linux-next: manual merge of the akpm tree with Linus' tree

[Stephen Rothwell]

Hi Andrew,

Today's linux-next merge of the akpm tree got a conflict in
kernel/kthread.c between commit f2530dc71cf0 ("kthread: Prevent unpark
race which puts threads on the wrong cpu") from Linus' tree and commit
"kthread: kill task_get_live_kthread()" from the akpm tree.

I fixed it up (see below) and can carry the fix as necessary (no action
is required).

-- 
Cheers,
Stephen Rothwell                    s...@canb.auug.org.au

diff --cc kernel/kthread.c
index e820aa6,b9db231..0000000
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@@ -324,28 -324,6 +324,22 @@@ struct task_struct *kthread_create_on_c
        return p;
  }
  
- static struct kthread *task_get_live_kthread(struct task_struct *k)
- {
-       get_task_struct(k);
-       return to_live_kthread(k);
- }
- 
 +static void __kthread_unpark(struct task_struct *k, struct kthread *kthread)
 +{
 +      clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
 +      /*
 +       * We clear the IS_PARKED bit here as we don't wait
 +       * until the task has left the park code. So if we'd
 +       * park before that happens we'd see the IS_PARKED bit
 +       * which might be about to be cleared.
 +       */
 +      if (test_and_clear_bit(KTHREAD_IS_PARKED, &kthread->flags)) {
 +              if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags))
 +                      __kthread_bind(k, kthread->cpu, TASK_PARKED);
 +              wake_up_state(k, TASK_PARKED);
 +      }
 +}
 +
  /**
   * kthread_unpark - unpark a thread created by kthread_create().
   * @k:                thread created by kthread_create().
@@@ -356,11 -334,22 +350,10 @@@
   */
  void kthread_unpark(struct task_struct *k)
  {
-       struct kthread *kthread = task_get_live_kthread(k);
+       struct kthread *kthread = to_live_kthread(k);
  
 -      if (kthread) {
 -              clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
 -              /*
 -               * We clear the IS_PARKED bit here as we don't wait
 -               * until the task has left the park code. So if we'd
 -               * park before that happens we'd see the IS_PARKED bit
 -               * which might be about to be cleared.
 -               */
 -              if (test_and_clear_bit(KTHREAD_IS_PARKED, &kthread->flags)) {
 -                      if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags))
 -                              __kthread_bind(k, kthread->cpu);
 -                      wake_up_process(k);
 -              }
 -      }
 +      if (kthread)
 +              __kthread_unpark(k, kthread);
-       put_task_struct(k);
  }
  
  /**
@@@ -415,9 -403,12 +407,12 @@@ int kthread_stop(struct task_struct *k
        int ret;
  
        trace_sched_kthread_stop(k);
+ 
+       get_task_struct(k);
+       kthread = to_live_kthread(k);
        if (kthread) {
                set_bit(KTHREAD_SHOULD_STOP, &kthread->flags);
 -              clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
 +              __kthread_unpark(k, kthread);
                wake_up_process(k);
                wait_for_completion(&kthread->exited);
        }

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