| /* |
| * 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> |
| * |
| * Made to use alloc_percpu by Christoph Lameter <clameter@sgi.com>. |
| */ |
| |
| #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> |
| #include <linux/hardirq.h> |
| #include <linux/mempolicy.h> |
| #include <linux/freezer.h> |
| #include <linux/kallsyms.h> |
| #include <linux/debug_locks.h> |
| |
| /* |
| * The per-CPU workqueue (if single thread, we always use the first |
| * possible cpu). |
| */ |
| struct cpu_workqueue_struct { |
| |
| spinlock_t lock; |
| |
| struct list_head worklist; |
| wait_queue_head_t more_work; |
| struct work_struct *current_work; |
| |
| struct workqueue_struct *wq; |
| struct task_struct *thread; |
| int should_stop; |
| |
| 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; |
| struct list_head list; |
| const char *name; |
| int singlethread; |
| int freezeable; /* Freeze threads during suspend */ |
| }; |
| |
| /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove |
| threads to each one as cpus come/go. */ |
| static DEFINE_MUTEX(workqueue_mutex); |
| static LIST_HEAD(workqueues); |
| |
| static int singlethread_cpu __read_mostly; |
| static cpumask_t cpu_singlethread_map __read_mostly; |
| /* optimization, we could use cpu_possible_map */ |
| static cpumask_t cpu_populated_map __read_mostly; |
| |
| /* If it's single threaded, it isn't in the list of workqueues. */ |
| static inline int is_single_threaded(struct workqueue_struct *wq) |
| { |
| return wq->singlethread; |
| } |
| |
| static const cpumask_t *wq_cpu_map(struct workqueue_struct *wq) |
| { |
| return is_single_threaded(wq) |
| ? &cpu_singlethread_map : &cpu_populated_map; |
| } |
| |
| static |
| struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu) |
| { |
| if (unlikely(is_single_threaded(wq))) |
| cpu = singlethread_cpu; |
| return per_cpu_ptr(wq->cpu_wq, cpu); |
| } |
| |
| /* |
| * Set the workqueue on which a work item is to be run |
| * - Must *only* be called if the pending flag is set |
| */ |
| static inline void set_wq_data(struct work_struct *work, |
| struct cpu_workqueue_struct *cwq) |
| { |
| unsigned long new; |
| |
| BUG_ON(!work_pending(work)); |
| |
| new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING); |
| new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); |
| atomic_long_set(&work->data, new); |
| } |
| |
| static inline |
| struct cpu_workqueue_struct *get_wq_data(struct work_struct *work) |
| { |
| return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); |
| } |
| |
| static void insert_work(struct cpu_workqueue_struct *cwq, |
| struct work_struct *work, int tail) |
| { |
| set_wq_data(work, cwq); |
| if (tail) |
| list_add_tail(&work->entry, &cwq->worklist); |
| else |
| list_add(&work->entry, &cwq->worklist); |
| wake_up(&cwq->more_work); |
| } |
| |
| /* 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); |
| insert_work(cwq, work, 1); |
| spin_unlock_irqrestore(&cwq->lock, flags); |
| } |
| |
| /** |
| * queue_work - queue work on a workqueue |
| * @wq: workqueue to use |
| * @work: work to queue |
| * |
| * Returns 0 if @work was already on a queue, non-zero otherwise. |
| * |
| * 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; |
| |
| if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
| BUG_ON(!list_empty(&work->entry)); |
| __queue_work(wq_per_cpu(wq, get_cpu()), work); |
| put_cpu(); |
| ret = 1; |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(queue_work); |
| |
| void delayed_work_timer_fn(unsigned long __data) |
| { |
| struct delayed_work *dwork = (struct delayed_work *)__data; |
| struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); |
| struct workqueue_struct *wq = cwq->wq; |
| |
| __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work); |
| } |
| |
| /** |
| * queue_delayed_work - queue work on a workqueue after delay |
| * @wq: workqueue to use |
| * @dwork: delayable work to queue |
| * @delay: number of jiffies to wait before queueing |
| * |
