[PATCH 1/6] ASoC: soc-pcm: use GFP_ATOMIC for dpcm structure

[PATCH 1/6] ASoC: soc-pcm: use GFP_ATOMIC for dpcm structure

[yixuanjiang]

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

[ Upstream commit d8a9c6e1f6766a16cf02b4e99a629f3c5512c183 ]

We allocate a structure in dpcm_be_connect(), which may be called in
atomic context. Using GFP_KERNEL is not quite right, we have to use
GFP_ATOMIC to prevent the allocator from sleeping.

Suggested-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20211207173745.15850-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Fixes: aa9ff6a4955f ("ASoC: soc-compress: Reposition and add pcm_mutex")
Signed-off-by: Yixuan Jiang <yixuanjiang@google.com>
Cc: stable@vger.kernel.org # 5.15+
---
 sound/soc/soc-pcm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 3b673477f6215..cffae9b7c2548 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1132,7 +1132,7 @@ static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 			return 0;
 	}
 
-	dpcm = kzalloc(sizeof(struct snd_soc_dpcm), GFP_KERNEL);
+	dpcm = kzalloc(sizeof(struct snd_soc_dpcm), GFP_ATOMIC);
 	if (!dpcm)
 		return -ENOMEM;
 
-- 
2.40.1.521.gf1e218fcd8-goog

Re: [PATCH 1/6] ASoC: soc-pcm: use GFP_ATOMIC for dpcm structure

[Sasha Levin]

On Thu, May 11, 2023 at 08:08:36PM +0800, yixuanjiang wrote:
>From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
>
>[ Upstream commit d8a9c6e1f6766a16cf02b4e99a629f3c5512c183 ]

Queued up, thanks!

-- 
Thanks,
Sasha

[PATCH 2/6] ASoC: soc-pcm: align BE 'atomicity' with that of the FE

[yixuanjiang]

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

[ Upstream commit bbf7d3b1c4f40eb02dd1dffb500ba00b0bff0303 ]

Since the flow for DPCM is based on taking a lock for the FE first, we
need to make sure during the connection between a BE and an FE that
they both use the same 'atomicity', otherwise we may sleep in atomic
context.

If the FE is nonatomic, this patch forces the BE to be nonatomic as
well. That should have no negative impact since the BE 'inherits' the
FE properties.

However, if the FE is atomic and the BE is not, then the configuration
is flagged as invalid.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
[ removed FE stream lock by tiwai ]
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20211207173745.15850-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Fixes: aa9ff6a4955f ("ASoC: soc-compress: Reposition and add pcm_mutex")
Signed-off-by: Yixuan Jiang <yixuanjiang@google.com>
Cc: stable@vger.kernel.org # 5.15+
---
 sound/soc/soc-pcm.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index cffae9b7c2548..373f20bd14301 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1123,6 +1123,8 @@ static snd_pcm_uframes_t soc_pcm_pointer(struct snd_pcm_substream *substream)
 static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 		struct snd_soc_pcm_runtime *be, int stream)
 {
+	struct snd_pcm_substream *fe_substream;
+	struct snd_pcm_substream *be_substream;
 	struct snd_soc_dpcm *dpcm;
 	unsigned long flags;
 
@@ -1132,6 +1134,20 @@ static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 			return 0;
 	}
 
+	fe_substream = snd_soc_dpcm_get_substream(fe, stream);
+	be_substream = snd_soc_dpcm_get_substream(be, stream);
+
+	if (!fe_substream->pcm->nonatomic && be_substream->pcm->nonatomic) {
+		dev_err(be->dev, "%s: FE is atomic but BE is nonatomic, invalid configuration\n",
+			__func__);
+		return -EINVAL;
+	}
+	if (fe_substream->pcm->nonatomic && !be_substream->pcm->nonatomic) {
+		dev_warn(be->dev, "%s: FE is nonatomic but BE is not, forcing BE as nonatomic\n",
+			 __func__);
+		be_substream->pcm->nonatomic = 1;
+	}
+
 	dpcm = kzalloc(sizeof(struct snd_soc_dpcm), GFP_ATOMIC);
 	if (!dpcm)
 		return -ENOMEM;
-- 
2.40.1.521.gf1e218fcd8-goog

[PATCH 3/6] ASoC: soc-pcm: Fix and cleanup DPCM locking

[yixuanjiang]

From: Takashi Iwai <tiwai@suse.de>

[ Upstream commit b7898396f4bbe160f546d0c5e9fa17cca9a7d153 ]

The existing locking for DPCM has several issues
a) a confusing mix of card->mutex and card->pcm_mutex.
b) a dpcm_lock spinlock added inconsistently and on paths that could
be recursively taken. The use of irqsave/irqrestore was also overkill.

The suggested model is:

1) The pcm_mutex is the top-most protection of BE links in the FE. The
pcm_mutex is applied always on either the top PCM callbacks or the
external call from DAPM, not taken in the internal functions.

