linux-master/kernel/kthread.c

16 #include <linux/kthread.h>
40 	/* Information passed to kthread() from kthreadd. */
53 struct kthread {
74 static inline struct kthread *to_kthread(struct task_struct *k)
81  * Variant of to_kthread() that doesn't assume @p is a kthread.
87  * the task is both a kthread and struct kthread is persistent. However
91 static inline struct kthread *__to_kthread(struct task_struct *p)
93 	void *kthread = p->worker_private;
94 	if (kthread && !(p->flags & PF_KTHREAD))
95 		kthread = NULL;
96 	return kthread;
101 	struct kthread *kthread = to_kthread(tsk);
103 	if (!kthread || !kthread->full_name) {
108 	strscpy_pad(buf, kthread->full_name, buf_size);
113 	struct kthread *kthread;
118 	kthread = kzalloc(sizeof(*kthread), GFP_KERNEL);
119 	if (!kthread)
122 	init_completion(&kthread->exited);
123 	init_completion(&kthread->parked);
124 	p->vfork_done = &kthread->exited;
126 	p->worker_private = kthread;
132 	struct kthread *kthread;
137 	kthread = to_kthread(k);
138 	if (!kthread)
142 	WARN_ON_ONCE(kthread->blkcg_css);
145 	kfree(kthread->full_name);
146 	kfree(kthread);
150  * kthread_should_stop - should this kthread return now?
152  * When someone calls kthread_stop() on your kthread, it will be woken
168  * kthread_should_park - should this kthread park now?
170  * When someone calls kthread_park() on your kthread, it will be woken
186 	struct kthread *kthread = __to_kthread(current);
188 	if (!kthread)
191 	return kthread->flags & (BIT(KTHREAD_SHOULD_STOP) | BIT(KTHREAD_SHOULD_PARK));
195  * kthread_freezable_should_stop - should this freezable kthread return now?
220  * kthread_func - return the function specified on kthread creation
221  * @task: kthread task in question
223  * Returns NULL if the task is not a kthread.
227 	struct kthread *kthread = __to_kthread(task);
228 	if (kthread)
229 		return kthread->threadfn;
235  * kthread_data - return data value specified on kthread creation
236  * @task: kthread task in question
238  * Return the data value specified when kthread @task was created.
250  * @task: possible kthread task in question
252  * @task could be a kthread task.  Return the data value specified when it
253  * was created if accessible.  If @task isn't a kthread task or its data is
259 	struct kthread *kthread = __to_kthread(task);
262 	if (kthread)
263 		copy_from_kernel_nofault(&data, &kthread->data, sizeof(data));
267 static void __kthread_parkme(struct kthread *self)
303  * kthread_exit - Cause the current kthread return @result to kthread_stop().
314 	struct kthread *kthread = to_kthread(current);
315 	kthread->result = result;
321  * kthread_complete_and_exit - Exit the current kthread.
341 static int kthread(void *_create)
344 	/* Copy data: it's on kthread's stack */
349 	struct kthread *self;
412 	pid = kernel_thread(kthread, create, create->full_name,
482  * kthread_create_on_node - create a kthread.
494  * in @node, to get NUMA affinity for kthread stack, or else give NUMA_NO_NODE.
547  * kthread_bind - bind a just-created kthread to a cpu.
562  * kthread_create_on_cpu - Create a cpu bound kthread
590 	struct kthread *kthread = to_kthread(k);
591 	if (!kthread)
597 		clear_bit(KTHREAD_IS_PER_CPU, &kthread->flags);
601 	kthread->cpu = cpu;
602 	set_bit(KTHREAD_IS_PER_CPU, &kthread->flags);
607 	struct kthread *kthread = __to_kthread(p);
608 	if (!kthread)
611 	return test_bit(KTHREAD_IS_PER_CPU, &kthread->flags);
624 	struct kthread *kthread = to_kthread(k);
627 	 * Newly created kthread was parked when the CPU was offline.
630 	if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags))
631 		__kthread_bind(k, kthread->cpu, TASK_PARKED);
633 	clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
651  * If called by the kthread itself just the park bit is set.
655 	struct kthread *kthread = to_kthread(k);
660 	if (WARN_ON_ONCE(test_bit(KTHREAD_SHOULD_PARK, &kthread->flags)))
663 	set_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
670 		wait_for_completion(&kthread->parked);
699 	struct kthread *kthread;
705 	kthread = to_kthread(k);
706 	set_bit(KTHREAD_SHOULD_STOP, &kthread->flags);
710 	wait_for_completion(&kthread->exited);
711 	ret = kthread->result;
788  * kthread_worker_fn - kthread function to process kthread_worker
791  * This function implements the main cycle of kthread worker. It processes
808 	 * FIXME: Update the check and remove the assignment when all kthread
893  * kthread_create_worker - create a kthread worker
895  * @namefmt: printf-style name for the kthread worker (task).
916  * kthread_create_worker_on_cpu - create a kthread worker and bind it
920  * @namefmt: printf-style name for the kthread worker (task).
922  * Use a valid CPU number if you want to bind the kthread worker
929  * The kthread worker API is simple and generic. It just provides a way
1031  * kthread_delayed_work_timer_fn - callback that queues the associated kthread
1096  * kthread_queue_delayed_work - queue the associated kthread work
1235  * kthread_mod_delayed_work - modify delay of or queue a kthread delayed work
1236  * @worker: kthread worker to use
1237  * @dwork: kthread delayed work to queue
1342  * kthread_cancel_work_sync - cancel a kthread work and wait for it to finish
1343  * @work: the kthread work to cancel
1364  * kthread_cancel_delayed_work_sync - cancel a kthread delayed work and
1366  * @dwork: the kthread delayed work to cancel
1398  * kthread_destroy_worker - destroy a kthread worker
1401  * Flush and destroy @worker.  The simple flush is enough because the kthread
1426  * kthread_use_mm - make the calling kthread operate on an address space
1459 	 * When a kthread starts operating on an address space, the loop
1484 	 * When a kthread stops operating on an address space, the loop
1506  * kthread_associate_blkcg - associate blkcg to current kthread
1509  * Current thread must be a kthread. The thread is running jobs on behalf of
1512  * original thread's cgroup info in current kthread context for later
1517 	struct kthread *kthread;
1521 	kthread = to_kthread(current);
1522 	if (!kthread)
1525 	if (kthread->blkcg_css) {
1526 		css_put(kthread->blkcg_css);
1527 		kthread->blkcg_css = NULL;
1531 		kthread->blkcg_css = css;
1537  * kthread_blkcg - get associated blkcg css of current kthread
1539  * Current thread must be a kthread.
1543 	struct kthread *kthread;
1546 		kthread = to_kthread(current);
1547 		if (kthread)
1548 			return kthread->blkcg_css;