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Commit dd2e3121 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Ingo Molnar
Browse files

stop_machine: Shift the 'done != NULL' check from cpu_stop_signal_done() to callers 



Change cpu_stop_queue_work() and cpu_stopper_thread() to check done != NULL
before cpu_stop_signal_done(done). This makes the code more clean imo, note
that cpu_stopper_thread() has to do this check anyway.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Milos Vyletel <milos@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20151115193329.GA8274@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 6fa3b826

kernel/stop_machine.c

+8 −10
Original line number Original line Diff line number Diff line
@@ -64,11 +64,9 @@ static void cpu_stop_init_done(struct cpu_stop_done *done, unsigned int nr_todo) 
/* signal completion unless @done is NULL */

/* signal completion unless @done is NULL */

static void cpu_stop_signal_done(struct cpu_stop_done *done)

static void cpu_stop_signal_done(struct cpu_stop_done *done)

{

{

	if (done) {

	if (atomic_dec_and_test(&done->nr_todo))

	if (atomic_dec_and_test(&done->nr_todo))

		complete(&done->completion);

		complete(&done->completion);

}

}

}





static void __cpu_stop_queue_work(struct cpu_stopper *stopper,

static void __cpu_stop_queue_work(struct cpu_stopper *stopper,

					struct cpu_stop_work *work)

					struct cpu_stop_work *work)
@@ -88,7 +86,7 @@ static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work) 
	enabled = stopper->enabled;

	enabled = stopper->enabled;

	if (enabled)

	if (enabled)

		__cpu_stop_queue_work(stopper, work);

		__cpu_stop_queue_work(stopper, work);

	else

	else if (work->done)

		cpu_stop_signal_done(work->done);

		cpu_stop_signal_done(work->done);

	spin_unlock_irqrestore(&stopper->lock, flags);

	spin_unlock_irqrestore(&stopper->lock, flags);
@@ -457,12 +455,12 @@ static void cpu_stopper_thread(unsigned int cpu) 




		/* cpu stop callbacks are not allowed to sleep */

		/* cpu stop callbacks are not allowed to sleep */

		preempt_disable();

		preempt_disable();



		ret = fn(arg);

		ret = fn(arg);

		if (ret && done)

		if (done) {

			if (ret)

				done->ret = ret;

				done->ret = ret;

			cpu_stop_signal_done(done);

			cpu_stop_signal_done(done);



		}

		/* restore preemption and check it's still balanced */

		/* restore preemption and check it's still balanced */

		preempt_enable();

		preempt_enable();

		WARN_ONCE(preempt_count(),

		WARN_ONCE(preempt_count(),