workqueue: Update cpumasks after only applying it successfully

Make workqueue_unbound_exclude_cpumask() and workqueue_set_unbound_cpumask()
only update wq_isolated_cpumask and wq_requested_unbound_cpumask when
workqueue_apply_unbound_cpumask() returns successfully.

Fixes: fe28f631("workqueue: Add workqueue_unbound_exclude_cpumask() to exclude CPUs from wq_unbound_cpumask")
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/workqueue.c

@@ -6848,9 +6848,6 @@ int workqueue_unbound_exclude_cpumask(cpumask_var_t exclude_cpumask)
 	lockdep_assert_cpus_held();
 	mutex_lock(&wq_pool_mutex);
 
-	/* Save the current isolated cpumask & export it via sysfs */
-	cpumask_copy(wq_isolated_cpumask, exclude_cpumask);
-
 	/*
 	 * If the operation fails, it will fall back to
 	 * wq_requested_unbound_cpumask which is initially set to
@@ -6862,6 +6859,10 @@ int workqueue_unbound_exclude_cpumask(cpumask_var_t exclude_cpumask)
 	if (!cpumask_equal(cpumask, wq_unbound_cpumask))
 		ret = workqueue_apply_unbound_cpumask(cpumask);
 
+	/* Save the current isolated cpumask & export it via sysfs */
+	if (!ret)
+		cpumask_copy(wq_isolated_cpumask, exclude_cpumask);
+
 	mutex_unlock(&wq_pool_mutex);
 	free_cpumask_var(cpumask);
 	return ret;
@@ -7197,7 +7198,6 @@ static int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
 	cpumask_and(cpumask, cpumask, cpu_possible_mask);
 	if (!cpumask_empty(cpumask)) {
 		apply_wqattrs_lock();
-		cpumask_copy(wq_requested_unbound_cpumask, cpumask);
 		if (cpumask_equal(cpumask, wq_unbound_cpumask)) {
 			ret = 0;
 			goto out_unlock;
@@ -7206,6 +7206,8 @@ static int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
 		ret = workqueue_apply_unbound_cpumask(cpumask);
 
 out_unlock:
+		if (!ret)
+			cpumask_copy(wq_requested_unbound_cpumask, cpumask);
 		apply_wqattrs_unlock();
 	}