| * Returns 0 if @work was already on a queue, non-zero otherwise. |
| */ |
| int fastcall queue_delayed_work(struct workqueue_struct *wq, |
| struct delayed_work *dwork, unsigned long delay) |
| { |
| timer_stats_timer_set_start_info(&dwork->timer); |
| if (delay == 0) |
| return queue_work(wq, &dwork->work); |
| |
| return queue_delayed_work_on(-1, wq, dwork, delay); |
| } |
| EXPORT_SYMBOL_GPL(queue_delayed_work); |
| |
| /** |
| * queue_delayed_work_on - queue work on specific CPU after delay |
| * @cpu: CPU number to execute work on |
| * @wq: workqueue to use |
| * @dwork: work to queue |
| * @delay: number of jiffies to wait before queueing |
| * |
| * Returns 0 if @work was already on a queue, non-zero otherwise. |
| */ |
| int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
| struct delayed_work *dwork, unsigned long delay) |
| { |
| int ret = 0; |
| struct timer_list *timer = &dwork->timer; |
| struct work_struct *work = &dwork->work; |
| |
| if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { |
| BUG_ON(timer_pending(timer)); |
| BUG_ON(!list_empty(&work->entry)); |
| |
| /* This stores cwq for the moment, for the timer_fn */ |
| set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id())); |
| timer->expires = jiffies + delay; |
| timer->data = (unsigned long)dwork; |
| timer->function = delayed_work_timer_fn; |
| |
| if (unlikely(cpu >= 0)) |
| add_timer_on(timer, cpu); |
| else |
| add_timer(timer); |
| ret = 1; |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
| |
| static void run_workqueue(struct cpu_workqueue_struct *cwq) |
| { |
| spin_lock_irq(&cwq->lock); |
| 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); |
| work_func_t f = work->func; |
| |
| cwq->current_work = work; |
| list_del_init(cwq->worklist.next); |
| spin_unlock_irq(&cwq->lock); |
| |
| BUG_ON(get_wq_data(work) != cwq); |
| work_clear_pending(work); |
| f(work); |
| |
| if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
| printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " |
| "%s/0x%08x/%d\n", |
| current->comm, preempt_count(), |
| current->pid); |
| printk(KERN_ERR " last function: "); |
| print_symbol("%s\n", (unsigned long)f); |
| debug_show_held_locks(current); |
| dump_stack(); |
| } |
| |
| spin_lock_irq(&cwq->lock); |
| cwq->current_work = NULL; |
| } |
| cwq->run_depth--; |
| spin_unlock_irq(&cwq->lock); |
| } |
| |
| /* |
| * NOTE: the caller must not touch *cwq if this func returns true |
| */ |
| static int cwq_should_stop(struct cpu_workqueue_struct *cwq) |
| { |
| int should_stop = cwq->should_stop; |
| |
| if (unlikely(should_stop)) { |
| spin_lock_irq(&cwq->lock); |
| should_stop = cwq->should_stop && list_empty(&cwq->worklist); |
| if (should_stop) |
| cwq->thread = NULL; |
| spin_unlock_irq(&cwq->lock); |
| } |
| |
| return should_stop; |
| } |
| |
| static int worker_thread(void *__cwq) |
| { |
| struct cpu_workqueue_struct *cwq = __cwq; |
| DEFINE_WAIT(wait); |
| struct k_sigaction sa; |
| |
| if (!cwq->wq->freezeable) |
| current->flags |= PF_NOFREEZE; |
| |
| set_user_nice(current, -5); |
| /* |
| * We inherited MPOL_INTERLEAVE from the booting kernel. |
| * Set MPOL_DEFAULT to insure node local allocations. |
| */ |
| numa_default_policy(); |
| |
| /* 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); |
| |
| for (;;) { |
| prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); |
| if (!freezing(current) && !cwq->should_stop |
| && list_empty(&cwq->worklist)) |
| schedule(); |
| finish_wait(&cwq->more_work, &wait); |
| |
| try_to_freeze(); |
| |
| if (cwq_should_stop(cwq)) |
| break; |
| |
| run_workqueue(cwq); |
| } |
| |
| return 0; |
| } |
| |
| struct wq_barrier { |
| struct work_struct work; |
| struct completion done; |
| }; |
| |
| static void wq_barrier_func(struct work_struct *work) |
| { |
| struct wq_barrier *barr = container_of(work, struct wq_barrier, work); |
| complete(&barr->done); |
| } |
| |
| static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
