The initial completion abstraction only added complete_all() and wait_for_completion(). complete_all() marks the completion permanently done, which makes a single Completion unsuitable for signalling the same event repeatedly: once complete_all() has run, every subsequent wait_for_completion() returns immediately without waiting.
Add complete(), which wakes a single waiter and increments the internal counter by one. Paired one-to-one with wait_for_completion(), it allows the same completion to be reused across multiple cycles, e.g. to wait for consecutive DMA transfers to finish. Acked-by: Gary Guo <[email protected]> Signed-off-by: Maurice Hieronymus <[email protected]> --- rust/kernel/sync/completion.rs | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/rust/kernel/sync/completion.rs b/rust/kernel/sync/completion.rs index 35ff049ff078..a54361b53644 100644 --- a/rust/kernel/sync/completion.rs +++ b/rust/kernel/sync/completion.rs @@ -90,6 +90,17 @@ fn as_raw(&self) -> *mut bindings::completion { self.inner.get() } + /// Signal a single task waiting on this completion. + /// + /// This method wakes up a single task waiting on this completion. + /// If no task is currently waiting, the next + /// [`Completion::wait_for_completion`] returns immediately. + #[inline] + pub fn complete(&self) { + // SAFETY: `self.as_raw()` is a pointer to a valid `struct completion`. + unsafe { bindings::complete(self.as_raw()) }; + } + /// Signal all tasks waiting on this completion. /// /// This method wakes up all tasks waiting on this completion; after this operation the -- 2.54.0
