[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>

1 files changed, 12 insertions, 0 deletions

diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index 3fa786448db3..ebdd41fd1082 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -70,6 +70,18 @@ void kthread_bind(struct task_struct *k, unsigned int cpu);
 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