rust: make pin-init its own crate

Rename relative paths inside of the crate to still refer to the same
items, also rename paths inside of the kernel crate and adjust the build
system to build the cr

rust: make pin-init its own crate

Rename relative paths inside of the crate to still refer to the same
items, also rename paths inside of the kernel crate and adjust the build
system to build the crate.

[ Remove the `expect` (and thus the `lint_reasons` feature) since
the tree now uses `quote!` from `rust/macros/export.rs`. Remove the
`TokenStream` import removal, since it is now used as well.

In addition, temporarily (i.e. just for this commit) use an `--extern
force:alloc` to prevent an unknown `new_uninit` error in the `rustdoc`
target. For context, please see a similar case in:

https://lore.kernel.org/lkml/[email protected]/

And adjusted the message above. - Miguel ]

Signed-off-by: Benno Lossin <[email protected]>
Reviewed-by: Fiona Behrens <[email protected]>
Tested-by: Andreas Hindborg <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: pin-init: move `InPlaceInit` and impls of `InPlaceWrite` into the kernel crate

In order to make pin-init a standalone crate, move kernel-specific code
directly into the kernel crate. This incl

rust: pin-init: move `InPlaceInit` and impls of `InPlaceWrite` into the kernel crate

In order to make pin-init a standalone crate, move kernel-specific code
directly into the kernel crate. This includes the `InPlaceInit<T>`
trait, its implementations and the implementations of `InPlaceWrite` for
`Arc` and `UniqueArc`. All of these use the kernel's error type which
will become unavailable in pin-init.

Signed-off-by: Benno Lossin <[email protected]>
Reviewed-by: Fiona Behrens <[email protected]>
Tested-by: Andreas Hindborg <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: sync: add `Arc::as_ptr`

Add a method to get a pointer to the data contained in an `Arc`.

Reviewed-by: Lyude Paul <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by:

rust: sync: add `Arc::as_ptr`

Add a method to get a pointer to the data contained in an `Arc`.

Reviewed-by: Lyude Paul <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Andreas Hindborg <[email protected]>

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rust: kernel: add improved version of `ForeignOwnable::borrow_mut`

Previously, the `ForeignOwnable` trait had a method called `borrow_mut`
that was intended to provide mutable access to the inner va

rust: kernel: add improved version of `ForeignOwnable::borrow_mut`

Previously, the `ForeignOwnable` trait had a method called `borrow_mut`
that was intended to provide mutable access to the inner value. However,
the method accidentally made it possible to change the address of the
object being modified, which usually isn't what we want. (And when we
want that, it can be done by calling `from_foreign` and `into_foreign`,
like how the old `borrow_mut` was implemented.)

In this patch, we introduce an alternate definition of `borrow_mut` that
solves the previous problem. Conceptually, given a pointer type `P` that
implements `ForeignOwnable`, the `borrow_mut` method gives you the same
kind of access as an `&mut P` would, except that it does not let you
change the pointer `P` itself.

This is analogous to how the existing `borrow` method provides the same
kind of access to the inner value as an `&P`.

Note that for types like `Arc`, having an `&mut Arc<T>` only gives you
immutable access to the inner `T`. This is because mutable references
assume exclusive access, but there might be other handles to the same
reference counted value, so the access isn't exclusive. The `Arc` type
implements this by making `borrow_mut` return the same type as `borrow`.

Signed-off-by: Alice Ryhl <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Reviewed-by: Andreas Hindborg <[email protected]>
Signed-off-by: Tamir Duberstein <[email protected]>
Acked-by: Danilo Krummrich <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Updated to `crate::ffi::`. Reworded title slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: kernel: reorder `ForeignOwnable` items

`{into,from}_foreign` before `borrow` is slightly more logical.

This removes an inconsistency with `kbox.rs` which already uses this
ordering.

Reviewed

rust: kernel: reorder `ForeignOwnable` items

`{into,from}_foreign` before `borrow` is slightly more logical.

This removes an inconsistency with `kbox.rs` which already uses this
ordering.

Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Andreas Hindborg <[email protected]>
Signed-off-by: Tamir Duberstein <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Reworded title slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: kernel: change `ForeignOwnable` pointer to mut

It is slightly more convenient to operate on mut pointers, and this also
properly conveys the desired ownership semantics of the trait.

