[PATCH] Add kthread_stop_sem()
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>
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2 changed files with 23 additions and 2 deletions
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@ -69,6 +69,18 @@ void kthread_bind(struct task_struct *k, unsigned int cpu);
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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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@ -164,6 +164,12 @@ void kthread_bind(struct task_struct *k, unsigned int cpu)
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EXPORT_SYMBOL(kthread_bind);
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int kthread_stop(struct task_struct *k)
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{
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return kthread_stop_sem(k, NULL);
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}
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EXPORT_SYMBOL(kthread_stop);
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int kthread_stop_sem(struct task_struct *k, struct semaphore *s)
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{
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int ret;
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@ -178,7 +184,10 @@ int kthread_stop(struct task_struct *k)
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/* Now set kthread_should_stop() to true, and wake it up. */
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kthread_stop_info.k = k;
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wake_up_process(k);
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if (s)
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up(s);
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else
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wake_up_process(k);
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put_task_struct(k);
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/* Once it dies, reset stop ptr, gather result and we're done. */
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@ -189,7 +198,7 @@ int kthread_stop(struct task_struct *k)
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return ret;
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}
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EXPORT_SYMBOL(kthread_stop);
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EXPORT_SYMBOL(kthread_stop_sem);
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static __init int helper_init(void)
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{
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