kthread: Add __kthread_should_park()

kthread_should_park() is used to check if the calling kthread ('current')
should park, but there is no function to check whether an arbitrary kthread
should be parked. The latter is required to plug a CPU hotplug race vs. a
parking ksoftirqd thread.

The new __kthread_should_park() receives a task_struct as parameter to
check if the corresponding kernel thread should be parked.

Call __kthread_should_park() from kthread_should_park() to avoid code
duplication.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Link: https://lkml.kernel.org/r/20190128234625.78241-2-mka@chromium.org

1 files changed, 7 insertions, 1 deletions

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 087d18d771b5..65234c89d85b 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -101,6 +101,12 @@ bool kthread_should_stop(void)
 }
 EXPORT_SYMBOL(kthread_should_stop);
 
+bool __kthread_should_park(struct task_struct *k)
+{
+	return test_bit(KTHREAD_SHOULD_PARK, &to_kthread(k)->flags);
+}
+EXPORT_SYMBOL_GPL(__kthread_should_park);
+
 /**
  * kthread_should_park - should this kthread park now?
  *
@@ -114,7 +120,7 @@ EXPORT_SYMBOL(kthread_should_stop);
  */
 bool kthread_should_park(void)
 {
-	return test_bit(KTHREAD_SHOULD_PARK, &to_kthread(current)->flags);
+	return __kthread_should_park(current);
 }
 EXPORT_SYMBOL_GPL(kthread_should_park);