ASoC: soc-compress: lock pcm_mutex to resolve lockdep error

If panic_on_warn=1 is added in bootargs and compress offload playback with
DPCM is started, kernel panic would be occurred because rtd->card->pcm_mutex
isn't held in soc_compr_open_fe() and soc_compr_free_fe() and it generates
lockdep warning in the following code.

void snd_soc_runtime_action(struct snd_soc_pcm_runtime *rtd,
			    int stream, int action)
{
	struct snd_soc_dai *dai;
	int i;

	lockdep_assert_held(&rtd->card->pcm_mutex);

To prevent lockdep warning but minimize side effect by adding mutex,
pcm_mutex is held just before snd_soc_runtime_activate() and
snd_soc_runtime_deactivate() and is released right after them.

Signed-off-by: Gyeongtaek Lee <gt82.lee@samsung.com>
Link: https://lore.kernel.org/r/1891546521.01617772502282.JavaMail.epsvc@epcpadp3
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/soc-compress.c b/sound/soc/soc-compress.c
index 83b511f..b4f5935 100644 (file)
--- a/sound/soc/soc-compress.c
+++ b/sound/soc/soc-compress.c
@@ -151,7 +151,9 @@ static int soc_compr_open_fe(struct snd_compr_stream *cstream)
        fe->dpcm[stream].state = SND_SOC_DPCM_STATE_OPEN;
        fe->dpcm[stream].runtime_update = SND_SOC_DPCM_UPDATE_NO;
 
+       mutex_lock_nested(&fe->card->pcm_mutex, fe->card->pcm_subclass);
        snd_soc_runtime_activate(fe, stream);
+       mutex_unlock(&fe->card->pcm_mutex);
 
        mutex_unlock(&fe->card->mutex);
 
@@ -178,7 +180,9 @@ static int soc_compr_free_fe(struct snd_compr_stream *cstream)
 
        mutex_lock_nested(&fe->card->mutex, SND_SOC_CARD_CLASS_RUNTIME);
 
+       mutex_lock_nested(&fe->card->pcm_mutex, fe->card->pcm_subclass);
        snd_soc_runtime_deactivate(fe, stream);
+       mutex_unlock(&fe->card->pcm_mutex);
 
        fe->dpcm[stream].runtime_update = SND_SOC_DPCM_UPDATE_FE;