ALSA: opl3: Fix possible negative array index access

Spotted by coverity CID 115196.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/drivers/opl3/opl3_midi.c b/sound/drivers/opl3/opl3_midi.c
index 0c796bc..6c6d09a 100644 (file)
--- a/sound/drivers/opl3/opl3_midi.c
+++ b/sound/drivers/opl3/opl3_midi.c
@@ -390,6 +390,11 @@ void snd_opl3_note_on(void *p, int note, int vel, struct snd_midi_channel *chan)
                voice = snd_opl3_oss_map[chan->number];         
        }
 
+       if (voice < 0) {
+               spin_unlock_irqrestore(&opl3->voice_lock, flags);
+               return;
+       }
+
        if (voice < MAX_OPL2_VOICES) {
                /* Left register block for voices 0 .. 8 */
                reg_side = OPL3_LEFT;