struct snd_riptide *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct pcmhw *data;
-       int index = substream->number;
+       int sub_num = substream->number;
 
-       chip->playback_substream[index] = substream;
+       chip->playback_substream[sub_num] = substream;
        runtime->hw = snd_riptide_playback;
        data = kzalloc(sizeof(struct pcmhw), GFP_KERNEL);
-       data->paths = lbus_play_paths[index];
-       data->id = play_ids[index];
-       data->source = play_sources[index];
+       data->paths = lbus_play_paths[sub_num];
+       data->id = play_ids[sub_num];
+       data->source = play_sources[sub_num];
        data->intdec[0] = 0xff;
        data->intdec[1] = 0xff;
        data->state = ST_STOP;
 {
        struct snd_riptide *chip = snd_pcm_substream_chip(substream);
        struct pcmhw *data = get_pcmhwdev(substream);
-       int index = substream->number;
+       int sub_num = substream->number;
 
        substream->runtime->private_data = NULL;
-       chip->playback_substream[index] = NULL;
+       chip->playback_substream[sub_num] = NULL;
        kfree(data);
        return 0;
 }