2) the FE stream lock is taken in higher levels before invoking
dpcm_be_dai_trigger()

3) when adding and deleting a BE, both the pcm_mutex and FE stream
lock are taken.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
[clarification of commit message by plbossart]
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20211207173745.15850-4-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Fixes: aa9ff6a4955f ("ASoC: soc-compress: Reposition and add pcm_mutex")
Signed-off-by: Yixuan Jiang <yixuanjiang@google.com>
Cc: stable@vger.kernel.org # 5.15+
---
 include/sound/soc.h  |   2 -
 sound/soc/soc-core.c |   1 -
 sound/soc/soc-pcm.c  | 229 ++++++++++++++++++++++++++++---------------
 3 files changed, 152 insertions(+), 80 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h
index 0fa0a34582322..c653c5ece68ca 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -907,8 +907,6 @@ struct snd_soc_card {
 	struct mutex pcm_mutex;
 	enum snd_soc_pcm_subclass pcm_subclass;
 
-	spinlock_t dpcm_lock;
-
 	int (*probe)(struct snd_soc_card *card);
 	int (*late_probe)(struct snd_soc_card *card);
 	int (*remove)(struct snd_soc_card *card);
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index edebb3f50a069..f24e32c765a24 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -2339,7 +2339,6 @@ 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);
 
 	return snd_soc_bind_card(card);
 }
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 373f20bd14301..a9869203804e7 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -27,6 +27,31 @@
 #include <sound/soc-link.h>
 #include <sound/initval.h>
 
+static inline void snd_soc_dpcm_mutex_lock(struct snd_soc_pcm_runtime *rtd)
+{
+	mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);
+}
+
+static inline void snd_soc_dpcm_mutex_unlock(struct snd_soc_pcm_runtime *rtd)
+{
+	mutex_unlock(&rtd->card->pcm_mutex);
+}
+
+#define snd_soc_dpcm_mutex_assert_held(rtd) \
+	lockdep_assert_held(&(rtd)->card->pcm_mutex)
+
+static inline void snd_soc_dpcm_stream_lock_irq(struct snd_soc_pcm_runtime *rtd,
+						int stream)
+{
+	snd_pcm_stream_lock_irq(snd_soc_dpcm_get_substream(rtd, stream));
+}
+
+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 DPCM_MAX_BE_USERS	8
 
 static inline const char *soc_cpu_dai_name(struct snd_soc_pcm_runtime *rtd)
@@ -73,7 +98,6 @@ 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,
@@ -101,7 +125,6 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
 		goto out;
 	}
 
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
 	for_each_dpcm_be(fe, stream, dpcm) {
 		struct snd_soc_pcm_runtime *be = dpcm->be;
 		params = &dpcm->hw_params;
@@ -122,7 +145,6 @@ 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);
 out:
 	return offset;
 }
@@ -145,11 +167,13 @@ static ssize_t dpcm_state_read_file(struct file *file, char __user *user_buf,
 	if (!buf)
 		return -ENOMEM;
 
+	snd_soc_dpcm_mutex_lock(fe);
 	for_each_pcm_streams(stream)
 		if (snd_soc_dai_stream_valid(asoc_rtd_to_cpu(fe, 0), stream))
 			offset += dpcm_show_state(fe, stream,
 						  buf + offset,
 						  out_count - offset);
+	snd_soc_dpcm_mutex_unlock(fe);
 
 	ret = simple_read_from_buffer(user_buf, count, ppos, buf, offset);
 
@@ -221,14 +245,14 @@ static void dpcm_set_fe_update_state(struct snd_soc_pcm_runtime *fe,
 	struct snd_pcm_substream *substream =
 		snd_soc_dpcm_get_substream(fe, stream);
 
-	snd_pcm_stream_lock_irq(substream);
+	snd_soc_dpcm_stream_lock_irq(fe, stream);
 	if (state == SND_SOC_DPCM_UPDATE_NO && fe->dpcm[stream].trigger_pending) {
 		dpcm_fe_dai_do_trigger(substream,
 				       fe->dpcm[stream].trigger_pending - 1);
 		fe->dpcm[stream].trigger_pending = 0;
 	}
 	fe->dpcm[stream].runtime_update = state;
-	snd_pcm_stream_unlock_irq(substream);
+	snd_soc_dpcm_stream_unlock_irq(fe, stream);
 }
 
 static void dpcm_set_be_update_state(struct snd_soc_pcm_runtime *be,
@@ -256,7 +280,7 @@ void snd_soc_runtime_action(struct snd_soc_pcm_runtime *rtd,
 	struct snd_soc_dai *dai;
 	int i;
 
-	lockdep_assert_held(&rtd->card->pcm_mutex);
+	snd_soc_dpcm_mutex_assert_held(rtd);
 
 	for_each_rtd_dais(rtd, i, dai)
 		snd_soc_dai_action(dai, stream, action);
@@ -309,6 +333,8 @@ int dpcm_dapm_stream_event(struct snd_soc_pcm_runtime *fe, int dir,
 {
 	struct snd_soc_dpcm *dpcm;
 
+	snd_soc_dpcm_mutex_assert_held(fe);
+
 	for_each_dpcm_be(fe, dir, dpcm) {
 
 		struct snd_soc_pcm_runtime *be = dpcm->be;
@@ -646,14 +672,14 @@ static int soc_pcm_components_close(struct snd_pcm_substream *substream,
 	return ret;
 }
 
-static int soc_pcm_clean(struct snd_pcm_substream *substream, int rollback)
+static int soc_pcm_clean(struct snd_soc_pcm_runtime *rtd,
+			 struct snd_pcm_substream *substream, int rollback)
 {
-	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
 	struct snd_soc_component *component;
 	struct snd_soc_dai *dai;
 	int i;
 
