297  * functions which do some additional work in non-modular code such as
777  * when they finish. There is defined a safe point for freezing when one work
786 	struct kthread_work *work;  in kthread_worker_fn()  local
809 	work = NULL;  in kthread_worker_fn()
812 		work = list_first_entry(&worker->work_list,  in kthread_worker_fn()
814 		list_del_init(&work->node);  in kthread_worker_fn()
816 	worker->current_work = work;  in kthread_worker_fn()
819 	if (work) {  in kthread_worker_fn()
820 		kthread_work_func_t func = work->func;  in kthread_worker_fn()
822 		trace_sched_kthread_work_execute_start(work);  in kthread_worker_fn()
823 		work->func(work);  in kthread_worker_fn()
825 		 * Avoid dereferencing work after this point.  The trace  in kthread_worker_fn()
828 		trace_sched_kthread_work_execute_end(work, func);  in kthread_worker_fn()
914  * how to handle pending work items, prevent queuing new ones, and
947  * Returns true when the work could not be queued at the moment.
952 				   struct kthread_work *work)  in queuing_blocked()  argument
956 	return !list_empty(&work->node) || work->canceling;  in queuing_blocked()
960 					     struct kthread_work *work)  in kthread_insert_work_sanity_check()  argument
963 	WARN_ON_ONCE(!list_empty(&work->node));  in kthread_insert_work_sanity_check()
964 	/* Do not use a work with >1 worker, see kthread_queue_work() */  in kthread_insert_work_sanity_check()
965 	WARN_ON_ONCE(work->worker && work->worker != worker);  in kthread_insert_work_sanity_check()
968 /* insert @work before @pos in @worker */
970 				struct kthread_work *work,  in kthread_insert_work()  argument
973 	kthread_insert_work_sanity_check(worker, work);  in kthread_insert_work()
975 	trace_sched_kthread_work_queue_work(worker, work);  in kthread_insert_work()
977 	list_add_tail(&work->node, pos);  in kthread_insert_work()
978 	work->worker = worker;  in kthread_insert_work()
986  * @work: kthread_work to queue
988  * Queue @work to work processor @task for async execution.  @task
990  * if @work was successfully queued, %false if it was already pending.
992  * Reinitialize the work if it needs to be used by another worker.
996 			struct kthread_work *work)  in kthread_queue_work()  argument
1002 	if (!queuing_blocked(worker, work)) {  in kthread_queue_work()
1003 		kthread_insert_work(worker, work, &worker->work_list);  in kthread_queue_work()
1013  *	delayed work when the timer expires.
1022 	struct kthread_work *work = &dwork->work;  in kthread_delayed_work_timer_fn()  local
1023 	struct kthread_worker *worker = work->worker;  in kthread_delayed_work_timer_fn()
1027 	 * This might happen when a pending work is reinitialized.  in kthread_delayed_work_timer_fn()
1034 	/* Work must not be used with >1 worker, see kthread_queue_work(). */  in kthread_delayed_work_timer_fn()
1035 	WARN_ON_ONCE(work->worker != worker);  in kthread_delayed_work_timer_fn()
1037 	/* Move the work from worker->delayed_work_list. */  in kthread_delayed_work_timer_fn()
1038 	WARN_ON_ONCE(list_empty(&work->node));  in kthread_delayed_work_timer_fn()
1039 	list_del_init(&work->node);  in kthread_delayed_work_timer_fn()
1040 	if (!work->canceling)  in kthread_delayed_work_timer_fn()
1041 		kthread_insert_work(worker, work, &worker->work_list);  in kthread_delayed_work_timer_fn()
1052 	struct kthread_work *work = &dwork->work;  in __kthread_queue_delayed_work()  local
1057 	 * If @delay is 0, queue @dwork->work immediately.  This is for  in __kthread_queue_delayed_work()
1063 		kthread_insert_work(worker, work, &worker->work_list);  in __kthread_queue_delayed_work()
1068 	kthread_insert_work_sanity_check(worker, work);  in __kthread_queue_delayed_work()
1070 	list_add(&work->node, &worker->delayed_work_list);  in __kthread_queue_delayed_work()
1071 	work->worker = worker;  in __kthread_queue_delayed_work()
1077  * kthread_queue_delayed_work - queue the associated kthread work
1083  * If the work has not been pending it starts a timer that will queue
1084  * the work after the given @delay. If @delay is zero, it queues the
1085  * work immediately.
1087  * Return: %false if the @work has already been pending. It means that
1088  * either the timer was running or the work was queued. It returns %true
1095 	struct kthread_work *work = &dwork->work;  in kthread_queue_delayed_work()  local
1101 	if (!queuing_blocked(worker, work)) {  in kthread_queue_delayed_work()
1112 	struct kthread_work	work;  member
1116 static void kthread_flush_work_fn(struct kthread_work *work)  in kthread_flush_work_fn()  argument
1119 		container_of(work, struct kthread_flush_work, work);  in kthread_flush_work_fn()
1125  * @work: work to flush
1127  * If @work is queued or executing, wait for it to finish execution.
