Merge "audio HAL: reverse mutex locking order" into mnc-dev
diff --git a/modules/usbaudio/audio_hal.c b/modules/usbaudio/audio_hal.c
index 872fa93..bbea5f5 100644
--- a/modules/usbaudio/audio_hal.c
+++ b/modules/usbaudio/audio_hal.c
@@ -80,6 +80,7 @@
struct audio_stream_out stream;
pthread_mutex_t lock; /* see note below on mutex acquisition order */
+ pthread_mutex_t pre_lock; /* acquire before lock to avoid DOS by playback thread */
bool standby;
struct audio_device *dev; /* hardware information - only using this for the lock */
@@ -103,7 +104,8 @@
struct stream_in {
struct audio_stream_in stream;
- pthread_mutex_t lock; /* see note below on mutex acquisition order */
+ pthread_mutex_t lock; /* see note below on mutex acquisition order */
+ pthread_mutex_t pre_lock; /* acquire before lock to avoid DOS by capture thread */
bool standby;
struct audio_device *dev; /* hardware information - only using this for the lock */
@@ -126,6 +128,13 @@
};
/*
+ * NOTE: when multiple mutexes have to be acquired, always take the
+ * stream_in or stream_out mutex first, followed by the audio_device mutex.
+ * stream pre_lock is always acquired before stream lock to prevent starvation of control thread by
+ * higher priority playback or capture thread.
+ */
+
+/*
* Extract the card and device numbers from the supplied key/value pairs.
* kvpairs A null-terminated string containing the key/value pairs or card and device.
* i.e. "card=1;device=42"
@@ -203,6 +212,20 @@
return result_str;
}
+void lock_input_stream(struct stream_in *in)
+{
+ pthread_mutex_lock(&in->pre_lock);
+ pthread_mutex_lock(&in->lock);
+ pthread_mutex_unlock(&in->pre_lock);
+}
+
+void lock_output_stream(struct stream_out *out)
+{
+ pthread_mutex_lock(&out->pre_lock);
+ pthread_mutex_lock(&out->lock);
+ pthread_mutex_unlock(&out->pre_lock);
+}
+
/*
* HAl Functions
*/
@@ -260,16 +283,14 @@
{
struct stream_out *out = (struct stream_out *)stream;
- pthread_mutex_lock(&out->dev->lock);
- pthread_mutex_lock(&out->lock);
-
+ lock_output_stream(out);
if (!out->standby) {
+ pthread_mutex_lock(&out->dev->lock);
proxy_close(&out->proxy);
+ pthread_mutex_unlock(&out->dev->lock);
out->standby = true;
}
-
pthread_mutex_unlock(&out->lock);
- pthread_mutex_unlock(&out->dev->lock);
return 0;
}
@@ -295,9 +316,9 @@
return ret_value;
}
+ lock_output_stream(out);
/* Lock the device because that is where the profile lives */
pthread_mutex_lock(&out->dev->lock);
- pthread_mutex_lock(&out->lock);
if (!profile_is_cached_for(out->profile, card, device)) {
/* cannot read pcm device info if playback is active */
@@ -316,8 +337,8 @@
}
}
- pthread_mutex_unlock(&out->lock);
pthread_mutex_unlock(&out->dev->lock);
+ pthread_mutex_unlock(&out->lock);
return ret_value;
}
@@ -325,8 +346,8 @@
static char * out_get_parameters(const struct audio_stream *stream, const char *keys)
{
struct stream_out *out = (struct stream_out *)stream;
+ lock_output_stream(out);
pthread_mutex_lock(&out->dev->lock);
- pthread_mutex_lock(&out->lock);
char * params_str = device_get_parameters(out->profile, keys);
@@ -360,17 +381,16 @@
int ret;
struct stream_out *out = (struct stream_out *)stream;
- pthread_mutex_lock(&out->dev->lock);
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
if (out->standby) {
+ pthread_mutex_lock(&out->dev->lock);
ret = start_output_stream(out);
+ pthread_mutex_unlock(&out->dev->lock);
if (ret != 0) {
- pthread_mutex_unlock(&out->dev->lock);
goto err;
}
out->standby = false;
}
- pthread_mutex_unlock(&out->dev->lock);
alsa_device_proxy* proxy = &out->proxy;
const void * write_buff = buffer;
@@ -480,6 +500,9 @@
out->stream.get_presentation_position = out_get_presentation_position;
out->stream.get_next_write_timestamp = out_get_next_write_timestamp;
+ pthread_mutex_init(&out->lock, (const pthread_mutexattr_t *) NULL);
+ pthread_mutex_init(&out->pre_lock, (const pthread_mutexattr_t *) NULL);
+
out->dev = adev;
pthread_mutex_lock(&adev->lock);
out->profile = &adev->out_profile;
@@ -639,16 +662,15 @@
{
struct stream_in *in = (struct stream_in *)stream;
- pthread_mutex_lock(&in->dev->lock);
- pthread_mutex_lock(&in->lock);
-
+ lock_input_stream(in);
if (!in->standby) {
+ pthread_mutex_lock(&in->dev->lock);
proxy_close(&in->proxy);
+ pthread_mutex_unlock(&in->dev->lock);
in->standby = true;
}
pthread_mutex_unlock(&in->lock);
- pthread_mutex_unlock(&in->dev->lock);
return 0;
}
@@ -676,8 +698,8 @@
return ret_value;
}
+ lock_input_stream(in);
pthread_mutex_lock(&in->dev->lock);
- pthread_mutex_lock(&in->lock);
if (card >= 0 && device >= 0 && !profile_is_cached_for(in->profile, card, device)) {
/* cannot read pcm device info if playback is active */
@@ -696,8 +718,8 @@
}
}
- pthread_mutex_unlock(&in->lock);
pthread_mutex_unlock(&in->dev->lock);
+ pthread_mutex_unlock(&in->lock);
return ret_value;
}
@@ -706,13 +728,13 @@
{
struct stream_in *in = (struct stream_in *)stream;
+ lock_input_stream(in);
pthread_mutex_lock(&in->dev->lock);
- pthread_mutex_lock(&in->lock);
char * params_str = device_get_parameters(in->profile, keys);
- pthread_mutex_unlock(&in->lock);
pthread_mutex_unlock(&in->dev->lock);
+ pthread_mutex_unlock(&in->lock);
return params_str;
}
@@ -750,16 +772,16 @@
struct stream_in * in = (struct stream_in *)stream;
- pthread_mutex_lock(&in->dev->lock);
- pthread_mutex_lock(&in->lock);
+ lock_input_stream(in);
if (in->standby) {
- if (start_input_stream(in) != 0) {
- pthread_mutex_unlock(&in->dev->lock);
+ pthread_mutex_lock(&in->dev->lock);
+ ret = start_input_stream(in);
+ pthread_mutex_unlock(&in->dev->lock);
+ if (ret != 0) {
goto err;
}
in->standby = false;
}
- pthread_mutex_unlock(&in->dev->lock);
alsa_device_profile * profile = in->profile;
@@ -858,6 +880,9 @@
in->stream.read = in_read;
in->stream.get_input_frames_lost = in_get_input_frames_lost;
+ pthread_mutex_init(&in->lock, (const pthread_mutexattr_t *) NULL);
+ pthread_mutex_init(&in->pre_lock, (const pthread_mutexattr_t *) NULL);
+
in->dev = (struct audio_device *)dev;
pthread_mutex_lock(&in->dev->lock);