make queue_delayed_work() friendly to flush_fork()
Currently typeof(delayed_work->work.data) is "struct workqueue_struct" when the timer is pending "struct cpu_workqueue_struct" whe the work is queued This makes impossible to use flush_fork(delayed_work->work) in addition to cancel_delayed_work/cancel_rearming_delayed_work, not good. Change queue_delayed_work/delayed_work_timer_fn to use cwq, not wq. This complicates (and uglifies) these functions a little bit, but alows us to use flush_fork(dwork) and imho makes the whole code more consistent. Also, document the fact that cancel_rearming_delayed_work() doesn't garantee the completion of work->func() upon return. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -90,18 +90,20 @@ static const cpumask_t *wq_cpu_map(struct workqueue_struct *wq)
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* Set the workqueue on which a work item is to be run
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* - Must *only* be called if the pending flag is set
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*/
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static inline void set_wq_data(struct work_struct *work, void *wq)
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static inline void set_wq_data(struct work_struct *work,
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struct cpu_workqueue_struct *cwq)
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{
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unsigned long new;
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BUG_ON(!work_pending(work));
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new = (unsigned long) wq | (1UL << WORK_STRUCT_PENDING);
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new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING);
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new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work);
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atomic_long_set(&work->data, new);
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}
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static inline void *get_wq_data(struct work_struct *work)
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static inline
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struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
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{
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return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK);
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}
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@ -157,7 +159,8 @@ EXPORT_SYMBOL_GPL(queue_work);
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void delayed_work_timer_fn(unsigned long __data)
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{
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struct delayed_work *dwork = (struct delayed_work *)__data;
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struct workqueue_struct *wq = get_wq_data(&dwork->work);
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struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work);
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struct workqueue_struct *wq = cwq->wq;
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int cpu = smp_processor_id();
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if (unlikely(is_single_threaded(wq)))
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@ -189,8 +192,9 @@ int fastcall queue_delayed_work(struct workqueue_struct *wq,
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BUG_ON(timer_pending(timer));
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BUG_ON(!list_empty(&work->entry));
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/* This stores wq for the moment, for the timer_fn */
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set_wq_data(work, wq);
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/* This stores cwq for the moment, for the timer_fn */
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set_wq_data(work,
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per_cpu_ptr(wq->cpu_wq, raw_smp_processor_id()));
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timer->expires = jiffies + delay;
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timer->data = (unsigned long)dwork;
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timer->function = delayed_work_timer_fn;
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@ -221,8 +225,9 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
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BUG_ON(timer_pending(timer));
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BUG_ON(!list_empty(&work->entry));
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/* This stores wq for the moment, for the timer_fn */
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set_wq_data(work, wq);
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/* This stores cwq for the moment, for the timer_fn */
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set_wq_data(work,
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per_cpu_ptr(wq->cpu_wq, raw_smp_processor_id()));
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timer->expires = jiffies + delay;
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timer->data = (unsigned long)dwork;
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timer->function = delayed_work_timer_fn;
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@ -562,9 +567,12 @@ void flush_work_keventd(struct work_struct *work)
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EXPORT_SYMBOL(flush_work_keventd);
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/**
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* cancel_rearming_delayed_workqueue - reliably kill off a delayed work whose handler rearms the delayed work.
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* cancel_rearming_delayed_workqueue - kill off a delayed work whose handler rearms the delayed work.
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* @wq: the controlling workqueue structure
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* @dwork: the delayed work struct
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*
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* Note that the work callback function may still be running on return from
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* cancel_delayed_work(). Run flush_workqueue() or flush_work() to wait on it.
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*/
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void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,
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struct delayed_work *dwork)
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@ -579,7 +587,7 @@ void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,
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EXPORT_SYMBOL(cancel_rearming_delayed_workqueue);
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/**
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* cancel_rearming_delayed_work - reliably kill off a delayed keventd work whose handler rearms the delayed work.
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* cancel_rearming_delayed_work - kill off a delayed keventd work whose handler rearms the delayed work.
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* @dwork: the delayed work struct
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*/
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void cancel_rearming_delayed_work(struct delayed_work *dwork)
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