Reviewed

rust: kernel: change `ForeignOwnable` pointer to mut

It is slightly more convenient to operate on mut pointers, and this also
properly conveys the desired ownership semantics of the trait.

Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Andreas Hindborg <[email protected]>
Signed-off-by: Tamir Duberstein <[email protected]>
Acked-by: Danilo Krummrich <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Reworded title slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: arc: split unsafe block, add missing comment

The new SAFETY comment style is taken from existing comments in `deref`
and `drop.

Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: And

rust: arc: split unsafe block, add missing comment

The new SAFETY comment style is taken from existing comments in `deref`
and `drop.

Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Andreas Hindborg <[email protected]>
Signed-off-by: Tamir Duberstein <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: types: avoid `as` casts

Replace `as` casts with `cast{,_mut}` calls which are a bit safer.

In one instance, remove an unnecessary `as` cast without replacement.

Reviewed-by: Alice Ryhl <alic

rust: types: avoid `as` casts

Replace `as` casts with `cast{,_mut}` calls which are a bit safer.

In one instance, remove an unnecessary `as` cast without replacement.

Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Andreas Hindborg <[email protected]>
Signed-off-by: Tamir Duberstein <[email protected]>
Acked-by: Danilo Krummrich <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: arc: use `NonNull::new_unchecked`

There is no need to check (and panic on violations of) the safety
requirements on `ForeignOwnable` functions. Avoiding the check is
consistent with the implem

rust: arc: use `NonNull::new_unchecked`

There is no need to check (and panic on violations of) the safety
requirements on `ForeignOwnable` functions. Avoiding the check is
consistent with the implementation of `ForeignOwnable` for `Box`.

Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Andreas Hindborg <[email protected]>
Signed-off-by: Tamir Duberstein <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: use derive(CoercePointee) on rustc >= 1.84.0

The `kernel` crate relies on both `coerce_unsized` and `dispatch_from_dyn`
unstable features.

Alice Ryhl has proposed [1] the introduction of the

rust: use derive(CoercePointee) on rustc >= 1.84.0

The `kernel` crate relies on both `coerce_unsized` and `dispatch_from_dyn`
unstable features.

Alice Ryhl has proposed [1] the introduction of the unstable macro
`SmartPointer` to reduce such dependence, along with a RFC patch [2].
Since Rust 1.81.0 this macro, later renamed to `CoercePointee` in
Rust 1.84.0 [3], has been fully implemented with the naming discussion
resolved.

This feature is now on track to stabilization in the language.
In order to do so, we shall start using this macro in the `kernel` crate
to prove the functionality and utility of the macro as the justification
of its stabilization.

This patch makes this switch in such a way that the crate remains
backward compatible with older Rust compiler versions,
via the new Kconfig option `RUSTC_HAS_COERCE_POINTEE`.

A minimal demonstration example is added to the
`samples/rust/rust_print_main.rs` module.

Link: https://rust-lang.github.io/rfcs/3621-derive-smart-pointer.html [1]
Link: https://lore.kernel.org/all/[email protected]/ [2]
Link: https://github.com/rust-lang/rust/pull/131284 [3]
Signed-off-by: Xiangfei Ding <[email protected]>
Reviewed-by: Fiona Behrens <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Fixed version to 1.84. Renamed option to `RUSTC_HAS_COERCE_POINTEE`
to match `CC_HAS_*` ones. Moved up new config option, closer to the
`CC_HAS_*` ones. Simplified Kconfig line. Fixed typos and slightly
reworded example and commit. Added Link to PR. - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: sync: document `PhantomData` in `Arc`

Add a comment explaining the relevant semantics of `PhantomData`. This
should help future readers who may, as I did, assume that this field is
redundant a

rust: sync: document `PhantomData` in `Arc`

Add a comment explaining the relevant semantics of `PhantomData`. This
should help future readers who may, as I did, assume that this field is
redundant at first glance.

Signed-off-by: Tamir Duberstein <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: use custom FFI integer types

Currently FFI integer types are defined in libcore. This commit creates
the `ffi` crate and asks bindgen to use that crate for FFI integer types
instead of `core::

rust: use custom FFI integer types

Currently FFI integer types are defined in libcore. This commit creates
the `ffi` crate and asks bindgen to use that crate for FFI integer types
instead of `core::ffi`.

