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

From: Herton Ronaldo Krzesinski
Date: Tue Jul 31 2012 - 12:11:02 EST


On Tue, Jul 31, 2012 at 05:43:45AM +0100, Ben Hutchings wrote:
> 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);
> +

Hi, this doesn't build on 3.2:

linux-stable/sound/soc/soc-dapm.c: In function 'soc_dapm_shutdown_codec':
linux-stable/sound/soc/soc-dapm.c:2982:18: error: 'struct snd_soc_card' has no member named 'dapm_mutex'
linux-stable/sound/soc/soc-dapm.c:3007:20: error: 'struct snd_soc_card' has no member named 'dapm_mutex'

Looking at it, I'm not sure the fix is needed on 3.2, and introducing
dapm_mutex would be several changes.

> 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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Herton
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