ALSA: seq: Fix race at creating a queue (4842e98f) · Commits · 戴 / test

sound/core/seq/seq_queue.c

+20 −13

Original line number	Original line	Diff line number	Diff line
	@@ -181,6 +181,8 @@ void __exit snd_seq_queues_delete(void)
	}		}
	}		}

			static void queue_use(struct snd_seq_queue *queue, int client, int use);

	/* allocate a new queue -		/* allocate a new queue -
	* return queue index value or negative value for error		* return queue index value or negative value for error
	*/		*/
	@@ -192,11 +194,11 @@ int snd_seq_queue_alloc(int client, int locked, unsigned int info_flags)
	if (q == NULL)		if (q == NULL)
	return -ENOMEM;		return -ENOMEM;
	q->info_flags = info_flags;		q->info_flags = info_flags;
			queue_use(q, client, 1);
	if (queue_list_add(q) < 0) {		if (queue_list_add(q) < 0) {
	queue_delete(q);		queue_delete(q);
	return -ENOMEM;		return -ENOMEM;
	}		}
	snd_seq_queue_use(q->queue, client, 1); /* use this queue */
	return q->queue;		return q->queue;
	}		}

	@@ -502,19 +504,9 @@ int snd_seq_queue_timer_set_tempo(int queueid, int client,
	return result;		return result;
	}		}

			/* use or unuse this queue */
	/* use or unuse this queue -		static void queue_use(struct snd_seq_queue *queue, int client, int use)
	* if it is the first client, starts the timer.
	* if it is not longer used by any clients, stop the timer.
	*/
	int snd_seq_queue_use(int queueid, int client, int use)
	{		{
	struct snd_seq_queue *queue;

	queue = queueptr(queueid);
	if (queue == NULL)
	return -EINVAL;
	mutex_lock(&queue->timer_mutex);
	if (use) {		if (use) {
	if (!test_and_set_bit(client, queue->clients_bitmap))		if (!test_and_set_bit(client, queue->clients_bitmap))
	queue->clients++;		queue->clients++;
	@@ -529,6 +521,21 @@ int snd_seq_queue_use(int queueid, int client, int use)
	} else {		} else {
	snd_seq_timer_close(queue);		snd_seq_timer_close(queue);
	}		}
			}

			/* use or unuse this queue -
			* if it is the first client, starts the timer.
			* if it is not longer used by any clients, stop the timer.
			*/
			int snd_seq_queue_use(int queueid, int client, int use)
			{
			struct snd_seq_queue *queue;

			queue = queueptr(queueid);
			if (queue == NULL)
			return -EINVAL;
			mutex_lock(&queue->timer_mutex);
			queue_use(queue, client, use);
	mutex_unlock(&queue->timer_mutex);		mutex_unlock(&queue->timer_mutex);
	queuefree(queue);		queuefree(queue);
	return 0;		return 0;

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