workqueue: set delayed_work->timer function on initialization
delayed_work->timer.function is currently initialized during
queue_delayed_work_on(). Export delayed_work_timer_fn() and set
delayed_work timer function during delayed_work initialization
together with other fields.
This ensures the timer function is always valid on an initialized
delayed_work. This is to help mod_delayed_work() implementation.
To detect delayed_work users which diddle with the internal timer,
trigger WARN if timer function doesn't match on queue.
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 30474c4..5539238 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1112,7 +1112,7 @@
}
EXPORT_SYMBOL_GPL(queue_work);
-static void delayed_work_timer_fn(unsigned long __data)
+void delayed_work_timer_fn(unsigned long __data)
{
struct delayed_work *dwork = (struct delayed_work *)__data;
struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work);
@@ -1121,6 +1121,7 @@
__queue_work(smp_processor_id(), cwq->wq, &dwork->work);
local_irq_enable();
}
+EXPORT_SYMBOL_GPL(delayed_work_timer_fn);
/**
* queue_delayed_work_on - queue work on specific CPU after delay
@@ -1145,6 +1146,8 @@
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
unsigned int lcpu;
+ WARN_ON_ONCE(timer->function != delayed_work_timer_fn ||
+ timer->data != (unsigned long)dwork);
BUG_ON(timer_pending(timer));
BUG_ON(!list_empty(&work->entry));
@@ -1168,8 +1171,6 @@
set_work_cwq(work, get_cwq(lcpu, wq), 0);
timer->expires = jiffies + delay;
- timer->data = (unsigned long)dwork;
- timer->function = delayed_work_timer_fn;
if (unlikely(cpu >= 0))
add_timer_on(timer, cpu);
