[PATCH] ASoC: hdmi-codec: re-introduce mutex locking

[PATCH] ASoC: hdmi-codec: re-introduce mutex locking

[Jerome Brunet]

Replace the bit atomic operations by a mutex to ensure only one dai
at a time is active on the hdmi codec.

This is a follow up on change:
3fcf94ef4d41 ("ASoC: hdmi-codec: remove reference to the current substream")

Suggested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 sound/soc/codecs/hdmi-codec.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/sound/soc/codecs/hdmi-codec.c b/sound/soc/codecs/hdmi-codec.c
index 90a892766625..6a0cc8d7e141 100644
--- a/sound/soc/codecs/hdmi-codec.c
+++ b/sound/soc/codecs/hdmi-codec.c
@@ -281,7 +281,7 @@ struct hdmi_codec_priv {
 	uint8_t eld[MAX_ELD_BYTES];
 	struct snd_pcm_chmap *chmap_info;
 	unsigned int chmap_idx;
-	unsigned long busy;
+	struct mutex lock;
 };
 
 static const struct snd_soc_dapm_widget hdmi_widgets[] = {
@@ -395,8 +395,8 @@ static int hdmi_codec_startup(struct snd_pcm_substream *substream,
 	struct hdmi_codec_priv *hcp = snd_soc_dai_get_drvdata(dai);
 	int ret = 0;
 
-	ret = test_and_set_bit(0, &hcp->busy);
-	if (ret) {
+	ret = mutex_trylock(&hcp->lock);
+	if (!ret) {
 		dev_err(dai->dev, "Only one simultaneous stream supported!\n");
 		return -EINVAL;
 	}
@@ -424,7 +424,7 @@ static int hdmi_codec_startup(struct snd_pcm_substream *substream,
 
 err:
 	/* Release the exclusive lock on error */
-	clear_bit(0, &hcp->busy);
+	mutex_unlock(&hcp->lock);
 	return ret;
 }
 
@@ -436,7 +436,7 @@ static void hdmi_codec_shutdown(struct snd_pcm_substream *substream,
 	hcp->chmap_idx = HDMI_CODEC_CHMAP_IDX_UNKNOWN;
 	hcp->hcd.ops->audio_shutdown(dai->dev->parent, hcp->hcd.data);
 
-	clear_bit(0, &hcp->busy);
+	mutex_unlock(&hcp->lock);
 }
 
 static int hdmi_codec_hw_params(struct snd_pcm_substream *substream,
@@ -773,6 +773,8 @@ static int hdmi_codec_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	hcp->hcd = *hcd;
+	mutex_init(&hcp->lock);
+
 	daidrv = devm_kcalloc(dev, dai_count, sizeof(*daidrv), GFP_KERNEL);
 	if (!daidrv)
 		return -ENOMEM;
-- 
2.20.1

Applied "ASoC: hdmi-codec: re-introduce mutex locking" to the asoc tree

[Mark Brown]

The patch

   ASoC: hdmi-codec: re-introduce mutex locking

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-5.3

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

From eb1ecadb7f67dde94ef0efd3ddaed5cb6c9a65ed Mon Sep 17 00:00:00 2001
From: Jerome Brunet <jbrunet@baylibre.com>
Date: Mon, 13 May 2019 10:18:47 +0200
Subject: [PATCH] ASoC: hdmi-codec: re-introduce mutex locking

Replace the bit atomic operations by a mutex to ensure only one dai
at a time is active on the hdmi codec.

This is a follow up on change:
3fcf94ef4d41 ("ASoC: hdmi-codec: remove reference to the current substream")

Suggested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 sound/soc/codecs/hdmi-codec.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/sound/soc/codecs/hdmi-codec.c b/sound/soc/codecs/hdmi-codec.c
index 90a892766625..6a0cc8d7e141 100644
--- a/sound/soc/codecs/hdmi-codec.c
+++ b/sound/soc/codecs/hdmi-codec.c
@@ -281,7 +281,7 @@ struct hdmi_codec_priv {
 	uint8_t eld[MAX_ELD_BYTES];
 	struct snd_pcm_chmap *chmap_info;
 	unsigned int chmap_idx;
-	unsigned long busy;
+	struct mutex lock;
 };
 
 static const struct snd_soc_dapm_widget hdmi_widgets[] = {
@@ -395,8 +395,8 @@ static int hdmi_codec_startup(struct snd_pcm_substream *substream,
 	struct hdmi_codec_priv *hcp = snd_soc_dai_get_drvdata(dai);
 	int ret = 0;
 
-	ret = test_and_set_bit(0, &hcp->busy);
-	if (ret) {
+	ret = mutex_trylock(&hcp->lock);
+	if (!ret) {
 		dev_err(dai->dev, "Only one simultaneous stream supported!\n");
 		return -EINVAL;
 	}
@@ -424,7 +424,7 @@ static int hdmi_codec_startup(struct snd_pcm_substream *substream,
 
 err:
 	/* Release the exclusive lock on error */
-	clear_bit(0, &hcp->busy);
+	mutex_unlock(&hcp->lock);
 	return ret;
 }
 
@@ -436,7 +436,7 @@ static void hdmi_codec_shutdown(struct snd_pcm_substream *substream,
 	hcp->chmap_idx = HDMI_CODEC_CHMAP_IDX_UNKNOWN;
 	hcp->hcd.ops->audio_shutdown(dai->dev->parent, hcp->hcd.data);
 
-	clear_bit(0, &hcp->busy);
+	mutex_unlock(&hcp->lock);
 }
 
 static int hdmi_codec_hw_params(struct snd_pcm_substream *substream,
@@ -773,6 +773,8 @@ static int hdmi_codec_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	hcp->hcd = *hcd;
+	mutex_init(&hcp->lock);
+
 	daidrv = devm_kcalloc(dev, dai_count, sizeof(*daidrv), GFP_KERNEL);
 	if (!daidrv)
 		return -ENOMEM;
-- 
2.20.1