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2023-04-22rust: sync: introduce `Lock` and `Guard`Wedson Almeida Filho
They are generic Rust implementations of a lock and a lock guard that contain code that is common to all locks. Different backends will be introduced in subsequent commits. Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Suggested-by: Gary Guo <gary@garyguo.net> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Link: https://lore.kernel.org/r/20230411054543.21278-2-wedsonaf@gmail.com [ Fixed typo. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12rust: sync: add functions for initializing `UniqueArc<MaybeUninit<T>>`Benno Lossin
Add two functions `init_with` and `pin_init_with` to `UniqueArc<MaybeUninit<T>>` to initialize the memory of already allocated `UniqueArc`s. This is useful when you want to allocate memory check some condition inside of a context where allocation is forbidden and then conditionally initialize an object. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Link: https://lore.kernel.org/r/20230408122429.1103522-16-y86-dev@protonmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12rust: sync: reduce stack usage of `UniqueArc::try_new_uninit`Benno Lossin
`UniqueArc::try_new_uninit` calls `Arc::try_new(MaybeUninit::uninit())`. This results in the uninitialized memory being placed on the stack, which may be arbitrarily large due to the generic `T` and thus could cause a stack overflow for large types. Change the implementation to use the pin-init API which enables in-place initialization. In particular it avoids having to first construct and then move the uninitialized memory from the stack into the final location. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Link: https://lore.kernel.org/r/20230408122429.1103522-15-y86-dev@protonmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointersBenno Lossin
The `InPlaceInit` trait that provides two functions, for initializing using `PinInit<T, E>` and `Init<T>`. It is implemented by `Arc<T>`, `UniqueArc<T>` and `Box<T>`. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Link: https://lore.kernel.org/r/20230408122429.1103522-9-y86-dev@protonmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12rust: sync: change error type of constructor functionsBenno Lossin
Change the error type of the constructors of `Arc` and `UniqueArc` to be `AllocError` instead of `Error`. This makes the API more clear as to what can go wrong when calling `try_new` or its variants. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20230408122429.1103522-4-y86-dev@protonmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12rust: sync: arc: Add UniqueArc<MaybeUninit<T>::assume_init()Asahi Lina
We can already create `UniqueArc<MaybeUninit<T>>` instances with `UniqueArc::try_new_uninit()` and write to them with `write()`. Add the missing unsafe `assume_init()` function to promote it to `UniqueArc<T>`, so users can do piece-wise initialization of the contents instead of doing it all at once as long as they keep the invariants (the same requirements as `MaybeUninit::assume_init()`). This mirrors the std `Arc::assume_init()` function. In the kernel, since we have `UniqueArc`, arguably this only belongs there since most use cases will initialize it immediately after creating it, before demoting it to `Arc` to share it. [ Miguel: The "Rust pin-init API for pinned initialization of structs" patch series [1] from Benno Lossin contains a very similar patch: rust: sync: add `assume_init` to `UniqueArc` Adds the `assume_init` function to `UniqueArc<MaybeUninit<T>>` that unsafely assumes the value to be initialized and yields a value of type `UniqueArc<T>`. This function is used when manually initializing the pointee of an `UniqueArc`. To make that patch a noop and thus drop it, I adjusted the `SAFETY` comment here to be the same as in the current latest version of that series (v7). I have also brought the `Reviewed-by`s there into here, and reworded the `Co-authored-by` into `Co-developed-by`. ] Link: https://lore.kernel.org/r/20230408122429.1103522-5-y86-dev@protonmail.com [1] Co-developed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Asahi Lina <lina@asahilina.net> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Wedson Almeida Filho <walmeida@microsoft.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20230224-rust-arc-v2-2-5c97a865b276@asahilina.net Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-10rust: sync: arc: Implement Arc<dyn Any + Send + Sync>::downcast()Asahi Lina
This mirrors the standard library's alloc::sync::Arc::downcast(). Based on the Rust standard library implementation, ver 1.62.0, licensed under "Apache-2.0 OR MIT", from: https://github.com/rust-lang/rust/tree/1.62.0/library/alloc/src For copyright details, please see: https://github.com/rust-lang/rust/blob/1.62.0/COPYRIGHT Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Asahi Lina <lina@asahilina.net> Link: https://lore.kernel.org/r/20230224-rust-arc-v2-1-5c97a865b276@asahilina.net [ Moved `mod std_vendor;` up. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-10rust: sync: impl {Debug,Display} for {Unique,}ArcBoqun Feng
This allows printing the inner data of `Arc` and its friends if the inner data implements `Display` or `Debug`. It's useful for logging and debugging purpose. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Link: https://lore.kernel.org/r/20230207185216.1314638-2-boqun.feng@gmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-02-07rust: types: implement `ForeignOwnable` for `Arc<T>`Wedson Almeida Filho
This allows us to hand ownership of Rust ref-counted objects to the C side of the kernel. Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-01-16rust: sync: add support for dispatching on Arc and ArcBorrow.Wedson Almeida Filho
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<T>` and `ArcBorrow<'_, T>` to the list of allowed types. Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-01-16rust: sync: introduce `UniqueArc`Wedson Almeida Filho
Since `Arc<T>` 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<T>` addresses this problem essentially being an `Arc<T>` that has a refcount of 1 and is therefore writable. Once initialisation is completed, it can be transitioned (without failure paths) into an `Arc<T>`. Suggested-by: Gary Guo <gary@garyguo.net> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-01-16rust: sync: allow type of `self` to be `ArcBorrow<T>`Wedson Almeida Filho
This allows associated functions whose `self` argument has `ArcBorrow<T>` as their type. This, in turn, allows callers to use the dot syntax to make calls. Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-01-16rust: sync: introduce `ArcBorrow`Wedson Almeida Filho
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<T>`. Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-01-16rust: sync: allow coercion from `Arc<T>` to `Arc<U>`Wedson Almeida Filho
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<X>` to be coerced into `Arc<dyn Y>`. Suggested-by: Gary Guo <gary@garyguo.net> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-01-16rust: sync: allow type of `self` to be `Arc<T>` or variantsWedson Almeida Filho
This allows associated functions whose `self` argument has `Arc<T>` or variants as their type. This, in turn, allows callers to use the dot syntax to make calls. Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-01-16rust: sync: add `Arc` for ref-counted allocationsWedson Almeida Filho
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 <will@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>