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workqueue: restructure __alloc_workqueue_key()

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* 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: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
This commit is contained in:
Tejun Heo 2013-03-12 11:30:04 -07:00
parent 493008a8e4
commit d2c1d40487
1 changed files with 38 additions and 29 deletions
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67
kernel/workqueue.c
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@ -3329,6 +3329,23 @@ fail:
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);
kfree(wq);
}
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);