/* * linux/kernel/workqueue.c * * Generic mechanism for defining kernel helper threads for running * arbitrary tasks in process context. * * Started by Ingo Molnar, Copyright (C) 2002 * * Derived from the taskqueue/keventd code by: * * David Woodhouse <dwmw2@infradead.org> * Andrew Morton <andrewm@uow.edu.au> * Kai Petzke <wpp@marie.physik.tu-berlin.de> * Theodore Ts'o <tytso@mit.edu> */ #include <linux/module.h>#include <linux/kernel.h>#include <linux/sched.h>#include <linux/init.h>#include <linux/signal.h>#include <linux/completion.h>#include <linux/workqueue.h>#include <linux/slab.h>#include <linux/cpu.h>#include <linux/notifier.h>#include <linux/kthread.h> /* * The per-CPU workqueue (if single thread, we always use cpu 0's). * * The sequence counters are for flush_scheduled_work(). It wants to wait * until until all currently-scheduled works are completed, but it doesn't * want to be livelocked by new, incoming ones. So it waits until * remove_sequence is >= the insert_sequence which pertained when * flush_scheduled_work() was called. */struct cpu_workqueue_struct { spinlock_t lock; long remove_sequence; /* Least-recently added (next to run) */ long insert_sequence; /* Next to add */ struct list_head worklist; wait_queue_head_t more_work; wait_queue_head_t work_done; struct workqueue_struct *wq; task_t *thread; int run_depth; /* Detect run_workqueue() recursion depth */} ____cacheline_aligned; /* * The externally visible workqueue abstraction is an array of * per-CPU workqueues: */struct workqueue_struct { struct cpu_workqueue_struct cpu_wq[NR_CPUS]; const char *name; struct list_head list; /* Empty if single thread */}; /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove threads to each one as cpus come/go. */static DEFINE_SPINLOCK(workqueue_lock);static LIST_HEAD(workqueues); /* If it's single threaded, it isn't in the list of workqueues. */static inline int is_single_threaded(struct workqueue_struct *wq){ return list_empty(&wq->list);} /* Preempt must be disabled. */static void __queue_work(struct cpu_workqueue_struct *cwq, struct work_struct *work){ unsigned long flags; spin_lock_irqsave(&cwq->lock, flags); work->wq_data = cwq; list_add_tail(&work->entry, &cwq->worklist); cwq->insert_sequence++; wake_up(&cwq->more_work); spin_unlock_irqrestore(&cwq->lock, flags);} /* * Queue work on a workqueue. Return non-zero if it was successfully * added. * * We queue the work to the CPU it was submitted, but there is no * guarantee that it will be processed by that CPU. */int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work){ int ret = 0, cpu = get_cpu(); if (!test_and_set_bit(0, &work->pending)) { if (unlikely(is_single_threaded(wq))) cpu = 0; BUG_ON(!list_empty(&work->entry)); __queue_work(wq->cpu_wq + cpu, work); ret = 1; } put_cpu(); return ret;} static void delayed_work_timer_fn(unsigned long __data){ struct work_struct *work = (struct work_struct *)__data; struct workqueue_struct *wq = work->wq_data; int cpu = smp_processor_id(); if (unlikely(is_single_threaded(wq))) cpu = 0; __queue_work(wq->cpu_wq + cpu, work);} int fastcall queue_delayed_work(struct workqueue_struct *wq, struct work_struct *work, unsigned long delay){ int ret = 0; struct timer_list *timer = &work->timer; if (!test_and_set_bit(0, &work->pending)) { BUG_ON(timer_pending(timer)); BUG_ON(!list_empty(&work->entry)); /* This stores wq for the moment, for the timer_fn */ work->wq_data = wq; timer->expires = jiffies + delay; timer->data = (unsigned long)work; timer->function = delayed_work_timer_fn; add_timer(timer); ret = 1; } return ret;} static inline void run_workqueue(struct cpu_workqueue_struct *cwq){ unsigned long flags; /* * Keep taking off work from the queue until * done. */ spin_lock_irqsave(&cwq->lock, flags); cwq->run_depth++; if (cwq->run_depth > 3) { /* morton gets to eat his hat */ printk("%s: recursion