diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/kthread.c | 61 |
1 files changed, 60 insertions, 1 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index c5f3c6613b6..24be714b04c 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -45,6 +45,13 @@ struct kthread_stop_info static DEFINE_MUTEX(kthread_stop_lock); static struct kthread_stop_info kthread_stop_info; +/** + * kthread_should_stop - should this kthread return now? + * + * When someone calls kthread_stop on your kthread, it will be woken + * and this will return true. You should then return, and your return + * value will be passed through to kthread_stop(). + */ int kthread_should_stop(void) { return (kthread_stop_info.k == current); @@ -122,6 +129,25 @@ static void keventd_create_kthread(void *_create) complete(&create->done); } +/** + * kthread_create - create a kthread. + * @threadfn: the function to run until signal_pending(current). + * @data: data ptr for @threadfn. + * @namefmt: printf-style name for the thread. + * + * Description: This helper function creates and names a kernel + * thread. The thread will be stopped: use wake_up_process() to start + * it. See also kthread_run(), kthread_create_on_cpu(). + * + * When woken, the thread will run @threadfn() with @data as its + * argument. @threadfn can either call do_exit() directly if it is a + * standalone thread for which noone will call kthread_stop(), or + * return when 'kthread_should_stop()' is true (which means + * kthread_stop() has been called). The return value should be zero + * or a negative error number; it will be passed to kthread_stop(). + * + * Returns a task_struct or ERR_PTR(-ENOMEM). + */ struct task_struct *kthread_create(int (*threadfn)(void *data), void *data, const char namefmt[], @@ -156,6 +182,15 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), } EXPORT_SYMBOL(kthread_create); +/** + * kthread_bind - bind a just-created kthread to a cpu. + * @k: thread created by kthread_create(). + * @cpu: cpu (might not be online, must be possible) for @k to run on. + * + * Description: This function is equivalent to set_cpus_allowed(), + * except that @cpu doesn't need to be online, and the thread must be + * stopped (i.e., just returned from kthread_create(). + */ void kthread_bind(struct task_struct *k, unsigned int cpu) { BUG_ON(k->state != TASK_INTERRUPTIBLE); @@ -166,12 +201,36 @@ void kthread_bind(struct task_struct *k, unsigned int cpu) } EXPORT_SYMBOL(kthread_bind); +/** + * kthread_stop - stop a thread created by kthread_create(). + * @k: thread created by kthread_create(). + * + * Sets kthread_should_stop() for @k to return true, wakes it, and + * waits for it to exit. Your threadfn() must not call do_exit() + * itself if you use this function! This can also be called after + * kthread_create() instead of calling wake_up_process(): the thread + * will exit without calling threadfn(). + * + * Returns the result of threadfn(), or %-EINTR if wake_up_process() + * was never called. + */ int kthread_stop(struct task_struct *k) { return kthread_stop_sem(k, NULL); } EXPORT_SYMBOL(kthread_stop); +/** + * kthread_stop_sem - stop a thread created by kthread_create(). + * @k: thread created by kthread_create(). + * @s: semaphore that @k waits on while idle. + * + * Does essentially the same thing as kthread_stop() above, but wakes + * @k by calling up(@s). + * + * Returns the result of threadfn(), or %-EINTR if wake_up_process() + * was never called. + */ int kthread_stop_sem(struct task_struct *k, struct semaphore *s) { int ret; @@ -210,5 +269,5 @@ static __init int helper_init(void) return 0; } -core_initcall(helper_init); +core_initcall(helper_init); |