ASoC: dapm: avoid container_of() to get component

commit 3fe9f58 upstream.

The current implementation does not work for widgets of DAPMs without
component, as snd_soc_dapm_to_component() requires it. If the widget is
directly owned by the card, e.g. as it is the case for the tegra
implementation, the call leads to UB. Therefore directly access the
component of the widget's DAPM to be able to check if a component is
available.

Fixes: f82eb06 ("ASoC: tegra: machine: Handle component name prefix")
Cc: stable@vger.kernel.org # v6.7+
Signed-off-by: Benjamin Bara <benjamin.bara@skidata.com>
Link: https://patch.msgid.link/20241008-tegra-dapm-v2-1-5e999cb5f0e7@skidata.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: benjamin-bara-skidata

sound/soc/soc-dapm.c

@@ -2786,10 +2786,10 @@ EXPORT_SYMBOL_GPL(snd_soc_dapm_update_dai);
 
 int snd_soc_dapm_widget_name_cmp(struct snd_soc_dapm_widget *widget, const char *s)
 {
-	struct snd_soc_component *component = snd_soc_dapm_to_component(widget->dapm);
+	struct snd_soc_component *component = widget->dapm->component;
 	const char *wname = widget->name;
 
-	if (component->name_prefix)
+	if (component && component->name_prefix)
 		wname += strlen(component->name_prefix) + 1; /* plus space */
 
 	return strcmp(wname, s);