depth exceeded: %d\n", __FUNCTION__, cwq->run_depth); dump_stack(); } while (!list_empty(&cwq->worklist)) { struct work_struct *work = list_entry(cwq->worklist.next, struct work_struct, entry); void (*f) (void *) = work->func; void *data = work->data; list_del_init(cwq->worklist.next); spin_unlock_irqrestore(&cwq->lock, flags); BUG_ON(work->wq_data != cwq); clear_bit(0, &work->pending); f(data); spin_lock_irqsave(&cwq->lock, flags); cwq->remove_sequence++; wake_up(&cwq->work_done); } cwq->run_depth--; spin_unlock_irqrestore(&cwq->lock, flags);} static int worker_thread(void *__cwq){ struct cpu_workqueue_struct *cwq = __cwq; DECLARE_WAITQUEUE(wait, current); struct k_sigaction sa; sigset_t blocked; current->flags |= PF_NOFREEZE; set_user_nice(current, -5); /* Block and flush all signals */ sigfillset(&blocked); sigprocmask(SIG_BLOCK, &blocked, NULL); flush_signals(current); /* SIG_IGN makes children autoreap: see do_notify_parent(). */ sa.sa.sa_handler = SIG_IGN; sa.sa.sa_flags = 0; siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); set_current_state(TASK_INTERRUPTIBLE); while (!kthread_should_stop()) { add_wait_queue(&cwq->more_work, &wait); if (list_empty(&cwq->worklist)) schedule(); else __set_current_state(TASK_RUNNING); remove_wait_queue(&cwq->more_work, &wait); if (!list_empty(&cwq->worklist)) run_workqueue(cwq); set_current_state(TASK_INTERRUPTIBLE); } __set_current_state(TASK_RUNNING); return 0;} static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq){ if (cwq->thread == current) { /* * Probably keventd trying to flush its own queue. So simply run * it by hand rather than deadlocking. */ run_workqueue(cwq); } else { DEFINE_WAIT(wait); long sequence_needed; spin_lock_irq(&cwq->lock); sequence_needed = cwq->insert_sequence; while (sequence_needed - cwq->remove_sequence > 0) { prepare_to_wait(&cwq->work_done, &wait, TASK_UNINTERRUPTIBLE); spin_unlock_irq(&cwq->lock); schedule(); spin_lock_irq(&cwq->lock); } finish_wait(&cwq->work_done, &wait); spin_unlock_irq(&cwq->lock); }} /* * flush_workqueue - ensure that any scheduled work has run to completion. * * Forces execution of the workqueue and blocks until its completion. * This is typically used in driver shutdown handlers. * * This function will sample each workqueue's current insert_sequence number and * will sleep until the head sequence is greater than or equal to that. This * means that we sleep until all works which were queued on entry have been * handled, but we are not livelocked by new incoming ones. * * This function used to run the workqueues itself. Now we just wait for the * helper threads to do it. */void fastcall flush_workqueue(struct workqueue_struct *wq){ might_sleep(); if (is_single_threaded(wq)) { /* Always use cpu 0's area. */ flush_cpu_workqueue(wq->cpu_wq + 0); } else { int cpu; lock_cpu_hotplug(); for_each_online_cpu(cpu) flush_cpu_workqueue(wq->cpu_wq + cpu); unlock_cpu_hotplug(); }} static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, int cpu){ struct cpu_workqueue_struct *cwq = wq->cpu_wq + cpu; struct task_struct *p; spin_lock_init(&cwq->lock); cwq->wq = wq; cwq->thread = NULL; cwq->insert_sequence = 0; cwq->remove_sequence = 0; INIT_LIST_HEAD(&cwq->worklist); init_waitqueue_head(&cwq->more_work); init_waitqueue_head(&cwq->work_done); if (is_single_threaded(wq)) p = kthread_create(worker_thread, cwq, "%s", wq->name); else p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu); if (IS_ERR(p)) return NULL; cwq->thread = p; return p;} struct workqueue_struct *__create_workqueue(const char *name, int singlethread){ int cpu, destroy = 0; struct workqueue_struct *wq; struct task_struct *p; BUG_ON(strlen(name) > 10); wq = kmalloc(sizeof(*wq), GFP_KERNEL); if (!wq) return NULL; memset(wq, 0, sizeof(*wq)); wq->name = name; /* We don't need the distraction of CPUs appearing and vanishing. */ lock_cpu_hotplug(); if (singlethread) { INIT_LIST_HEAD(&wq->list); p = create_workqueue_thread(wq, 0); if (!p) destroy = 1; else wake_up_process(p); } else { spin_lock(&workqueue_lock); list_add(&wq->list, &workqueues); spin_unlock(&workqueue_lock); for_each_online_cpu(cpu) { p = create_workqueue_thread(wq, cpu); if (p) { kthread_bind(p, cpu); wake_up_process(p); } else destroy = 1; } } unlock_cpu_hotplug(); /* * Was there any error during startup? If yes then clean up: */ if (destroy) { destroy_workqueue(wq); wq = NULL; } return wq;} static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu){ struct cpu_workqueue_struct *cwq; unsigned long flags; struct task_struct *p; cwq = wq->cpu_wq + cpu; spin_lock_irqsave(&cwq->lock, flags); p = cwq->thread; cwq->thread = NULL; spin_unlock_irqrestore(&cwq->lock, flags); if (p) kthread_stop(p);} void destroy_workqueue(struct workqueue_struct *wq){ int cpu; flush_workqueue(wq); /* We don't need the distraction of CPUs appearing and vanishing. */ lock_cpu_hotplug(); if (is_single_threaded(wq)) cleanup_workqueue_thread(wq, 0); else { for_each_online_cpu(cpu) cleanup_workqueue_thread(wq, cpu); spin_lock(&workqueue_lock); list_del(&wq->list); spin_unlock(&workqueue_lock); } unlock_cpu_hotplug(); kfree(wq);} static struct workqueue_struct *keventd_wq; int fastcall schedule_work(struct work_struct *work){ return queue_work(keventd_wq, work);} int fastcall schedule_delayed_work(struct work_struct *work, unsigned long delay){ return queue_delayed_work(keventd_wq, work, delay);} int schedule_delayed_work_on(int cpu, struct work_struct *work, unsigned long delay){ int ret = 0; struct timer_list *timer = &work->timer; if (!test_and_set_bit(0, &work->pending)) { BUG_ON(timer_pending(timer)); BUG_ON(!list_empty(&work->entry)); /* This stores keventd_wq for the moment, for the timer_fn */ work->wq_data = keventd_wq; timer->expires = jiffies + delay; timer->data = (unsigned long)work; timer->function = delayed_work_timer_fn; add_timer_on(timer, cpu); ret = 1; } return ret;} void flush_scheduled_work(void){ flush_workqueue(keventd_wq);} /** * cancel_rearming_delayed_workqueue - reliably kill off a delayed * work whose handler rearms the delayed work. * @wq: the controlling workqueue structure * @work: the delayed work struct */void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, struct work_struct *work){ while (!cancel_delayed_work(work)) flush_workqueue(wq);}EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); /** * cancel_rearming_delayed_work - reliably kill off a delayed keventd * work whose handler rearms the delayed work. * @work: the delayed work struct */void cancel_rearming_delayed_work(struct work_struct *work){ cancel_rearming_delayed_workqueue(keventd_wq, work);}EXPORT_SYMBOL(cancel_rearming_delayed_work); int keventd_up(void){ return keventd_wq != NULL;} int current_is_keventd(void){ struct cpu_workqueue_struct *cwq; int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ int ret = 0; BUG_ON(!keventd_wq); cwq = keventd_wq->cpu_wq + cpu; if (current == cwq->thread) ret = 1; return ret; } #ifdef CONFIG_HOTPLUG_CPU/* Take the work from this (downed) CPU. */static void take_over_work(struct workqueue_struct *wq, unsigned int cpu){ struct cpu_workqueue_struct *cwq = wq->cpu_wq + cpu; LIST_HEAD(list); struct work_struct *work; spin_lock_irq(&cwq->lock); list_splice_init(&cwq->worklist, &list); while (!list_empty(&list)) { printk("Taking work for %s\n", wq->name); work = list_entry(list.next,struct work_struct,entry); list_del(&work->entry); __queue_work(wq->cpu_wq + smp_processor_id(), work); } spin_unlock_irq(&cwq->lock);} /* We're holding the cpucontrol mutex here */static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu){ unsigned int hotcpu = (unsigned long)hcpu; struct workqueue_struct *wq; switch (action) {Lines 1–500 of 556. 