`include/linux/workqueue.h`](../../../../include/linux/workqueue.h)
>  
>  use crate::{bindings, prelude::*, sync::Arc, types::Opaque};
  

On 01.06.23 15:49, Alice Ryhl 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>

Reviewed-by: Benno Lossin <benno.lossin@proton.me>

I really like that you added these examples!
Is there some particular reason you decided to not use
0 as the first index in the second example? (you can keep
it this way)
  

Benno Lossin <benno.lossin@proton.me> writes:
> On 01.06.23 15:49, Alice Ryhl 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>
> 
> Reviewed-by: Benno Lossin <benno.lossin@proton.me>
> 
> I really like that you added these examples!
> Is there some particular reason you decided to not use
> 0 as the first index in the second example? (you can keep
> it this way)

In my head, it felt more natural for the first field to be called 1 and
the second field to be called 2. But it doesn't really matter which
numbers you use.

Alice