snd_pcm_plug_first
plugin = snd_pcm_plug_first(plug);
plugin = snd_pcm_plug_first(plug);
plugin = snd_pcm_plug_first(plug);
plugin = snd_pcm_plug_first(plug);
if (snd_BUG_ON(!snd_pcm_plug_first(plug)))
struct snd_pcm_plugin *plugin = snd_pcm_plug_first(plug);