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

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
...@@ -419,18 +419,22 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) ...@@ -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) ...@@ -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) ...@@ -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);
......
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