workqueue: invert the order between pool->lock and wq_mayday_lock (b2d82909) · Commits · 戴 / test

Currently, pool->lock nests inside pool->lock. There's no inherent reason for this order. The only place where the two locks are held together is pool_mayday_timeout() and it just got decided that way. This nesting order turns out to complicate things with the planned rescuer_thread() update. Let's invert them. This doesn't cause any behavior differences. Signed-off-by:

Tejun Heo <tj@kernel.org> Reviewed-by:

Lai Jiangshan <laijs@cn.fujitsu.com> Cc: NeilBrown <neilb@suse.de> Cc: Dongsu Park <dongsu.park@profitbricks.com>

kernel/workqueue.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -1804,8 +1804,8 @@ static void pool_mayday_timeout(unsigned long __pool)
		struct worker_pool pool = (void )__pool;
		struct work_struct *work;

		spin_lock_irq(&wq_mayday_lock); /* for wq->maydays */
		spin_lock(&pool->lock);
		spin_lock_irq(&pool->lock);
		spin_lock(&wq_mayday_lock); /* for wq->maydays */

		if (need_to_create_worker(pool)) {
		/*
		@@ -1818,8 +1818,8 @@ static void pool_mayday_timeout(unsigned long __pool)
		send_mayday(work);
		}

		spin_unlock(&pool->lock);
		spin_unlock_irq(&wq_mayday_lock);
		spin_unlock(&wq_mayday_lock);
		spin_unlock_irq(&pool->lock);

		mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL);
		}

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