1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_KTHREAD_H
3#define _LINUX_KTHREAD_H
4/* Simple interface for creating and stopping kernel threads without mess. */
5#include <linux/err.h>
6#include <linux/sched.h>
7
8struct mm_struct;
9
10__printf(4, 5)
11struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
12					   void *data,
13					   int node,
14					   const char namefmt[], ...);
15
16/**
17 * kthread_create - create a kthread on the current node
18 * @threadfn: the function to run in the thread
19 * @data: data pointer for @threadfn()
20 * @namefmt: printf-style format string for the thread name
21 * @arg: arguments for @namefmt.
22 *
23 * This macro will create a kthread on the current node, leaving it in
24 * the stopped state.  This is just a helper for kthread_create_on_node();
25 * see the documentation there for more details.
26 */
27#define kthread_create(threadfn, data, namefmt, arg...) \
28	kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)
29
30
31struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
32					  void *data,
33					  unsigned int cpu,
34					  const char *namefmt);
35
36void get_kthread_comm(char *buf, size_t buf_size, struct task_struct *tsk);
37bool set_kthread_struct(struct task_struct *p);
38
39void kthread_set_per_cpu(struct task_struct *k, int cpu);
40bool kthread_is_per_cpu(struct task_struct *k);
41
42/**
43 * kthread_run - create and wake a thread.
44 * @threadfn: the function to run until signal_pending(current).
45 * @data: data ptr for @threadfn.
46 * @namefmt: printf-style name for the thread.
47 *
48 * Description: Convenient wrapper for kthread_create() followed by
49 * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
50 */
51#define kthread_run(threadfn, data, namefmt, ...)			   \
52({									   \
53	struct task_struct *__k						   \
54		= kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
55	if (!IS_ERR(__k))						   \
56		wake_up_process(__k);					   \
57	__k;								   \
58})
59
60/**
61 * kthread_run_on_cpu - create and wake a cpu bound thread.
62 * @threadfn: the function to run until signal_pending(current).
63 * @data: data ptr for @threadfn.
64 * @cpu: The cpu on which the thread should be bound,
65 * @namefmt: printf-style name for the thread. Format is restricted
66 *	     to "name.*%u". Code fills in cpu number.
67 *
68 * Description: Convenient wrapper for kthread_create_on_cpu()
69 * followed by wake_up_process().  Returns the kthread or
70 * ERR_PTR(-ENOMEM).
71 */
72static inline struct task_struct *
73kthread_run_on_cpu(int (*threadfn)(void *data), void *data,
74			unsigned int cpu, const char *namefmt)
75{
76	struct task_struct *p;
77
78	p = kthread_create_on_cpu(threadfn, data, cpu, namefmt);
79	if (!IS_ERR(p))
80		wake_up_process(p);
81
82	return p;
83}
84
85void free_kthread_struct(struct task_struct *k);
86void kthread_bind(struct task_struct *k, unsigned int cpu);
87void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
88int kthread_stop(struct task_struct *k);
89int kthread_stop_put(struct task_struct *k);
90bool kthread_should_stop(void);
91bool kthread_should_park(void);
92bool kthread_should_stop_or_park(void);
93bool kthread_freezable_should_stop(bool *was_frozen);
94void *kthread_func(struct task_struct *k);
95void *kthread_data(struct task_struct *k);
96void *kthread_probe_data(struct task_struct *k);
97int kthread_park(struct task_struct *k);
98void kthread_unpark(struct task_struct *k);
99void kthread_parkme(void);
100void kthread_exit(long result) __noreturn;
101void kthread_complete_and_exit(struct completion *, long) __noreturn;
102
103int kthreadd(void *unused);
104extern struct task_struct *kthreadd_task;
105extern int tsk_fork_get_node(struct task_struct *tsk);
106
107/*
108 * Simple work processor based on kthread.
109 *
110 * This provides easier way to make use of kthreads.  A kthread_work
111 * can be queued and flushed using queue/kthread_flush_work()
112 * respectively.  Queued kthread_works are processed by a kthread
113 * running kthread_worker_fn().
