[ 35/73] ASoC: dapm: Fix locking during codec shutdown

[Ben Hutchings]

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Liam Girdwood <lrg@xxxxxx>

commit 01005a729a17ab419f61a366e22f3419e7a2c3fe upstream.

Codec shutdown performs a DAPM power sequence that might cause conflicts
and/or race conditions if another stream power event is running simultaneously.
Use card's dapm mutex to protect any potential race condition between them.

Signed-off-by: Misael Lopez Cruz <misael.lopez@xxxxxx>
Signed-off-by: Liam Girdwood <lrg@xxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 sound/soc/soc-dapm.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 5be4f9a..114f2af 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -3537,10 +3537,13 @@ EXPORT_SYMBOL_GPL(snd_soc_dapm_free);
 
 static void soc_dapm_shutdown_codec(struct snd_soc_dapm_context *dapm)
 {
+	struct snd_soc_card *card = dapm->card;
 	struct snd_soc_dapm_widget *w;
 	LIST_HEAD(down_list);
 	int powerdown = 0;
 
+	mutex_lock(&card->dapm_mutex);
+
 	list_for_each_entry(w, &dapm->card->widgets, list) {
 		if (w->dapm != dapm)
 			continue;
@@ -3563,6 +3566,8 @@ static void soc_dapm_shutdown_codec(struct snd_soc_dapm_context *dapm)
 			snd_soc_dapm_set_bias_level(dapm,
 						    SND_SOC_BIAS_STANDBY);
 	}
+
+	mutex_unlock(&card->dapm_mutex);
 }
 
 /*


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