1#ifndef _LINUX_KTHREAD_H
2#define _LINUX_KTHREAD_H
3/* Simple interface for creating and stopping kernel threads without mess. */
4#include <linux/err.h>
5#include <linux/sched.h>
6
7__printf(4, 5)
8struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
9					   void *data,
10					   int node,
11					   const char namefmt[], ...);
12
13#define kthread_create(threadfn, data, namefmt, arg...) \
14	kthread_create_on_node(threadfn, data, -1, namefmt, ##arg)
15
16
17struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
18					  void *data,
19					  unsigned int cpu,
20					  const char *namefmt);
21
22/**
23 * kthread_run - create and wake a thread.
24 * @threadfn: the function to run until signal_pending(current).
25 * @data: data ptr for @threadfn.
26 * @namefmt: printf-style name for the thread.
27 *
28 * Description: Convenient wrapper for kthread_create() followed by
29 * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
30 */
31#define kthread_run(threadfn, data, namefmt, ...)			   \
32({									   \
33	struct task_struct *__k						   \
34		= kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
35	if (!IS_ERR(__k))						   \
36		wake_up_process(__k);					   \
37	__k;								   \
38})
39
40void kthread_bind(struct task_struct *k, unsigned int cpu);
41int kthread_stop(struct task_struct *k);
42bool kthread_should_stop(void);
43bool kthread_should_park(void);
44bool kthread_freezable_should_stop(bool *was_frozen);
45void *kthread_data(struct task_struct *k);
46void *probe_kthread_data(struct task_struct *k);
47int kthread_park(struct task_struct *k);
48void kthread_unpark(struct task_struct *k);
49void kthread_parkme(void);
50
51int kthreadd(void *unused);
52extern struct task_struct *kthreadd_task;
53extern int tsk_fork_get_node(struct task_struct *tsk);
54
55/*
56 * Simple work processor based on kthread.
57 *
58 * This provides easier way to make use of kthreads.  A kthread_work
59 * can be queued and flushed using queue/flush_kthread_work()
60 * respectively.  Queued kthread_works are processed by a kthread
61 * running kthread_worker_fn().
62 */
63struct kthread_work;
64typedef void (*kthread_work_func_t)(struct kthread_work *work);
65
66struct kthread_worker {
67	spinlock_t		lock;
68	struct list_head	work_list;
69	struct task_struct	*task;
70	struct kthread_work	*current_work;
71};
72
73struct kthread_work {
74	struct list_head	node;
75	kthread_work_func_t	func;
76	struct kthread_worker	*worker;
77};
78
79#define KTHREAD_WORKER_INIT(worker)	{				\
80	.lock = __SPIN_LOCK_UNLOCKED((worker).lock),			\
81	.work_list = LIST_HEAD_INIT((worker).work_list),		\
82	}
83
84#define KTHREAD_WORK_INIT(work, fn)	{				\
85	.node = LIST_HEAD_INIT((work).node),				\
86	.func = (fn),							\
87	}
88
89#define DEFINE_KTHREAD_WORKER(worker)					\
90	struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
91
92#define DEFINE_KTHREAD_WORK(work, fn)					\
93	struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
94
95/*
96 * kthread_worker.lock needs its own lockdep class key when defined on
97 * stack with lockdep enabled.  Use the following macros in such cases.
98 */
99#ifdef CONFIG_LOCKDEP
100# define KTHREAD_WORKER_INIT_ONSTACK(worker)				\
101	({ init_kthread_worker(&worker); worker; })
102# define DEFINE_KTHREAD_WORKER_ONSTACK(worker)				\
103	struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
104#else
105# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
106#endif
107
108extern void __init_kthread_worker(struct kthread_worker *worker,
109			const char *name, struct lock_class_key *key);
110
111#define init_kthread_worker(worker)					\
112	do {								\
113		static struct lock_class_key __key;			\
114		__init_kthread_worker((worker), "("#worker")->lock", &__key); \
115	} while (0)
116
117#define init_kthread_work(work, fn)					\
118	do {								\
119		memset((work), 0, sizeof(struct kthread_work));		\
120		INIT_LIST_HEAD(&(work)->node);				\
121		(work)->func = (fn);					\
122	} while (0)
123
124int kthread_worker_fn(void *worker_ptr);
125
126bool queue_kthread_work(struct kthread_worker *worker,
127			struct kthread_work *work);
128void flush_kthread_work(struct kthread_work *work);
129void flush_kthread_worker(struct kthread_worker *worker);
130
131#endif /* _LINUX_KTHREAD_H */
132