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

Stephen Rothwell
2013-04-16T07:26:09Z

[-- Attachment #1: Type: text/plain, Size: 2727 bytes --]

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 sfr@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);
}

[-- Attachment #2: Type: application/pgp-signature, Size: 836 bytes --]