Re: [alsa-devel] [PATCH] ASoC: core: Move pcm_mutex up to card level from snd_soc_pcm_runtime

On 8/13/19 5:45 AM, Peter Ujfalusi wrote:

The pcm_mutex is used to prevent concurrent execution of snd_pcm_ops callbacks. This works fine most of the cases but it can not handle setups when the same DAI is used by different rtd, for example: pcm3168a have two DAIs: one for Playback and one for Capture. If the codec is connected to a single CPU DAI we need to have two dai_link to support both playback and capture.

In this case the snd_pcm_ops callbacks can be executed in parallel causing unexpected races in DAI drivers.

By moving the pcm_mutex up to card level this can be solved while - hopefully - not breaking other setups.

Signed-off-by: Peter Ujfalusi peter.ujfalusi@ti.com

Hi,

I have tested the patch on several boards. it fixes the issue with single card with multiple dai_links where the CPU side (mcasp) is the same.

However I can not test with anything which use DPCM. It would be great if the patch would gather few tested-by from folks having access to more complicated setups.

Actually you *can* test by submitting a PR for SOF, it'll trigger some tests on Intel platforms using DPCM. It's not going to test anything related to the compressed API but it's better than nothing.

I took this patch and created one PR as an example https://github.com/thesofproject/linux/pull/1132

Will share results when I have them. -Pierre

The backround of this patch: https://mailman.alsa-project.org/pipermail/alsa-devel/2019-August/153864.htm...

Regards, Peter

include/sound/soc.h | 6 +++-- sound/soc/soc-compress.c | 48 ++++++++++++++++++++-------------------- sound/soc/soc-core.c | 2 +- sound/soc/soc-pcm.c | 36 +++++++++++++++--------------- 4 files changed, 47 insertions(+), 45 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h index 6ac6481b4882..ec2dbe0ac2aa 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -990,6 +990,10 @@ struct snd_soc_card { struct mutex mutex; struct mutex dapm_mutex;

• /* Mutex for PCM operations */

• struct mutex pcm_mutex;

• enum snd_soc_pcm_subclass pcm_subclass;

• spinlock_t dpcm_lock;

  bool instantiated;

@@ -1107,8 +1111,6 @@ struct snd_soc_pcm_runtime { struct device *dev; struct snd_soc_card *card; struct snd_soc_dai_link *dai_link;

• struct mutex pcm_mutex;

• enum snd_soc_pcm_subclass pcm_subclass; struct snd_pcm_ops ops;

  unsigned int params_select; /* currently selected param for dai link */

diff --git a/sound/soc/soc-compress.c b/sound/soc/soc-compress.c index 289211069a1e..9e54d8ae6d2c 100644 --- a/sound/soc/soc-compress.c +++ b/sound/soc/soc-compress.c @@ -80,7 +80,7 @@ static int soc_compr_open(struct snd_compr_stream *cstream) struct snd_soc_dai *cpu_dai = rtd->cpu_dai; int ret;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  if (cpu_dai->driver->cops && cpu_dai->driver->cops->startup) { ret = cpu_dai->driver->cops->startup(cstream, cpu_dai);

@@ -108,7 +108,7 @@ static int soc_compr_open(struct snd_compr_stream *cstream)

snd_soc_runtime_activate(rtd, cstream->direction);

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex);

  return 0;

@@ -118,7 +118,7 @@ static int soc_compr_open(struct snd_compr_stream *cstream) if (cpu_dai->driver->cops && cpu_dai->driver->cops->shutdown) cpu_dai->driver->cops->shutdown(cstream, cpu_dai); out:

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

@@ -224,7 +224,7 @@ static void close_delayed_work(struct work_struct *work) container_of(work, struct snd_soc_pcm_runtime, delayed_work.work); struct snd_soc_dai *codec_dai = rtd->codec_dai;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  dev_dbg(rtd->dev, "Compress ASoC: pop wq checking: %s status: %s waiting: %s\n",

@@ -239,7 +239,7 @@ static void close_delayed_work(struct work_struct *work) SND_SOC_DAPM_STREAM_STOP); }

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); }

  static int soc_compr_free(struct snd_compr_stream *cstream)

@@ -249,7 +249,7 @@ static int soc_compr_free(struct snd_compr_stream *cstream) struct snd_soc_dai *codec_dai = rtd->codec_dai; int stream;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  if (cstream->direction == SND_COMPRESS_PLAYBACK) stream = SNDRV_PCM_STREAM_PLAYBACK;

@@ -292,7 +292,7 @@ static int soc_compr_free(struct snd_compr_stream *cstream) SND_SOC_DAPM_STREAM_STOP); }

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return 0; }

@@ -375,7 +375,7 @@ static int soc_compr_trigger(struct snd_compr_stream *cstream, int cmd) struct snd_soc_dai *cpu_dai = rtd->cpu_dai; int ret;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  ret = soc_compr_components_trigger(cstream, cmd); if (ret < 0)

