[PATCH v2 1/5] rust: task: add safe schedule_timeout() wrapper

[Danilo Krummrich <dakr@kernel.org>]

Add a safe wrapper around schedule_timeout() that takes and returns
Jiffies, handling the c_long conversion internally.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 rust/kernel/task.rs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/rust/kernel/task.rs b/rust/kernel/task.rs
index 3336df493dec..a733816fd5dd 100644
--- a/rust/kernel/task.rs
+++ b/rust/kernel/task.rs
@@ -10,6 +10,7 @@
     pid_namespace::PidNamespace,
     prelude::*,
     sync::aref::ARef,
+    time::Jiffies,
     types::{NotThreadSafe, Opaque},
 };
 use core::{
@@ -20,6 +21,21 @@
 /// A sentinel value used for infinite timeouts.
 pub const MAX_SCHEDULE_TIMEOUT: c_long = c_long::MAX;
 
+/// Sleeps for the given timeout in [`Jiffies`], or until woken.
+///
+/// Returns the remaining time in [`Jiffies`], or zero if the timeout expired.  The task state
+/// should be set before calling this.
+///
+/// Timeouts at or above [`MAX_SCHEDULE_TIMEOUT`] mean an indefinite wait. In that case, the return
+/// value is `MAX_SCHEDULE_TIMEOUT` as [`Jiffies`].
+#[inline]
+pub fn schedule_timeout(timeout: Jiffies) -> Jiffies {
+    let timeout = timeout.try_into().unwrap_or(MAX_SCHEDULE_TIMEOUT);
+
+    // SAFETY: `schedule_timeout()` is always safe to call.
+    unsafe { bindings::schedule_timeout(timeout) as Jiffies }
+}
+
 /// Bitmask for tasks that are sleeping in an interruptible state.
 pub const TASK_INTERRUPTIBLE: c_int = bindings::TASK_INTERRUPTIBLE as c_int;
 /// Bitmask for tasks that are sleeping in an uninterruptible state.
-- 
2.56.0