workqueue: drop apply_wqattrs_lock()/unlock() wrappers

The apply_wqattrs_lock()/unlock() helpers were introduced by commit a0111cf6710b ("workqueue: separate out and refactor the locking of applying attrs") to encapsulate the get_online_cpus() (later cpus_read_lock()) + mutex_lock(&wq_pool_mutex) acquire pair that was duplicated across the apply-attrs paths. Since commit 19af45757383 ("workqueue: Remove cpus_read_lock() from apply_wqattrs_lock()") removed the cpus_read_lock() (pwq creation and installation now operate on wq_online_cpumask, so CPU hotplug no longer needs to be excluded), the wrappers have been one-line forwarders to mutex_lock(&wq_pool_mutex)/mutex_unlock(&wq_pool_mutex). They no longer encode any non-trivial locking rule and obscure the fact that callers just take the existing wq_pool_mutex. This align with the "unnecessary" helpers that got discussed in [1] Inline the eight call sites and remove the wrappers. No functional change.

Breno Leitao committed 6 months ago

Commit dfca4631 parent 7fcb7af1 file · +14 −24Browse files

Unified · Split

kernel/workqueue.c+14−24

 	return pwq;
 }
-static void apply_wqattrs_lock(void)
-{
-	mutex_lock(&wq_pool_mutex);
-}
-static void apply_wqattrs_unlock(void)
-{
-	mutex_unlock(&wq_pool_mutex);
-}
 /**
  * wq_calc_pod_cpumask - calculate a wq_attrs' cpumask for a pod
  * @attrs: the wq_attrs of the default pwq of the target workqueue
 	 * wq_pool_mutex protects the workqueues list, allocations of PWQs,
 	 * and the global freeze state.
 	 */
-	apply_wqattrs_lock();
+	mutex_lock(&wq_pool_mutex);
 	if (alloc_and_link_pwqs(wq) < 0)
 		goto err_unlock_free_node_nr_active;
 	if (wq_online && init_rescuer(wq) < 0)
 		goto err_unlock_destroy;
-	apply_wqattrs_unlock();
+	mutex_unlock(&wq_pool_mutex);
 	if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
 		goto err_destroy;
 	return wq;
 err_unlock_free_node_nr_active:
-	apply_wqattrs_unlock();
+	mutex_unlock(&wq_pool_mutex);
 	/*
 	 * Failed alloc_and_link_pwqs() may leave pending pwq->release_work,
 	 * flushing the pwq_release_worker ensures that the pwq_release_workfn()
 	kfree(wq);
 	return NULL;
 err_unlock_destroy:
-	apply_wqattrs_unlock();
+	mutex_unlock(&wq_pool_mutex);
 err_destroy:
 	destroy_workqueue(wq);
 	return NULL;
 	struct workqueue_attrs *attrs;
 	int ret = -ENOMEM;
-	apply_wqattrs_lock();
+	mutex_lock(&wq_pool_mutex);
 	attrs = wq_sysfs_prep_attrs(wq);
 	if (!attrs)
 		ret = -EINVAL;
 out_unlock:
-	apply_wqattrs_unlock();
+	mutex_unlock(&wq_pool_mutex);
 	free_workqueue_attrs(attrs);
 	return ret ?: count;
 }
 	struct workqueue_attrs *attrs;
 	int ret = -ENOMEM;
-	apply_wqattrs_lock();
+	mutex_lock(&wq_pool_mutex);
 	attrs = wq_sysfs_prep_attrs(wq);
 	if (!attrs)
 		ret = apply_workqueue_attrs_locked(wq, attrs);
 out_unlock:
-	apply_wqattrs_unlock();
+	mutex_unlock(&wq_pool_mutex);
 	free_workqueue_attrs(attrs);
 	return ret ?: count;
 }
 	if (affn < 0)
 		return affn;
-	apply_wqattrs_lock();
+	mutex_lock(&wq_pool_mutex);
 	attrs = wq_sysfs_prep_attrs(wq);
 	if (attrs) {
 		attrs->affn_scope = affn;
 		ret = apply_workqueue_attrs_locked(wq, attrs);
 	}
-	apply_wqattrs_unlock();
+	mutex_unlock(&wq_pool_mutex);
 	free_workqueue_attrs(attrs);
 	return ret ?: count;
 }
 	if (sscanf(buf, "%d", &v) != 1)
 		return -EINVAL;
-	apply_wqattrs_lock();
+	mutex_lock(&wq_pool_mutex);
 	attrs = wq_sysfs_prep_attrs(wq);
 	if (attrs) {
 		attrs->affn_strict = (bool)v;
 		ret = apply_workqueue_attrs_locked(wq, attrs);
 	}
-	apply_wqattrs_unlock();
+	mutex_unlock(&wq_pool_mutex);
 	free_workqueue_attrs(attrs);
 	return ret ?: count;
 }
 	cpumask_and(cpumask, cpumask, cpu_possible_mask);
 	if (!cpumask_empty(cpumask)) {
 		ret = 0;
-		apply_wqattrs_lock();
+		mutex_lock(&wq_pool_mutex);
 		if (!cpumask_equal(cpumask, wq_unbound_cpumask))
 			ret = workqueue_apply_unbound_cpumask(cpumask);
 		if (!ret)
 			cpumask_copy(wq_requested_unbound_cpumask, cpumask);
-		apply_wqattrs_unlock();
+		mutex_unlock(&wq_pool_mutex);
 	}
 	return ret;