Linux kernel mirror (for testing)
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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/**
8 * kthread_create: create a kthread.
9 * @threadfn: the function to run until signal_pending(current).
10 * @data: data ptr for @threadfn.
11 * @namefmt: printf-style name for the thread.
12 *
13 * Description: This helper function creates and names a kernel
14 * thread. The thread will be stopped: use wake_up_process() to start
15 * it. See also kthread_run(), kthread_create_on_cpu().
16 *
17 * When woken, the thread will run @threadfn() with @data as its
18 * argument. @threadfn can either call do_exit() directly if it is a
19 * standalone thread for which noone will call kthread_stop(), or
20 * return when 'kthread_should_stop()' is true (which means
21 * kthread_stop() has been called). The return value should be zero
22 * or a negative error number: it will be passed to kthread_stop().
23 *
24 * Returns a task_struct or ERR_PTR(-ENOMEM).
25 */
26struct task_struct *kthread_create(int (*threadfn)(void *data),
27 void *data,
28 const char namefmt[], ...);
29
30/**
31 * kthread_run: create and wake a thread.
32 * @threadfn: the function to run until signal_pending(current).
33 * @data: data ptr for @threadfn.
34 * @namefmt: printf-style name for the thread.
35 *
36 * Description: Convenient wrapper for kthread_create() followed by
37 * wake_up_process(). Returns the kthread, or ERR_PTR(-ENOMEM). */
38#define kthread_run(threadfn, data, namefmt, ...) \
39({ \
40 struct task_struct *__k \
41 = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
42 if (!IS_ERR(__k)) \
43 wake_up_process(__k); \
44 __k; \
45})
46
47/**
48 * kthread_bind: bind a just-created kthread to a cpu.
49 * @k: thread created by kthread_create().
50 * @cpu: cpu (might not be online, must be possible) for @k to run on.
51 *
52 * Description: This function is equivalent to set_cpus_allowed(),
53 * except that @cpu doesn't need to be online, and the thread must be
54 * stopped (ie. just returned from kthread_create().
55 */
56void kthread_bind(struct task_struct *k, unsigned int cpu);
57
58/**
59 * kthread_stop: stop a thread created by kthread_create().
60 * @k: thread created by kthread_create().
61 *
62 * Sets kthread_should_stop() for @k to return true, wakes it, and
63 * waits for it to exit. Your threadfn() must not call do_exit()
64 * itself if you use this function! This can also be called after
65 * kthread_create() instead of calling wake_up_process(): the thread
66 * will exit without calling threadfn().
67 *
68 * Returns the result of threadfn(), or -EINTR if wake_up_process()
69 * was never called. */
70int kthread_stop(struct task_struct *k);
71
72/**
73 * kthread_stop_sem: stop a thread created by kthread_create().
74 * @k: thread created by kthread_create().
75 * @s: semaphore that @k waits on while idle.
76 *
77 * Does essentially the same thing as kthread_stop() above, but wakes
78 * @k by calling up(@s).
79 *
80 * Returns the result of threadfn(), or -EINTR if wake_up_process()
81 * was never called. */
82int kthread_stop_sem(struct task_struct *k, struct semaphore *s);
83
84/**
85 * kthread_should_stop: should this kthread return now?
86 *
87 * When someone calls kthread_stop on your kthread, it will be woken
88 * and this will return true. You should then return, and your return
89 * value will be passed through to kthread_stop().
90 */
91int kthread_should_stop(void);
92
93#endif /* _LINUX_KTHREAD_H */