307  * functions which do some additional work in non-modular code such as
795  * when they finish. There is defined a safe point for freezing when one work
804 	struct kthread_work *work;  in kthread_worker_fn()  local
827 	work = NULL;  in kthread_worker_fn()
830 		work = list_first_entry(&worker->work_list,  in kthread_worker_fn()
832 		list_del_init(&work->node);  in kthread_worker_fn()
834 	worker->current_work = work;  in kthread_worker_fn()
837 	if (work) {  in kthread_worker_fn()
838 		kthread_work_func_t func = work->func;  in kthread_worker_fn()
840 		trace_sched_kthread_work_execute_start(work);  in kthread_worker_fn()
841 		work->func(work);  in kthread_worker_fn()
843 		 * Avoid dereferencing work after this point.  The trace  in kthread_worker_fn()
846 		trace_sched_kthread_work_execute_end(work, func);  in kthread_worker_fn()
932  * how to handle pending work items, prevent queuing new ones, and
965  * Returns true when the work could not be queued at the moment.
970 				   struct kthread_work *work)  in queuing_blocked()  argument
974 	return !list_empty(&work->node) || work->canceling;  in queuing_blocked()
978 					     struct kthread_work *work)  in kthread_insert_work_sanity_check()  argument
981 	WARN_ON_ONCE(!list_empty(&work->node));  in kthread_insert_work_sanity_check()
982 	/* Do not use a work with >1 worker, see kthread_queue_work() */  in kthread_insert_work_sanity_check()
983 	WARN_ON_ONCE(work->worker && work->worker != worker);  in kthread_insert_work_sanity_check()
986 /* insert @work before @pos in @worker */
988 				struct kthread_work *work,  in kthread_insert_work()  argument
991 	kthread_insert_work_sanity_check(worker, work);  in kthread_insert_work()
993 	trace_sched_kthread_work_queue_work(worker, work);  in kthread_insert_work()
995 	list_add_tail(&work->node, pos);  in kthread_insert_work()
996 	work->worker = worker;  in kthread_insert_work()
1004  * @work: kthread_work to queue
1006  * Queue @work to work processor @task for async execution.  @task
1008  * if @work was successfully queued, %false if it was already pending.
1010  * Reinitialize the work if it needs to be used by another worker.
1014 			struct kthread_work *work)  in kthread_queue_work()  argument
1020 	if (!queuing_blocked(worker, work)) {  in kthread_queue_work()
1021 		kthread_insert_work(worker, work, &worker->work_list);  in kthread_queue_work()
1031  *	delayed work when the timer expires.
1040 	struct kthread_work *work = &dwork->work;  in kthread_delayed_work_timer_fn()  local
1041 	struct kthread_worker *worker = work->worker;  in kthread_delayed_work_timer_fn()
1045 	 * This might happen when a pending work is reinitialized.  in kthread_delayed_work_timer_fn()
1052 	/* Work must not be used with >1 worker, see kthread_queue_work(). */  in kthread_delayed_work_timer_fn()
1053 	WARN_ON_ONCE(work->worker != worker);  in kthread_delayed_work_timer_fn()
1055 	/* Move the work from worker->delayed_work_list. */  in kthread_delayed_work_timer_fn()
1056 	WARN_ON_ONCE(list_empty(&work->node));  in kthread_delayed_work_timer_fn()
1057 	list_del_init(&work->node);  in kthread_delayed_work_timer_fn()
1058 	if (!work->canceling)  in kthread_delayed_work_timer_fn()
1059 		kthread_insert_work(worker, work, &worker->work_list);  in kthread_delayed_work_timer_fn()
1070 	struct kthread_work *work = &dwork->work;  in __kthread_queue_delayed_work()  local
1075 	 * If @delay is 0, queue @dwork->work immediately.  This is for  in __kthread_queue_delayed_work()
1081 		kthread_insert_work(worker, work, &worker->work_list);  in __kthread_queue_delayed_work()
1086 	kthread_insert_work_sanity_check(worker, work);  in __kthread_queue_delayed_work()
1088 	list_add(&work->node, &worker->delayed_work_list);  in __kthread_queue_delayed_work()
1089 	work->worker = worker;  in __kthread_queue_delayed_work()
1095  * kthread_queue_delayed_work - queue the associated kthread work
1101  * If the work has not been pending it starts a timer that will queue
1102  * the work after the given @delay. If @delay is zero, it queues the
1103  * work immediately.
1105  * Return: %false if the @work has already been pending. It means that
1106  * either the timer was running or the work was queued. It returns %true
1113 	struct kthread_work *work = &dwork->work;  in kthread_queue_delayed_work()  local
1119 	if (!queuing_blocked(worker, work)) {  in kthread_queue_delayed_work()
1130 	struct kthread_work	work;  member
1134 static void kthread_flush_work_fn(struct kthread_work *work)  in kthread_flush_work_fn()  argument
1137 		container_of(work, struct kthread_flush_work, work);  in kthread_flush_work_fn()
1143  * @work: work to flush
1145  * If @work is queued or executing, wait for it to finish execution.