-	mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);
+	snd_soc_dpcm_mutex_assert_held(rtd);
 
 	if (!rollback)
 		snd_soc_runtime_deactivate(rtd, substream->stream);
@@ -665,9 +691,6 @@ static int soc_pcm_clean(struct snd_pcm_substream *substream, int rollback)
 
 	soc_pcm_components_close(substream, rollback);
 
-
-	mutex_unlock(&rtd->card->pcm_mutex);
-
 	snd_soc_pcm_component_pm_runtime_put(rtd, substream, rollback);
 
 	for_each_rtd_components(rtd, i, component)
@@ -682,9 +705,21 @@ static int soc_pcm_clean(struct snd_pcm_substream *substream, int rollback)
  * freed here. The cpu DAI, codec DAI, machine and components are also
  * shutdown.
  */
+static int __soc_pcm_close(struct snd_soc_pcm_runtime *rtd,
+			   struct snd_pcm_substream *substream)
+{
+	return soc_pcm_clean(rtd, substream, 0);
+}
+
+/* PCM close ops for non-DPCM streams */
 static int soc_pcm_close(struct snd_pcm_substream *substream)
 {
-	return soc_pcm_clean(substream, 0);
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+
+	snd_soc_dpcm_mutex_lock(rtd);
+	soc_pcm_clean(rtd, substream, 0);
+	snd_soc_dpcm_mutex_unlock(rtd);
+	return 0;
 }
 
 static int soc_hw_sanity_check(struct snd_pcm_substream *substream)
@@ -730,21 +765,21 @@ static int soc_hw_sanity_check(struct snd_pcm_substream *substream)
  * then initialized and any private data can be allocated. This also calls
  * startup for the cpu DAI, component, machine and codec DAI.
  */
-static int soc_pcm_open(struct snd_pcm_substream *substream)
+static int __soc_pcm_open(struct snd_soc_pcm_runtime *rtd,
+			  struct snd_pcm_substream *substream)
 {
-	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
 	struct snd_soc_component *component;
 	struct snd_soc_dai *dai;
 	int i, ret = 0;
 
+	snd_soc_dpcm_mutex_assert_held(rtd);
+
 	for_each_rtd_components(rtd, i, component)
 		pinctrl_pm_select_default_state(component->dev);
 
 	ret = snd_soc_pcm_component_pm_runtime_get(rtd, substream);
 	if (ret < 0)
-		goto pm_err;
-
-	mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);
+		goto err;
 
 	ret = soc_pcm_components_open(substream);
 	if (ret < 0)
@@ -786,16 +821,26 @@ static int soc_pcm_open(struct snd_pcm_substream *substream)
 	snd_soc_runtime_activate(rtd, substream->stream);
 	ret = 0;
 err:
-	mutex_unlock(&rtd->card->pcm_mutex);
-pm_err:
 	if (ret < 0) {
-		soc_pcm_clean(substream, 1);
+		soc_pcm_clean(rtd, substream, 1);
 		dev_err(rtd->dev, "%s() failed (%d)", __func__, ret);
 	}
 
 	return ret;
 }
 
+/* PCM open ops for non-DPCM streams */
+static int soc_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+	int ret;
+
+	snd_soc_dpcm_mutex_lock(rtd);
+	ret = __soc_pcm_open(rtd, substream);
+	snd_soc_dpcm_mutex_unlock(rtd);
+	return ret;
+}
+
 static void codec2codec_close_delayed_work(struct snd_soc_pcm_runtime *rtd)
 {
 	/*
@@ -811,13 +856,13 @@ static void codec2codec_close_delayed_work(struct snd_soc_pcm_runtime *rtd)
  * rate, etc.  This function is non atomic and can be called multiple times,
  * it can refer to the runtime info.
  */
-static int soc_pcm_prepare(struct snd_pcm_substream *substream)
+static int __soc_pcm_prepare(struct snd_soc_pcm_runtime *rtd,
+			     struct snd_pcm_substream *substream)
 {
-	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
 	struct snd_soc_dai *dai;
 	int i, ret = 0;
 
-	mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);
+	snd_soc_dpcm_mutex_assert_held(rtd);
 
 	ret = snd_soc_link_prepare(substream);
 	if (ret < 0)
@@ -845,14 +890,24 @@ static int soc_pcm_prepare(struct snd_pcm_substream *substream)
 		snd_soc_dai_digital_mute(dai, 0, substream->stream);
 
 out:
-	mutex_unlock(&rtd->card->pcm_mutex);
-
 	if (ret < 0)
 		dev_err(rtd->dev, "ASoC: %s() failed (%d)\n", __func__, ret);
 
 	return ret;
 }
 
+/* PCM prepare ops for non-DPCM streams */
+static int soc_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+	int ret;
+
+	snd_soc_dpcm_mutex_lock(rtd);
+	ret = __soc_pcm_prepare(rtd, substream);
+	snd_soc_dpcm_mutex_unlock(rtd);
+	return ret;
+}
+
 static void soc_pcm_codec_params_fixup(struct snd_pcm_hw_params *params,
 				       unsigned int mask)
 {
@@ -864,13 +919,13 @@ static void soc_pcm_codec_params_fixup(struct snd_pcm_hw_params *params,
 	interval->max = channels;
 }
 
-static int soc_pcm_hw_clean(struct snd_pcm_substream *substream, int rollback)
+static int soc_pcm_hw_clean(struct snd_soc_pcm_runtime *rtd,
+			    struct snd_pcm_substream *substream, int rollback)
 {
-	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
 	struct snd_soc_dai *dai;
 	int i;
 