@@ -394,7 +394,7 @@ static int soc_compr_trigger(struct snd_compr_stream *cstream, int cmd) }

out:

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

@@ -480,7 +480,7 @@ static int soc_compr_set_params(struct snd_compr_stream *cstream, struct snd_soc_dai *cpu_dai = rtd->cpu_dai; int ret;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  /*

  • First we call set_params for the CPU DAI, then the component

@@ -514,14 +514,14 @@ static int soc_compr_set_params(struct snd_compr_stream *cstream,

/* cancel any delayed stream shutdown that is pending */ rtd->pop_wait = 0;

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex);

  cancel_delayed_work_sync(&rtd->delayed_work);

  return 0;

  err:

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

@@ -593,7 +593,7 @@ static int soc_compr_get_params(struct snd_compr_stream *cstream, struct snd_soc_dai *cpu_dai = rtd->cpu_dai; int ret = 0;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  if (cpu_dai->driver->cops && cpu_dai->driver->cops->get_params) { ret = cpu_dai->driver->cops->get_params(cstream, params, cpu_dai);

@@ -613,7 +613,7 @@ static int soc_compr_get_params(struct snd_compr_stream *cstream, }

err:

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

@@ -625,7 +625,7 @@ static int soc_compr_get_caps(struct snd_compr_stream *cstream, struct snd_soc_rtdcom_list *rtdcom; int ret = 0;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  for_each_rtdcom(rtd, rtdcom) { component = rtdcom->component;

@@ -638,7 +638,7 @@ static int soc_compr_get_caps(struct snd_compr_stream *cstream, break; }

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

@@ -650,7 +650,7 @@ static int soc_compr_get_codec_caps(struct snd_compr_stream *cstream, struct snd_soc_rtdcom_list *rtdcom; int ret = 0;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  for_each_rtdcom(rtd, rtdcom) { component = rtdcom->component;

@@ -664,7 +664,7 @@ static int soc_compr_get_codec_caps(struct snd_compr_stream *cstream, break; }

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

@@ -676,7 +676,7 @@ static int soc_compr_ack(struct snd_compr_stream *cstream, size_t bytes) struct snd_soc_dai *cpu_dai = rtd->cpu_dai; int ret = 0;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  if (cpu_dai->driver->cops && cpu_dai->driver->cops->ack) { ret = cpu_dai->driver->cops->ack(cstream, bytes, cpu_dai);

@@ -697,7 +697,7 @@ static int soc_compr_ack(struct snd_compr_stream *cstream, size_t bytes) }

err:

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

@@ -710,7 +710,7 @@ static int soc_compr_pointer(struct snd_compr_stream *cstream, int ret = 0; struct snd_soc_dai *cpu_dai = rtd->cpu_dai;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  if (cpu_dai->driver->cops && cpu_dai->driver->cops->pointer) cpu_dai->driver->cops->pointer(cstream, tstamp, cpu_dai);

@@ -726,7 +726,7 @@ static int soc_compr_pointer(struct snd_compr_stream *cstream, break; }

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

@@ -738,7 +738,7 @@ static int soc_compr_copy(struct snd_compr_stream *cstream, struct snd_soc_rtdcom_list *rtdcom; int ret = 0;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  for_each_rtdcom(rtd, rtdcom) { component = rtdcom->component;

@@ -751,7 +751,7 @@ static int soc_compr_copy(struct snd_compr_stream *cstream, break; }

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index bb1e9e2c4ff4..7f2064889a23 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -1344,7 +1344,6 @@ static int soc_post_component_init(struct snd_soc_pcm_runtime *rtd, rtd->dev->groups = soc_dev_attr_groups; dev_set_name(rtd->dev, "%s", name); dev_set_drvdata(rtd->dev, rtd);

• mutex_init(&rtd->pcm_mutex); INIT_LIST_HEAD(&rtd->dpcm[SNDRV_PCM_STREAM_PLAYBACK].be_clients); INIT_LIST_HEAD(&rtd->dpcm[SNDRV_PCM_STREAM_CAPTURE].be_clients); INIT_LIST_HEAD(&rtd->dpcm[SNDRV_PCM_STREAM_PLAYBACK].fe_clients);

@@ -2395,6 +2394,7 @@ int snd_soc_register_card(struct snd_soc_card *card) card->instantiated = 0; 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 77c986fe08d0..93bb4a347779 100644 --- a/sound/soc/soc-pcm.c +++ b/sound/soc/soc-pcm.c @@ -36,7 +36,7 @@

• Increments the active count for all the DAIs and components attached to a PCM
• runtime. Should typically be called when a stream is opened.

