diff --git a/include/sound/pcm_oss.h b/include/sound/pcm_oss.h
index c854647..1cd4f64 100644
--- a/include/sound/pcm_oss.h
+++ b/include/sound/pcm_oss.h
@@ -56,6 +56,7 @@
 	size_t mmap_bytes;
 	char *buffer;				/* vmallocated period */
 	size_t buffer_used;			/* used length from period buffer */
+	struct mutex params_lock;
 #ifdef CONFIG_SND_PCM_OSS_PLUGINS
 	struct snd_pcm_plugin *plugin_first;
 	struct snd_pcm_plugin *plugin_last;