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: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index d448eda..3ac2c4d 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -226,7 +226,7 @@
* 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 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 @@
* 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 @@
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);