forked from mirrors/linux
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
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#define _LINUX_KTHREAD_H
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/* Simple interface for creating and stopping kernel threads without mess. */
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#include <linux/err.h>
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#include <linux/sched.h>
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/**
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* kthread_create: create a kthread.
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* @threadfn: the function to run until signal_pending(current).
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* @data: data ptr for @threadfn.
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* @namefmt: printf-style name for the thread.
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*
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* Description: This helper function creates and names a kernel
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* thread. The thread will be stopped: use wake_up_process() to start
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* it. See also kthread_run(), kthread_create_on_cpu().
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*
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* When woken, the thread will run @threadfn() with @data as its
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* argument. @threadfn can either call do_exit() directly if it is a
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* standalone thread for which noone will call kthread_stop(), or
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* return when 'kthread_should_stop()' is true (which means
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* kthread_stop() has been called). The return value should be zero
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* or a negative error number: it will be passed to kthread_stop().
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*
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* Returns a task_struct or ERR_PTR(-ENOMEM).
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*/
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struct task_struct *kthread_create(int (*threadfn)(void *data),
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void *data,
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const char namefmt[], ...);
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/**
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* kthread_run: create and wake a thread.
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* @threadfn: the function to run until signal_pending(current).
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* @data: data ptr for @threadfn.
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* @namefmt: printf-style name for the thread.
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*
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* Description: Convenient wrapper for kthread_create() followed by
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* wake_up_process(). Returns the kthread, or ERR_PTR(-ENOMEM). */
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#define kthread_run(threadfn, data, namefmt, ...) \
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({ \
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struct task_struct *__k \
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= kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
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if (!IS_ERR(__k)) \
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wake_up_process(__k); \
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__k; \
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})
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/**
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* kthread_bind: bind a just-created kthread to a cpu.
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* @k: thread created by kthread_create().
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* @cpu: cpu (might not be online, must be possible) for @k to run on.
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*
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* Description: This function is equivalent to set_cpus_allowed(),
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* except that @cpu doesn't need to be online, and the thread must be
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* stopped (ie. just returned from kthread_create().
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*/
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void kthread_bind(struct task_struct *k, unsigned int cpu);
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/**
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* kthread_stop: stop a thread created by kthread_create().
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* @k: thread created by kthread_create().
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*
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* Sets kthread_should_stop() for @k to return true, wakes it, and
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* waits for it to exit. Your threadfn() must not call do_exit()
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* itself if you use this function! This can also be called after
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* kthread_create() instead of calling wake_up_process(): the thread
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* will exit without calling threadfn().
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*
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* Returns the result of threadfn(), or -EINTR if wake_up_process()
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* was never called. */
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int kthread_stop(struct task_struct *k);
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/**
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* kthread_stop_sem: stop a thread created by kthread_create().
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* @k: thread created by kthread_create().
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* @s: semaphore that @k waits on while idle.
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*
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* Does essentially the same thing as kthread_stop() above, but wakes
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* @k by calling up(@s).
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*
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* Returns the result of threadfn(), or -EINTR if wake_up_process()
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* was never called. */
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int kthread_stop_sem(struct task_struct *k, struct semaphore *s);
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/**
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* kthread_should_stop: should this kthread return now?
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*
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* When someone calls kthread_stop on your kthread, it will be woken
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* and this will return true. You should then return, and your return
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* value will be passed through to kthread_stop().
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*/
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int kthread_should_stop(void);
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#endif /* _LINUX_KTHREAD_H */
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