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/* * linux/kernel/workqueue.c * * Generic mechanism for defining kernel helper threads for running * arbitrary tasks in process context. * * Started by Ingo Molnar, Copyright (C) 2002 * * Derived from the taskqueue/keventd code by: * * David Woodhouse <dwmw2@infradead.org> * Andrew Morton <andrewm@uow.edu.au> * Kai Petzke <wpp@marie.physik.tu-berlin.de> * Theodore Ts'o <tytso@mit.edu> */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/init.h> #include <linux/signal.h> #include <linux/completion.h> #include <linux/workqueue.h> #include <linux/slab.h> #include <linux/cpu.h> #include <linux/notifier.h> #include <linux/kthread.h> /* * The per-CPU workqueue (if single thread, we always use cpu 0's). * * The sequence counters are for flush_scheduled_work(). It wants to wait * until until all currently-scheduled works are completed, but it doesn't * want to be livelocked by new, incoming ones. So it waits until * remove_sequence is >= the insert_sequence which pertained when * flush_scheduled_work() was called. */ struct cpu_workqueue_struct { spinlock_t lock; long remove_sequence; /* Least-recently added (next to run) */ long insert_sequence; /* Next to add */ struct list_head worklist; wait_queue_head_t more_work; wait_queue_head_t work_done; struct workqueue_struct *wq; task_t *thread; int run_depth; /* Detect run_workqueue() recursion depth */ } ____cacheline_aligned; /* * The externally visible workqueue abstraction is an array of * per-CPU workqueues: */ struct workqueue_struct { struct cpu_workqueue_struct cpu_wq[NR_CPUS]; const char *name; struct list_head list; /* Empty if single thread */ }; /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove threads to each one as cpus come/go. */ static DEFINE_SPINLOCK(workqueue_lock); static LIST_HEAD(workqueues); /* If it's single threaded, it isn't in the list of workqueues. */ static inline int is_single_threaded(struct workqueue_struct *wq) { return list_empty(&wq->list); } /* Preempt must be disabled. */ static void __queue_work(struct cpu_workqueue_struct *cwq, struct work_struct *work) { unsigned long flags; spin_lock_irqsave(&cwq->lock, flags); work->wq_data = cwq; list_add_tail(&work->entry, &cwq->worklist); cwq->insert_sequence++; wake_up(&cwq->more_work); spin_unlock_irqrestore(&cwq->lock, flags); } /* * Queue work on a workqueue. Return non-zero if it was successfully * added. * * We queue the work to the CPU it was submitted, but there is no * guarantee that it will be processed by that CPU. */ int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) { int ret = 0, cpu = get_cpu(); if (!test_and_set_bit(0, &work->pending)) { if (unlikely(is_single_threaded(wq))) cpu = 0; BUG_ON(!list_empty(&work->entry)); __queue_work(wq->cpu_wq + cpu, work); ret = 1; } put_cpu(); return ret; } static void delayed_work_timer_fn(unsigned long __data) { struct work_struct *work = (struct work_struct *)__data; struct workqueue_struct *wq = work->wq_data; int cpu = smp_processor_id(); if (unlikely(is_single_threaded(wq))) cpu = 0; __queue_work(wq->cpu_wq + cpu, work); } int fastcall queue_delayed_work(struct workqueue_struct *wq, struct work_struct *work, unsigned long delay) { int ret = 0; struct timer_list *timer = &work->timer; if (!test_and_set_bit(0, &work->pending)) { BUG_ON(timer_pending(timer)); BUG_ON(!list_empty(&work->entry)); /* This stores wq for the moment, for the timer_fn */ work->wq_data = wq; timer->expires = jiffies + delay; timer->data = (unsigned long)work; timer->function = delayed_work_timer_fn; add_timer(timer); ret = 1; } return ret; } static inline void run_workqueue(struct cpu_workqueue_struct *cwq) { unsigned long flags; /* * Keep taking off work from the queue until * done. */ spin_lock_irqsave(&cwq->lock, flags); cwq->run_depth++; if (cwq->run_depth > 3) { /* morton gets to eat his hat */ printk("%s: recursion depth exceeded: %d\n", __FUNCTION__, cwq->run_depth); dump_stack(); } while (!list_empty(&cwq->worklist)) { struct work_struct *work = list_entry(cwq->worklist.next, struct work_struct, entry); void (*f) (void *) = work->func; void *data = work->data; list_del_init(cwq->worklist.next); spin_unlock_irqrestore(&cwq->lock, flags); BUG_ON(work->wq_data != cwq); clear_bit(0, &work->pending); f(data); spin_lock_irqsave(&cwq->lock, flags); cwq->remove_sequence++; wake_up(&cwq->work_done); } cwq->run_depth--; spin_unlock_irqrestore(&cwq->lock, flags); } static int worker_thread(void *__cwq) { struct cpu_workqueue_struct *cwq = __cwq; DECLARE_WAITQUEUE(wait, current); struct k_sigaction sa; sigset_t blocked; current->flags |= PF_NOFREEZE; set_user_nice(current, -5); /* Block and flush all signals */ sigfillset(&blocked); sigprocmask(SIG_BLOCK, &blocked, NULL); flush_signals(current); /* SIG_IGN makes children autoreap: see do_notify_parent(). */ sa.sa.sa_handler = SIG_IGN; sa.sa.sa_flags = 0; siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); set_current_state(TASK_INTERRUPTIBLE); while (!kthread_should_stop()) { add_wait_queue(&cwq->more_work, &wait); if (list_empty(&cwq->worklist)) schedule(); else __set_current_state(TASK_RUNNING); remove_wait_queue(&cwq->more_work, &wait); if (!list_empty(&cwq->worklist)) run_workqueue(cwq); set_current_state(TASK_INTERRUPTIBLE); } __set_current_state(TASK_RUNNING); return 0; } static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) { if (cwq->thread == current) { /* * Probably keventd trying to flush its own queue. So simply run * it by hand rather than deadlocking. */ run_workqueue(cwq); } else { DEFINE_WAIT(wait); long sequence_needed; spin_lock_irq(&cwq->lock); sequence_needed = cwq->insert_sequence; while (sequence_needed - cwq->remove_sequence > 0) { prepare_to_wait(&cwq->work_done, &wait, TASK_UNINTERRUPTIBLE); spin_unlock_irq(&cwq->lock); schedule(); spin_lock_irq(&cwq->lock); } finish_wait(&cwq->work_done, &wait); spin_unlock_irq(&cwq->lock); } } /* * flush_workqueue - ensure that any scheduled work has run to completion. * * Forces execution of the workqueue and blocks until its completion. * This is typically used in driver shutdown handlers. * * This function will sample each workqueue's current insert_sequence number and * will sleep until the head sequence is greater than or equal to that. This * means that we sleep until all works which were queued on entry have been * handled, but we are not livelocked by new incoming ones. * * This function used to run the workqueues itself. Now we just wait for the * helper threads to do it. */ void fastcall flush_workqueue(struct workqueue_struct *wq) { might_sleep(); if (is_single_threaded(wq)) { /* Always use cpu 0's area. */ flush_cpu_workqueue(wq->cpu_wq + 0); } else { int cpu; lock_cpu_hotplug(); for_each_online_cpu(cpu) flush_cpu_workqueue(wq->cpu_wq + cpu); unlock_cpu_hotplug(); } } static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, int cpu) { struct cpu_workqueue_struct *cwq = wq->cpu_wq + cpu; struct task_struct *p; spin_lock_init(&cwq->lock); cwq->wq = wq; cwq->thread = NULL; cwq->insert_sequence = 0; cwq->remove_sequence = 0; INIT_LIST_HEAD(&cwq->worklist); init_waitqueue_head(&cwq->more_work); init_waitqueue_head(&cwq->work_done); if (is_single_threaded(wq)) p = kthread_create(worker_thread, cwq, "%s", wq->name); else p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu); if (IS_ERR(p)) return NULL; cwq->thread = p; return p; } struct workqueue_struct *__create_workqueue(const char *name, int singlethread) { int cpu, destroy = 0; struct workqueue_struct *wq; struct task_struct *p; BUG_ON(strlen(name) > 10); wq = kmalloc(sizeof(*wq), GFP_KERNEL); if (!wq) return NULL; memset(wq, 0, sizeof(*wq)); wq->name = name; /* We don't need the distraction of CPUs