workqueue: make workqueue_lock irq-safe

workqueue_lock will be used to synchronize areas which require
irq-safety and there isn't much benefit in keeping it not irq-safe.
Make it irq-safe.

This patch doesn't introduce any visible behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>

kernel/workqueue.c

@@ -2715,10 +2715,10 @@ void drain_workqueue(struct workqueue_struct *wq)
 	 * hotter than drain_workqueue() and already looks at @wq->flags.
 	 * Use WQ_DRAINING so that queue doesn't have to check nr_drainers.
 	 */
-	spin_lock(&workqueue_lock);
+	spin_lock_irq(&workqueue_lock);
 	if (!wq->nr_drainers++)
 		wq->flags |= WQ_DRAINING;
-	spin_unlock(&workqueue_lock);
+	spin_unlock_irq(&workqueue_lock);
 reflush:
 	flush_workqueue(wq);
 
@@ -2740,10 +2740,10 @@ void drain_workqueue(struct workqueue_struct *wq)
 		goto reflush;
 	}
 
-	spin_lock(&workqueue_lock);
+	spin_lock_irq(&workqueue_lock);
 	if (!--wq->nr_drainers)
 		wq->flags &= ~WQ_DRAINING;
-	spin_unlock(&workqueue_lock);
+	spin_unlock_irq(&workqueue_lock);
 }
 EXPORT_SYMBOL_GPL(drain_workqueue);
 
@@ -3233,7 +3233,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
 	 * list.  Grab it, set max_active accordingly and add the new
 	 * workqueue to workqueues list.
 	 */
-	spin_lock(&workqueue_lock);
+	spin_lock_irq(&workqueue_lock);
 
 	if (workqueue_freezing && wq->flags & WQ_FREEZABLE)
 		for_each_pwq_cpu(cpu, wq)
@@ -3241,7 +3241,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
 
 	list_add(&wq->list, &workqueues);
 
-	spin_unlock(&workqueue_lock);
+	spin_unlock_irq(&workqueue_lock);
 
 	return wq;
 err:
@@ -3285,9 +3285,9 @@ 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.
 	 */
-	spin_lock(&workqueue_lock);
+	spin_lock_irq(&workqueue_lock);
 	list_del(&wq->list);
-	spin_unlock(&workqueue_lock);
+	spin_unlock_irq(&workqueue_lock);
 
 	if (wq->flags & WQ_RESCUER) {
 		kthread_stop(wq->rescuer->task);
@@ -3336,7 +3336,7 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
 
 	max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
 
-	spin_lock(&workqueue_lock);
+	spin_lock_irq(&workqueue_lock);
 
 	wq->saved_max_active = max_active;
 
@@ -3344,16 +3344,16 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
 		struct pool_workqueue *pwq = get_pwq(cpu, wq);
 		struct worker_pool *pool = pwq->pool;
 
-		spin_lock_irq(&pool->lock);
+		spin_lock(&pool->lock);
 
 		if (!(wq->flags & WQ_FREEZABLE) ||
 		    !(pool->flags & POOL_FREEZING))
 			pwq_set_max_active(pwq, max_active);
 
-		spin_unlock_irq(&pool->lock);
+		spin_unlock(&pool->lock);
 	}
 
-	spin_unlock(&workqueue_lock);
+	spin_unlock_irq(&workqueue_lock);
 }
 EXPORT_SYMBOL_GPL(workqueue_set_max_active);
 
@@ -3599,7 +3599,7 @@ void freeze_workqueues_begin(void)
 {
 	unsigned int cpu;
 
-	spin_lock(&workqueue_lock);
+	spin_lock_irq(&workqueue_lock);
 
 	WARN_ON_ONCE(workqueue_freezing);
 	workqueue_freezing = true;
@@ -3609,7 +3609,7 @@ void freeze_workqueues_begin(void)
 		struct workqueue_struct *wq;
 
 		for_each_std_worker_pool(pool, cpu) {
-			spin_lock_irq(&pool->lock);
+			spin_lock(&pool->lock);
 
 			WARN_ON_ONCE(pool->flags & POOL_FREEZING);
 			pool->flags |= POOL_FREEZING;
@@ -3622,11 +3622,11 @@ void freeze_workqueues_begin(void)
 					pwq->max_active = 0;
 			}
 
-			spin_unlock_irq(&pool->lock);
+			spin_unlock(&pool->lock);
 		}
 	}
 
-	spin_unlock(&workqueue_lock);
+	spin_unlock_irq(&workqueue_lock);
 }
 
 /**
@@ -3647,7 +3647,7 @@ bool freeze_workqueues_busy(void)
 	unsigned int cpu;
 	bool busy = false;
 
-	spin_lock(&workqueue_lock);
+	spin_lock_irq(&workqueue_lock);
 
 	WARN_ON_ONCE(!workqueue_freezing);
 
@@ -3671,7 +3671,7 @@ bool freeze_workqueues_busy(void)
 		}
 	}
 out_unlock:
-	spin_unlock(&workqueue_lock);
+	spin_unlock_irq(&workqueue_lock);
 	return busy;
 }
 
@@ -3688,7 +3688,7 @@ void thaw_workqueues(void)
 {
 	unsigned int cpu;
 
-	spin_lock(&workqueue_lock);
+	spin_lock_irq(&workqueue_lock);
 
 	if (!workqueue_freezing)
 		goto out_unlock;
@@ -3698,7 +3698,7 @@ void thaw_workqueues(void)
 		struct workqueue_struct *wq;
 
 		for_each_std_worker_pool(pool, cpu) {
-			spin_lock_irq(&pool->lock);
+			spin_lock(&pool->lock);
 
 			WARN_ON_ONCE(!(pool->flags & POOL_FREEZING));
 			pool->flags &= ~POOL_FREEZING;
@@ -3716,13 +3716,13 @@ void thaw_workqueues(void)
 
 			wake_up_worker(pool);
 
-			spin_unlock_irq(&pool->lock);
+			spin_unlock(&pool->lock);
 		}
 	}
 
 	workqueue_freezing = false;
 out_unlock:
-	spin_unlock(&workqueue_lock);
+	spin_unlock_irq(&workqueue_lock);
 }
 #endif /* CONFIG_FREEZER */