This commit is preparatory and no type changes are made in this commit
yet.

Signed-off-by: Gary Guo <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Added `rustdoc`, `rusttest` and KUnit tests support. Rebased on top of
`rust-next` (e.g. migrated more `core::ffi` cases). Reworded crate
docs slightly and formatted. - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: treewide: switch to our kernel `Box` type

Now that we got the kernel `Box` type in place, convert all existing
`Box` users to make use of it.

Reviewed-by: Alice Ryhl <[email protected]>
Re

rust: treewide: switch to our kernel `Box` type

Now that we got the kernel `Box` type in place, convert all existing
`Box` users to make use of it.

Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Gary Guo <[email protected]>
Signed-off-by: Danilo Krummrich <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: enable arbitrary_self_types and remove `Receiver`

The term "receiver" means that a type can be used as the type of `self`,
and thus enables method call syntax `foo.bar()` instead of
`Foo::bar(

rust: enable arbitrary_self_types and remove `Receiver`

The term "receiver" means that a type can be used as the type of `self`,
and thus enables method call syntax `foo.bar()` instead of
`Foo::bar(foo)`. Stable Rust as of today (1.81) enables a limited
selection of types (primitives and types in std, e.g. `Box` and `Arc`)
to be used as receivers, while custom types cannot.

We want the kernel `Arc` type to have the same functionality as the Rust
std `Arc`, so we use the `Receiver` trait (gated behind `receiver_trait`
unstable feature) to gain the functionality.

The `arbitrary_self_types` RFC [1] (tracking issue [2]) is accepted and
it will allow all types that implement a new `Receiver` trait (different
from today's unstable trait) to be used as receivers. This trait will be
automatically implemented for all `Deref` types, which include our `Arc`
type, so we no longer have to opt-in to be used as receiver. To prepare
us for the change, remove the `Receiver` implementation and the
associated feature. To still allow `Arc` and others to be used as method
receivers, turn on `arbitrary_self_types` feature instead.

This feature gate is introduced in 1.23.0. It used to enable both
`Deref` types and raw pointer types to be used as receivers, but the
latter is now split into a different feature gate in Rust 1.83 nightly.
We do not need receivers on raw pointers so this change would not affect
us and usage of `arbitrary_self_types` feature would work for all Rust
versions that we support (>=1.78).

Cc: Adrian Taylor <[email protected]>
Link: https://github.com/rust-lang/rfcs/pull/3519 [1]
Link: https://github.com/rust-lang/rust/issues/44874 [2]
Signed-off-by: Gary Guo <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: enable `clippy::unnecessary_safety_comment` lint

In Rust 1.67.0, Clippy added the `unnecessary_safety_comment` lint [1],
which is the "inverse" of `undocumented_unsafe_blocks`: it finds places

rust: enable `clippy::unnecessary_safety_comment` lint

In Rust 1.67.0, Clippy added the `unnecessary_safety_comment` lint [1],
which is the "inverse" of `undocumented_unsafe_blocks`: it finds places
where safe code has a `// SAFETY` comment attached.

The lint currently finds 3 places where we had such mistakes, thus it
seems already quite useful.

Thus clean those and enable it.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#/unnecessary_safety_comment [1]
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Trevor Gross <[email protected]>
Reviewed-by: Vincenzo Palazzo <[email protected]>
Tested-by: Gary Guo <[email protected]>
Reviewed-by: Gary Guo <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: Implement the smart pointer `InPlaceInit` for `Arc`

For pinned and unpinned initialization of structs, a trait named
`InPlaceInit` exists for uniform access. `Arc` did not implement
`InPlaceIn

rust: Implement the smart pointer `InPlaceInit` for `Arc`

For pinned and unpinned initialization of structs, a trait named
`InPlaceInit` exists for uniform access. `Arc` did not implement
`InPlaceInit` yet, although the functions already existed. The main
reason for that, was that the trait itself returned a `Pin<Self>`. The
`Arc` implementation of the kernel is already implicitly pinned.

