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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: Vaibhav Agarwal <vaibhav.agarwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
hifive-unleashed-5.1
Vaibhav Agarwal 2016-01-28 21:15:40 +05:30 committed by Greg Kroah-Hartman
parent 796fad441c
commit 3994e0b139
3 changed files with 38 additions and 1 deletions
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17
drivers/staging/greybus/audio_codec.c
View File

@ -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);

10
drivers/staging/greybus/audio_codec.h
View File

@ -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,

12
drivers/staging/greybus/audio_topology.c
View File

@ -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;