linux.git/rust/kernel/types.rs, branch v6.5.4

rust: delete `ForeignOwnable::borrow_mut`

2023-08-04T15:10:50+00:00

We discovered that the current design of `borrow_mut` is problematic.
This patch removes it until a better solution can be found.

Specifically, the current design gives you access to a `&mut T`, which
lets you change where the `ForeignOwnable` points (e.g., with
`core::mem::swap`). No upcoming user of this API intended to make that
possible, making all of them unsound.

Signed-off-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Reviewed-by: Benno Lossin 
Reviewed-by: Martin Rodriguez Reboredo 
Fixes: 0fc4424d24a2 ("rust: types: introduce `ForeignOwnable`")
Link: https://lore.kernel.org/r/20230706094615.3080784-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda

rust: specify when `ARef` is thread safe

2023-05-31T16:53:10+00:00

An `ARef` behaves just like the `Arc` when it comes to thread safety, so
we can reuse the thread safety comments from `Arc` here.

This is necessary because without this change, the Rust compiler will
assume that things are not thread safe even though they are.

Signed-off-by: Alice Ryhl 
Reviewed-by: Andreas Hindborg 
Reviewed-by: Boqun Feng 
Reviewed-by: Martin Rodriguez Reboredo 
Reviewed-by: Benno Lossin 
Link: https://lore.kernel.org/r/20230531145939.3714886-4-aliceryhl@google.com
Signed-off-by: Miguel Ojeda

rust: introduce `ARef`

2023-04-21T22:20:00+00:00

This is an owned reference to an object that is always ref-counted. This
is meant to be used in wrappers for C types that have their own ref
counting functions, for example, tasks, files, inodes, dentries, etc.

Reviewed-by: Martin Rodriguez Reboredo 
Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Gary Guo 
Link: https://lore.kernel.org/r/20230411054543.21278-8-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda

rust: types: add `Opaque::ffi_init`

2023-04-12T16:41:05+00:00

This function allows to easily initialize `Opaque` with the pin-init
API. `Opaque::ffi_init` takes a closure and returns a pin-initializer.
This pin-initiailizer calls the given closure with a pointer to the
inner `T`.

Co-developed-by: Gary Guo 
Signed-off-by: Gary Guo 
Signed-off-by: Benno Lossin 
Reviewed-by: Andreas Hindborg 
Reviewed-by: Alice Ryhl 
Link: https://lore.kernel.org/r/20230408122429.1103522-14-y86-dev@protonmail.com
[ Fixed typo. ]
Signed-off-by: Miguel Ojeda

rust: types: add `Opaque::raw_get`

2023-04-12T16:41:05+00:00

This function mirrors `UnsafeCell::raw_get`. It avoids creating a
reference and allows solely using raw pointers.
The `pin-init` API will be using this, since uninitialized memory
requires raw pointers.

Signed-off-by: Benno Lossin 
Reviewed-by: Gary Guo 
Reviewed-by: Andreas Hindborg 
Reviewed-by: Alice Ryhl 
Link: https://lore.kernel.org/r/20230408122429.1103522-6-y86-dev@protonmail.com
Signed-off-by: Miguel Ojeda

rust: types: implement `ForeignOwnable` for the unit type

2023-02-01T12:24:36+00:00

This allows us to use the unit type `()` when we have no object whose
ownership must be managed but one implementing the `ForeignOwnable`
trait is needed.

Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Vincenzo Palazzo 
Reviewed-by: Gary Guo 
Reviewed-by: Andreas Hindborg 
Signed-off-by: Miguel Ojeda

rust: types: implement `ForeignOwnable` for `Box`

2023-02-01T12:24:19+00:00

This allows us to hand ownership of Rust dynamically allocated
objects to the C side of the kernel.

Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Gary Guo 
Reviewed-by: Vincenzo Palazzo 
Reviewed-by: Alice Ferrazzi 
Reviewed-by: Andreas Hindborg 
Signed-off-by: Miguel Ojeda

rust: types: introduce `ForeignOwnable`

2023-02-01T12:24:07+00:00

It was originally called `PointerWrapper`. It is used to convert
a Rust object to a pointer representation (void *) that can be
stored on the C side, used, and eventually returned to Rust.

Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Vincenzo Palazzo 
Reviewed-by: Martin Rodriguez Reboredo 
Reviewed-by: Gary Guo 
Reviewed-by: Andreas Hindborg 
Signed-off-by: Miguel Ojeda

rust: types: introduce `ScopeGuard`

2023-01-31T23:14:01+00:00

This allows us to run some code when the guard is dropped (e.g.,
implicitly when it goes out of scope). We can also prevent the
guard from running by calling its `dismiss()` method.

Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Vincenzo Palazzo 
Reviewed-by: Andreas Hindborg 
Signed-off-by: Miguel Ojeda

rust: types: add `Opaque` type

2022-12-04T00:59:16+00:00

Add the `Opaque` type, which is meant to be used with FFI objects
that are never interpreted by Rust code, e.g.:

    struct Waiter {
        completion: Opaque,
        next: *mut Waiter,
    }

It has the advantage that the objects don't have to be
zero-initialised before calling their init functions, making
the code performance closer to C.

Signed-off-by: Wedson Almeida Filho 
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda