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

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>

1 files changed, 10 insertions, 0 deletions

diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
new file mode 100644
index 000000000000..39b379dd548f
--- /dev/null
+++ b/rust/kernel/sync.rs
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Synchronisation primitives.
+//!
+//! This module contains the kernel APIs related to synchronisation that have been ported or
+//! wrapped for usage by Rust code in the kernel.
+
+mod arc;
+
+pub use arc::Arc;