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Commit edab2516 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
Browse files

flush_workqueue(): use preempt_disable to hold off cpu hotplug 



Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Gautham Shenoy <ego@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b89deed3

kernel/workqueue.c

+10 −6
Original line number Original line Diff line number Diff line
@@ -419,18 +419,22 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) 
		 * Probably keventd trying to flush its own queue. So simply run

		 * Probably keventd trying to flush its own queue. So simply run

		 * it by hand rather than deadlocking.

		 * it by hand rather than deadlocking.

		 */

		 */

		mutex_unlock(&workqueue_mutex);

		preempt_enable();

		/*

		 * We can still touch *cwq here because we are keventd, and

		 * hot-unplug will be waiting us to exit.

		 */

		run_workqueue(cwq);

		run_workqueue(cwq);

		mutex_lock(&workqueue_mutex);

		preempt_disable();

	} else {

	} else {

		struct wq_barrier barr;

		struct wq_barrier barr;





		init_wq_barrier(&barr);

		init_wq_barrier(&barr);

		__queue_work(cwq, &barr.work);

		__queue_work(cwq, &barr.work);





		mutex_unlock(&workqueue_mutex);

		preempt_enable();	/* Can no longer touch *cwq */

		wait_for_completion(&barr.done);

		wait_for_completion(&barr.done);

		mutex_lock(&workqueue_mutex);

		preempt_disable();

	}

	}

}

}
@@ -449,7 +453,7 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) 
 */

 */

void fastcall flush_workqueue(struct workqueue_struct *wq)

void fastcall flush_workqueue(struct workqueue_struct *wq)

{

{

	mutex_lock(&workqueue_mutex);

	preempt_disable();		/* CPU hotplug */

	if (is_single_threaded(wq)) {

	if (is_single_threaded(wq)) {

		/* Always use first cpu's area. */

		/* Always use first cpu's area. */

		flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu));

		flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu));
@@ -459,7 +463,7 @@ void fastcall flush_workqueue(struct workqueue_struct *wq) 
		for_each_online_cpu(cpu)

		for_each_online_cpu(cpu)

			flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));

			flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));

	}

	}

	mutex_unlock(&workqueue_mutex);

	preempt_enable();

}

}

EXPORT_SYMBOL_GPL(flush_workqueue);

EXPORT_SYMBOL_GPL(flush_workqueue);