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)
8 struct 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 
17 struct 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 
40 void kthread_bind(struct task_struct *k, unsigned int cpu);
41 int kthread_stop(struct task_struct *k);
42 bool kthread_should_stop(void);
43 bool kthread_should_park(void);
44 bool kthread_freezable_should_stop(bool *was_frozen);
45 void *kthread_data(struct task_struct *k);
46 void *probe_kthread_data(struct task_struct *k);
47 int kthread_park(struct task_struct *k);
48 void kthread_unpark(struct task_struct *k);
49 void kthread_parkme(void);
50 
51 int kthreadd(void *unused);
52 extern struct task_struct *kthreadd_task;
53 extern 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  */
63 struct kthread_work;
64 typedef void (*kthread_work_func_t)(struct kthread_work *work);
65 
66 struct 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 
73 struct 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 
108 extern 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 
124 int kthread_worker_fn(void *worker_ptr);
125 
126 bool queue_kthread_work(struct kthread_worker *worker,
127 			struct kthread_work *work);
128 void flush_kthread_work(struct kthread_work *work);
129 void flush_kthread_worker(struct kthread_worker *worker);
130 
131 #endif /* _LINUX_KTHREAD_H */
132