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Commit 87fc741e authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Tejun Heo
Browse files

workqueue: protect wq->nr_drainers and ->flags with wq->mutex 



We're expanding wq->mutex to cover all fields specific to each
workqueue with the end goal of replacing pwq_lock which will make
locking simpler and easier to understand.

wq->nr_drainers and ->flags are specific to each workqueue.  Protect
->nr_drainers and ->flags with wq->mutex instead of pool_mutex.

tj: Rebased on top of the current dev branch.  Updated description.

Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 3c25a55d

kernel/workqueue.c

+6 −6
Original line number Diff line number Diff line
@@ -226,7 +226,7 @@ struct wq_device; 
 * the appropriate worker_pool through its pool_workqueues.

 */

struct workqueue_struct {

	unsigned int		flags;		/* PL: WQ_* flags */

	unsigned int		flags;		/* WQ: WQ_* flags */

	struct pool_workqueue __percpu *cpu_pwqs; /* I: per-cpu pwq's */

	struct list_head	pwqs;		/* WR: all pwqs of this wq */

	struct list_head	list;		/* PL: list of all workqueues */
@@ -242,7 +242,7 @@ struct workqueue_struct { 
	struct list_head	maydays;	/* MD: pwqs requesting rescue */

	struct worker		*rescuer;	/* I: rescue worker */



	int			nr_drainers;	/* PL: drain in progress */

	int			nr_drainers;	/* WQ: drain in progress */

	int			saved_max_active; /* PW: saved pwq max_active */



#ifdef CONFIG_SYSFS
@@ -2684,10 +2684,10 @@ void drain_workqueue(struct workqueue_struct *wq) 
	 * hotter than drain_workqueue() and already looks at @wq->flags.

	 * Use __WQ_DRAINING so that queue doesn't have to check nr_drainers.

	 */

	mutex_lock(&wq_pool_mutex);

	mutex_lock(&wq->mutex);

	if (!wq->nr_drainers++)

		wq->flags |= __WQ_DRAINING;

	mutex_unlock(&wq_pool_mutex);

	mutex_unlock(&wq->mutex);

reflush:

	flush_workqueue(wq);
@@ -2714,10 +2714,10 @@ void drain_workqueue(struct workqueue_struct *wq) 


	local_irq_enable();



	mutex_lock(&wq_pool_mutex);

	mutex_lock(&wq->mutex);

	if (!--wq->nr_drainers)

		wq->flags &= ~__WQ_DRAINING;

	mutex_unlock(&wq_pool_mutex);

	mutex_unlock(&wq->mutex);

}

EXPORT_SYMBOL_GPL(drain_workqueue);