snd_pcm_stream_lock - Lock the PCM stream
void snd_pcm_stream_lock(struct snd_pcm_substream * substream);
This locks the PCM stream's spinlock or mutex depending on the nonatomic flag of the given substream. This also takes the global link rw lock (or rw sem), too, for avoiding the race with linked streams.
|January 2017||Kernel Hackers Manual 4.8.|