-	mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);
+	snd_soc_dpcm_mutex_assert_held(rtd);
 
 	/* clear the corresponding DAIs parameters when going to be inactive */
 	for_each_rtd_dais(rtd, i, dai) {
@@ -900,16 +955,28 @@ static int soc_pcm_hw_clean(struct snd_pcm_substream *substream, int rollback)
 		snd_soc_dai_hw_free(dai, substream, rollback);
 	}
 
-	mutex_unlock(&rtd->card->pcm_mutex);
 	return 0;
 }
 
 /*
  * Frees resources allocated by hw_params, can be called multiple times
  */
+static int __soc_pcm_hw_free(struct snd_soc_pcm_runtime *rtd,
+			     struct snd_pcm_substream *substream)
+{
+	return soc_pcm_hw_clean(rtd, substream, 0);
+}
+
+/* hw_free PCM ops for non-DPCM streams */
 static int soc_pcm_hw_free(struct snd_pcm_substream *substream)
 {
-	return soc_pcm_hw_clean(substream, 0);
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+	int ret;
+
+	snd_soc_dpcm_mutex_lock(rtd);
+	ret = __soc_pcm_hw_free(rtd, substream);
+	snd_soc_dpcm_mutex_unlock(rtd);
+	return ret;
 }
 
 /*
@@ -917,15 +984,15 @@ static int soc_pcm_hw_free(struct snd_pcm_substream *substream)
  * function can also be called multiple times and can allocate buffers
  * (using snd_pcm_lib_* ). It's non-atomic.
  */
-static int soc_pcm_hw_params(struct snd_pcm_substream *substream,
-				struct snd_pcm_hw_params *params)
+static int __soc_pcm_hw_params(struct snd_soc_pcm_runtime *rtd,
+			       struct snd_pcm_substream *substream,
+			       struct snd_pcm_hw_params *params)
 {
-	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
 	struct snd_soc_dai *cpu_dai;
 	struct snd_soc_dai *codec_dai;
 	int i, ret = 0;
 
-	mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);
+	snd_soc_dpcm_mutex_assert_held(rtd);
 
 	ret = soc_pcm_params_symmetry(substream, params);
 	if (ret)
@@ -997,16 +1064,27 @@ static int soc_pcm_hw_params(struct snd_pcm_substream *substream,
 
 	ret = snd_soc_pcm_component_hw_params(substream, params);
 out:
-	mutex_unlock(&rtd->card->pcm_mutex);
-
 	if (ret < 0) {
-		soc_pcm_hw_clean(substream, 1);
+		soc_pcm_hw_clean(rtd, substream, 1);
 		dev_err(rtd->dev, "ASoC: %s() failed (%d)\n", __func__, ret);
 	}
 
 	return ret;
 }
 
+/* hw_params PCM ops for non-DPCM streams */
+static int soc_pcm_hw_params(struct snd_pcm_substream *substream,
+			     struct snd_pcm_hw_params *params)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+	int ret;
+
+	snd_soc_dpcm_mutex_lock(rtd);
+	ret = __soc_pcm_hw_params(rtd, substream, params);
+	snd_soc_dpcm_mutex_unlock(rtd);
+	return ret;
+}
+
 static int soc_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
@@ -1126,7 +1204,8 @@ static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 	struct snd_pcm_substream *fe_substream;
 	struct snd_pcm_substream *be_substream;
 	struct snd_soc_dpcm *dpcm;
-	unsigned long flags;
+
+	snd_soc_dpcm_mutex_assert_held(fe);
 
 	/* only add new dpcms */
 	for_each_dpcm_be(fe, stream, dpcm) {
@@ -1156,10 +1235,10 @@ 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);
+	snd_soc_dpcm_stream_lock_irq(fe, stream);
 	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);
+	snd_soc_dpcm_stream_unlock_irq(fe, stream);
 
 	dev_dbg(fe->dev, "connected new DPCM %s path %s %s %s\n",
 			stream ? "capture" : "playback",  fe->dai_link->name,
@@ -1204,8 +1283,10 @@ 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;
 
+	snd_soc_dpcm_mutex_assert_held(fe);
+
+	snd_soc_dpcm_stream_lock_irq(fe, stream);
 	for_each_dpcm_be_safe(fe, stream, dpcm, d) {
 		dev_dbg(fe->dev, "ASoC: BE %s disconnect check for %s\n",
 				stream ? "capture" : "playback",
@@ -1223,12 +1304,11 @@ 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);
 		list_del(&dpcm->list_be);
 		list_del(&dpcm->list_fe);
-		spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
 		kfree(dpcm);
 	}
+	snd_soc_dpcm_stream_unlock_irq(fe, stream);
 }
 
 /* get BE for DAI widget and stream */
@@ -1442,12 +1522,9 @@ 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);
 	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);
 }
 
 void dpcm_be_dai_stop(struct snd_soc_pcm_runtime *fe, int stream,
@@ -1483,12 +1560,12 @@ void dpcm_be_dai_stop(struct snd_soc_pcm_runtime *fe, int stream,
 				continue;
 
 			if (be->dpcm[stream].state != SND_SOC_DPCM_STATE_HW_FREE) {
-				soc_pcm_hw_free(be_substream);
+				__soc_pcm_hw_free(be, be_substream);
 				be->dpcm[stream].state = SND_SOC_DPCM_STATE_HW_FREE;
 			}
 		}
 