114 */
115struct kthread_work;
116typedef void (*kthread_work_func_t)(struct kthread_work *work);
117void kthread_delayed_work_timer_fn(struct timer_list *t);
118
119enum {
120	KTW_FREEZABLE		= 1 << 0,	/* freeze during suspend */
121};
122
123struct kthread_worker {
124	unsigned int		flags;
125	raw_spinlock_t		lock;
126	struct list_head	work_list;
127	struct list_head	delayed_work_list;
128	struct task_struct	*task;
129	struct kthread_work	*current_work;
130};
131
132struct kthread_work {
133	struct list_head	node;
134	kthread_work_func_t	func;
135	struct kthread_worker	*worker;
136	/* Number of canceling calls that are running at the moment. */
137	int			canceling;
138};
139
140struct kthread_delayed_work {
141	struct kthread_work work;
142	struct timer_list timer;
143};
144
145#define KTHREAD_WORK_INIT(work, fn)	{				\
146	.node = LIST_HEAD_INIT((work).node),				\
147	.func = (fn),							\
148	}
149
150#define KTHREAD_DELAYED_WORK_INIT(dwork, fn) {				\
151	.work = KTHREAD_WORK_INIT((dwork).work, (fn)),			\
152	.timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
153				     TIMER_IRQSAFE),			\
154	}
155
156#define DEFINE_KTHREAD_WORK(work, fn)					\
157	struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
158
159#define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn)				\
160	struct kthread_delayed_work dwork =				\
161		KTHREAD_DELAYED_WORK_INIT(dwork, fn)
162
163extern void __kthread_init_worker(struct kthread_worker *worker,
164			const char *name, struct lock_class_key *key);
165
166#define kthread_init_worker(worker)					\
167	do {								\
168		static struct lock_class_key __key;			\
169		__kthread_init_worker((worker), "("#worker")->lock", &__key); \
170	} while (0)
171
172#define kthread_init_work(work, fn)					\
173	do {								\
174		memset((work), 0, sizeof(struct kthread_work));		\
175		INIT_LIST_HEAD(&(work)->node);				\
176		(work)->func = (fn);					\
177	} while (0)
178
179#define kthread_init_delayed_work(dwork, fn)				\
180	do {								\
181		kthread_init_work(&(dwork)->work, (fn));		\
182		timer_setup(&(dwork)->timer,				\
183			     kthread_delayed_work_timer_fn,		\
184			     TIMER_IRQSAFE);				\
185	} while (0)
186
187int kthread_worker_fn(void *worker_ptr);
188
189__printf(2, 3)
190struct kthread_worker *
191kthread_create_worker(unsigned int flags, const char namefmt[], ...);
192
193__printf(3, 4) struct kthread_worker *
194kthread_create_worker_on_cpu(int cpu, unsigned int flags,
195			     const char namefmt[], ...);
196
197bool kthread_queue_work(struct kthread_worker *worker,
198			struct kthread_work *work);
199
200bool kthread_queue_delayed_work(struct kthread_worker *worker,
201				struct kthread_delayed_work *dwork,
202				unsigned long delay);
203
204bool kthread_mod_delayed_work(struct kthread_worker *worker,
205			      struct kthread_delayed_work *dwork,
206			      unsigned long delay);
207
208void kthread_flush_work(struct kthread_work *work);
209void kthread_flush_worker(struct kthread_worker *worker);
210
211bool kthread_cancel_work_sync(struct kthread_work *work);
212bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
213
214void kthread_destroy_worker(struct kthread_worker *worker);
215
216void kthread_use_mm(struct mm_struct *mm);
217void kthread_unuse_mm(struct mm_struct *mm);
218
219struct cgroup_subsys_state;
220
221#ifdef CONFIG_BLK_CGROUP
222void kthread_associate_blkcg(struct cgroup_subsys_state *css);
223struct cgroup_subsys_state *kthread_blkcg(void);
224#else
225static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
226#endif
227#endif /* _LINUX_KTHREAD_H */
228