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

[Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>]

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@xxxxxx>
> ---
> 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.html
>
> 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;
>   }
>   
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