rust: kernel: remove redundant imports

Rust's `unused_imports` lint covers both unused and redundant imports.
In the upcoming 1.78.0, the lint detects more cases of redundant imports
[1], e.g.:

rust: kernel: remove redundant imports

Rust's `unused_imports` lint covers both unused and redundant imports.
In the upcoming 1.78.0, the lint detects more cases of redundant imports
[1], e.g.:

error: the item `bindings` is imported redundantly
--> rust/kernel/print.rs:38:9
|
38 | use crate::bindings;
| ^^^^^^^^^^^^^^^ the item `bindings` is already defined by prelude

Most cases are `use crate::bindings`, plus a few other items like `Box`.
Thus clean them up.

Note that, in the `bindings` case, the message "defined by prelude"
above means the extern prelude, i.e. the `--extern` flags we pass.

Link: https://github.com/rust-lang/rust/pull/117772 [1]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240401212303.537355-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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rust: remove unneeded `kernel::prelude` imports from doctests

Rust doctests implicitly include `kernel::prelude::*`.

Removes explicit `kernel::prelude` imports from doctests.

Suggested-by: Miguel

rust: remove unneeded `kernel::prelude` imports from doctests

Rust doctests implicitly include `kernel::prelude::*`.

Removes explicit `kernel::prelude` imports from doctests.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1064
Signed-off-by: Nell Shamrell-Harrington <nells@linux.microsoft.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240411225331.274662-1-nells@linux.microsoft.com
[ Add it back for `module_phy_driver`'s example since it is within a `mod`,
and thus it cannot be removed. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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rust: kernel: remove usage of `allocator_api` unstable feature

With the adoption of `BoxExt` and `VecExt`, we don't need the functions
provided by this feature (namely the methods prefixed with `try

rust: kernel: remove usage of `allocator_api` unstable feature

With the adoption of `BoxExt` and `VecExt`, we don't need the functions
provided by this feature (namely the methods prefixed with `try_` and
different allocator per collection instance).

We do need `AllocError`, but we define our own as it is a trivial empty
struct.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240328013603.206764-11-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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rust: init: update `init` module to take allocation flags

This is the last component in the conversion for allocators to take
allocation flags as parameters.

Reviewed-by: Benno Lossin <benno.lossin

rust: init: update `init` module to take allocation flags

This is the last component in the conversion for allocators to take
allocation flags as parameters.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240328013603.206764-10-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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rust: workqueue: add `#[pin_data]` to `Work`

The previous two patches made it possible to add `#[pin_data]` on
structs with default generic parameter values.
This patch makes `Work` use `#[pin_data]

rust: workqueue: add `#[pin_data]` to `Work`

The previous two patches made it possible to add `#[pin_data]` on
structs with default generic parameter values.
This patch makes `Work` use `#[pin_data]` and removes an invocation of
`pin_init_from_closure`. This function is intended as a low level manual
escape hatch, so it is better to rely on the safe `pin_init!` macro.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240309155243.482334-3-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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rust: kernel: add reexports for macros

Currently, all macros are reexported with #[macro_export] only, which
means that to access `new_work!` from the workqueue, you need to import
it from the path

rust: kernel: add reexports for macros

Currently, all macros are reexported with #[macro_export] only, which
means that to access `new_work!` from the workqueue, you need to import
it from the path `kernel::new_work` instead of importing it from the
workqueue module like all other items in the workqueue. By adding
reexports of the macros, it becomes possible to import the macros from
the correct modules.

It's still possible to import the macros from the root, but I don't
think we can do anything about that.

There is no functional change. This is merely a code cleanliness
improvement.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240129145837.1419880-1-aliceryhl@google.com
[ Removed new `use kernel::prelude::*`s, reworded title. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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rust: kernel: remove unneeded doclink targets

Remove explicit targets for doclinks in cases where rustdoc can
determine the correct target by itself. The goal is to reduce unneeded
verbosity in the

rust: kernel: remove unneeded doclink targets

Remove explicit targets for doclinks in cases where rustdoc can
determine the correct target by itself. The goal is to reduce unneeded
verbosity in the source code.