| struct wq_barrier *barr, int tail) |
| { |
| INIT_WORK(&barr->work, wq_barrier_func); |
| __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); |
| |
| init_completion(&barr->done); |
| |
| insert_work(cwq, &barr->work, tail); |
| } |
| |
| 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 { |
| struct wq_barrier barr; |
| int active = 0; |
| |
| spin_lock_irq(&cwq->lock); |
| if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { |
| insert_wq_barrier(cwq, &barr, 1); |
| active = 1; |
| } |
| spin_unlock_irq(&cwq->lock); |
| |
| if (active) |
| wait_for_completion(&barr.done); |
| } |
| } |
| |
| /** |
| * flush_workqueue - ensure that any scheduled work has run to completion. |
| * @wq: workqueue to flush |
| * |
| * Forces execution of the workqueue and blocks until its completion. |
| * This is typically used in driver shutdown handlers. |
| * |
| * 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) |
| { |
| const cpumask_t *cpu_map = wq_cpu_map(wq); |
| int cpu; |
| |
| might_sleep(); |
| for_each_cpu_mask(cpu, *cpu_map) |
| flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
| } |
| EXPORT_SYMBOL_GPL(flush_workqueue); |
| |
| static void wait_on_work(struct cpu_workqueue_struct *cwq, |
| struct work_struct *work) |
| { |
| struct wq_barrier barr; |
| int running = 0; |
| |
| spin_lock_irq(&cwq->lock); |
| if (unlikely(cwq->current_work == work)) { |
| insert_wq_barrier(cwq, &barr, 0); |
| running = 1; |
| } |
| spin_unlock_irq(&cwq->lock); |
| |
| if (unlikely(running)) |
| wait_for_completion(&barr.done); |
| } |
| |
| /** |
| * cancel_work_sync - block until a work_struct's callback has terminated |
| * @work: the work which is to be flushed |
| * |
| * cancel_work_sync() will attempt to cancel the work if it is queued. If the |
| * work's callback appears to be running, cancel_work_sync() will block until |
| * it has completed. |
| * |
| * cancel_work_sync() is designed to be used when the caller is tearing down |
| * data structures which the callback function operates upon. It is expected |
| * that, prior to calling cancel_work_sync(), the caller has arranged for the |
| * work to not be requeued. |
| */ |
| void cancel_work_sync(struct work_struct *work) |
| { |
| struct cpu_workqueue_struct *cwq; |
| struct workqueue_struct *wq; |
| const cpumask_t *cpu_map; |
| int cpu; |
| |
| might_sleep(); |
| |
| cwq = get_wq_data(work); |
| /* Was it ever queued ? */ |
| if (!cwq) |
| return; |
| |
| /* |
| * This work can't be re-queued, no need to re-check that |
| * get_wq_data() is still the same when we take cwq->lock. |
| */ |
| spin_lock_irq(&cwq->lock); |
| list_del_init(&work->entry); |
| work_clear_pending(work); |
| spin_unlock_irq(&cwq->lock); |
| |
| wq = cwq->wq; |
| cpu_map = wq_cpu_map(wq); |
| |
| for_each_cpu_mask(cpu, *cpu_map) |
| wait_on_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
| } |
| EXPORT_SYMBOL_GPL(cancel_work_sync); |
| |
| |
| static struct workqueue_struct *keventd_wq; |
| |
| /** |
| * schedule_work - put work task in global workqueue |
| * @work: job to be done |
| * |
| * This puts a job in the kernel-global workqueue. |
| */ |
| int fastcall schedule_work(struct work_struct *work) |
| { |
| return queue_work(keventd_wq, work); |
| } |
| EXPORT_SYMBOL(schedule_work); |
| |
| /** |
| * schedule_delayed_work - put work task in global workqueue after delay |
| * @dwork: job to be done |
| * @delay: number of jiffies to wait or 0 for immediate execution |
| * |
| * After waiting for a given time this puts a job in the kernel-global |
| * workqueue. |
| */ |
| int fastcall schedule_delayed_work(struct delayed_work *dwork, |
| unsigned long delay) |
| { |
| timer_stats_timer_set_start_info(&dwork->timer); |
| return queue_delayed_work(keventd_wq, dwork, delay); |
| } |
| EXPORT_SYMBOL(schedule_delayed_work); |
| |
| /** |
| * schedule_delayed_work_on - queue work in global workqueue on CPU after delay |
| * @cpu: cpu to use |
| * @dwork: job to be done |
| * @delay: number of jiffies to wait |
