[PATCH v4 1/3] rust: helpers: add workqueue helpers

[Aakash Bollineni <aakash.bollineni@multicorewareinc.com>]

Add C-helpers to bridge the Rust workqueue abstraction with the
kernel's C workqueue macros. These helpers wrap core workqueue
functions that are either inline or macros in C, making them
accessible to Rust FFI.
New wrappers:
- rust_helper_work_pending(): Wraps work_pending().
- rust_helper_cancel_work_sync(): Wraps cancel_work_sync().
- rust_helper_cancel_delayed_work_sync(): Wraps cancel_delayed_work_sync().
- rust_helper_init_delayed_work(): Performs robust initialization of
  a delayed_work structure, ensuring the correct timer function
  (delayed_work_timer_fn) and lockdep maps are initialized using
  standard kernel macros.
These helpers are essential for supporting safe cancellation and
correct DelayedWork lifecycle management in the Rust workqueue API.

Signed-off-by: Aakash Bollineni <aakash.bollineni@multicorewareinc.com>
---
 rust/helpers/workqueue.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/rust/helpers/workqueue.c b/rust/helpers/workqueue.c
index ce1c3a5b2150..85a6c0b9e4d5 100644
--- a/rust/helpers/workqueue.c
+++ b/rust/helpers/workqueue.c
@@ -14,3 +14,35 @@ __rust_helper void rust_helper_init_work_with_key(struct work_struct *work,
 	INIT_LIST_HEAD(&work->entry);
 	work->func = func;
 }
+
+__rust_helper bool rust_helper_work_pending(struct work_struct *work)
+{
+	return work_pending(work);
+}
+
+__rust_helper bool rust_helper_cancel_work_sync(struct work_struct *work)
+{
+	return cancel_work_sync(work);
+}
+
+__rust_helper bool rust_helper_cancel_delayed_work_sync(struct delayed_work *dwork)
+{
+	return cancel_delayed_work_sync(dwork);
+}
+
+__rust_helper void rust_helper_init_delayed_work(struct delayed_work *dwork,
+						 work_func_t func,
+						 const char *name,
+						 struct lock_class_key *key,
+						 const char *tname,
+						 struct lock_class_key *tkey)
+{
+	INIT_DELAYED_WORK(dwork, func);
+	lockdep_init_map(&dwork->work.lockdep_map, name, key, 0);
+	timer_init_key(&dwork->timer, dwork->timer.function, TIMER_IRQSAFE, tname, tkey);
+}
+
+__rust_helper void *rust_helper_get_dwork_timer_fn(void)
+{
+	return (void *)delayed_work_timer_fn;
+}

-- 
2.43.0