[alsa-devel] [PATCH v4 4/7] soundwire: Handle multiple master instances in a stream

[Pierre-Louis Bossart]

>   /**
> @@ -918,13 +951,22 @@ static void sdw_release_master_stream(struct sdw_stream_runtime *stream)
>   int sdw_stream_remove_master(struct sdw_bus *bus,
>   		struct sdw_stream_runtime *stream)
>   {
> +	struct sdw_master_runtime *m_rt, *_m_rt;
> +
>   	mutex_lock(&bus->bus_lock);
>   
> -	sdw_release_master_stream(stream);
> -	sdw_master_port_release(bus, stream->m_rt);
> -	stream->state = SDW_STREAM_RELEASED;
> -	kfree(stream->m_rt);
> -	stream->m_rt = NULL;
> +	list_for_each_entry_safe(m_rt, _m_rt,
> +			&stream->master_list, stream_node) {
> +
> +		if (m_rt->bus != bus)
> +			continue;
> +
> +		sdw_master_port_release(bus, m_rt);
> +		sdw_release_master_stream(m_rt, stream);
> +	}
> +
> +	if (list_empty(&stream->master_list))
> +		stream->state = SDW_STREAM_RELEASED;
When a master is removed, there is an explicit test to make sure the 
stream state changes when there are no masters left in the list, but...

>   
>   	mutex_unlock(&bus->bus_lock);
>   
> @@ -1127,7 +1169,7 @@ int sdw_stream_add_master(struct sdw_bus *bus,
>   	stream->state = SDW_STREAM_CONFIGURED;
... it's not symmetrical for the add_master case. The stream state 
changes on the first added master. In addition the stream state changes 
both when a slave is added and a master is added.
Is this intentional or not - and are there side effects resulting from 
this inconsistency?