History

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.

Oleg Nesterov committed 19 years ago

Commit ed7c0fe1 parent 06ba38a1 file · +18 −10Browse files

Showing the changes to kernel/workqueue.c (1 of 1 file). Show all

Unified · Split

kernel/workqueue.c+18−10
@@ -90,18 +90,20 @@ static const cpumask_t *wq_cpu_map(struct workqueue_struct *wq) · 89 unmodified lines
90 * Set the workqueue on which a work item is to be run90 * Set the workqueue on which a work item is to be run
91 * - Must *only* be called if the pending flag is set91 * - Must *only* be called if the pending flag is set
92 */92 */
93static inline void set_wq_data(struct work_struct *work, void *wq)93static inline void set_wq_data(struct work_struct *work,
94 struct cpu_workqueue_struct *cwq)
94{95{
95 unsigned long new;96 unsigned long new;
96 97
97 BUG_ON(!work_pending(work));98 BUG_ON(!work_pending(work));
98 99
99 new = (unsigned long) wq | (1UL << WORK_STRUCT_PENDING);100 new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING);
100 new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work);101 new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work);
101 atomic_long_set(&work->data, new);102 atomic_long_set(&work->data, new);
102}103}
103 104
104static inline void *get_wq_data(struct work_struct *work)105static inline
106struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
105{107{
106 return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK);108 return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK);
107}109}
@@ -157,7 +159,8 @@ EXPORT_SYMBOL_GPL(queue_work); · 49 unmodified lines
157void delayed_work_timer_fn(unsigned long __data)159void delayed_work_timer_fn(unsigned long __data)
158{160{
159 struct delayed_work *dwork = (struct delayed_work *)__data;161 struct delayed_work *dwork = (struct delayed_work *)__data;
160 struct workqueue_struct *wq = get_wq_data(&dwork->work);162 struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work);
163 struct workqueue_struct *wq = cwq->wq;
161 int cpu = smp_processor_id();164 int cpu = smp_processor_id();
162 165
163 if (unlikely(is_single_threaded(wq)))166 if (unlikely(is_single_threaded(wq)))
@@ -189,8 +192,9 @@ int fastcall queue_delayed_work(struct workqueue_struct *wq, · 25 unmodified lines
189 BUG_ON(timer_pending(timer));192 BUG_ON(timer_pending(timer));
190 BUG_ON(!list_empty(&work->entry));193 BUG_ON(!list_empty(&work->entry));
191 194
192 /* This stores wq for the moment, for the timer_fn */195 /* This stores cwq for the moment, for the timer_fn */
193 set_wq_data(work, wq);196 set_wq_data(work,
197 per_cpu_ptr(wq->cpu_wq, raw_smp_processor_id()));
194 timer->expires = jiffies + delay;198 timer->expires = jiffies + delay;
195 timer->data = (unsigned long)dwork;199 timer->data = (unsigned long)dwork;
196 timer->function = delayed_work_timer_fn;200 timer->function = delayed_work_timer_fn;
@@ -221,8 +225,9 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, · 24 unmodified lines
221 BUG_ON(timer_pending(timer));225 BUG_ON(timer_pending(timer));
222 BUG_ON(!list_empty(&work->entry));226 BUG_ON(!list_empty(&work->entry));
223 227
224 /* This stores wq for the moment, for the timer_fn */228 /* This stores cwq for the moment, for the timer_fn */
225 set_wq_data(work, wq);229 set_wq_data(work,
230 per_cpu_ptr(wq->cpu_wq, raw_smp_processor_id()));
226 timer->expires = jiffies + delay;231 timer->expires = jiffies + delay;
227 timer->data = (unsigned long)dwork;232 timer->data = (unsigned long)dwork;
228 timer->function = delayed_work_timer_fn;233 timer->function = delayed_work_timer_fn;
@@ -562,9 +567,12 @@ void flush_work_keventd(struct work_struct *work) · 333 unmodified lines
562EXPORT_SYMBOL(flush_work_keventd);567EXPORT_SYMBOL(flush_work_keventd);
563 568
564/**569/**
565 * cancel_rearming_delayed_workqueue - reliably kill off a delayed work whose handler rearms the delayed work.570 * cancel_rearming_delayed_workqueue - kill off a delayed work whose handler rearms the delayed work.
566 * @wq: the controlling workqueue structure571 * @wq: the controlling workqueue structure
567 * @dwork: the delayed work struct572 * @dwork: the delayed work struct
573 *
574 * Note that the work callback function may still be running on return from
575 * cancel_delayed_work(). Run flush_workqueue() or flush_work() to wait on it.
568 */576 */
569void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,577void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,
570 struct delayed_work *dwork)578 struct delayed_work *dwork)
@@ -579,7 +587,7 @@ void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, · 8 unmodified lines
579EXPORT_SYMBOL(cancel_rearming_delayed_workqueue);587EXPORT_SYMBOL(cancel_rearming_delayed_workqueue);
580 588
581/**589/**
582 * cancel_rearming_delayed_work - reliably kill off a delayed keventd work whose handler rearms the delayed work.590 * cancel_rearming_delayed_work - kill off a delayed keventd work whose handler rearms the delayed work.
583 * @dwork: the delayed work struct591 * @dwork: the delayed work struct
584 */592 */
585void cancel_rearming_delayed_work(struct delayed_work *dwork)593void cancel_rearming_delayed_work(struct delayed_work *dwork)