linux-toradex.git/rust/kernel/sync, branch v6.3-rc3

rust: types: implement `ForeignOwnable` for `Arc`

2023-02-07T10:24:24+00:00

This allows us to hand ownership of Rust ref-counted 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: sync: add support for dispatching on Arc and ArcBorrow.

2023-01-16T22:48:06+00:00

Trait objects (`dyn T`) require trait `T` to be "object safe". One of
the requirements for "object safety" is that the receiver have one of
the allowed types. This commit adds `Arc` and `ArcBorrow<'_, T>` to
the list of allowed types.

Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Reviewed-by: Vincenzo Palazzo 
Acked-by: Boqun Feng 
Signed-off-by: Miguel Ojeda

rust: sync: introduce `UniqueArc`

2023-01-16T22:48:06+00:00

Since `Arc` does not allow mutating `T` directly (i.e., without inner
mutability), it is currently not possible to do some initialisation of
`T` post construction but before being shared.

`UniqueArc` addresses this problem essentially being an `Arc` that
has a refcount of 1 and is therefore writable. Once initialisation is
completed, it can be transitioned (without failure paths) into an
`Arc`.

Suggested-by: Gary Guo 
Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Reviewed-by: Vincenzo Palazzo 
Acked-by: Boqun Feng 
Signed-off-by: Miguel Ojeda

rust: sync: allow type of `self` to be `ArcBorrow`

2023-01-16T22:48:06+00:00

This allows associated functions whose `self` argument has
`ArcBorrow` as their type. This, in turn, allows callers to use the
dot syntax to make calls.

Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Reviewed-by: Vincenzo Palazzo 
Acked-by: Boqun Feng 
Signed-off-by: Miguel Ojeda

rust: sync: introduce `ArcBorrow`

2023-01-16T22:47:57+00:00

This allows us to create references to a ref-counted allocation without
double-indirection and that still allow us to increment the refcount to
a new `Arc`.

Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Alice Ryhl 
Acked-by: Boqun Feng 
Reviewed-by: Gary Guo 
Reviewed-by: Vincenzo Palazzo 
Signed-off-by: Miguel Ojeda

rust: sync: allow coercion from `Arc` to `Arc`

2023-01-16T21:20:24+00:00

The coercion is only allowed if `U` is a compatible dynamically-sized
type (DST). For example, if we have some type `X` that implements trait
`Y`, then this allows `Arc` to be coerced into `Arc`.

Suggested-by: Gary Guo 
Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Reviewed-by: Vincenzo Palazzo 
Acked-by: Boqun Feng 
Signed-off-by: Miguel Ojeda

rust: sync: allow type of `self` to be `Arc` or variants

2023-01-16T21:20:18+00:00

This allows associated functions whose `self` argument has `Arc` or
variants as their type. This, in turn, allows callers to use the dot
syntax to make calls.

Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Reviewed-by: Vincenzo Palazzo 
Acked-by: Boqun Feng 
Signed-off-by: Miguel Ojeda

rust: sync: add `Arc` for ref-counted allocations

2023-01-16T21:20:03+00:00

This is a basic implementation of `Arc` backed by C's `refcount_t`. It
allows Rust code to idiomatically allocate memory that is ref-counted.

Cc: Will Deacon 
Cc: Peter Zijlstra 
Cc: Boqun Feng 
Cc: Mark Rutland 
Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Reviewed-by: Vincenzo Palazzo 
Acked-by: Boqun Feng 
Signed-off-by: Miguel Ojeda