>From 3c41e986a386fd157dd8270d0ce3e402df1bfd0e Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Fri, 15 Oct 2021 17:17:55 +0200
Subject: [PATCH 3/3] ASoC: DPCM: Take a stream lock at BE trigger operation

For avoiding the race among concurrent accesses to BEs.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/soc/soc-pcm.c | 46 ++++++++++++++++++++++++++++-----------------
 1 file changed, 29 insertions(+), 17 deletions(-)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 5bd4f953359a..edfda2e30c7f 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -46,12 +46,18 @@ static inline void snd_soc_dpcm_stream_lock_irq(struct snd_soc_pcm_runtime *rtd,
 	snd_pcm_stream_lock_irq(snd_soc_dpcm_get_substream(rtd, stream));
 }
 
+#define snd_soc_dpcm_stream_lock_irqsave(rtd, stream, flags) \
+	snd_pcm_stream_lock_irqsave(snd_soc_dpcm_get_substream(rtd, stream), flags)
+
 static inline void snd_soc_dpcm_stream_unlock_irq(struct snd_soc_pcm_runtime *rtd,
 						  int stream)
 {
 	snd_pcm_stream_unlock_irq(snd_soc_dpcm_get_substream(rtd, stream));
 }
 
+#define snd_soc_dpcm_stream_unlock_irqrestore(rtd, stream, flags) \
+	snd_pcm_stream_unlock_irqrestore(snd_soc_dpcm_get_substream(rtd, stream), flags)
+
 #define DPCM_MAX_BE_USERS	8
 
 static inline const char *soc_cpu_dai_name(struct snd_soc_pcm_runtime *rtd)
@@ -2093,6 +2099,7 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
 {
 	struct snd_soc_pcm_runtime *be;
 	struct snd_soc_dpcm *dpcm;
+	unsigned long flags;
 	int ret = 0;
 
 	for_each_dpcm_be(fe, stream, dpcm) {
@@ -2101,9 +2108,11 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
 		be = dpcm->be;
 		be_substream = snd_soc_dpcm_get_substream(be, stream);
 
+		snd_soc_dpcm_stream_lock_irqsave(be, stream, flags);
+
 		/* is this op for this BE ? */
 		if (!snd_soc_dpcm_be_can_update(fe, be, stream))
-			continue;
+			goto next;
 
 		dev_dbg(be->dev, "ASoC: trigger BE %s cmd %d\n",
 			be->dai_link->name, cmd);
@@ -2113,77 +2122,80 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
 			if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_PREPARE) &&
 			    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_STOP) &&
 			    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED))
-				continue;
+				goto next;
 
 			ret = soc_pcm_trigger(be_substream, cmd);
 			if (ret)
-				goto end;
+				goto next;
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_START;
 			break;
 		case SNDRV_PCM_TRIGGER_RESUME:
 			if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_SUSPEND))
-				continue;
+				goto next;
 
 			ret = soc_pcm_trigger(be_substream, cmd);
 			if (ret)
-				goto end;
+				goto next;
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_START;
 			break;
 		case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 			if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED))
-				continue;
+				goto next;
 
 			ret = soc_pcm_trigger(be_substream, cmd);
 			if (ret)
-				goto end;
+				goto next;
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_START;
 			break;
 		case SNDRV_PCM_TRIGGER_STOP:
 			if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_START) &&
 			    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED))
-				continue;
+				goto next;
 
 			if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream))
-				continue;
+				goto next;
 
 			ret = soc_pcm_trigger(be_substream, cmd);
 			if (ret)
-				goto end;
+				goto next;
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_STOP;
 			break;
 		case SNDRV_PCM_TRIGGER_SUSPEND:
 			if (be->dpcm[stream].state != SND_SOC_DPCM_STATE_START)
-				continue;
+				goto next;
 
 			if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream))
-				continue;
+				goto next;
 
 			ret = soc_pcm_trigger(be_substream, cmd);
 			if (ret)
-				goto end;
+				goto next;
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_SUSPEND;
 			break;
 		case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 			if (be->dpcm[stream].state != SND_SOC_DPCM_STATE_START)
-				continue;
+				goto next;
 
 			if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream))
-				continue;
+				goto next;
 
 			ret = soc_pcm_trigger(be_substream, cmd);
 			if (ret)
-				goto end;
+				goto next;
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_PAUSED;
 			break;
 		}
+	next:
+		snd_soc_dpcm_stream_unlock_irqrestore(be, stream, flags);
+		if (ret)
+			break;
 	}
-end:
 	if (ret < 0)
 		dev_err(fe->dev, "ASoC: %s() failed at %s (%d)\n",
 			__func__, be->dai_link->name, ret);
-- 
2.31.1

