X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fworkqueue.c;h=ff06611655af71e82f915b3790b81aaa0193e61a;hb=320787c75ccac3189a1b7aae81f0efc1055f6d3a;hp=3bebf73be976592cab56a218e93b7449a5de7df4;hpb=7dfb1716d717e41c07410bab52760d865caee12b;p=linux-2.6 diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 3bebf73be9..ff06611655 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -32,6 +32,7 @@ #include #include #include +#include /* * The per-CPU workqueue (if single thread, we always use the first @@ -61,11 +62,13 @@ struct workqueue_struct { const char *name; int singlethread; int freezeable; /* Freeze threads during suspend */ +#ifdef CONFIG_LOCKDEP + struct lockdep_map lockdep_map; +#endif }; -/* 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); +/* Serializes the accesses to the list of workqueues. */ +static DEFINE_SPINLOCK(workqueue_lock); static LIST_HEAD(workqueues); static int singlethread_cpu __read_mostly; @@ -158,7 +161,7 @@ static void __queue_work(struct cpu_workqueue_struct *cwq, * 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 queue_work(struct workqueue_struct *wq, struct work_struct *work) { int ret = 0; @@ -172,7 +175,7 @@ int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) } EXPORT_SYMBOL_GPL(queue_work); -void delayed_work_timer_fn(unsigned long __data) +static 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); @@ -189,7 +192,7 @@ void delayed_work_timer_fn(unsigned long __data) * * Returns 0 if @work was already on a queue, non-zero otherwise. */ -int fastcall queue_delayed_work(struct workqueue_struct *wq, +int queue_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, unsigned long delay) { timer_stats_timer_set_start_info(&dwork->timer); @@ -250,6 +253,17 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq) struct work_struct *work = list_entry(cwq->worklist.next, struct work_struct, entry); work_func_t f = work->func; +#ifdef CONFIG_LOCKDEP + /* + * It is permissible to free the struct work_struct + * from inside the function that is called from it, + * this we need to take into account for lockdep too. + * To avoid bogus "held lock freed" warnings as well + * as problems when looking into work->lockdep_map, + * make a copy and use that here. + */ + struct lockdep_map lockdep_map = work->lockdep_map; +#endif cwq->current_work = work; list_del_init(cwq->worklist.next); @@ -257,13 +271,17 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq) BUG_ON(get_wq_data(work) != cwq); work_clear_pending(work); + lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); + lock_acquire(&lockdep_map, 0, 0, 0, 2, _THIS_IP_); f(work); + lock_release(&lockdep_map, 1, _THIS_IP_); + lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_); 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); + task_pid_nr(current)); printk(KERN_ERR " last function: "); print_symbol("%s\n", (unsigned long)f); debug_show_held_locks(current); @@ -282,8 +300,8 @@ static int worker_thread(void *__cwq) struct cpu_workqueue_struct *cwq = __cwq; DEFINE_WAIT(wait); - if (!cwq->wq->freezeable) - current->flags |= PF_NOFREEZE; + if (cwq->wq->freezeable) + set_freezable(); set_user_nice(current, -5); @@ -370,28 +388,30 @@ static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) * 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) +void flush_workqueue(struct workqueue_struct *wq) { const cpumask_t *cpu_map = wq_cpu_map(wq); int cpu; might_sleep(); + lock_acquire(&wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); + lock_release(&wq->lockdep_map, 1, _THIS_IP_); for_each_cpu_mask(cpu, *cpu_map) flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); } EXPORT_SYMBOL_GPL(flush_workqueue); /* - * Upon a successful return, the caller "owns" WORK_STRUCT_PENDING bit, + * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, * so this work can't be re-armed in any way. */ static int try_to_grab_pending(struct work_struct *work) { struct cpu_workqueue_struct *cwq; - int ret = 0; + int ret = -1; if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) - return 1; + return 0; /* * The queueing is in progress, or it is already queued. Try to @@ -446,6 +466,9 @@ static void wait_on_work(struct work_struct *work) might_sleep(); + lock_acquire(&work->lockdep_map, 0, 0, 0, 2, _THIS_IP_); + lock_release(&work->lockdep_map, 1, _THIS_IP_); + cwq = get_wq_data(work); if (!cwq) return; @@ -457,10 +480,28 @@ static void wait_on_work(struct work_struct *work) wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work); } +static int __cancel_work_timer(struct work_struct *work, + struct timer_list* timer) +{ + int ret; + + do { + ret = (timer && likely(del_timer(timer))); + if (!ret) + ret = try_to_grab_pending(work); + wait_on_work(work); + } while (unlikely(ret < 0)); + + work_clear_pending(work); + return ret; +} + /** * cancel_work_sync - block until a work_struct's callback has terminated * @work: the work which is to be flushed * + * Returns true if @work was pending. + * * cancel_work_sync() will 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. @@ -476,31 +517,26 @@ static void wait_on_work(struct work_struct *work) * The caller must ensure that workqueue_struct on which this work was last * queued can't be destroyed before this function returns. */ -void cancel_work_sync(struct work_struct *work) +int cancel_work_sync(struct work_struct *work) { - while (!try_to_grab_pending(work)) - cpu_relax(); - wait_on_work(work); - work_clear_pending(work); + return __cancel_work_timer(work, NULL); } EXPORT_SYMBOL_GPL(cancel_work_sync); /** - * cancel_rearming_delayed_work - reliably kill off a delayed work. + * cancel_delayed_work_sync - reliably kill off a delayed work. * @dwork: the delayed work struct * + * Returns true if @dwork was pending. + * * It is possible to use this function if @dwork rearms itself via queue_work() * or queue_delayed_work(). See also the comment for cancel_work_sync(). */ -void cancel_rearming_delayed_work(struct delayed_work *dwork) +int cancel_delayed_work_sync(struct delayed_work *dwork) { - while (!del_timer(&dwork->timer) && - !try_to_grab_pending(&dwork->work)) - cpu_relax(); - wait_on_work(&dwork->work); - work_clear_pending(&dwork->work); + return __cancel_work_timer(&dwork->work, &dwork->timer); } -EXPORT_SYMBOL(cancel_rearming_delayed_work); +EXPORT_SYMBOL(cancel_delayed_work_sync); static struct workqueue_struct *keventd_wq __read_mostly; @@ -510,7 +546,7 @@ static struct workqueue_struct *keventd_wq __read_mostly; * * This puts a job in the kernel-global workqueue. */ -int fastcall schedule_work(struct work_struct *work) +int schedule_work(struct work_struct *work) { return queue_work(keventd_wq, work); } @@ -524,7 +560,7 @@ EXPORT_SYMBOL(schedule_work); * After waiting for a given time this puts a job in the kernel-global * workqueue. */ -int fastcall schedule_delayed_work(struct delayed_work *dwork, +int schedule_delayed_work(struct delayed_work *dwork, unsigned long delay) { timer_stats_timer_set_start_info(&dwork->timer); @@ -555,8 +591,6 @@ EXPORT_SYMBOL(schedule_delayed_work_on); * 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) @@ -568,7 +602,7 @@ int schedule_on_each_cpu(work_func_t func) if (!works) return -ENOMEM; - preempt_disable(); /* CPU hotplug */ + get_online_cpus(); for_each_online_cpu(cpu) { struct work_struct *work = per_cpu_ptr(works, cpu); @@ -576,8 +610,8 @@ int schedule_on_each_cpu(work_func_t 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); + put_online_cpus(); free_percpu(works); return 0; } @@ -622,7 +656,7 @@ int keventd_up(void) int current_is_keventd(void) { struct cpu_workqueue_struct *cwq; - int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ + int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ int ret = 0; BUG_ON(!keventd_wq); @@ -682,8 +716,11 @@ static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) } } -struct workqueue_struct *__create_workqueue(const char *name, - int singlethread, int freezeable) +struct workqueue_struct *__create_workqueue_key(const char *name, + int singlethread, + int freezeable, + struct lock_class_key *key, + const char *lock_name) { struct workqueue_struct *wq; struct cpu_workqueue_struct *cwq; @@ -700,6 +737,7 @@ struct workqueue_struct *__create_workqueue(const char *name, } wq->name = name; + lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); wq->singlethread = singlethread; wq->freezeable = freezeable; INIT_LIST_HEAD(&wq->list); @@ -709,8 +747,10 @@ struct workqueue_struct *__create_workqueue(const char *name, err = create_workqueue_thread(cwq, singlethread_cpu); start_workqueue_thread(cwq, -1); } else { - mutex_lock(&workqueue_mutex); + get_online_cpus(); + spin_lock(&workqueue_lock); list_add(&wq->list, &workqueues); + spin_unlock(&workqueue_lock); for_each_possible_cpu(cpu) { cwq = init_cpu_workqueue(wq, cpu); @@ -719,7 +759,7 @@ struct workqueue_struct *__create_workqueue(const char *name, err = create_workqueue_thread(cwq, cpu); start_workqueue_thread(cwq, cpu); } - mutex_unlock(&workqueue_mutex); + put_online_cpus(); } if (err) { @@ -728,29 +768,31 @@ struct workqueue_struct *__create_workqueue(const char *name, } return wq; } -EXPORT_SYMBOL_GPL(__create_workqueue); +EXPORT_SYMBOL_GPL(__create_workqueue_key); static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) { /* * Our caller is either destroy_workqueue() or CPU_DEAD, - * workqueue_mutex protects cwq->thread + * get_online_cpus() protects cwq->thread. */ if (cwq->thread == NULL) return; + lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); + lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_); + + flush_cpu_workqueue(cwq); /* - * If the caller is CPU_DEAD the single flush_cpu_workqueue() - * is not enough, a concurrent flush_workqueue() can insert a - * barrier after us. + * If the caller is CPU_DEAD and cwq->worklist was not empty, + * a concurrent flush_workqueue() can insert a barrier after us. + * However, in that case run_workqueue() won't return and check + * kthread_should_stop() until it flushes all work_struct's. * When ->worklist becomes empty it is safe to exit because no * more work_structs can be queued on this cwq: flush_workqueue * checks list_empty(), and a "normal" queue_work() can't use * a dead CPU. */ - while (flush_cpu_workqueue(cwq)) - ; - kthread_stop(cwq->thread); cwq->thread = NULL; } @@ -767,9 +809,11 @@ void destroy_workqueue(struct workqueue_struct *wq) struct cpu_workqueue_struct *cwq; int cpu; - mutex_lock(&workqueue_mutex); + get_online_cpus(); + spin_lock(&workqueue_lock); list_del(&wq->list); - mutex_unlock(&workqueue_mutex); + spin_unlock(&workqueue_lock); + put_online_cpus(); for_each_cpu_mask(cpu, *cpu_map) { cwq = per_cpu_ptr(wq->cpu_wq, cpu); @@ -792,13 +836,6 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, action &= ~CPU_TASKS_FROZEN; 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); @@ -811,7 +848,8 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, case CPU_UP_PREPARE: if (!create_workqueue_thread(cwq, cpu)) break; - printk(KERN_ERR "workqueue for %i failed\n", cpu); + printk(KERN_ERR "workqueue [%s] for %i failed\n", + wq->name, cpu); return NOTIFY_BAD; case CPU_ONLINE: