stop_machine: Shift the 'done != NULL' check from cpu_stop_signal_done() to callers (dd2e3121) · Commits · 戴 / test

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:

Oleg Nesterov <oleg@redhat.com> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:

Tejun 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:

Ingo Molnar <mingo@kernel.org>

kernel/stop_machine.c

+8 −10

Original line number	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 */
		static void cpu_stop_signal_done(struct cpu_stop_done *done)
		{
		if (done) {
		if (atomic_dec_and_test(&done->nr_todo))
		complete(&done->completion);
		}
		}

		static void __cpu_stop_queue_work(struct cpu_stopper *stopper,
		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;
		if (enabled)
		__cpu_stop_queue_work(stopper, work);
		else
		else if (work->done)
		cpu_stop_signal_done(work->done);
		spin_unlock_irqrestore(&stopper->lock, flags);

		@@ -457,12 +455,12 @@ repeat:

		/* cpu stop callbacks are not allowed to sleep */
		preempt_disable();

		ret = fn(arg);
		if (ret && done)
		if (done) {
		if (ret)
		done->ret = ret;
		cpu_stop_signal_done(done);

		}
		/* restore preemption and check it's still balanced */
		preempt_enable();
		WARN_ONCE(preempt_count(),

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