[PATCH v2] ASoC: dapm: avoid container_of() to get component

[Benjamin Bara]

From: Benjamin Bara <benjamin.bara@xxxxxxxxxxx>

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: f82eb06a40c8 ("ASoC: tegra: machine: Handle component name prefix")
Cc: stable@xxxxxxxxxxxxxxx # v6.7+
Signed-off-by: Benjamin Bara <benjamin.bara@xxxxxxxxxxx>
---
Hi!

I handled the new patch as V2 of the initial one, although it has a
different summary. Hope this is fine.
---
Changes in v2:
- fix snd_soc_dapm_widget_name_cmp() instead of reverting commit
- don't pick up R-b of Krzysztof, as different implementation
- Link to v1: https://lore.kernel.org/r/20241007-tegra-dapm-v1-1-bede7983fa76@xxxxxxxxxxx
---
 sound/soc/soc-dapm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 9330f1a3f7589dc467c04238830f2009a619a998..c34934c31ffec3970b34b24dcaa0826dfb7d8e86 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -2785,10 +2785,10 @@ 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);

---
base-commit: 8cf0b93919e13d1e8d4466eb4080a4c4d9d66d7b
change-id: 20241007-tegra-dapm-ef969b8f762a

Best regards,
-- 
Benjamin Bara <benjamin.bara@xxxxxxxxxxx>