61e1a9ea4b
Enhance the kthread API by adding kthread_stop_sem, for use in stopping threads that spend their idle time waiting on a semaphore. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
93 lines
3.4 KiB
C
93 lines
3.4 KiB
C
#ifndef _LINUX_KTHREAD_H
|
|
#define _LINUX_KTHREAD_H
|
|
/* Simple interface for creating and stopping kernel threads without mess. */
|
|
#include <linux/err.h>
|
|
#include <linux/sched.h>
|
|
|
|
/**
|
|
* 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[], ...);
|
|
|
|
/**
|
|
* kthread_run: create and wake a thread.
|
|
* @threadfn: the function to run until signal_pending(current).
|
|
* @data: data ptr for @threadfn.
|
|
* @namefmt: printf-style name for the thread.
|
|
*
|
|
* Description: Convenient wrapper for kthread_create() followed by
|
|
* wake_up_process(). Returns the kthread, or ERR_PTR(-ENOMEM). */
|
|
#define kthread_run(threadfn, data, namefmt, ...) \
|
|
({ \
|
|
struct task_struct *__k \
|
|
= kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
|
|
if (!IS_ERR(__k)) \
|
|
wake_up_process(__k); \
|
|
__k; \
|
|
})
|
|
|
|
/**
|
|
* 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 (ie. just returned from kthread_create().
|
|
*/
|
|
void kthread_bind(struct task_struct *k, unsigned int cpu);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
#endif /* _LINUX_KTHREAD_H */
|