To enable `Arc` to implement `InPlaceInit` and to have uniform access,
for in-place and pinned in-place initialization, an associated type is
introduced for `InPlaceInit`. The new implementation of `InPlaceInit`
for `Arc` sets `Arc` as the associated type. Older implementations use
an explicit `Pin<T>` as the associated type. The implemented methods for
`Arc` are mostly moved from a direct implementation on `Arc`. There
should be no user impact. The implementation for `ListArc` is omitted,
because it is not merged yet.

Link: https://github.com/Rust-for-Linux/linux/issues/1079
Signed-off-by: Alex Mantel <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Removed "Rusts" (Benno). - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>

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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 <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: sync: add `Arc::into_unique_or_drop`

Decrement the refcount of an `Arc`, but handle the case where it hits
zero by taking ownership of the now-unique `Arc`, instead of destroying
and deallocat

rust: sync: add `Arc::into_unique_or_drop`

Decrement the refcount of an `Arc`, but handle the case where it hits
zero by taking ownership of the now-unique `Arc`, instead of destroying
and deallocating it.

This is a dependency of the linked list that Rust Binder uses. The
linked list uses this method as part of its `ListArc` abstraction [1].

Boqun Feng has authored the examples.

Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Link: https://lore.kernel.org/r/[email protected] [1]
Co-developed-by: Boqun Feng <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Signed-off-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Replace `try_new` with `new` in example since we now have the new
allocation APIs. - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: sync: add `ArcBorrow::from_raw`

Allows access to a value in an `Arc` that is currently held as a raw
pointer due to use of `Arc::into_raw`, without destroying or otherwise
consuming that raw p

rust: sync: add `ArcBorrow::from_raw`

Allows access to a value in an `Arc` that is currently held as a raw
pointer due to use of `Arc::into_raw`, without destroying or otherwise
consuming that raw pointer.

This is a dependency of the linked list that Rust Binder uses. The
linked list uses this method when iterating over the linked list [1].

Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Link: https://lore.kernel.org/r/[email protected] [1]
Signed-off-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

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 <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

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 <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: sync: update `Arc` and `UniqueArc` to take allocation flags

We also remove the `try_` prefix to align with how `Box` and `Vec` are
providing methods now.

`init` is temporarily updated with us

rust: sync: update `Arc` and `UniqueArc` to take allocation flags

We also remove the `try_` prefix to align with how `Box` and `Vec` are
providing methods now.

`init` is temporarily updated with uses of GFP_KERNEL. These will be
updated in a subsequent patch to take flags as well.

Reviewed-by: Benno Lossin <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: alloc: introduce the `BoxExt` trait

Make fallible versions of `new` and `new_uninit` methods available in
`Box` even though it doesn't implement them because we build `alloc`
with the `no_glob

rust: alloc: introduce the `BoxExt` trait

Make fallible versions of `new` and `new_uninit` methods available in
`Box` even though it doesn't implement them because we build `alloc`
with the `no_global_oom_handling` config.

They also have an extra `flags` parameter that allows callers to pass
flags to the allocator.

Signed-off-by: Wedson Almeida Filho <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Used `Box::write()` to avoid one `unsafe` block as suggested by Boqun. ]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: kernel: stop using ptr_metadata feature

The `byte_sub` method was stabilized in Rust 1.75.0. By using that
method, we no longer need the unstable `ptr_metadata` feature for
implementing `Arc::

rust: kernel: stop using ptr_metadata feature

The `byte_sub` method was stabilized in Rust 1.75.0. By using that
method, we no longer need the unstable `ptr_metadata` feature for
implementing `Arc::from_raw`.

This brings us one step closer towards not using unstable compiler
features.

Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Reviewed-by: Trevor Gross <[email protected]>
Signed-off-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Reworded title. ]
Signed-off-by: Miguel Ojeda <[email protected]>

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rust: kernel: add doclinks

Add doclinks to existing documentation.

Signed-off-by: Valentin Obst <[email protected]>
Reviewed-by: Trevor Gross <[email protected]>
Reviewed-by: Martin Rodriguez

rust: kernel: add doclinks

Add doclinks to existing documentation.

Signed-off-by: Valentin Obst <[email protected]>
Reviewed-by: Trevor Gross <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...