-		soc_pcm_close(be_substream);
+		__soc_pcm_close(be, be_substream);
 		be_substream->runtime = NULL;
 		be->dpcm[stream].state = SND_SOC_DPCM_STATE_CLOSE;
 	}
@@ -1536,7 +1613,7 @@ int dpcm_be_dai_startup(struct snd_soc_pcm_runtime *fe, int stream)
 			stream ? "capture" : "playback", be->dai_link->name);
 
 		be_substream->runtime = be->dpcm[stream].runtime;
-		err = soc_pcm_open(be_substream);
+		err = __soc_pcm_open(be, be_substream);
 		if (err < 0) {
 			be->dpcm[stream].users--;
 			if (be->dpcm[stream].users < 0)
@@ -1780,7 +1857,7 @@ static int dpcm_fe_dai_startup(struct snd_pcm_substream *fe_substream)
 	dev_dbg(fe->dev, "ASoC: open FE %s\n", fe->dai_link->name);
 
 	/* start the DAI frontend */
-	ret = soc_pcm_open(fe_substream);
+	ret = __soc_pcm_open(fe, fe_substream);
 	if (ret < 0)
 		goto unwind;
 
@@ -1811,6 +1888,8 @@ static int dpcm_fe_dai_shutdown(struct snd_pcm_substream *substream)
 	struct snd_soc_pcm_runtime *fe = asoc_substream_to_rtd(substream);
 	int stream = substream->stream;
 
+	snd_soc_dpcm_mutex_assert_held(fe);
+
 	dpcm_set_fe_update_state(fe, stream, SND_SOC_DPCM_UPDATE_FE);
 
 	/* shutdown the BEs */
@@ -1819,7 +1898,7 @@ static int dpcm_fe_dai_shutdown(struct snd_pcm_substream *substream)
 	dev_dbg(fe->dev, "ASoC: close FE %s\n", fe->dai_link->name);
 
 	/* now shutdown the frontend */
-	soc_pcm_close(substream);
+	__soc_pcm_close(fe, substream);
 
 	/* run the stream stop event */
 	dpcm_dapm_stream_event(fe, stream, SND_SOC_DAPM_STREAM_STOP);
@@ -1864,7 +1943,7 @@ void dpcm_be_dai_hw_free(struct snd_soc_pcm_runtime *fe, int stream)
 		dev_dbg(be->dev, "ASoC: hw_free BE %s\n",
 			be->dai_link->name);
 
-		soc_pcm_hw_free(be_substream);
+		__soc_pcm_hw_free(be, be_substream);
 
 		be->dpcm[stream].state = SND_SOC_DPCM_STATE_HW_FREE;
 	}
@@ -1875,13 +1954,13 @@ static int dpcm_fe_dai_hw_free(struct snd_pcm_substream *substream)
 	struct snd_soc_pcm_runtime *fe = asoc_substream_to_rtd(substream);
 	int stream = substream->stream;
 
-	mutex_lock_nested(&fe->card->mutex, SND_SOC_CARD_CLASS_RUNTIME);
+	snd_soc_dpcm_mutex_lock(fe);
 	dpcm_set_fe_update_state(fe, stream, SND_SOC_DPCM_UPDATE_FE);
 
 	dev_dbg(fe->dev, "ASoC: hw_free FE %s\n", fe->dai_link->name);
 
 	/* call hw_free on the frontend */
-	soc_pcm_hw_free(substream);
+	soc_pcm_hw_clean(fe, substream, 0);
 
 	/* only hw_params backends that are either sinks or sources
 	 * to this frontend DAI */
@@ -1890,7 +1969,7 @@ static int dpcm_fe_dai_hw_free(struct snd_pcm_substream *substream)
 	fe->dpcm[stream].state = SND_SOC_DPCM_STATE_HW_FREE;
 	dpcm_set_fe_update_state(fe, stream, SND_SOC_DPCM_UPDATE_NO);
 
-	mutex_unlock(&fe->card->mutex);
+	snd_soc_dpcm_mutex_unlock(fe);
 	return 0;
 }
 
@@ -1934,7 +2013,7 @@ int dpcm_be_dai_hw_params(struct snd_soc_pcm_runtime *fe, int stream)
 		dev_dbg(be->dev, "ASoC: hw_params BE %s\n",
 			be->dai_link->name);
 
-		ret = soc_pcm_hw_params(be_substream, &dpcm->hw_params);
+		ret = __soc_pcm_hw_params(be, be_substream, &dpcm->hw_params);
 		if (ret < 0)
 			goto unwind;
 
@@ -1964,7 +2043,7 @@ int dpcm_be_dai_hw_params(struct snd_soc_pcm_runtime *fe, int stream)
 		   (be->dpcm[stream].state != SND_SOC_DPCM_STATE_STOP))
 			continue;
 
-		soc_pcm_hw_free(be_substream);
+		__soc_pcm_hw_free(be, be_substream);
 	}
 
 	return ret;
@@ -1976,7 +2055,7 @@ static int dpcm_fe_dai_hw_params(struct snd_pcm_substream *substream,
 	struct snd_soc_pcm_runtime *fe = asoc_substream_to_rtd(substream);
 	int ret, stream = substream->stream;
 
