workqueue: introduce put_pwq_unlocked()

Factor out lock pool, put_pwq(), unlock sequence into put_pwq_unlocked(). The two existing places are converted and there will be more with NUMA affinity support. This is to prepare for NUMA affinity support for unbound workqueues and doesn't introduce any functional difference.

Tejun Heo committed 13 years ago

Commit dce90d41 parent 1befcf31 file · +23 −13Browse files

Showing the changes to kernel/workqueue.c (1 of 1 file). Show all

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kernel/workqueue.c+23−13

 	schedule_work(&pwq->unbound_release_work);
 }
+/**
+ * put_pwq_unlocked - put_pwq() with surrounding pool lock/unlock
+ * @pwq: pool_workqueue to put (can be %NULL)
+ *
+ * put_pwq() with locking.  This function also allows %NULL @pwq.
+ */
+static void put_pwq_unlocked(struct pool_workqueue *pwq)
+{
+	if (pwq) {
+		/*
+		 * As both pwqs and pools are sched-RCU protected, the
+		 * following lock operations are safe.
+		 */
+		spin_lock_irq(&pwq->pool->lock);
+		put_pwq(pwq);
+		spin_unlock_irq(&pwq->pool->lock);
+	}
+}
 static void pwq_activate_delayed_work(struct work_struct *work)
 {
 	struct pool_workqueue *pwq = get_work_pwq(work);
 	mutex_unlock(&wq->mutex);
-	if (last_pwq) {
+	put_pwq_unlocked(last_pwq);
-		spin_lock_irq(&last_pwq->pool->lock);
-		put_pwq(last_pwq);
-		spin_unlock_irq(&last_pwq->pool->lock);
-	}
 	ret = 0;
 	/* fall through */
 out_free:
 	} else {
 		/*
 		 * We're the sole accessor of @wq at this point.  Directly
-		 * access the first pwq and put the base ref.  As both pwqs
+		 * access the first pwq and put the base ref.  @wq will be
-		 * and pools are sched-RCU protected, the lock operations
+		 * freed when the last pwq is released.
-		 * are safe.  @wq will be freed when the last pwq is
-		 * released.
 		 */
 		pwq = list_first_entry(&wq->pwqs, struct pool_workqueue,
 				       pwqs_node);
-		spin_lock_irq(&pwq->pool->lock);
+		put_pwq_unlocked(pwq);
-		put_pwq(pwq);
-		spin_unlock_irq(&pwq->pool->lock);
 	}
 }
 EXPORT_SYMBOL_GPL(destroy_workqueue);