1147 void kthread_flush_work(struct kthread_work *work)  in kthread_flush_work()  argument
1150 		KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),  in kthread_flush_work()
1156 	worker = work->worker;  in kthread_flush_work()
1161 	/* Work must not be used with >1 worker, see kthread_queue_work(). */  in kthread_flush_work()
1162 	WARN_ON_ONCE(work->worker != worker);  in kthread_flush_work()
1164 	if (!list_empty(&work->node))  in kthread_flush_work()
1165 		kthread_insert_work(worker, &fwork.work, work->node.next);  in kthread_flush_work()
1166 	else if (worker->current_work == work)  in kthread_flush_work()
1167 		kthread_insert_work(worker, &fwork.work,  in kthread_flush_work()
1181  * not manipulate the work list_head any longer.
1186 static void kthread_cancel_delayed_work_timer(struct kthread_work *work,  in kthread_cancel_delayed_work_timer()  argument
1190 		container_of(work, struct kthread_delayed_work, work);  in kthread_cancel_delayed_work_timer()
1191 	struct kthread_worker *worker = work->worker;  in kthread_cancel_delayed_work_timer()
1199 	work->canceling++;  in kthread_cancel_delayed_work_timer()
1203 	work->canceling--;  in kthread_cancel_delayed_work_timer()
1207  * This function removes the work from the worker queue.
1210  * the timer used by delayed work is not running, e.g. by calling
1213  * The work might still be in use when this function finishes. See the
1216  * Return: %true if @work was pending and successfully canceled,
1217  *	%false if @work was not pending
1219 static bool __kthread_cancel_work(struct kthread_work *work)  in __kthread_cancel_work()  argument
1222 	 * Try to remove the work from a worker list. It might either  in __kthread_cancel_work()
1225 	if (!list_empty(&work->node)) {  in __kthread_cancel_work()
1226 		list_del_init(&work->node);  in __kthread_cancel_work()
1234  * kthread_mod_delayed_work - modify delay of or queue a kthread delayed work
1236  * @dwork: kthread delayed work to queue
1241  * @work is guaranteed to be queued immediately.
1245  * A special case is when the work is being canceled in parallel.
1260 	struct kthread_work *work = &dwork->work;  in kthread_mod_delayed_work()  local
1267 	if (!work->worker) {  in kthread_mod_delayed_work()
1272 	/* Work must not be used with >1 worker, see kthread_queue_work() */  in kthread_mod_delayed_work()
1273 	WARN_ON_ONCE(work->worker != worker);  in kthread_mod_delayed_work()
1276 	 * Temporary cancel the work but do not fight with another command  in kthread_mod_delayed_work()
1277 	 * that is canceling the work as well.  in kthread_mod_delayed_work()
1283 	 * when doing so. But the work can be removed from the queue (list)  in kthread_mod_delayed_work()
1287 	kthread_cancel_delayed_work_timer(work, &flags);  in kthread_mod_delayed_work()
1288 	if (work->canceling) {  in kthread_mod_delayed_work()
1293 	ret = __kthread_cancel_work(work);  in kthread_mod_delayed_work()
1303 static bool __kthread_cancel_work_sync(struct kthread_work *work, bool is_dwork)  in __kthread_cancel_work_sync()  argument
1305 	struct kthread_worker *worker = work->worker;  in __kthread_cancel_work_sync()
1313 	/* Work must not be used with >1 worker, see kthread_queue_work(). */  in __kthread_cancel_work_sync()
1314 	WARN_ON_ONCE(work->worker != worker);  in __kthread_cancel_work_sync()
1317 		kthread_cancel_delayed_work_timer(work, &flags);  in __kthread_cancel_work_sync()
1319 	ret = __kthread_cancel_work(work);  in __kthread_cancel_work_sync()
1321 	if (worker->current_work != work)  in __kthread_cancel_work_sync()
1325 	 * The work is in progress and we need to wait with the lock released.  in __kthread_cancel_work_sync()
1328 	work->canceling++;  in __kthread_cancel_work_sync()
1330 	kthread_flush_work(work);  in __kthread_cancel_work_sync()
1332 	work->canceling--;  in __kthread_cancel_work_sync()
1341  * kthread_cancel_work_sync - cancel a kthread work and wait for it to finish
1342  * @work: the kthread work to cancel
1344  * Cancel @work and wait for its execution to finish.  This function
1345  * can be used even if the work re-queues itself. On return from this
1346  * function, @work is guaranteed to be not pending or executing on any CPU.
1348  * kthread_cancel_work_sync(&delayed_work->work) must not be used for
1351  * The caller must ensure that the worker on which @work was last
1354  * Return: %true if @work was pending, %false otherwise.
1356 bool kthread_cancel_work_sync(struct kthread_work *work)  in kthread_cancel_work_sync()  argument
1358 	return __kthread_cancel_work_sync(work, false);  in kthread_cancel_work_sync()
1363  * kthread_cancel_delayed_work_sync - cancel a kthread delayed work and
1365  * @dwork: the kthread delayed work to cancel
1373 	return __kthread_cancel_work_sync(&dwork->work, true);  in kthread_cancel_delayed_work_sync()
1387 		KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),  in kthread_flush_worker()
1391 	kthread_queue_work(worker, &fwork.work);  in kthread_flush_worker()
1404  * Note that this function is not responsible for handling delayed work, so
1405  * caller should be responsible for queuing or canceling all delayed work items