[PATCH] rust: sync: Makes `CondVar::wait()` an uninterruptible wait

From: Boqun Feng
Date: Thu Dec 14 2023 - 15:04:49 EST


Currently, `CondVar::wait()` is an interruptible wait, and this is
different than `wait_event()` in include/linux/wait.h (which is an
uninterruptible wait). To avoid confusion between different APIs on the
interruptible/uninterruptible, make `CondVar::wait()` an uninterruptible
wait same as `wait_event()`, also rename the old `wait()` to
`CondVar::wait_interruptible()`.

Spotted-by: Tiago Lam <tiagolam@xxxxxxxxx>
Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
---
rust/kernel/sync/condvar.rs | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs
index b679b6f6dbeb..8630faa29b78 100644
--- a/rust/kernel/sync/condvar.rs
+++ b/rust/kernel/sync/condvar.rs
@@ -50,7 +50,7 @@ macro_rules! new_condvar {
/// fn wait_for_value(e: &Example, v: u32) {
/// let mut guard = e.value.lock();
/// while *guard != v {
-/// e.value_changed.wait_uninterruptible(&mut guard);
+/// e.value_changed.wait(&mut guard);
/// }
/// }
///
@@ -120,28 +120,28 @@ fn wait_internal<T: ?Sized, B: Backend>(&self, wait_state: u32, guard: &mut Guar
unsafe { bindings::finish_wait(self.wait_list.get(), wait.get()) };
}

- /// Releases the lock and waits for a notification in interruptible mode.
+ /// Releases the lock and waits for a notification in uninterruptible mode.
///
/// Atomically releases the given lock (whose ownership is proven by the guard) and puts the
/// thread to sleep, reacquiring the lock on wake up. It wakes up when notified by
- /// [`CondVar::notify_one`] or [`CondVar::notify_all`], or when the thread receives a signal.
- /// It may also wake up spuriously.
+ /// [`CondVar::notify_one`] or [`CondVar::notify_all`]. Note that it may also wake up
+ /// spuriously.
+ pub fn wait<T: ?Sized, B: Backend>(&self, guard: &mut Guard<'_, T, B>) {
+ self.wait_internal(bindings::TASK_UNINTERRUPTIBLE, guard);
+ }
+
+ /// Releases the lock and waits for a notification in interruptible mode.
+ ///
+ /// Similar to [`CondVar::wait`], except that the wait is interruptible. That is, the thread may
+ /// wake up due to signals. It may also wake up spuriously.
///
/// Returns whether there is a signal pending.
- #[must_use = "wait returns if a signal is pending, so the caller must check the return value"]
- pub fn wait<T: ?Sized, B: Backend>(&self, guard: &mut Guard<'_, T, B>) -> bool {
+ #[must_use = "wait_interruptible returns if a signal is pending, so the caller must check the return value"]
+ pub fn wait_interruptible<T: ?Sized, B: Backend>(&self, guard: &mut Guard<'_, T, B>) -> bool {
self.wait_internal(bindings::TASK_INTERRUPTIBLE, guard);
crate::current!().signal_pending()
}

- /// Releases the lock and waits for a notification in uninterruptible mode.
- ///
- /// Similar to [`CondVar::wait`], except that the wait is not interruptible. That is, the
- /// thread won't wake up due to signals. It may, however, wake up supirously.
- pub fn wait_uninterruptible<T: ?Sized, B: Backend>(&self, guard: &mut Guard<'_, T, B>) {
- self.wait_internal(bindings::TASK_UNINTERRUPTIBLE, guard)
- }
-
/// Calls the kernel function to notify the appropriate number of threads with the given flags.
fn notify(&self, count: i32, flags: u32) {
// SAFETY: `wait_list` points to valid memory.
--
2.43.0