ASoC: soc-core: fixup dead-lock at snd_soc_unregister_component()

snd_soc_unregister_component() is calling snd_soc_lookup_component()
under mutex_lock(). But, snd_soc_lookup_component() itself is using
mutex_lock(), thus it will be dead-lock.
This patch adds _nolocked version of it, and avoid dead-lock issue.

Fixes: ac6a4dd3e9f0("ASoC: soc-core: use snd_soc_lookup_component() at snd_soc_unregister_component()")
Reported-by: "kernelci.org bot" <bot@kernelci.org>"
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87bltph4da.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index a7ad81e..55014e7 100644 (file)
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -356,14 +356,13 @@ struct snd_soc_component *snd_soc_rtdcom_lookup(struct snd_soc_pcm_runtime *rtd,
 }
 EXPORT_SYMBOL_GPL(snd_soc_rtdcom_lookup);
 
-struct snd_soc_component *snd_soc_lookup_component(struct device *dev,
-                                                  const char *driver_name)
+static struct snd_soc_component
+*snd_soc_lookup_component_nolocked(struct device *dev, const char *driver_name)
 {
        struct snd_soc_component *component;
        struct snd_soc_component *found_component;
 
        found_component = NULL;
-       mutex_lock(&client_mutex);
        for_each_component(component) {
                if ((dev == component->dev) &&
                    (!driver_name ||
@@ -373,10 +372,21 @@ struct snd_soc_component *snd_soc_lookup_component(struct device *dev,
                        break;
                }
        }
-       mutex_unlock(&client_mutex);
 
        return found_component;
 }
+
+struct snd_soc_component *snd_soc_lookup_component(struct device *dev,
+                                                  const char *driver_name)
+{
+       struct snd_soc_component *component;
+
+       mutex_lock(&client_mutex);
+       component = snd_soc_lookup_component_nolocked(dev, driver_name);
+       mutex_unlock(&client_mutex);
+
+       return component;
+}
 EXPORT_SYMBOL_GPL(snd_soc_lookup_component);
 
 struct snd_pcm_substream *snd_soc_get_dai_substream(struct snd_soc_card *card,
@@ -2855,7 +2865,7 @@ void snd_soc_unregister_component(struct device *dev)
 
        mutex_lock(&client_mutex);
        while (1) {
-               component = snd_soc_lookup_component(dev, NULL);
+               component = snd_soc_lookup_component_nolocked(dev, NULL);
                if (!component)
                        break;