-	mutex_lock_nested(&fe->card->mutex, SND_SOC_CARD_CLASS_RUNTIME);
+	snd_soc_dpcm_mutex_lock(fe);
 	dpcm_set_fe_update_state(fe, stream, SND_SOC_DPCM_UPDATE_FE);
 
 	memcpy(&fe->dpcm[stream].hw_params, params,
@@ -1990,7 +2069,7 @@ static int dpcm_fe_dai_hw_params(struct snd_pcm_substream *substream,
 			params_channels(params), params_format(params));
 
 	/* call hw_params on the frontend */
-	ret = soc_pcm_hw_params(substream, params);
+	ret = __soc_pcm_hw_params(fe, substream, params);
 	if (ret < 0)
 		dpcm_be_dai_hw_free(fe, stream);
 	else
@@ -1998,7 +2077,7 @@ static int dpcm_fe_dai_hw_params(struct snd_pcm_substream *substream,
 
 out:
 	dpcm_set_fe_update_state(fe, stream, SND_SOC_DPCM_UPDATE_NO);
-	mutex_unlock(&fe->card->mutex);
+	snd_soc_dpcm_mutex_unlock(fe);
 
 	if (ret < 0)
 		dev_err(fe->dev, "ASoC: %s failed (%d)\n", __func__, ret);
@@ -2269,7 +2348,7 @@ int dpcm_be_dai_prepare(struct snd_soc_pcm_runtime *fe, int stream)
 		dev_dbg(be->dev, "ASoC: prepare BE %s\n",
 			be->dai_link->name);
 
-		ret = soc_pcm_prepare(be_substream);
+		ret = __soc_pcm_prepare(be, be_substream);
 		if (ret < 0)
 			break;
 
@@ -2287,7 +2366,7 @@ static int dpcm_fe_dai_prepare(struct snd_pcm_substream *substream)
 	struct snd_soc_pcm_runtime *fe = asoc_substream_to_rtd(substream);
 	int stream = substream->stream, ret = 0;
 
-	mutex_lock_nested(&fe->card->mutex, SND_SOC_CARD_CLASS_RUNTIME);
+	snd_soc_dpcm_mutex_lock(fe);
 
 	dev_dbg(fe->dev, "ASoC: prepare FE %s\n", fe->dai_link->name);
 
@@ -2306,7 +2385,7 @@ static int dpcm_fe_dai_prepare(struct snd_pcm_substream *substream)
 		goto out;
 
 	/* call prepare on the frontend */
-	ret = soc_pcm_prepare(substream);
+	ret = __soc_pcm_prepare(fe, substream);
 	if (ret < 0)
 		goto out;
 
@@ -2314,7 +2393,7 @@ static int dpcm_fe_dai_prepare(struct snd_pcm_substream *substream)
 
 out:
 	dpcm_set_fe_update_state(fe, stream, SND_SOC_DPCM_UPDATE_NO);
-	mutex_unlock(&fe->card->mutex);
+	snd_soc_dpcm_mutex_unlock(fe);
 
 	if (ret < 0)
 		dev_err(fe->dev, "ASoC: %s() failed (%d)\n", __func__, ret);
@@ -2365,7 +2444,6 @@ 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);
@@ -2434,7 +2512,6 @@ 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);
 	for_each_dpcm_be(fe, stream, dpcm) {
 		struct snd_soc_pcm_runtime *be = dpcm->be;
 
@@ -2446,7 +2523,6 @@ 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);
 
 	if (ret < 0)
 		dev_err(fe->dev, "ASoC: %s() failed (%d)\n", __func__, ret);
@@ -2521,7 +2597,7 @@ int snd_soc_dpcm_runtime_update(struct snd_soc_card *card)
 	struct snd_soc_pcm_runtime *fe;
 	int ret = 0;
 
-	mutex_lock_nested(&card->mutex, SND_SOC_CARD_CLASS_RUNTIME);
+	mutex_lock_nested(&card->pcm_mutex, card->pcm_subclass);
 	/* shutdown all old paths first */
 	for_each_card_rtds(card, fe) {
 		ret = soc_dpcm_fe_runtime_update(fe, 0);
@@ -2537,7 +2613,7 @@ int snd_soc_dpcm_runtime_update(struct snd_soc_card *card)
 	}
 
 out:
-	mutex_unlock(&card->mutex);
+	mutex_unlock(&card->pcm_mutex);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(snd_soc_dpcm_runtime_update);
@@ -2548,6 +2624,8 @@ static void dpcm_fe_dai_cleanup(struct snd_pcm_substream *fe_substream)
 	struct snd_soc_dpcm *dpcm;
 	int stream = fe_substream->stream;
 
+	snd_soc_dpcm_mutex_assert_held(fe);
+
 	/* mark FE's links ready to prune */
 	for_each_dpcm_be(fe, stream, dpcm)
 		dpcm->state = SND_SOC_DPCM_LINK_STATE_FREE;
@@ -2562,12 +2640,12 @@ static int dpcm_fe_dai_close(struct snd_pcm_substream *fe_substream)
 	struct snd_soc_pcm_runtime *fe = asoc_substream_to_rtd(fe_substream);
 	int ret;
 
-	mutex_lock_nested(&fe->card->mutex, SND_SOC_CARD_CLASS_RUNTIME);
+	snd_soc_dpcm_mutex_lock(fe);
 	ret = dpcm_fe_dai_shutdown(fe_substream);
 
 	dpcm_fe_dai_cleanup(fe_substream);
 
