[PATCH v8 3/4] rust: workqueue: take a Delta<Jiffy> for the enqueue delay

[FUJITA Tomonori <tomo@flapping.org>]

From: FUJITA Tomonori <fujita.tomonori@gmail.com>

enqueue_delayed() takes the delay as a raw Jiffies, which is a c_ulong
alias. The type does not show the unit, so callers pass a bare integer.

Take the delay as Delta<Jiffy> instead. A caller that already has a
value in jiffies passes it without conversion. A caller that has a
Delta in nanoseconds converts it with Delta::to_jiffies_timeout(),
which rounds up, so a short delay does not become zero.

Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
 rust/kernel/workqueue.rs | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
index 7e253b6f299c..6dc33bac07aa 100644
--- a/rust/kernel/workqueue.rs
+++ b/rust/kernel/workqueue.rs
@@ -171,7 +171,7 @@
 //! /// This method will enqueue the struct for execution on the system workqueue, where its value
 //! /// will be printed 12 jiffies later.
 //! fn print_later(val: Arc<MyStruct>) {
-//!     let _ = workqueue::system().enqueue_delayed(val, 12);
+//!     let _ = workqueue::system().enqueue_delayed(val, kernel::time::Delta::from_jiffies(12));
 //! }
 //!
 //! /// It is also possible to use the ordinary `enqueue` method together with `DelayedWork`. This
@@ -197,7 +197,10 @@
         Arc,
         LockClassKey, //
     },
-    time::Jiffies,
+    time::{
+        Delta,
+        Jiffy, //
+    },
     types::Opaque,
 };
 use core::{marker::PhantomData, ptr::NonNull};
@@ -303,7 +306,9 @@ pub fn enqueue<W, const ID: u64>(&self, w: W) -> W::EnqueueOutput
     /// This may fail if the work item is already enqueued in a workqueue.
     ///
     /// The work item will be submitted using `WORK_CPU_UNBOUND`.
-    pub fn enqueue_delayed<W, const ID: u64>(&self, w: W, delay: Jiffies) -> W::EnqueueOutput
+    ///
+    /// A negative delay is treated as zero.
+    pub fn enqueue_delayed<W, const ID: u64>(&self, w: W, delay: Delta<Jiffy>) -> W::EnqueueOutput
     where
         W: RawDelayedWorkItem<ID> + Send + 'static,
     {
@@ -328,7 +333,7 @@ pub fn enqueue_delayed<W, const ID: u64>(&self, w: W, delay: Jiffies) -> W::Enqu
                     bindings::wq_misc_consts_WORK_CPU_UNBOUND as ffi::c_int,
                     queue_ptr,
                     container_of!(work_ptr, bindings::delayed_work, work),
-                    delay,
+                    delay.as_jiffies_unsigned(),
                 )
             })
         }
-- 
2.43.0