[PATCH] ASoC: topology: Perform component check upfront

[Amadeusz Sławiński <amadeuszx.slawinski@xxxxxxxxxxxxxxx>]

Function soc_tplg_dbytes_create(), calls soc_tplg_init_kcontrol() to
perform additional driver specific initialization. While
soc_tplg_init_kcontrol() ensures that component is valid before invoking
ops->control_load, there is no such check at the end of
soc_tplg_dbytes_create() where list_add() is used.

Also in quite a few places, there is reference of tplg->comp->dapm or
tplg->comp->card, without any checks for tplg->comp.

In consequence of the above this may lead to referencing NULL pointer.

This allows for removal of now unnecessary checks.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@xxxxxxxxxxxxxxx>
---
 sound/soc/soc-topology.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/sound/soc/soc-topology.c b/sound/soc/soc-topology.c
index 575da6aba807..66958c57d884 100644
--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -251,7 +251,7 @@ static int soc_tplg_vendor_load_(struct soc_tplg *tplg,
 {
 	int ret = 0;
 
-	if (tplg->comp && tplg->ops && tplg->ops->vendor_load)
+	if (tplg->ops && tplg->ops->vendor_load)
 		ret = tplg->ops->vendor_load(tplg->comp, tplg->index, hdr);
 	else {
 		dev_err(tplg->dev, "ASoC: no vendor load callback for ID %d\n",
@@ -283,7 +283,7 @@ static int soc_tplg_vendor_load(struct soc_tplg *tplg,
 static int soc_tplg_widget_load(struct soc_tplg *tplg,
 	struct snd_soc_dapm_widget *w, struct snd_soc_tplg_dapm_widget *tplg_w)
 {
-	if (tplg->comp && tplg->ops && tplg->ops->widget_load)
+	if (tplg->ops && tplg->ops->widget_load)
 		return tplg->ops->widget_load(tplg->comp, tplg->index, w,
 			tplg_w);
 
@@ -295,7 +295,7 @@ static int soc_tplg_widget_load(struct soc_tplg *tplg,
 static int soc_tplg_widget_ready(struct soc_tplg *tplg,
 	struct snd_soc_dapm_widget *w, struct snd_soc_tplg_dapm_widget *tplg_w)
 {
-	if (tplg->comp && tplg->ops && tplg->ops->widget_ready)
+	if (tplg->ops && tplg->ops->widget_ready)
 		return tplg->ops->widget_ready(tplg->comp, tplg->index, w,
 			tplg_w);
 
@@ -307,7 +307,7 @@ static int soc_tplg_dai_load(struct soc_tplg *tplg,
 	struct snd_soc_dai_driver *dai_drv,
 	struct snd_soc_tplg_pcm *pcm, struct snd_soc_dai *dai)
 {
-	if (tplg->comp && tplg->ops && tplg->ops->dai_load)
+	if (tplg->ops && tplg->ops->dai_load)
 		return tplg->ops->dai_load(tplg->comp, tplg->index, dai_drv,
 			pcm, dai);
 
@@ -318,7 +318,7 @@ static int soc_tplg_dai_load(struct soc_tplg *tplg,
 static int soc_tplg_dai_link_load(struct soc_tplg *tplg,
 	struct snd_soc_dai_link *link, struct snd_soc_tplg_link_config *cfg)
 {
-	if (tplg->comp && tplg->ops && tplg->ops->link_load)
+	if (tplg->ops && tplg->ops->link_load)
 		return tplg->ops->link_load(tplg->comp, tplg->index, link, cfg);
 
 	return 0;
@@ -327,7 +327,7 @@ static int soc_tplg_dai_link_load(struct soc_tplg *tplg,
 /* tell the component driver that all firmware has been loaded in this request */
 static void soc_tplg_complete(struct soc_tplg *tplg)
 {
-	if (tplg->comp && tplg->ops && tplg->ops->complete)
+	if (tplg->ops && tplg->ops->complete)
 		tplg->ops->complete(tplg->comp);
 }
 
@@ -684,7 +684,7 @@ EXPORT_SYMBOL_GPL(snd_soc_tplg_widget_bind_event);
 static int soc_tplg_init_kcontrol(struct soc_tplg *tplg,
 	struct snd_kcontrol_new *k, struct snd_soc_tplg_ctl_hdr *hdr)
 {
-	if (tplg->comp && tplg->ops && tplg->ops->control_load)
+	if (tplg->ops && tplg->ops->control_load)
 		return tplg->ops->control_load(tplg->comp, tplg->index, k,
 			hdr);
 
@@ -1174,7 +1174,7 @@ static int soc_tplg_kcontrol_elems_load(struct soc_tplg *tplg,
 static int soc_tplg_add_route(struct soc_tplg *tplg,
 	struct snd_soc_dapm_route *route)
 {
-	if (tplg->comp && tplg->ops && tplg->ops->dapm_route_load)
+	if (tplg->ops && tplg->ops->dapm_route_load)
 		return tplg->ops->dapm_route_load(tplg->comp, tplg->index,
 			route);
 
@@ -2564,7 +2564,7 @@ static int soc_tplg_manifest_load(struct soc_tplg *tplg,
 	}
 
 	/* pass control to component driver for optional further init */
-	if (tplg->comp && tplg->ops && tplg->ops->manifest)
+	if (tplg->ops && tplg->ops->manifest)
 		ret = tplg->ops->manifest(tplg->comp, tplg->index, _manifest);
 
 	if (!abi_match)	/* free the duplicated one */
@@ -2736,6 +2736,10 @@ int snd_soc_tplg_component_load(struct snd_soc_component *comp,
 	struct soc_tplg tplg;
 	int ret;
 
+	/* component needs to exist to keep and reference data while parsing */
+	if (!comp)
+		return -EINVAL;
+
 	/* setup parsing context */
 	memset(&tplg, 0, sizeof(tplg));
 	tplg.fw = fw;
-- 
2.17.1