• • Must be called with the rtd->pcm_mutex being held

• • Must be called with the rtd->card->pcm_mutex being held
  */ void snd_soc_runtime_activate(struct snd_soc_pcm_runtime *rtd, int stream) {

@@ -44,7 +44,7 @@ void snd_soc_runtime_activate(struct snd_soc_pcm_runtime *rtd, int stream) struct snd_soc_dai *codec_dai; int i;

• lockdep_assert_held(&rtd->pcm_mutex);

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

  if (stream == SNDRV_PCM_STREAM_PLAYBACK) { cpu_dai->playback_active++;

@@ -72,7 +72,7 @@ void snd_soc_runtime_activate(struct snd_soc_pcm_runtime *rtd, int stream)

• Decrements the active count for all the DAIs and components attached to a PCM
• runtime. Should typically be called when a stream is closed.

• • Must be called with the rtd->pcm_mutex being held

• • Must be called with the rtd->card->pcm_mutex being held
  */ void snd_soc_runtime_deactivate(struct snd_soc_pcm_runtime *rtd, int stream) {

@@ -80,7 +80,7 @@ void snd_soc_runtime_deactivate(struct snd_soc_pcm_runtime *rtd, int stream) struct snd_soc_dai *codec_dai; int i;

• lockdep_assert_held(&rtd->pcm_mutex);

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

  if (stream == SNDRV_PCM_STREAM_PLAYBACK) { cpu_dai->playback_active--;

@@ -506,7 +506,7 @@ static int soc_pcm_open(struct snd_pcm_substream *substream) pm_runtime_get_sync(component->dev); }

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  /* startup the audio subsystem */ ret = snd_soc_dai_startup(cpu_dai, substream);

@@ -604,7 +604,7 @@ static int soc_pcm_open(struct snd_pcm_substream *substream)

snd_soc_runtime_activate(rtd, substream->stream);

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return 0;

  config_err:

@@ -623,7 +623,7 @@ static int soc_pcm_open(struct snd_pcm_substream *substream)

snd_soc_dai_shutdown(cpu_dai, substream); out:

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex);

  for_each_rtdcom(rtd, rtdcom) { component = rtdcom->component;

@@ -653,7 +653,7 @@ static void close_delayed_work(struct work_struct *work) container_of(work, struct snd_soc_pcm_runtime, delayed_work.work); struct snd_soc_dai *codec_dai = rtd->codec_dais[0];

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  dev_dbg(rtd->dev, "ASoC: pop wq checking: %s status: %s waiting: %s\n", codec_dai->driver->playback.stream_name,

@@ -667,7 +667,7 @@ static void close_delayed_work(struct work_struct *work) SND_SOC_DAPM_STREAM_STOP); }

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); }

  static void codec2codec_close_delayed_work(struct work_struct *work)

@@ -694,7 +694,7 @@ static int soc_pcm_close(struct snd_pcm_substream *substream) struct snd_soc_dai *codec_dai; int i;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  snd_soc_runtime_deactivate(rtd, substream->stream);

@@ -738,7 +738,7 @@ static int soc_pcm_close(struct snd_pcm_substream *substream) SND_SOC_DAPM_STREAM_STOP); }

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex);

  for_each_rtdcom(rtd, rtdcom) { component = rtdcom->component;

@@ -771,7 +771,7 @@ static int soc_pcm_prepare(struct snd_pcm_substream *substream) struct snd_soc_dai *codec_dai; int i, ret = 0;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  if (rtd->dai_link->ops->prepare) { ret = rtd->dai_link->ops->prepare(substream);

@@ -826,7 +826,7 @@ static int soc_pcm_prepare(struct snd_pcm_substream *substream) snd_soc_dai_digital_mute(cpu_dai, 0, substream->stream);

out:

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

@@ -876,7 +876,7 @@ static int soc_pcm_hw_params(struct snd_pcm_substream *substream, struct snd_soc_dai *codec_dai; int i, ret = 0;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass); if (rtd->dai_link->ops->hw_params) { ret = rtd->dai_link->ops->hw_params(substream, params); if (ret < 0) {

@@ -962,7 +962,7 @@ static int soc_pcm_hw_params(struct snd_pcm_substream *substream, if (ret) goto component_err; out:

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret;

  component_err:

@@ -986,7 +986,7 @@ static int soc_pcm_hw_params(struct snd_pcm_substream *substream, if (rtd->dai_link->ops->hw_free) rtd->dai_link->ops->hw_free(substream);

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return ret; }

@@ -1001,7 +1001,7 @@ static int soc_pcm_hw_free(struct snd_pcm_substream *substream) bool playback = substream->stream == SNDRV_PCM_STREAM_PLAYBACK; int i;

• mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);

• mutex_lock_nested(&rtd->card->pcm_mutex, rtd->card->pcm_subclass);

  /* clear the corresponding DAIs parameters when going to be inactive */ if (cpu_dai->active == 1) {

@@ -1043,7 +1043,7 @@ static int soc_pcm_hw_free(struct snd_pcm_substream *substream)

snd_soc_dai_hw_free(cpu_dai, substream);

• mutex_unlock(&rtd->pcm_mutex);

• mutex_unlock(&rtd->card->pcm_mutex); return 0; }