Signed-off-by: Valentin Obst <kernel@valentinobst.de>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240131-doc-fixes-v3-v3-11-0c8af94ed7de@valentinobst.de
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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rust: kernel: add doclinks

Add doclinks to existing documentation.

Signed-off-by: Valentin Obst <kernel@valentinobst.de>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez

rust: kernel: add doclinks

Add doclinks to existing documentation.

Signed-off-by: Valentin Obst <kernel@valentinobst.de>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240131-doc-fixes-v3-v3-10-0c8af94ed7de@valentinobst.de
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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rust: kernel: mark code fragments in docs with backticks

Fix places where comments include code fragments that are not enclosed
in backticks.

Signed-off-by: Valentin Obst <kernel@valentinobst.de>
R

rust: kernel: mark code fragments in docs with backticks

Fix places where comments include code fragments that are not enclosed
in backticks.

Signed-off-by: Valentin Obst <kernel@valentinobst.de>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240131-doc-fixes-v3-v3-8-0c8af94ed7de@valentinobst.de
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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rust: kernel: fix multiple typos in documentation

Fixes multiple trivial typos in documentation and comments of the
kernel crate.

allocator:
- Fix a trivial list item alignment issue in the last SA

rust: kernel: fix multiple typos in documentation

Fixes multiple trivial typos in documentation and comments of the
kernel crate.

allocator:
- Fix a trivial list item alignment issue in the last SAFETY comment of
`krealloc_aligned`.

init:
- Replace 'type' with 'trait' in the doc comments of the `PinInit` and
`Init` traits.
- Add colons before starting lists.
- Add spaces between the type and equal sign to respect the code
formatting rules in example code.
- End a sentence with a full stop instead of a colon.

ioctl:
- Replace 'an' with 'a' where appropriate.

str:
- Replace 'Return' with 'Returns' in the doc comment of `bytes_written`
as the text describes what the function does.

sync/lock:
- Fix a trivial list item alignment issue in the Safety section of the
`Backend` trait's description.

sync/lock/spinlock:
- The code in this module operates on spinlocks, not mutexes. Thus,
replace 'mutex' with 'spinlock' in the SAFETY comment of `unlock`.

workqueue:
- Replace "wont" with "won't" in the doc comment of `__enqueue`.

Signed-off-by: Valentin Obst <kernel@valentinobst.de>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240131-doc-fixes-v3-v3-1-0c8af94ed7de@valentinobst.de
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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workqueue: rust: sync with `WORK_CPU_UNBOUND` change

Commit e563d0a7cdc1 ("workqueue: Break up enum definitions and give
names to the types") gives a name to the `enum` where `WORK_CPU_UNBOUND`
was

workqueue: rust: sync with `WORK_CPU_UNBOUND` change

Commit e563d0a7cdc1 ("workqueue: Break up enum definitions and give
names to the types") gives a name to the `enum` where `WORK_CPU_UNBOUND`
was defined, so `bindgen` changes its output from e.g.:

pub type _bindgen_ty_10 = core::ffi::c_uint;
pub const WORK_CPU_UNBOUND: _bindgen_ty_10 = 64;

to e.g.:

pub type wq_misc_consts = core::ffi::c_uint;
pub const wq_misc_consts_WORK_CPU_UNBOUND: wq_misc_consts = 64;

Thus update Rust's side to match the change (which requires a slight
reformat of the code), fixing the build error.

Closes: https://lore.kernel.org/rust-for-linux/CANiq72=9PZ89bCAVX0ZV4cqrYSLoZWyn-d_K4KpBMHjwUMdC3A@mail.gmail.com/
Fixes: e563d0a7cdc1 ("workqueue: Break up enum definitions and give names to the types")
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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rust: support `srctree`-relative links

Some of our links use relative paths in order to point to files in the
source tree, e.g.:

//! C header: [`include/linux/printk.h`](../../../../include/lin

rust: support `srctree`-relative links

Some of our links use relative paths in order to point to files in the
source tree, e.g.:

//! C header: [`include/linux/printk.h`](../../../../include/linux/printk.h)
/// [`struct mutex`]: ../../../../include/linux/mutex.h

These are problematic because they are hard to maintain and do not support
`O=` builds.

