/* * 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 *   Kai Petzke <wpp@marie.physik.tu-berlin.de> *   Theodore Ts'o <tytso@mit.edu> * * Made to use alloc_percpu by Christoph Lameter. */ #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>#include <linux/lockdep.h>#define CREATE_TRACE_POINTS#include <trace/events/workqueue.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;} ____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 */	int rt;#ifdef CONFIG_LOCKDEP	struct lockdep_map lockdep_map;#endif}; #ifdef CONFIG_DEBUG_OBJECTS_WORK static struct debug_obj_descr work_debug_descr; /* * fixup_init is called when: * - an active object is initialized */static int work_fixup_init(void *addr, enum debug_obj_state state){	struct work_struct *work = addr; 	switch (state) {	case ODEBUG_STATE_ACTIVE:		cancel_work_sync(work);		debug_object_init(work, &work_debug_descr);		return 1;	default:		return 0;	}} /* * fixup_activate is called when: * - an active object is activated * - an unknown object is activated (might be a statically initialized object) */static int work_fixup_activate(void *addr, enum debug_obj_state state){	struct work_struct *work = addr; 	switch (state) { 	case ODEBUG_STATE_NOTAVAILABLE:		/*		 * This is not really a fixup. The work struct was		 * statically initialized. We just make sure that it		 * is tracked in the object tracker.		 */		if (test_bit(WORK_STRUCT_STATIC, work_data_bits(work))) {			debug_object_init(work, &work_debug_descr);			debug_object_activate(work, &work_debug_descr);			return 0;		}		WARN_ON_ONCE(1);		return 0; 	case ODEBUG_STATE_ACTIVE:		WARN_ON(1); 	default:		return 0;	}} /* * fixup_free is called when: * - an active object is freed */static int work_fixup_free(void *addr, enum debug_obj_state state){	struct work_struct *work = addr; 	switch (state) {	case ODEBUG_STATE_ACTIVE:		cancel_work_sync(work);		debug_object_free(work, &work_debug_descr);		return 1;	default:		return 0;	}} static struct debug_obj_descr work_debug_descr = {	.name		= "work_struct",	.fixup_init	= work_fixup_init,	.fixup_activate	= work_fixup_activate,	.fixup_free	= work_fixup_free,}; static inline void debug_work_activate(struct work_struct *work){	debug_object_activate(work, &work_debug_descr);} static inline void debug_work_deactivate(struct work_struct *work){	debug_object_deactivate(work, &work_debug_descr);} void __init_work(struct work_struct *work, int onstack){	if (onstack)		debug_object_init_on_stack(work, &work_debug_descr);	else		debug_object_init(work, &work_debug_descr);}EXPORT_SYMBOL_GPL(__init_work); void destroy_work_on_stack(struct work_struct *work){	debug_object_free(work, &work_debug_descr);}EXPORT_SYMBOL_GPL(destroy_work_on_stack); #elsestatic inline void debug_work_activate(struct work_struct *work) { }static inline void debug_work_deactivate(struct work_struct *work) { }#endif /* Serializes the accesses to the list of workqueues. */static DEFINE_SPINLOCK(workqueue_lock);static LIST_HEAD(workqueues); static int singlethread_cpu __read_mostly;static const struct cpumask *cpu_singlethread_map __read_mostly;/* * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD * flushes cwq->worklist. This means that flush_workqueue/wait_on_work * which comes in between can't use for_each_online_cpu(). We could * use cpu_possible_map, the cpumask below is more a documentation * than optimization. */static cpumask_var_t cpu_populated_map __read_mostly; /* If it's single threaded, it isn't in the list of workqueues. */static inline int is_wq_single_threaded(struct workqueue_struct *wq){	return wq->singlethread;} static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq){	return is_wq_single_threaded(wq)		? cpu_singlethread_map : cpu_populated_map;} staticstruct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu){	if (unlikely(is_wq_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);} /* * Clear WORK_STRUCT_PENDING and the workqueue on which it was queued. */static inline void clear_wq_data(struct work_struct *work){	unsigned long flags = *work_data_bits(work) &				(1UL << WORK_STRUCT_STATIC);	atomic_long_set(&work->data, flags);} static inlinestruct 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, struct list_head *head){	trace_workqueue_insertion(cwq->thread, work); 	set_wq_data(work, cwq);	/*	 * Ensure that we get the right work->data if we see the	 * result of list_add() below, see try_to_grab_pending().	 */	smp_wmb();	list_add_tail(&work->entry, head);	wake_up(&cwq->more_work);} static void __queue_work(struct cpu_workqueue_struct *cwq,			 struct work_struct *work){	unsigned long flags; 	debug_work_activate(work);	spin_lock_irqsave(&cwq->lock, flags);	insert_work(cwq, work, &cwq->worklist);	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 on which it was submitted, but if the CPU dies * it can be processed by another CPU. */int queue_work(struct workqueue_struct *wq, struct work_struct *work){	int ret; 	ret = queue_work_on(get_cpu(), wq, work);	put_cpu(); 	return ret;}EXPORT_SYMBOL_GPL(queue_work); /** * queue_work_on - queue work on specific cpu * @cpu: CPU number to execute work on * @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 a specific CPU, the caller must ensure it * can't go away. */intqueue_work_on(int cpu, 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, cpu), work);		ret = 1;	}	return ret;}EXPORT_SYMBOL_GPL(queue_work_on); 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);	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 queue_delayed_work(struct workqueue_struct *wq,			struct delayed_work *dwork, unsigned long delay){	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)); 		timer_stats_timer_set_start_info(&dwork->timer); 		/* 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);	while (!list_empty(&cwq->worklist)) {		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		trace_workqueue_execution(cwq->thread, work);		debug_work_deactivate(work);		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);		lock_map_acquire(&cwq->wq->lockdep_map);		lock_map_acquire(&lockdep_map);		f(work);		lock_map_release(&lockdep_map);		lock_map_release(&cwq->wq->lockdep_map); 		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(),				       	task_pid_nr(current));			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;	}	spin_unlock_irq(&cwq->lock);} static int worker_thread(void *__cwq){	struct cpu_workqueue_struct *cwq = __cwq;	DEFINE_WAIT(wait); 	if (cwq->wq->freezeable)		set_freezable(); 	for (;;) {		prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE);		if (!freezing(current) &&		    !kthread_should_stop() &&		    list_empty(&cwq->worklist))			schedule();		finish_wait(&cwq->more_work, &wait); 		try_to_freeze(); 		if (kthread_should_stop())			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, struct list_head *head){	/*	 * debugobject calls are safe here even with cwq->lock locked	 * as we know for sure that this will not trigger any of the	 * checks and call back into the fixup functions where we	 * might deadlock.	 */	INIT_WORK_ON_STACK(&barr->work, wq_barrier_func);	__set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); 	init_completion(&barr->done); 	debug_work_activate(&barr->work);	insert_work(cwq, &barr->work, head);} static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq){	int active = 0;	struct wq_barrier barr; 	WARN_ON(cwq->thread == current); 	spin_lock_irq(&cwq->lock);	if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) {		insert_wq_barrier(cwq, &barr, &cwq->worklist);		active = 1;

Lines 1–500 of 1214. Load more