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Commit d2c1d404 authored by Tejun Heo's avatar Tejun Heo
Browse files

workqueue: restructure __alloc_workqueue_key() 



* Move initialization and linking of pool_workqueues into
  init_and_link_pwq().

* Make the failure path use destroy_workqueue() once pool_workqueue
  initialization succeeds.

These changes are to prepare for dynamic management of pool_workqueues
and don't introduce any functional changes.

While at it, convert list_del(&wq->list) to list_del_init() as a
precaution as scheduled changes will make destruction more complex.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
parent 493008a8

kernel/workqueue.c

+38 −29
Original line number Diff line number Diff line
@@ -3329,6 +3329,23 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) 
	return NULL;

}



/* initialize @pwq which interfaces with @pool for @wq and link it in */

static void init_and_link_pwq(struct pool_workqueue *pwq,

			      struct workqueue_struct *wq,

			      struct worker_pool *pool)

{

	BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK);



	pwq->pool = pool;

	pwq->wq = wq;

	pwq->flush_color = -1;

	pwq->max_active = wq->saved_max_active;

	INIT_LIST_HEAD(&pwq->delayed_works);

	INIT_LIST_HEAD(&pwq->mayday_node);



	list_add_tail_rcu(&pwq->pwqs_node, &wq->pwqs);

}



static int alloc_and_link_pwqs(struct workqueue_struct *wq)

{

	bool highpri = wq->flags & WQ_HIGHPRI;
@@ -3345,23 +3362,23 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq) 
			struct worker_pool *cpu_pools =

				per_cpu(cpu_worker_pools, cpu);



			pwq->pool = &cpu_pools[highpri];

			list_add_tail_rcu(&pwq->pwqs_node, &wq->pwqs);

			init_and_link_pwq(pwq, wq, &cpu_pools[highpri]);

		}

	} else {

		struct pool_workqueue *pwq;

		struct worker_pool *pool;



		pwq = kmem_cache_zalloc(pwq_cache, GFP_KERNEL);

		if (!pwq)

			return -ENOMEM;



		pwq->pool = get_unbound_pool(unbound_std_wq_attrs[highpri]);

		if (!pwq->pool) {

		pool = get_unbound_pool(unbound_std_wq_attrs[highpri]);

		if (!pool) {

			kmem_cache_free(pwq_cache, pwq);

			return -ENOMEM;

		}



		list_add_tail_rcu(&pwq->pwqs_node, &wq->pwqs);

		init_and_link_pwq(pwq, wq, pool);

	}



	return 0;
@@ -3406,7 +3423,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, 


	wq = kzalloc(sizeof(*wq) + namelen, GFP_KERNEL);

	if (!wq)

		goto err;

		return NULL;



	vsnprintf(wq->name, namelen, fmt, args1);

	va_end(args);
@@ -3429,18 +3446,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, 
	INIT_LIST_HEAD(&wq->list);



	if (alloc_and_link_pwqs(wq) < 0)

		goto err;



	local_irq_disable();

	for_each_pwq(pwq, wq) {

		BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK);

		pwq->wq = wq;

		pwq->flush_color = -1;

		pwq->max_active = max_active;

		INIT_LIST_HEAD(&pwq->delayed_works);

		INIT_LIST_HEAD(&pwq->mayday_node);

	}

	local_irq_enable();

		goto err_free_wq;



	/*

	 * Workqueues which may be used during memory reclaim should
@@ -3449,16 +3455,19 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, 
	if (flags & WQ_MEM_RECLAIM) {

		struct worker *rescuer;



		wq->rescuer = rescuer = alloc_worker();

		rescuer = alloc_worker();

		if (!rescuer)

			goto err;

			goto err_destroy;



		rescuer->rescue_wq = wq;

		rescuer->task = kthread_create(rescuer_thread, rescuer, "%s",

					       wq->name);

		if (IS_ERR(rescuer->task))

			goto err;

		if (IS_ERR(rescuer->task)) {

			kfree(rescuer);

			goto err_destroy;

		}



		wq->rescuer = rescuer;

		rescuer->task->flags |= PF_THREAD_BOUND;

		wake_up_process(rescuer->task);

	}
@@ -3479,12 +3488,12 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, 
	spin_unlock_irq(&workqueue_lock);



	return wq;

err:

	if (wq) {

		free_pwqs(wq);

		kfree(wq->rescuer);



err_free_wq:

	kfree(wq);

	}

	return NULL;

err_destroy:

	destroy_workqueue(wq);

	return NULL;

}

EXPORT_SYMBOL_GPL(__alloc_workqueue_key);
@@ -3526,7 +3535,7 @@ void destroy_workqueue(struct workqueue_struct *wq) 
	 * wq list is used to freeze wq, remove from list after

	 * flushing is complete in case freeze races us.

	 */

	list_del(&wq->list);

	list_del_init(&wq->list);



	spin_unlock_irq(&workqueue_lock);