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-rw-r--r--Documentation/DocBook/kernel-api.tmpl2
-rw-r--r--include/linux/kthread.h65
-rw-r--r--kernel/kthread.c61
3 files changed, 65 insertions, 63 deletions
diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl
index 5a4abe0d5165..8305eb7b8c15 100644
--- a/Documentation/DocBook/kernel-api.tmpl
+++ b/Documentation/DocBook/kernel-api.tmpl
@@ -62,6 +62,8 @@
62 <sect1><title>Internal Functions</title> 62 <sect1><title>Internal Functions</title>
63!Ikernel/exit.c 63!Ikernel/exit.c
64!Ikernel/signal.c 64!Ikernel/signal.c
65!Iinclude/linux/kthread.h
66!Ekernel/kthread.c
65 </sect1> 67 </sect1>
66 68
67 <sect1><title>Kernel objects manipulation</title> 69 <sect1><title>Kernel objects manipulation</title>
diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index ebdd41fd1082..7cce5dfa092f 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -4,37 +4,19 @@
4#include <linux/err.h> 4#include <linux/err.h>
5#include <linux/sched.h> 5#include <linux/sched.h>
6 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), 7struct task_struct *kthread_create(int (*threadfn)(void *data),
27 void *data, 8 void *data,
28 const char namefmt[], ...); 9 const char namefmt[], ...);
29 10
30/** 11/**
31 * kthread_run: create and wake a thread. 12 * kthread_run - create and wake a thread.
32 * @threadfn: the function to run until signal_pending(current). 13 * @threadfn: the function to run until signal_pending(current).
33 * @data: data ptr for @threadfn. 14 * @data: data ptr for @threadfn.
34 * @namefmt: printf-style name for the thread. 15 * @namefmt: printf-style name for the thread.
35 * 16 *
36 * Description: Convenient wrapper for kthread_create() followed by 17 * Description: Convenient wrapper for kthread_create() followed by
37 * wake_up_process(). Returns the kthread, or ERR_PTR(-ENOMEM). */ 18 * wake_up_process(). Returns the kthread or ERR_PTR(-ENOMEM).
19 */
38#define kthread_run(threadfn, data, namefmt, ...) \ 20#define kthread_run(threadfn, data, namefmt, ...) \
39({ \ 21({ \
40 struct task_struct *__k \ 22 struct task_struct *__k \
@@ -44,50 +26,9 @@ struct task_struct *kthread_create(int (*threadfn)(void *data),
44 __k; \ 26 __k; \
45}) 27})
46 28
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); 29void 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); 30int 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); 31int 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); 32int kthread_should_stop(void);
92 33
93#endif /* _LINUX_KTHREAD_H */ 34#endif /* _LINUX_KTHREAD_H */
diff --git a/kernel/kthread.c b/kernel/kthread.c
index c5f3c6613b6d..24be714b04c7 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -45,6 +45,13 @@ struct kthread_stop_info
45static DEFINE_MUTEX(kthread_stop_lock); 45static DEFINE_MUTEX(kthread_stop_lock);
46static struct kthread_stop_info kthread_stop_info; 46static struct kthread_stop_info kthread_stop_info;
47 47
48/**
49 * kthread_should_stop - should this kthread return now?
50 *
51 * When someone calls kthread_stop on your kthread, it will be woken
52 * and this will return true. You should then return, and your return
53 * value will be passed through to kthread_stop().
54 */
48int kthread_should_stop(void) 55int kthread_should_stop(void)
49{ 56{
50 return (kthread_stop_info.k == current); 57 return (kthread_stop_info.k == current);
@@ -122,6 +129,25 @@ static void keventd_create_kthread(void *_create)
122 complete(&create->done); 129 complete(&create->done);
123} 130}
124 131
132/**
133 * kthread_create - create a kthread.
134 * @threadfn: the function to run until signal_pending(current).
135 * @data: data ptr for @threadfn.
136 * @namefmt: printf-style name for the thread.
137 *
138 * Description: This helper function creates and names a kernel
139 * thread. The thread will be stopped: use wake_up_process() to start
140 * it. See also kthread_run(), kthread_create_on_cpu().
141 *
142 * When woken, the thread will run @threadfn() with @data as its
143 * argument. @threadfn can either call do_exit() directly if it is a
144 * standalone thread for which noone will call kthread_stop(), or
145 * return when 'kthread_should_stop()' is true (which means
146 * kthread_stop() has been called). The return value should be zero
147 * or a negative error number; it will be passed to kthread_stop().
148 *
149 * Returns a task_struct or ERR_PTR(-ENOMEM).
150 */
125struct task_struct *kthread_create(int (*threadfn)(void *data), 151struct task_struct *kthread_create(int (*threadfn)(void *data),
126 void *data, 152 void *data,
127 const char namefmt[], 153 const char namefmt[],
@@ -156,6 +182,15 @@ struct task_struct *kthread_create(int (*threadfn)(void *data),
156} 182}
157EXPORT_SYMBOL(kthread_create); 183EXPORT_SYMBOL(kthread_create);
158 184
185/**
186 * kthread_bind - bind a just-created kthread to a cpu.
187 * @k: thread created by kthread_create().
188 * @cpu: cpu (might not be online, must be possible) for @k to run on.
189 *
190 * Description: This function is equivalent to set_cpus_allowed(),
191 * except that @cpu doesn't need to be online, and the thread must be
192 * stopped (i.e., just returned from kthread_create().
193 */
159void kthread_bind(struct task_struct *k, unsigned int cpu) 194void kthread_bind(struct task_struct *k, unsigned int cpu)
160{ 195{
161 BUG_ON(k->state != TASK_INTERRUPTIBLE); 196 BUG_ON(k->state != TASK_INTERRUPTIBLE);
@@ -166,12 +201,36 @@ void kthread_bind(struct task_struct *k, unsigned int cpu)
166} 201}
167EXPORT_SYMBOL(kthread_bind); 202EXPORT_SYMBOL(kthread_bind);
168 203
204/**
205 * kthread_stop - stop a thread created by kthread_create().
206 * @k: thread created by kthread_create().
207 *
208 * Sets kthread_should_stop() for @k to return true, wakes it, and
209 * waits for it to exit. Your threadfn() must not call do_exit()
210 * itself if you use this function! This can also be called after
211 * kthread_create() instead of calling wake_up_process(): the thread
212 * will exit without calling threadfn().
213 *
214 * Returns the result of threadfn(), or %-EINTR if wake_up_process()
215 * was never called.
216 */
169int kthread_stop(struct task_struct *k) 217int kthread_stop(struct task_struct *k)
170{ 218{
171 return kthread_stop_sem(k, NULL); 219 return kthread_stop_sem(k, NULL);
172} 220}
173EXPORT_SYMBOL(kthread_stop); 221EXPORT_SYMBOL(kthread_stop);
174 222
223/**
224 * kthread_stop_sem - stop a thread created by kthread_create().
225 * @k: thread created by kthread_create().
226 * @s: semaphore that @k waits on while idle.
227 *
228 * Does essentially the same thing as kthread_stop() above, but wakes
229 * @k by calling up(@s).
230 *
231 * Returns the result of threadfn(), or %-EINTR if wake_up_process()
232 * was never called.
233 */
175int kthread_stop_sem(struct task_struct *k, struct semaphore *s) 234int kthread_stop_sem(struct task_struct *k, struct semaphore *s)
176{ 235{
177 int ret; 236 int ret;
@@ -210,5 +269,5 @@ static __init int helper_init(void)
210 269
211 return 0; 270 return 0;
212} 271}
213core_initcall(helper_init);
214 272
273core_initcall(helper_init);