rust: completion: implement initial abstraction

Implement a minimal abstraction for the completion synchronization
primitive.

This initial abstraction only adds complete_all() and
wait_for_completion(), since that is what is required for the subsequent
Devres patch.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250612121817.1621-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
index 36a719015583..c23a12639924 100644
--- a/rust/kernel/sync.rs
+++ b/rust/kernel/sync.rs
@@ -10,6 +10,7 @@ use crate::types::Opaque;
 use pin_init;
 
 mod arc;
+pub mod completion;
 mod condvar;
 pub mod lock;
 mod locked_by;
@@ -17,6 +18,7 @@ pub mod poll;
 pub mod rcu;
 
 pub use arc::{Arc, ArcBorrow, UniqueArc};
+pub use completion::Completion;
 pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult};
 pub use lock::global::{global_lock, GlobalGuard, GlobalLock, GlobalLockBackend, GlobalLockedBy};
 pub use lock::mutex::{new_mutex, Mutex, MutexGuard};