[PATCH] ASoC: wm_adsp: Pass full name to snd_ctl_notify

[Charles Keepax]

From: Adam Brickman <Adam.Brickman at cirrus.com>

A call to wm_adsp_write_ctl() could cause a kernel crash if it
does not retrieve a valid kcontrol from snd_soc_card_get_kcontrol().
This can happen due to a missing control name prefix. Then,
snd_ctl_notify() crashes when it tries to use the id field.

Modified wm_adsp_write_ctl() to incorporate the name_prefix (if applicable)
such that it is able to retrieve a valid id field from the kcontrol
once the platform has booted.

Fixes: eb65ccdb0836 ("ASoC: wm_adsp: Expose mixer control API")
Signed-off-by: Adam Brickman <Adam.Brickman at cirrus.com>
Signed-off-by: Charles Keepax <ckeepax at opensource.cirrus.com>
---
 sound/soc/codecs/wm_adsp.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/wm_adsp.c b/sound/soc/codecs/wm_adsp.c
index 410cca57da52d..344bd2c33bea1 100644
--- a/sound/soc/codecs/wm_adsp.c
+++ b/sound/soc/codecs/wm_adsp.c
@@ -2049,6 +2049,7 @@ int wm_adsp_write_ctl(struct wm_adsp *dsp, const char *name, int type,
 {
 	struct wm_coeff_ctl *ctl;
 	struct snd_kcontrol *kcontrol;
+	char ctl_name[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
 	int ret;
 
 	ctl = wm_adsp_get_ctl(dsp, name, type, alg);
@@ -2059,8 +2060,25 @@ int wm_adsp_write_ctl(struct wm_adsp *dsp, const char *name, int type,
 		return -EINVAL;
 
 	ret = wm_coeff_write_ctrl(ctl, buf, len);
+	if (ret)
+		return ret;
+
+	if (ctl->flags & WMFW_CTL_FLAG_SYS)
+		return 0;
+
+	if (dsp->component->name_prefix)
+		snprintf(ctl_name, SNDRV_CTL_ELEM_ID_NAME_MAXLEN, "%s %s",
+			 dsp->component->name_prefix, ctl->name);
+	else
+		snprintf(ctl_name, SNDRV_CTL_ELEM_ID_NAME_MAXLEN, "%s",
+			 ctl->name);
+
+	kcontrol = snd_soc_card_get_kcontrol(dsp->component->card, ctl_name);
+	if (!kcontrol) {
+		adsp_err(dsp, "Can't find kcontrol %s\n", ctl_name);
+		return -EINVAL;
+	}
 
-	kcontrol = snd_soc_card_get_kcontrol(dsp->component->card, ctl->name);
 	snd_ctl_notify(dsp->component->card->snd_card,
 		       SNDRV_CTL_EVENT_MASK_VALUE, &kcontrol->id);
 
-- 
2.11.0