appearing and vanishing. */ lock_cpu_hotplug(); if (singlethread) { INIT_LIST_HEAD(&wq->list); p = create_workqueue_thread(wq, 0); if (!p) destroy = 1; else wake_up_process(p); } else { spin_lock(&workqueue_lock); list_add(&wq->list, &workqueues); spin_unlock(&workqueue_lock); for_each_online_cpu(cpu) { p = create_workqueue_thread(wq, cpu); if (p) { kthread_bind(p, cpu); wake_up_process(p); } else destroy = 1; } } unlock_cpu_hotplug(); /* * Was there any error during startup? If yes then clean up: */ if (destroy) { destroy_workqueue(wq); wq = NULL; } return wq; } static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu) { struct cpu_workqueue_struct *cwq; unsigned long flags; struct task_struct *p; cwq = wq->cpu_wq + cpu; spin_lock_irqsave(&cwq->lock, flags); p = cwq->thread; cwq->thread = NULL; spin_unlock_irqrestore(&cwq->lock, flags); if (p) kthread_stop(p); } void destroy_workqueue(struct workqueue_struct *wq) { int cpu; flush_workqueue(wq); /* We don't need the distraction of CPUs appearing and vanishing. */ lock_cpu_hotplug(); if (is_single_threaded(wq)) cleanup_workqueue_thread(wq, 0); else { for_each_online_cpu(cpu) cleanup_workqueue_thread(wq, cpu); spin_lock(&workqueue_lock); list_del(&wq->list); spin_unlock(&workqueue_lock); } unlock_cpu_hotplug(); kfree(wq); } static struct workqueue_struct *keventd_wq; int fastcall schedule_work(struct work_struct *work) { return queue_work(keventd_wq, work); } int fastcall schedule_delayed_work(struct work_struct *work, unsigned long delay) { return queue_delayed_work(keventd_wq, work, delay); } int schedule_delayed_work_on(int cpu, struct work_struct *work, unsigned long delay) { int ret = 0; struct timer_list *timer = &work->timer; if (!test_and_set_bit(0, &work->pending)) { BUG_ON(timer_pending(timer)); BUG_ON(!list_empty(&work->entry)); /* This stores keventd_wq for the moment, for the timer_fn */ work->wq_data = keventd_wq; timer->expires = jiffies + delay; timer->data = (unsigned long)work; timer->function = delayed_work_timer_fn; add_timer_on(timer, cpu); ret = 1; } return ret; } void flush_scheduled_work(void) { flush_workqueue(keventd_wq); } /** * cancel_rearming_delayed_workqueue - reliably kill off a delayed * work whose handler rearms the delayed work. * @wq: the controlling workqueue structure * @work: the delayed work struct */ void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, struct work_struct *work) { while (!cancel_delayed_work(work)) flush_workqueue(wq); } EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); /** * cancel_rearming_delayed_work - reliably kill off a delayed keventd * work whose handler rearms the delayed work. * @work: the delayed work struct */ void cancel_rearming_delayed_work(struct work_struct *work) { cancel_rearming_delayed_workqueue(keventd_wq, work); } EXPORT_SYMBOL(cancel_rearming_delayed_work); int keventd_up(void) { return keventd_wq != NULL; } int current_is_keventd(void) { struct cpu_workqueue_struct *cwq; int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ int ret = 0; BUG_ON(!keventd_wq); cwq = keventd_wq->cpu_wq + cpu; if (current == cwq->thread) ret = 1; return ret; } #ifdef CONFIG_HOTPLUG_CPU /* Take the work from this (downed) CPU. */ static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) { struct cpu_workqueue_struct *cwq = wq->cpu_wq + cpu; LIST_HEAD(list); struct work_struct *work; spin_lock_irq(&cwq->lock); list_splice_init(&cwq->worklist, &list); while (!list_empty(&list)) { printk("Taking work for %s\n", wq->name); work = list_entry(list.next,struct work_struct,entry); list_del(&work->entry); __queue_work(wq->cpu_wq + smp_processor_id(), work); } spin_unlock_irq(&cwq->lock); } /* We're holding the cpucontrol mutex here */ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { unsigned int hotcpu = (unsigned long)hcpu; struct workqueue_struct *wq; switch (action) {