-	mutex_unlock(&fe->card->mutex);
+	snd_soc_dpcm_mutex_unlock(fe);
 	return ret;
 }
 
@@ -2578,7 +2656,7 @@ static int dpcm_fe_dai_open(struct snd_pcm_substream *fe_substream)
 	int ret;
 	int stream = fe_substream->stream;
 
-	mutex_lock_nested(&fe->card->mutex, SND_SOC_CARD_CLASS_RUNTIME);
+	snd_soc_dpcm_mutex_lock(fe);
 	fe->dpcm[stream].runtime = fe_substream->runtime;
 
 	ret = dpcm_path_get(fe, stream, &list);
@@ -2595,7 +2673,7 @@ static int dpcm_fe_dai_open(struct snd_pcm_substream *fe_substream)
 	dpcm_clear_pending_state(fe, stream);
 	dpcm_path_put(&list);
 open_end:
-	mutex_unlock(&fe->card->mutex);
+	snd_soc_dpcm_mutex_unlock(fe);
 	return ret;
 }
 
@@ -2856,10 +2934,8 @@ 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);
 	for_each_dpcm_fe(be, stream, dpcm) {
 
 		if (dpcm->fe == fe)
@@ -2873,7 +2949,6 @@ static int snd_soc_dpcm_check_state(struct snd_soc_pcm_runtime *fe,
 			}
 		}
 	}
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
 
 	/* it's safe to do this BE DAI */
 	return ret;
-- 
2.40.1.521.gf1e218fcd8-goog

[PATCH 4/6] ASoC: soc-pcm: serialize BE triggers

[yixuanjiang]

From: Takashi Iwai <tiwai@suse.de>

[ Upstream commit b2ae80663008a7662febe7d13f14ea1b2eb0cd51 ]

When more than one FE is connected to a BE, e.g. in a mixing use case,
the BE can be triggered multiple times when the FE are opened/started
concurrently. This race condition is problematic in the case of
SoundWire BE dailinks, and this is not desirable in a general
case.

This patch relies on the existing BE PCM lock, which takes atomicity into
account. The locking model assumes that all interactions start with
the FE, so that there is no deadlock between FE and BE locks.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
[test, checkpatch fix and clarification of commit message by plbossart]
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20211207173745.15850-5-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Fixes: aa9ff6a4955f ("ASoC: soc-compress: Reposition and add pcm_mutex")
Signed-off-by: Yixuan Jiang <yixuanjiang@google.com>
Cc: stable@vger.kernel.org # 5.15+
---
 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 a9869203804e7..7903516c89a6a 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)
@@ -2090,6 +2096,7 @@ 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) {
@@ -2098,9 +2105,11 @@ 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);
@@ -2110,77 +2119,80 @@ 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);
-- 
2.40.1.521.gf1e218fcd8-goog

[PATCH 5/6] ASoC: soc-pcm: test refcount before triggering

[yixuanjiang]

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

[ Upstream commit 848aedfdc6ba25ad5652797db9266007773e44dd ]

On start/pause_release/resume, when more than one FE is connected to
the same BE, it's possible that the trigger is sent more than
once. This is not desirable, we only want to trigger a BE once, which
is straightforward to implement with a refcount.

For stop/pause/suspend, the problem is more complicated: the check
implemented in snd_soc_dpcm_can_be_free_stop() may fail due to a
conceptual deadlock when we trigger the BE before the FE. In this
case, the FE states have not yet changed, so there are corner cases
where the TRIGGER_STOP is never sent - the dual case of start where
multiple triggers might be sent.

This patch suggests an unconditional trigger in all cases, without
checking the FE states, using a refcount protected by the BE PCM
stream lock.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20211207173745.15850-6-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Fixes: aa9ff6a4955f ("ASoC: soc-compress: Reposition and add pcm_mutex")
Signed-off-by: Yixuan Jiang <yixuanjiang@google.com>
Cc: stable@vger.kernel.org # 5.15+
---
 include/sound/soc-dpcm.h |  2 ++
 sound/soc/soc-pcm.c      | 53 +++++++++++++++++++++++++++++++---------
 2 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/include/sound/soc-dpcm.h b/include/sound/soc-dpcm.h
index e296a3949b18b..d963f3b608489 100644
--- a/include/sound/soc-dpcm.h
+++ b/include/sound/soc-dpcm.h
@@ -101,6 +101,8 @@ struct snd_soc_dpcm_runtime {
 	enum snd_soc_dpcm_state state;
 
 	int trigger_pending; /* trigger cmd + 1 if pending, 0 if not */
+
+	int be_start; /* refcount protected by BE stream pcm lock */
 };
 
 #define for_each_dpcm_fe(be, stream, _dpcm)				\
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 7903516c89a6a..b6099d36518f5 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1630,7 +1630,7 @@ int dpcm_be_dai_startup(struct snd_soc_pcm_runtime *fe, int stream)
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_CLOSE;
 			goto unwind;
 		}
-
+		be->dpcm[stream].be_start = 0;
 		be->dpcm[stream].state = SND_SOC_DPCM_STATE_OPEN;
 		count++;
 	}
@@ -2116,14 +2116,21 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
 
 		switch (cmd) {
 		case SNDRV_PCM_TRIGGER_START:
-			if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_PREPARE) &&
+			if (!be->dpcm[stream].be_start &&
+			    (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))
 				goto next;
 
