ALSA: hda - Sanity check of access to SPDIF controls array

Put WARN_ON() and bail out if the given index is over the allocated
array of the given SPDIF controls.  It's merely a sanity check to
catch any potential issues (if any).
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_codec.c

@@ -2175,6 +2175,8 @@ static int snd_hda_spdif_default_get(struct snd_kcontrol *kcontrol,
 	int idx = kcontrol->private_value;
 	struct hda_spdif_out *spdif;
 
+	if (WARN_ON(codec->spdif_out.used <= idx))
+		return -EINVAL;
 	mutex_lock(&codec->spdif_mutex);
 	spdif = snd_array_elem(&codec->spdif_out, idx);
 	ucontrol->value.iec958.status[0] = spdif->status & 0xff;
@@ -2282,6 +2284,8 @@ static int snd_hda_spdif_default_put(struct snd_kcontrol *kcontrol,
 	unsigned short val;
 	int change;
 
+	if (WARN_ON(codec->spdif_out.used <= idx))
+		return -EINVAL;
 	mutex_lock(&codec->spdif_mutex);
 	spdif = snd_array_elem(&codec->spdif_out, idx);
 	nid = spdif->nid;
@@ -2308,6 +2312,8 @@ static int snd_hda_spdif_out_switch_get(struct snd_kcontrol *kcontrol,
 	int idx = kcontrol->private_value;
 	struct hda_spdif_out *spdif;
 
+	if (WARN_ON(codec->spdif_out.used <= idx))
+		return -EINVAL;
 	mutex_lock(&codec->spdif_mutex);
 	spdif = snd_array_elem(&codec->spdif_out, idx);
 	ucontrol->value.integer.value[0] = spdif->ctls & AC_DIG1_ENABLE;
@@ -2336,6 +2342,8 @@ static int snd_hda_spdif_out_switch_put(struct snd_kcontrol *kcontrol,
 	unsigned short val;
 	int change;
 
+	if (WARN_ON(codec->spdif_out.used <= idx))
+		return -EINVAL;
 	mutex_lock(&codec->spdif_mutex);
 	spdif = snd_array_elem(&codec->spdif_out, idx);
 	nid = spdif->nid;
@@ -2483,6 +2491,8 @@ void snd_hda_spdif_ctls_unassign(struct hda_codec *codec, int idx)
 {
 	struct hda_spdif_out *spdif;
 
+	if (WARN_ON(codec->spdif_out.used <= idx))
+		return;
 	mutex_lock(&codec->spdif_mutex);
 	spdif = snd_array_elem(&codec->spdif_out, idx);
 	spdif->nid = (u16)-1;
@@ -2503,6 +2513,8 @@ void snd_hda_spdif_ctls_assign(struct hda_codec *codec, int idx, hda_nid_t nid)
 	struct hda_spdif_out *spdif;
 	unsigned short val;
 
+	if (WARN_ON(codec->spdif_out.used <= idx))
+		return;
 	mutex_lock(&codec->spdif_mutex);
 	spdif = snd_array_elem(&codec->spdif_out, idx);
 	if (spdif->nid != nid) {