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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>
This commit is contained in:
Tejun Heo 2012-08-03 10:30:45 -07:00
parent 8930caba3d
commit d8e794dfd5
2 changed files with 15 additions and 5 deletions
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13
include/linux/workqueue.h
View File

@ -16,6 +16,7 @@ struct workqueue_struct;
struct work_struct;
typedef void (*work_func_t)(struct work_struct *work);
void delayed_work_timer_fn(unsigned long __data);
/*
* The first word is the work queue pointer and the flags rolled into
@ -124,12 +125,14 @@ struct execute_work {
#define __DELAYED_WORK_INITIALIZER(n, f) { \
.work = __WORK_INITIALIZER((n).work, (f)), \
.timer = TIMER_INITIALIZER(NULL, 0, 0), \
.timer = TIMER_INITIALIZER(delayed_work_timer_fn, \
0, (unsigned long)&(n)), \
}
#define __DEFERRED_WORK_INITIALIZER(n, f) { \
.work = __WORK_INITIALIZER((n).work, (f)), \
.timer = TIMER_DEFERRED_INITIALIZER(NULL, 0, 0), \
.timer = TIMER_DEFERRED_INITIALIZER(delayed_work_timer_fn, \
0, (unsigned long)&(n)), \
}
#define DECLARE_WORK(n, f) \
@ -207,18 +210,24 @@ static inline unsigned int work_static(struct work_struct *work) { return 0; }
do { \
INIT_WORK(&(_work)->work, (_func)); \
init_timer(&(_work)->timer); \
(_work)->timer.function = delayed_work_timer_fn;\
(_work)->timer.data = (unsigned long)(_work); \
} while (0)
#define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
do { \
INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
init_timer_on_stack(&(_work)->timer); \
(_work)->timer.function = delayed_work_timer_fn;\
(_work)->timer.data = (unsigned long)(_work); \
} while (0)
#define INIT_DELAYED_WORK_DEFERRABLE(_work, _func) \
do { \
INIT_WORK(&(_work)->work, (_func)); \
init_timer_deferrable(&(_work)->timer); \
(_work)->timer.function = delayed_work_timer_fn;\
(_work)->timer.data = (unsigned long)(_work); \
} while (0)
/**

7
kernel/workqueue.c
View File

@ -1112,7 +1112,7 @@ bool queue_work(struct workqueue_struct *wq, struct work_struct *work)
}
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 @@ static void delayed_work_timer_fn(unsigned long __data)
__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 @@ bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
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 @@ bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
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);