+			be->dpcm[stream].be_start++;
+			if (be->dpcm[stream].be_start != 1)
+				goto next;
+
 			ret = soc_pcm_trigger(be_substream, cmd);
-			if (ret)
+			if (ret) {
+				be->dpcm[stream].be_start--;
 				goto next;
+			}
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_START;
 			break;
@@ -2131,9 +2138,15 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
 			if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_SUSPEND))
 				goto next;
 
+			be->dpcm[stream].be_start++;
+			if (be->dpcm[stream].be_start != 1)
+				goto next;
+
 			ret = soc_pcm_trigger(be_substream, cmd);
-			if (ret)
+			if (ret) {
+				be->dpcm[stream].be_start--;
 				goto next;
+			}
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_START;
 			break;
@@ -2141,9 +2154,15 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
 			if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED))
 				goto next;
 
+			be->dpcm[stream].be_start++;
+			if (be->dpcm[stream].be_start != 1)
+				goto next;
+
 			ret = soc_pcm_trigger(be_substream, cmd);
-			if (ret)
+			if (ret) {
+				be->dpcm[stream].be_start--;
 				goto next;
+			}
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_START;
 			break;
@@ -2152,12 +2171,18 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
 			    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED))
 				goto next;
 
-			if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream))
+			if (be->dpcm[stream].state == SND_SOC_DPCM_STATE_START)
+				be->dpcm[stream].be_start--;
+
+			if (be->dpcm[stream].be_start != 0)
 				goto next;
 
 			ret = soc_pcm_trigger(be_substream, cmd);
-			if (ret)
+			if (ret) {
+				if (be->dpcm[stream].state == SND_SOC_DPCM_STATE_START)
+					be->dpcm[stream].be_start++;
 				goto next;
+			}
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_STOP;
 			break;
@@ -2165,12 +2190,15 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
 			if (be->dpcm[stream].state != SND_SOC_DPCM_STATE_START)
 				goto next;
 
-			if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream))
+			be->dpcm[stream].be_start--;
+			if (be->dpcm[stream].be_start != 0)
 				goto next;
 
 			ret = soc_pcm_trigger(be_substream, cmd);
-			if (ret)
+			if (ret) {
+				be->dpcm[stream].be_start++;
 				goto next;
+			}
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_SUSPEND;
 			break;
@@ -2178,12 +2206,15 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
 			if (be->dpcm[stream].state != SND_SOC_DPCM_STATE_START)
 				goto next;
 
-			if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream))
+			be->dpcm[stream].be_start--;
+			if (be->dpcm[stream].be_start != 0)
 				goto next;
 
 			ret = soc_pcm_trigger(be_substream, cmd);
-			if (ret)
+			if (ret) {
+				be->dpcm[stream].be_start++;
 				goto next;
+			}
 
 			be->dpcm[stream].state = SND_SOC_DPCM_STATE_PAUSED;
 			break;
-- 
2.40.1.521.gf1e218fcd8-goog

[PATCH 6/6] ASoC: soc-pcm: fix BE handling of PAUSE_RELEASE

[yixuanjiang]

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

[ Upstream commit 3aa1e96a2b95e2ece198f8dd01e96818971b84df ]

A BE connected to more than one FE, e.g. in a mixer case, can go
through the following transitions.

play FE1    -> BE state is START
pause FE1   -> BE state is PAUSED
play FE2    -> BE state is START
stop FE2    -> BE state is STOP (see note [1] below)
release FE1 -> BE state is START
stop FE1    -> BE state is STOP

play FE1    -> BE state is START
pause FE1   -> BE state is PAUSED
play FE2    -> BE state is START
release FE1 -> BE state is START
stop FE2    -> BE state is START
stop FE1    -> BE state is STOP

play FE1    -> BE state is START
play FE2    -> BE state is START (no change)
pause FE1   -> BE state is START (no change)
pause FE2   -> BE state is PAUSED
release FE1 -> BE state is START
release FE2 -> BE state is START (no change)
stop FE1    -> BE state is START (no change)
stop FE2    -> BE state is STOP

The existing code for PAUSE_RELEASE only allows for the case where the
BE is paused, which clearly would not work in the sequences above.

Extend the allowed states to restart the BE when PAUSE_RELEASE is
received, and increase the refcount if the BE is already in START.

[1] the existing logic does not move the BE state back to PAUSED when
the FE2 is stopped. This patch does not change the logic; it would be
painful to keep a history of changes on the FE side, the state machine
is already rather complicated with transitions based on the last BE
state and the trigger type.

Reported-by: Bard Liao <bard.liao@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20211207173745.15850-7-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Fixes: aa9ff6a4955f ("ASoC: soc-compress: Reposition and add pcm_mutex")
Signed-off-by: Yixuan Jiang <yixuanjiang@google.com>
Cc: stable@vger.kernel.org # 5.15+
---
 sound/soc/soc-pcm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index b6099d36518f5..6e589708b9338 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -2151,7 +2151,10 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
 			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))
+			if (!be->dpcm[stream].be_start &&
+			    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_START) &&
+			    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_STOP) &&
+			    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED))
 				goto next;
 
 			be->dpcm[stream].be_start++;
-- 
2.40.1.521.gf1e218fcd8-goog