ALSA: hda - fix ELD memory leak

memset(eld) clears eld->proc_entry which will leak the struct
snd_info_entry when unloading module.

Fix it by
- memset only the fields before eld->eld_buffer
- set eld->eld_valid to true _after_ all eld fields have been filled

Cc: <stable@kernel.org>
Cc: Pierre-louis Bossart <pierre-louis.bossart@intel.com>
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_eld.c

@@ -297,10 +297,10 @@ static int hdmi_update_eld(struct hdmi_eld *e,
 					buf + ELD_FIXED_BYTES + mnl + 3 * i);
 	}
 
+	e->eld_valid = true;
 	return 0;
 
 out_fail:
-	e->eld_ver = 0;
 	return -EINVAL;
 }
 
@@ -323,9 +323,6 @@ int snd_hdmi_get_eld(struct hdmi_eld *eld,
 	 * ELD is valid, actual eld_size is assigned in hdmi_update_eld()
 	 */
 
-	if (!eld->eld_valid)
-		return -ENOENT;
-
 	size = snd_hdmi_get_eld_size(codec, nid);
 	if (size == 0) {
 		/* wfg: workaround for ASUS P5E-VM HDMI board */

sound/pci/hda/hda_local.h

@@ -653,6 +653,9 @@ struct hdmi_eld {
 	int	spk_alloc;
 	int	sad_count;
 	struct cea_sad sad[ELD_MAX_SAD];
+	/*
+	 * all fields above eld_buffer will be cleared before updating ELD
+	 */
 	char    eld_buffer[ELD_MAX_SIZE];
 #ifdef CONFIG_PROC_FS
 	struct snd_info_entry *proc_entry;

sound/pci/hda/patch_hdmi.c

@@ -980,20 +980,19 @@ static void hdmi_present_sense(struct hda_codec *codec, hda_nid_t pin_nid,
 	 * the unsolicited response to avoid custom WARs.
 	 */
 	int present = snd_hda_pin_sense(codec, pin_nid);
+	bool eld_valid = false;
 
-	memset(eld, 0, sizeof(*eld));
+	memset(eld, 0, offsetof(struct hdmi_eld, eld_buffer));
 
 	eld->monitor_present	= !!(present & AC_PINSENSE_PRESENCE);
 	if (eld->monitor_present)
-		eld->eld_valid	= !!(present & AC_PINSENSE_ELDV);
-	else
-		eld->eld_valid	= 0;
+		eld_valid	= !!(present & AC_PINSENSE_ELDV);
 
 	printk(KERN_INFO
 		"HDMI status: Codec=%d Pin=%d Presence_Detect=%d ELD_Valid=%d\n",
-		codec->addr, pin_nid, eld->monitor_present, eld->eld_valid);
+		codec->addr, pin_nid, eld->monitor_present, eld_valid);
 
-	if (eld->eld_valid)
+	if (eld_valid)
 		if (!snd_hdmi_get_eld(eld, codec, pin_nid))
 			snd_hdmi_show_eld(eld);