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Commit 3994e0b1 authored by Vaibhav Agarwal's avatar Vaibhav Agarwal Committed by Greg Kroah-Hartman
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greybus: audio: use variable 'is_connected' to maintain module state 



there is race condition between _disconnect() request &
stop_trigger() in case of abrupt module removal.
And sometimes this can lead to deadlock while acquiring
codec_info->lock.
To avoid such situation, atomic variable is used to maintain
codec connected state.
During dai operations (trigger, shutdown, etc.), 'is_connected'
variable is validated to avoid unnecessary lock acquire in
case module already removed.

Signed-off-by: default avatarVaibhav Agarwal <vaibhav.agarwal@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
parent 796fad44

drivers/staging/greybus/audio_codec.c

+17 −0
Original line number Diff line number Diff line
@@ -44,6 +44,9 @@ static int gbcodec_startup(struct snd_pcm_substream *substream, 
	struct gbaudio_dai *gb_dai;

	struct gbaudio_codec_info *gb = dev_get_drvdata(dai->dev);



	if (!atomic_read(&gb->is_connected))

		return -ENODEV;



	/* find the dai */

	mutex_lock(&gb->lock);

	gb_dai = gbaudio_find_dai(gb, -1, dai->name);
@@ -77,6 +80,9 @@ static void gbcodec_shutdown(struct snd_pcm_substream *substream, 
	struct gbaudio_dai *gb_dai;

	struct gbaudio_codec_info *gb = dev_get_drvdata(dai->dev);



	if (!atomic_read(&gb->is_connected))

		return;



	/* find the dai */

	mutex_lock(&gb->lock);

	gb_dai = gbaudio_find_dai(gb, -1, dai->name);
@@ -129,6 +135,9 @@ static int gbcodec_hw_params(struct snd_pcm_substream *substream, 
	struct gbaudio_dai *gb_dai;

	struct gbaudio_codec_info *gb = dev_get_drvdata(dai->dev);



	if (!atomic_read(&gb->is_connected))

		return -ENODEV;



	/* find the dai */

	mutex_lock(&gb->lock);

	gb_dai = gbaudio_find_dai(gb, -1, dai->name);
@@ -204,6 +213,9 @@ static int gbcodec_prepare(struct snd_pcm_substream *substream, 
	struct gbaudio_dai *gb_dai;

	struct gbaudio_codec_info *gb = dev_get_drvdata(dai->dev);



	if (!atomic_read(&gb->is_connected))

		return -ENODEV;



	/* find the dai */

	mutex_lock(&gb->lock);

	gb_dai = gbaudio_find_dai(gb, -1, dai->name);
@@ -278,6 +290,9 @@ static int gbcodec_trigger(struct snd_pcm_substream *substream, int cmd, 
	struct gbaudio_dai *gb_dai;

	struct gbaudio_codec_info *gb = dev_get_drvdata(dai->dev);



	if (!atomic_read(&gb->is_connected))

		return -ENODEV;



	/* find the dai */

	mutex_lock(&gb->lock);

	gb_dai = gbaudio_find_dai(gb, -1, dai->name);
@@ -776,6 +791,7 @@ static int gb_audio_probe(struct gb_bundle *bundle, 
	desc.devices = 0x2; /* todo */

	gbcodec->manager_id = gb_audio_manager_add(&desc);



	atomic_set(&gbcodec->is_connected, 1);

	list_add(&gbcodec->list, &gb_codec_list);

	dev_dbg(dev, "Add GB Audio device:%s\n", gbcodec->name);

	mutex_unlock(&gb_codec_list_lock);
@@ -809,6 +825,7 @@ static void gb_audio_disconnect(struct gb_bundle *bundle) 
	struct gbaudio_dai *dai, *_dai;



	mutex_lock(&gb_codec_list_lock);

	atomic_set(&gbcodec->is_connected, 0);

	list_del(&gbcodec->list);

	/* inform uevent to above layers */

	gb_audio_manager_remove(gbcodec->manager_id);

drivers/staging/greybus/audio_codec.h

+9 −1
Original line number Diff line number Diff line
@@ -108,6 +108,15 @@ struct gbaudio_codec_info { 
	int manager_id;

	char name[NAME_SIZE];



	/*

	 * there can be a rece condition between gb_audio_disconnect()

	 * and dai->trigger from above ASoC layer.

	 * To avoid any deadlock over codec_info->lock, atomic variable

	 * is used.

	 */

	atomic_t is_connected;

	struct mutex lock;



	/* soc related data */

	struct snd_soc_codec *codec;

	struct device *dev;
@@ -139,7 +148,6 @@ struct gbaudio_codec_info { 
	struct list_head widget_list;

	struct list_head codec_ctl_list;

	struct list_head widget_ctl_list;

	struct mutex lock;

};



struct gbaudio_dai *gbaudio_find_dai(struct gbaudio_codec_info *gbcodec,

drivers/staging/greybus/audio_topology.c

+12 −0
Original line number Diff line number Diff line
@@ -140,6 +140,9 @@ static int gbcodec_mixer_ctl_get(struct snd_kcontrol *kcontrol, 
	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);

	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);



	if (!atomic_read(&gb->is_connected))

		return -ENODEV;



	data = (struct gbaudio_ctl_pvt *)kcontrol->private_value;

	info = (struct gb_audio_ctl_elem_info *)data->info;
@@ -187,6 +190,9 @@ static int gbcodec_mixer_ctl_put(struct snd_kcontrol *kcontrol, 
	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);

	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);



	if (!atomic_read(&gb->is_connected))

		return -ENODEV;



	data = (struct gbaudio_ctl_pvt *)kcontrol->private_value;

	info = (struct gb_audio_ctl_elem_info *)data->info;
@@ -281,6 +287,9 @@ static int gbcodec_mixer_dapm_ctl_get(struct snd_kcontrol *kcontrol, 
	struct snd_soc_codec *codec = widget->codec;

	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);



	if (!atomic_read(&gb->is_connected))

		return -ENODEV;



	data = (struct gbaudio_ctl_pvt *)kcontrol->private_value;

	info = (struct gb_audio_ctl_elem_info *)data->info;
@@ -315,6 +324,9 @@ static int gbcodec_mixer_dapm_ctl_put(struct snd_kcontrol *kcontrol, 
	struct snd_soc_codec *codec = widget->codec;

	struct gbaudio_codec_info *gb = snd_soc_codec_get_drvdata(codec);



	if (!atomic_read(&gb->is_connected))

		return -ENODEV;



	data = (struct gbaudio_ctl_pvt *)kcontrol->private_value;

	info = (struct gb_audio_ctl_elem_info *)data->info;