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sound: Change AudioFrame allocation

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When qemu (for example) delivers audio samples to the spice server, it
does so by requesting a buffer from the spice server
(spice_server_playback_get_buffer()), filling them with audio data, and
then calling spice_server_playback_put_samples() to send them to the
client. Between the call to _get_buffer() and the call to
_put_samples(), we need to ensure that the buffer remains valid. Since
this buffer is allocated within PlaybackChannelClient, we did this by
incrementing a ref on the PlaybackChannelClient in _get_buffer(), and
decrementing the ref in _put_samples(). This has the effect of
potentially keeping the PlaybackChannelClient alive after the spice
client has disconnected.

This was not a problem when PlaybackChannelClient was a simple helper
class. But we intend to change PlaybackChannelClient so that it
inherits from RedChannelClient. In that case, the reference taken in
_get_buffer() would result in the RedChannelClient (and associated
RedChannel, etc) being kept alive longer than expected. To avoid this,
we add an additional ref-counted adapter class (AudioFrameContainer)
that owns the allocated audio frames and can outlive the
RedChannelClient if necessary. When the client is freed, the
AudioFrameContainer is just unreferenced.

Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Acked-by: Jonathon Jongsma <jjongsma@redhat.com>
This commit is contained in:
Frediano Ziglio 2016-12-02 09:57:21 +00:00
parent f301d3efc1
commit 852202a049
1 changed files with 49 additions and 13 deletions
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62
server/sound.c
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@ -77,6 +77,8 @@ typedef struct SndChannelClient SndChannelClient;
typedef struct SndChannel SndChannel;
typedef struct PlaybackChannelClient PlaybackChannelClient;
typedef struct RecordChannelClient RecordChannelClient;
typedef struct AudioFrame AudioFrame;
typedef struct AudioFrameContainer AudioFrameContainer;
typedef struct SpicePlaybackState PlaybackChannel;
typedef struct SpiceRecordState RecordChannel;
@ -126,11 +128,21 @@ struct AudioFrame {
uint32_t samples[SND_CODEC_MAX_FRAME_SIZE];
PlaybackChannelClient *client;
AudioFrame *next;
AudioFrameContainer *container;
gboolean allocated;
};
#define NUM_AUDIO_FRAMES 3
struct AudioFrameContainer
{
int refs;
AudioFrame items[NUM_AUDIO_FRAMES];
};
struct PlaybackChannelClient {
SndChannelClient base;
AudioFrame frames[3];
AudioFrameContainer *frames;
AudioFrame *free_frames;
AudioFrame *in_progress; /* Frame being sent to the client */
AudioFrame *pending_frame; /* Next frame to send to the client */
@ -218,12 +230,7 @@ static SndChannel *snd_channels;
static void snd_receive(SndChannelClient *client);
static void snd_playback_start(SndChannel *channel);
static void snd_record_start(SndChannel *channel);
static SndChannelClient *snd_channel_ref(SndChannelClient *client)
{
client->refs++;
return client;
}
static void snd_playback_alloc_frames(PlaybackChannelClient *playback);
static SndChannelClient *snd_channel_unref(SndChannelClient *client)
{
@ -1147,7 +1154,10 @@ SPICE_GNUC_VISIBLE void spice_server_playback_get_buffer(SpicePlaybackInstance *
return;
}
spice_assert(playback_client->base.active);
snd_channel_ref(client);
if (!playback_client->free_frames->allocated) {
playback_client->free_frames->allocated = TRUE;
++playback_client->frames->refs;
}
*frame = playback_client->free_frames->samples;
playback_client->free_frames = playback_client->free_frames->next;
@ -1160,9 +1170,15 @@ SPICE_GNUC_VISIBLE void spice_server_playback_put_samples(SpicePlaybackInstance
AudioFrame *frame;
frame = SPICE_CONTAINEROF(samples, AudioFrame, samples[0]);
if (frame->allocated) {
frame->allocated = FALSE;
if (--frame->container->refs == 0) {
free(frame->container);
return;
}
}
playback_client = frame->client;
spice_assert(playback_client);
if (!snd_channel_unref(&playback_client->base) ||
if (!playback_client ||
sin->st->channel.connection != &playback_client->base) {
/* lost last reference, client has been destroyed previously */
spice_info("audio samples belong to a disconnected client");
@ -1240,6 +1256,15 @@ static void on_new_playback_channel(SndChannel *channel, SndChannelClient *snd_c
static void snd_playback_cleanup(SndChannelClient *client)
{
PlaybackChannelClient *playback_client = SPICE_CONTAINEROF(client, PlaybackChannelClient, base);
int i;
// free frames, unref them
for (i = 0; i < NUM_AUDIO_FRAMES; ++i) {
playback_client->frames->items[i].client = NULL;
}
if (--playback_client->frames->refs == 0) {
free(playback_client->frames);
}
if (playback_client->base.active) {
reds_enable_mm_time(snd_channel_get_server(client));
@ -1271,9 +1296,8 @@ static void snd_set_playback_peer(RedChannel *red_channel, RedClient *client, Re
caps, num_caps))) {
return;
}
snd_playback_free_frame(playback_client, &playback_client->frames[0]);
snd_playback_free_frame(playback_client, &playback_client->frames[1]);
snd_playback_free_frame(playback_client, &playback_client->frames[2]);
snd_playback_alloc_frames(playback_client);
int client_can_celt = red_channel_client_test_remote_cap(playback_client->base.channel_client,
SPICE_PLAYBACK_CAP_CELT_0_5_1);
@ -1716,3 +1740,15 @@ void snd_set_playback_compression(int on)
}
}
}
static void snd_playback_alloc_frames(PlaybackChannelClient *playback)
{
int i;
playback->frames = spice_new0(AudioFrameContainer, 1);
playback->frames->refs = 1;
for (i = 0; i < NUM_AUDIO_FRAMES; ++i) {
playback->frames->items[i].container = playback->frames;
snd_playback_free_frame(playback, &playback->frames->items[i]);
}
}