[RFC PATCH v2 3/5] ASoC: soc-pcm: replace dpcm_lock with dpcm_mutex

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

It's not clear why a spinlock was used, and even less why the
'dpcm_lock' is used with the irqsave/irqrestore: DPCM functions are
typically not used in interrupt context.

Move to a mutex which will allow us to sleep for longer periods of
time and handle non-atomic triggers.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 include/sound/soc.h  |  2 +-
 sound/soc/soc-core.c |  2 +-
 sound/soc/soc-pcm.c  | 30 ++++++++++++------------------
 3 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h
index 8e6dd8a257c5..c13d8ec72d62 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -893,7 +893,7 @@ struct snd_soc_card {
 	struct mutex pcm_mutex;
 	enum snd_soc_pcm_subclass pcm_subclass;
 
-	spinlock_t dpcm_lock;
+	struct mutex dpcm_mutex; /* protect all dpcm states and updates */
 
 	int (*probe)(struct snd_soc_card *card);
 	int (*late_probe)(struct snd_soc_card *card);
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index c830e96afba2..e94d43c392e0 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -2339,7 +2339,7 @@ int snd_soc_register_card(struct snd_soc_card *card)
 	mutex_init(&card->mutex);
 	mutex_init(&card->dapm_mutex);
 	mutex_init(&card->pcm_mutex);
-	spin_lock_init(&card->dpcm_lock);
+	mutex_init(&card->dpcm_mutex);
 
 	return snd_soc_bind_card(card);
 }
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 360811f8a18c..af12593b033a 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -85,7 +85,6 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
 	struct snd_pcm_hw_params *params = &fe->dpcm[stream].hw_params;
 	struct snd_soc_dpcm *dpcm;
 	ssize_t offset = 0;
-	unsigned long flags;
 
 	/* FE state */
 	offset += scnprintf(buf + offset, size - offset,
@@ -113,7 +112,7 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
 		goto out;
 	}
 
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	mutex_lock(&fe->card->dpcm_mutex);
 	for_each_dpcm_be(fe, stream, dpcm) {
 		struct snd_soc_pcm_runtime *be = dpcm->be;
 		params = &dpcm->hw_params;
@@ -134,7 +133,7 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
 					   params_channels(params),
 					   params_rate(params));
 	}
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	mutex_unlock(&fe->card->dpcm_mutex);
 out:
 	return offset;
 }
@@ -1141,7 +1140,6 @@ static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 		struct snd_soc_pcm_runtime *be, int stream)
 {
 	struct snd_soc_dpcm *dpcm;
-	unsigned long flags;
 
 	/* only add new dpcms */
 	for_each_dpcm_be(fe, stream, dpcm) {
@@ -1157,10 +1155,10 @@ static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 	dpcm->fe = fe;
 	be->dpcm[stream].runtime = fe->dpcm[stream].runtime;
 	dpcm->state = SND_SOC_DPCM_LINK_STATE_NEW;
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	mutex_lock(&fe->card->dpcm_mutex);
 	list_add(&dpcm->list_be, &fe->dpcm[stream].be_clients);
 	list_add(&dpcm->list_fe, &be->dpcm[stream].fe_clients);
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	mutex_unlock(&fe->card->dpcm_mutex);
 
 	dev_dbg(fe->dev, "connected new DPCM %s path %s %s %s\n",
 			stream ? "capture" : "playback",  fe->dai_link->name,
@@ -1203,7 +1201,6 @@ static void dpcm_be_reparent(struct snd_soc_pcm_runtime *fe,
 void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream)
 {
 	struct snd_soc_dpcm *dpcm, *d;
-	unsigned long flags;
 
 	for_each_dpcm_be_safe(fe, stream, dpcm, d) {
 		dev_dbg(fe->dev, "ASoC: BE %s disconnect check for %s\n",
@@ -1222,10 +1219,10 @@ void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream)
 
 		dpcm_remove_debugfs_state(dpcm);
 
-		spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+		mutex_lock(&fe->card->dpcm_mutex);
 		list_del(&dpcm->list_be);
 		list_del(&dpcm->list_fe);
-		spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+		mutex_unlock(&fe->card->dpcm_mutex);
 		kfree(dpcm);
 	}
 }
@@ -1441,12 +1438,11 @@ int dpcm_process_paths(struct snd_soc_pcm_runtime *fe,
 void dpcm_clear_pending_state(struct snd_soc_pcm_runtime *fe, int stream)
 {
 	struct snd_soc_dpcm *dpcm;
-	unsigned long flags;
 
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	mutex_lock(&fe->card->dpcm_mutex);
 	for_each_dpcm_be(fe, stream, dpcm)
 		dpcm_set_be_update_state(dpcm->be, stream, SND_SOC_DPCM_UPDATE_NO);
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	mutex_unlock(&fe->card->dpcm_mutex);
 }
 
 void dpcm_be_dai_stop(struct snd_soc_pcm_runtime *fe, int stream,
@@ -2364,7 +2360,6 @@ static int dpcm_run_update_startup(struct snd_soc_pcm_runtime *fe, int stream)
 	struct snd_soc_dpcm *dpcm;
 	enum snd_soc_dpcm_trigger trigger = fe->dai_link->trigger[stream];
 	int ret = 0;
-	unsigned long flags;
 
 	dev_dbg(fe->dev, "ASoC: runtime %s open on FE %s\n",
 			stream ? "capture" : "playback", fe->dai_link->name);
@@ -2433,7 +2428,7 @@ static int dpcm_run_update_startup(struct snd_soc_pcm_runtime *fe, int stream)
 	dpcm_be_dai_shutdown(fe, stream);
 disconnect:
 	/* disconnect any pending BEs */
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	mutex_lock(&fe->card->dpcm_mutex);
 	for_each_dpcm_be(fe, stream, dpcm) {
 		struct snd_soc_pcm_runtime *be = dpcm->be;
 
@@ -2445,7 +2440,7 @@ static int dpcm_run_update_startup(struct snd_soc_pcm_runtime *fe, int stream)
 			be->dpcm[stream].state == SND_SOC_DPCM_STATE_NEW)
 				dpcm->state = SND_SOC_DPCM_LINK_STATE_FREE;
 	}
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	mutex_unlock(&fe->card->dpcm_mutex);
 
 	if (ret < 0)
 		dev_err(fe->dev, "ASoC: %s() failed (%d)\n", __func__, ret);
@@ -2845,10 +2840,9 @@ static int snd_soc_dpcm_check_state(struct snd_soc_pcm_runtime *fe,
 	struct snd_soc_dpcm *dpcm;
 	int state;
 	int ret = 1;
-	unsigned long flags;
 	int i;
 
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	mutex_lock(&fe->card->dpcm_mutex);
 	for_each_dpcm_fe(be, stream, dpcm) {
 
 		if (dpcm->fe == fe)
@@ -2862,7 +2856,7 @@ static int snd_soc_dpcm_check_state(struct snd_soc_pcm_runtime *fe,
 			}
 		}
 	}
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	mutex_unlock(&fe->card->dpcm_mutex);
 
 	/* it's safe to do this BE DAI */
 	return ret;
-- 
2.25.1