stop_machine: Change __stop_cpus() to rely on cpu_stop_queue_work() (4aff1ca6) · Commits · 戴 / test

Change queue_stop_cpus_work() to return true if it queues at least one work, this means that the caller should wait. __stop_cpus() can check the value returned by queue_stop_cpus_work() and avoid done.executed, just like stop_one_cpu() does. 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/20151115193323.GA8262@redhat.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

kernel/stop_machine.c

+10 −4

Original line number	Diff line number	Diff line
		@@ -318,12 +318,13 @@ bool stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,
		/* static data for stop_cpus */
		static DEFINE_MUTEX(stop_cpus_mutex);

		static void queue_stop_cpus_work(const struct cpumask *cpumask,
		static bool queue_stop_cpus_work(const struct cpumask *cpumask,
		cpu_stop_fn_t fn, void *arg,
		struct cpu_stop_done *done)
		{
		struct cpu_stop_work *work;
		unsigned int cpu;
		bool queued = false;

		/*
		* Disable preemption while queueing to avoid getting
		@@ -336,9 +337,12 @@ static void queue_stop_cpus_work(const struct cpumask *cpumask,
		work->fn = fn;
		work->arg = arg;
		work->done = done;
		cpu_stop_queue_work(cpu, work);
		if (cpu_stop_queue_work(cpu, work))
		queued = true;
		}
		lg_global_unlock(&stop_cpus_lock);

		return queued;
		}

		static int __stop_cpus(const struct cpumask *cpumask,
		@@ -347,9 +351,11 @@ static int __stop_cpus(const struct cpumask *cpumask,
		struct cpu_stop_done done;

		cpu_stop_init_done(&done, cpumask_weight(cpumask));
		queue_stop_cpus_work(cpumask, fn, arg, &done);
		if (!queue_stop_cpus_work(cpumask, fn, arg, &done))
		return -ENOENT;
		wait_for_completion(&done.completion);
		return done.executed ? done.ret : -ENOENT;
		WARN_ON(!done.executed);
		return done.ret;
		}

		/**

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