ASoC: tegra-alt: check the allocation of dai link

kzalloc() can be failed under low memory condition. In such a case, the
following memcpy() can cause a panic. Thus, the return value of
kzalloc() should be checked. If tegra_machine_get_dai_link_t18x() is
called, the return value should also be checked.

Bug 2647682

Change-Id: Ia200436a3b1877933932b9a086862f5507c8da54
Signed-off-by: Kwangwoo Lee <kwangwool@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2159959
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Sameer Pujar <spujar@nvidia.com>
Reviewed-by: Ravindra Lokhande <rlokhande@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

sound/soc/tegra-alt/utils/tegra_asoc_machine_alt.c

@@ -2915,6 +2915,9 @@ struct snd_soc_dai_link *tegra_machine_get_dai_link(void)
 	tegra_asoc_machine_links = kzalloc(size *
 		sizeof(struct snd_soc_dai_link), GFP_KERNEL);
 
+	if (!tegra_asoc_machine_links)
+		return NULL;
+
 	memcpy(tegra_asoc_machine_links, link,
 		size * sizeof(struct snd_soc_dai_link));
 
@@ -3024,6 +3027,9 @@ struct snd_soc_codec_conf *tegra_machine_get_codec_conf(void)
 	tegra_asoc_codec_conf = kzalloc(size *
 		sizeof(struct snd_soc_codec_conf), GFP_KERNEL);
 
+	if (!tegra_asoc_codec_conf)
+		return NULL;
+
 	memcpy(tegra_asoc_codec_conf, conf,
 		size * sizeof(struct snd_soc_codec_conf));
 
@@ -3446,6 +3452,9 @@ struct snd_soc_dai_link *tegra_machine_get_dai_link_t18x(void)
 	tegra_asoc_machine_links_t18x = kzalloc(size *
 		sizeof(struct snd_soc_dai_link), GFP_KERNEL);
 
+	if (!tegra_asoc_machine_links_t18x)
+		return NULL;
+
 	memcpy(tegra_asoc_machine_links_t18x, link,
 		size * sizeof(struct snd_soc_dai_link));
 
@@ -3504,6 +3513,9 @@ struct snd_soc_codec_conf *tegra_machine_get_codec_conf_t18x(void)
 	tegra_asoc_codec_conf_t18x = kzalloc(size *
 		sizeof(struct snd_soc_codec_conf), GFP_KERNEL);
 
+	if (!tegra_asoc_codec_conf_t18x)
+		return NULL;
+
 	memcpy(tegra_asoc_codec_conf_t18x, conf,
 		size * sizeof(struct snd_soc_codec_conf));