| * |
| * After waiting for a given time this puts a job in the kernel-global |
| * workqueue on the specified CPU. |
| */ |
| int schedule_delayed_work_on(int cpu, |
| struct delayed_work *dwork, unsigned long delay) |
| { |
| return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); |
| } |
| EXPORT_SYMBOL(schedule_delayed_work_on); |
| |
| /** |
| * schedule_on_each_cpu - call a function on each online CPU from keventd |
| * @func: the function to call |
| * |
| * Returns zero on success. |
| * Returns -ve errno on failure. |
| * |
| * Appears to be racy against CPU hotplug. |
| * |
| * schedule_on_each_cpu() is very slow. |
| */ |
| int schedule_on_each_cpu(work_func_t func) |
| { |
| int cpu; |
| struct work_struct *works; |
| |
| works = alloc_percpu(struct work_struct); |
| if (!works) |
| return -ENOMEM; |
| |
| preempt_disable(); /* CPU hotplug */ |
| for_each_online_cpu(cpu) { |
| struct work_struct *work = per_cpu_ptr(works, cpu); |
| |
| INIT_WORK(work, func); |
| set_bit(WORK_STRUCT_PENDING, work_data_bits(work)); |
| __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work); |
| } |
| preempt_enable(); |
| flush_workqueue(keventd_wq); |
| free_percpu(works); |
| return 0; |
| } |
| |
| void flush_scheduled_work(void) |
| { |
| flush_workqueue(keventd_wq); |
| } |
| EXPORT_SYMBOL(flush_scheduled_work); |
| |
| /** |
| * cancel_rearming_delayed_work - kill off a delayed work whose handler rearms the delayed work. |
| * @dwork: the delayed work struct |
| * |
| * Note that the work callback function may still be running on return from |
| * cancel_delayed_work(). Run flush_workqueue() or cancel_work_sync() to wait |
| * on it. |
| */ |
| void cancel_rearming_delayed_work(struct delayed_work *dwork) |
| { |
| struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); |
| |
| /* Was it ever queued ? */ |
| if (cwq != NULL) { |
| struct workqueue_struct *wq = cwq->wq; |
| |
| while (!cancel_delayed_work(dwork)) |
| flush_workqueue(wq); |
| } |
| } |
| EXPORT_SYMBOL(cancel_rearming_delayed_work); |
| |
| /** |
| * execute_in_process_context - reliably execute the routine with user context |
| * @fn: the function to execute |
| * @ew: guaranteed storage for the execute work structure (must |
| * be available when the work executes) |
| * |
| * Executes the function immediately if process context is available, |
| * otherwise schedules the function for delayed execution. |
| * |
| * Returns: 0 - function was executed |
| * 1 - function was scheduled for execution |
| */ |
| int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
| { |
| if (!in_interrupt()) { |
| fn(&ew->work); |
| return 0; |
| } |
| |
| INIT_WORK(&ew->work, fn); |
| schedule_work(&ew->work); |
| |
| return 1; |
| } |
| EXPORT_SYMBOL_GPL(execute_in_process_context); |
| |
| 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 = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
| if (current == cwq->thread) |
| ret = 1; |
| |
| return ret; |
| |
| } |
| |
| static struct cpu_workqueue_struct * |
| init_cpu_workqueue(struct workqueue_struct *wq, int cpu) |
| { |
| struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
| |
| cwq->wq = wq; |
| spin_lock_init(&cwq->lock); |
| INIT_LIST_HEAD(&cwq->worklist); |
| init_waitqueue_head(&cwq->more_work); |
| |
| return cwq; |
| } |
| |
| static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
| { |
| struct workqueue_struct *wq = cwq->wq; |
| const char *fmt = is_single_threaded(wq) ? "%s" : "%s/%d"; |
| struct task_struct *p; |
| |
| p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu); |
| /* |
| * Nobody can add the work_struct to this cwq, |
| * if (caller is __create_workqueue) |
| * nobody should see this wq |
| * else // caller is CPU_UP_PREPARE |
| * cpu is not on cpu_online_map |
| * so we can abort safely. |
| */ |
| if (IS_ERR(p)) |
| return PTR_ERR(p); |
| |
| cwq->thread = p; |
| cwq->should_stop = 0; |
| |
| return 0; |
| } |
| |
| static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
