ALSA: compress: stop active streams on disconnect

Track open compressed streams per device so disconnect can stop
active streams and wake waiters before snd_unregister_device().

This aligns compressed stream teardown with PCM disconnect behavior
and prevents active userspace streams from running into unregister
races.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

Author: ujfalusi

include/sound/compress_driver.h

@@ -188,6 +188,7 @@ struct snd_compr_ops {
  * @card: sound card pointer
  * @direction: Playback or capture direction
  * @lock: device lock
+ * @open_list: list of open compress files
  * @device: device id
  * @use_pause_in_draining: allow pause in draining, true when set
  */
@@ -199,6 +200,7 @@ struct snd_compr {
 	struct snd_card *card;
 	unsigned int direction;
 	struct mutex lock;
+	struct list_head open_list;
 	int device;
 	bool use_pause_in_draining;
 #ifdef CONFIG_SND_VERBOSE_PROCFS

sound/core/compress_offload.c

@@ -42,6 +42,7 @@
 #endif
 
 struct snd_compr_file {
+	struct list_head list;
 	unsigned long caps;
 	struct snd_compr_stream stream;
 };
@@ -117,6 +118,7 @@ static int snd_compr_open(struct inode *inode, struct file *f)
 		ret = -ENOMEM;
 		goto __error;
 	}
+	INIT_LIST_HEAD(&data->list);
 
 	INIT_DELAYED_WORK(&data->stream.error_work, error_delayed_work);
 
@@ -136,8 +138,11 @@ static int snd_compr_open(struct inode *inode, struct file *f)
 #endif
 	data->stream.runtime = runtime;
 	f->private_data = (void *)data;
-	scoped_guard(mutex, &compr->lock)
+	scoped_guard(mutex, &compr->lock) {
 		ret = compr->ops->open(&data->stream);
+		if (!ret)
+			list_add_tail(&data->list, &compr->open_list);
+	}
 
 __error:
 	if (ret) {
@@ -153,17 +158,23 @@ static int snd_compr_free(struct inode *inode, struct file *f)
 {
 	struct snd_compr_file *data = f->private_data;
 	struct snd_compr_runtime *runtime = data->stream.runtime;
+	struct snd_compr *compr = data->stream.device;
 
 	cancel_delayed_work_sync(&data->stream.error_work);
 
-	switch (runtime->state) {
-	case SNDRV_PCM_STATE_RUNNING:
-	case SNDRV_PCM_STATE_DRAINING:
-	case SNDRV_PCM_STATE_PAUSED:
-		data->stream.ops->trigger(&data->stream, SNDRV_PCM_TRIGGER_STOP);
-		break;
-	default:
-		break;
+	scoped_guard(mutex, &compr->lock) {
+		if (!list_empty(&data->list))
+			list_del_init(&data->list);
+
+		switch (runtime->state) {
+		case SNDRV_PCM_STATE_RUNNING:
+		case SNDRV_PCM_STATE_DRAINING:
+		case SNDRV_PCM_STATE_PAUSED:
+			data->stream.ops->trigger(&data->stream, SNDRV_PCM_TRIGGER_STOP);
+			break;
+		default:
+			break;
+		}
 	}
 
 	snd_compr_task_free_all(&data->stream);
@@ -1440,8 +1451,27 @@ static int snd_compress_dev_register(struct snd_device *device)
 static int snd_compress_dev_disconnect(struct snd_device *device)
 {
 	struct snd_compr *compr;
+	struct snd_compr_file *data;
 
 	compr = device->device_data;
+	scoped_guard(mutex, &compr->lock) {
+		list_for_each_entry(data, &compr->open_list, list) {
+			switch (data->stream.runtime->state) {
+			case SNDRV_PCM_STATE_RUNNING:
+			case SNDRV_PCM_STATE_DRAINING:
+			case SNDRV_PCM_STATE_PAUSED:
+				data->stream.ops->trigger(&data->stream,
+							 SNDRV_PCM_TRIGGER_STOP);
+				break;
+			default:
+				break;
+			}
+
+			data->stream.runtime->state = SNDRV_PCM_STATE_DISCONNECTED;
+			wake_up(&data->stream.runtime->sleep);
+		}
+	}
+
 	snd_unregister_device(compr->dev);
 	return 0;
 }
@@ -1549,6 +1579,7 @@ int snd_compress_new(struct snd_card *card, int device,
 	compr->device = device;
 	compr->direction = dirn;
 	mutex_init(&compr->lock);
+	INIT_LIST_HEAD(&compr->open_list);
 
 	snd_compress_set_id(compr, id);