1129 void kthread_flush_work(struct kthread_work *work)  in kthread_flush_work()  argument
1132 		KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),  in kthread_flush_work()
1138 	worker = work->worker;  in kthread_flush_work()
1143 	/* Work must not be used with >1 worker, see kthread_queue_work(). */  in kthread_flush_work()
1144 	WARN_ON_ONCE(work->worker != worker);  in kthread_flush_work()
1146 	if (!list_empty(&work->node))  in kthread_flush_work()
1147 		kthread_insert_work(worker, &fwork.work, work->node.next);  in kthread_flush_work()
1148 	else if (worker->current_work == work)  in kthread_flush_work()
1149 		kthread_insert_work(worker, &fwork.work,  in kthread_flush_work()
1163  * not manipulate the work list_head any longer.
1168 static void kthread_cancel_delayed_work_timer(struct kthread_work *work,  in kthread_cancel_delayed_work_timer()  argument
1172 		container_of(work, struct kthread_delayed_work, work);  in kthread_cancel_delayed_work_timer()
1173 	struct kthread_worker *worker = work->worker;  in kthread_cancel_delayed_work_timer()
1181 	work->canceling++;  in kthread_cancel_delayed_work_timer()
1185 	work->canceling--;  in kthread_cancel_delayed_work_timer()
1189  * This function removes the work from the worker queue.
1192  * the timer used by delayed work is not running, e.g. by calling
1195  * The work might still be in use when this function finishes. See the
1198  * Return: %true if @work was pending and successfully canceled,
1199  *	%false if @work was not pending
1201 static bool __kthread_cancel_work(struct kthread_work *work)  in __kthread_cancel_work()  argument
1204 	 * Try to remove the work from a worker list. It might either  in __kthread_cancel_work()
1207 	if (!list_empty(&work->node)) {  in __kthread_cancel_work()
1208 		list_del_init(&work->node);  in __kthread_cancel_work()
1216  * kthread_mod_delayed_work - modify delay of or queue a kthread delayed work
1218  * @dwork: kthread delayed work to queue
1223  * @work is guaranteed to be queued immediately.
1227  * A special case is when the work is being canceled in parallel.
1242 	struct kthread_work *work = &dwork->work;  in kthread_mod_delayed_work()  local
1249 	if (!work->worker) {  in kthread_mod_delayed_work()
1254 	/* Work must not be used with >1 worker, see kthread_queue_work() */  in kthread_mod_delayed_work()
1255 	WARN_ON_ONCE(work->worker != worker);  in kthread_mod_delayed_work()
1258 	 * Temporary cancel the work but do not fight with another command  in kthread_mod_delayed_work()
1259 	 * that is canceling the work as well.  in kthread_mod_delayed_work()
1265 	 * when doing so. But the work can be removed from the queue (list)  in kthread_mod_delayed_work()
1269 	kthread_cancel_delayed_work_timer(work, &flags);  in kthread_mod_delayed_work()
1270 	if (work->canceling) {  in kthread_mod_delayed_work()
1275 	ret = __kthread_cancel_work(work);  in kthread_mod_delayed_work()
1285 static bool __kthread_cancel_work_sync(struct kthread_work *work, bool is_dwork)  in __kthread_cancel_work_sync()  argument
1287 	struct kthread_worker *worker = work->worker;  in __kthread_cancel_work_sync()
1295 	/* Work must not be used with >1 worker, see kthread_queue_work(). */  in __kthread_cancel_work_sync()
1296 	WARN_ON_ONCE(work->worker != worker);  in __kthread_cancel_work_sync()
1299 		kthread_cancel_delayed_work_timer(work, &flags);  in __kthread_cancel_work_sync()
1301 	ret = __kthread_cancel_work(work);  in __kthread_cancel_work_sync()
1303 	if (worker->current_work != work)  in __kthread_cancel_work_sync()
1307 	 * The work is in progress and we need to wait with the lock released.  in __kthread_cancel_work_sync()
1310 	work->canceling++;  in __kthread_cancel_work_sync()
1312 	kthread_flush_work(work);  in __kthread_cancel_work_sync()
1314 	work->canceling--;  in __kthread_cancel_work_sync()
1323  * kthread_cancel_work_sync - cancel a kthread work and wait for it to finish
1324  * @work: the kthread work to cancel
1326  * Cancel @work and wait for its execution to finish.  This function
1327  * can be used even if the work re-queues itself. On return from this
1328  * function, @work is guaranteed to be not pending or executing on any CPU.
1330  * kthread_cancel_work_sync(&delayed_work->work) must not be used for
1333  * The caller must ensure that the worker on which @work was last
1336  * Return: %true if @work was pending, %false otherwise.
1338 bool kthread_cancel_work_sync(struct kthread_work *work)  in kthread_cancel_work_sync()  argument
1340 	return __kthread_cancel_work_sync(work, false);  in kthread_cancel_work_sync()
1345  * kthread_cancel_delayed_work_sync - cancel a kthread delayed work and
1347  * @dwork: the kthread delayed work to cancel
1355 	return __kthread_cancel_work_sync(&dwork->work, true);  in kthread_cancel_delayed_work_sync()
1369 		KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),  in kthread_flush_worker()
1373 	kthread_queue_work(worker, &fwork.work);  in kthread_flush_worker()