| { |
| struct task_struct *p = cwq->thread; |
| |
| if (p != NULL) { |
| if (cpu >= 0) |
| kthread_bind(p, cpu); |
| wake_up_process(p); |
| } |
| } |
| |
| struct workqueue_struct *__create_workqueue(const char *name, |
| int singlethread, int freezeable) |
| { |
| struct workqueue_struct *wq; |
| struct cpu_workqueue_struct *cwq; |
| int err = 0, cpu; |
| |
| wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
| if (!wq) |
| return NULL; |
| |
| wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); |
| if (!wq->cpu_wq) { |
| kfree(wq); |
| return NULL; |
| } |
| |
| wq->name = name; |
| wq->singlethread = singlethread; |
| wq->freezeable = freezeable; |
| INIT_LIST_HEAD(&wq->list); |
| |
| if (singlethread) { |
| cwq = init_cpu_workqueue(wq, singlethread_cpu); |
| err = create_workqueue_thread(cwq, singlethread_cpu); |
| start_workqueue_thread(cwq, -1); |
| } else { |
| mutex_lock(&workqueue_mutex); |
| list_add(&wq->list, &workqueues); |
| |
| for_each_possible_cpu(cpu) { |
| cwq = init_cpu_workqueue(wq, cpu); |
| if (err || !cpu_online(cpu)) |
| continue; |
| err = create_workqueue_thread(cwq, cpu); |
| start_workqueue_thread(cwq, cpu); |
| } |
| mutex_unlock(&workqueue_mutex); |
| } |
| |
| if (err) { |
| destroy_workqueue(wq); |
| wq = NULL; |
| } |
| return wq; |
| } |
| EXPORT_SYMBOL_GPL(__create_workqueue); |
| |
| static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) |
| { |
| struct wq_barrier barr; |
| int alive = 0; |
| |
| spin_lock_irq(&cwq->lock); |
| if (cwq->thread != NULL) { |
| insert_wq_barrier(cwq, &barr, 1); |
| cwq->should_stop = 1; |
| alive = 1; |
| } |
| spin_unlock_irq(&cwq->lock); |
| |
| if (alive) { |
| wait_for_completion(&barr.done); |
| |
| while (unlikely(cwq->thread != NULL)) |
| cpu_relax(); |
| /* |
| * Wait until cwq->thread unlocks cwq->lock, |
| * it won't touch *cwq after that. |
| */ |
| smp_rmb(); |
| spin_unlock_wait(&cwq->lock); |
| } |
| } |
| |
| /** |
| * destroy_workqueue - safely terminate a workqueue |
| * @wq: target workqueue |
| * |
| * Safely destroy a workqueue. All work currently pending will be done first. |
| */ |
| void destroy_workqueue(struct workqueue_struct *wq) |
| { |
| const cpumask_t *cpu_map = wq_cpu_map(wq); |
| struct cpu_workqueue_struct *cwq; |
| int cpu; |
| |
| mutex_lock(&workqueue_mutex); |
| list_del(&wq->list); |
| mutex_unlock(&workqueue_mutex); |
| |
| for_each_cpu_mask(cpu, *cpu_map) { |
| cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
| cleanup_workqueue_thread(cwq, cpu); |
| } |
| |
| free_percpu(wq->cpu_wq); |
| kfree(wq); |
| } |
| EXPORT_SYMBOL_GPL(destroy_workqueue); |
| |
| static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, |
| unsigned long action, |
| void *hcpu) |
| { |
| unsigned int cpu = (unsigned long)hcpu; |
| struct cpu_workqueue_struct *cwq; |
| struct workqueue_struct *wq; |
| |
| switch (action) { |
| case CPU_LOCK_ACQUIRE: |
| mutex_lock(&workqueue_mutex); |
| return NOTIFY_OK; |
| |
| case CPU_LOCK_RELEASE: |
| mutex_unlock(&workqueue_mutex); |
| return NOTIFY_OK; |
| |
| case CPU_UP_PREPARE: |
| cpu_set(cpu, cpu_populated_map); |
| } |
| |
| list_for_each_entry(wq, &workqueues, list) { |
| cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
| |
| switch (action) { |
| case CPU_UP_PREPARE: |
| if (!create_workqueue_thread(cwq, cpu)) |
| break; |
| printk(KERN_ERR "workqueue for %i failed\n", cpu); |
| return NOTIFY_BAD; |
| |
| case CPU_ONLINE: |
| start_workqueue_thread(cwq, cpu); |
| break; |
| |
| case CPU_UP_CANCELED: |
| start_workqueue_thread(cwq, -1); |
| case CPU_DEAD: |
| cleanup_workqueue_thread(cwq, cpu); |
| break; |
| } |
| } |
| |
| return NOTIFY_OK; |
| } |
| |
| void __init init_workqueues(void) |
| { |
| cpu_populated_map = cpu_online_map; |
| singlethread_cpu = first_cpu(cpu_possible_map); |
| cpu_singlethread_map = cpumask_of_cpu(singlethread_cpu); |
| hotcpu_notifier(workqueue_cpu_callback, 0); |
| keventd_wq = create_workqueue("events"); |
| BUG_ON(!keventd_wq); |
| } |