Instead, provide support for `srctree`-relative links, e.g.:

//! C header: [`include/linux/printk.h`](srctree/include/linux/printk.h)
/// [`struct mutex`]: srctree/include/linux/mutex.h

The links are fixed after `rustdoc` generation to be based on the absolute
path to the source tree.

Essentially, this is the automatic version of Tomonori's fix [1],
suggested by Gary [2].

Suggested-by: Gary Guo <gary@garyguo.net>
Reported-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Closes: https://lore.kernel.org/r/20231026.204058.2167744626131849993.fujita.tomonori@gmail.com [1]
Fixes: 48fadf440075 ("docs: Move rustdoc output, cross-reference it")
Link: https://lore.kernel.org/rust-for-linux/20231026154525.6d14b495@eugeo/ [2]
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20231215235428.243211-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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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 t

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>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
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>

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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

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>

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rust: workqueue: implement `WorkItemPointer` for pointer types

This implements the `WorkItemPointer` trait for the pointer types that
you are likely to use the workqueue with. The `Arc` type is for

rust: workqueue: implement `WorkItemPointer` for pointer types

This implements the `WorkItemPointer` trait for the pointer types that
you are likely to use the workqueue with. The `Arc` type is for
reference counted objects, and the `Pin<Box<T>>` type is for objects
where the caller has exclusive ownership of the object.

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>

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rust: workqueue: add helper for defining work_struct fields

The main challenge with defining `work_struct` fields is making sure
that the function pointer stored in the `work_struct` is appropriate

rust: workqueue: add helper for defining work_struct fields

The main challenge with defining `work_struct` fields is making sure
that the function pointer stored in the `work_struct` is appropriate for
the work item type it is embedded in. It needs to know the offset of the
`work_struct` field being used (even if there are several!) so that it
can do a `container_of`, and it needs to know the type of the work item
so that it can call into the right user-provided code. All of this needs
to happen in a way that provides a safe API to the user, so that users
of the workqueue cannot mix up the function pointers.

There are three important pieces that are relevant when doing this:

* The pointer type.
* The work item struct. This is what the pointer points at.
* The `work_struct` field. This is a field of the work item struct.

This patch introduces a separate trait for each piece. The pointer type
is given a `WorkItemPointer` trait, which pointer types need to
implement to be usable with the workqueue. This trait will be
implemented for `Arc` and `Box` in a later patch in this patchset.
Implementing this trait is unsafe because this is where the
`container_of` operation happens, but user-code will not need to
implement it themselves.

The work item struct should then implement the `WorkItem` trait. This
trait is where user-code specifies what they want to happen when a work
item is executed. It also specifies what the correct pointer type is.

Finally, to make the work item struct know the offset of its
`work_struct` field, we use a trait called `HasWork<T, ID>`. If a type
implements this trait, then the type declares that, at the given offset,
there is a field of type `Work<T, ID>`. The trait is marked unsafe
because the OFFSET constant must be correct, but we provide an
`impl_has_work!` macro that can safely implement `HasWork<T>` on a type.
The macro expands to something that only compiles if the specified field
really has the type `Work<T>`. It is used like this:

```
struct MyWorkItem {
work_field: Work<MyWorkItem, 1>,
}

impl_has_work! {
impl HasWork<MyWorkItem, 1> for MyWorkItem { self.work_field }
}
```

Note that since the `Work` type is annotated with an id, you can have
several `work_struct` fields by using a different id for each one.

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: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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rust: workqueue: define built-in queues

We provide these methods because it lets us access these queues from
Rust without using unsafe code.

These methods return `&'static Queue`. References annota

rust: workqueue: define built-in queues

We provide these methods because it lets us access these queues from
Rust without using unsafe code.

These methods return `&'static Queue`. References annotated with the
'static lifetime are used when the referent will stay alive forever.
That is ok for these queues because they are global variables and cannot
be destroyed.

Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Co-developed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
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>

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rust: workqueue: add low-level workqueue bindings

Define basic low-level bindings to a kernel workqueue. The API defined
here can only be used unsafely. Later commits will provide safe
wrappers.

Co

rust: workqueue: add low-level workqueue bindings

Define basic low-level bindings to a kernel workqueue. The API defined
here can only be used unsafely. Later commits will provide safe
wrappers.

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>

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