stream: protect time updates with atomic seqlock

This commit is contained in:
Wim Taymans 2018-09-21 16:39:06 +02:00
parent 3af7b42193
commit 375df60384

View file

@ -125,7 +125,7 @@ struct stream {
bool free_data;
struct data data;
uint32_t seq1, seq2;
uintptr_t seq;
struct pw_time time;
};
@ -647,13 +647,13 @@ static int process_notify(struct stream *impl, struct spa_pod_sequence *sequence
static inline void copy_quantum(struct stream *impl, int64_t queued)
{
struct pw_driver_quantum *q = impl->node->rt.quantum;
impl->seq1++;
__atomic_add_fetch(&impl->seq, 1, __ATOMIC_SEQ_CST);
impl->time.now = q->nsec;
impl->time.rate = q->rate;
impl->time.ticks = q->position;
impl->time.delay = q->delay;
impl->time.queued = queued;
impl->seq2 = impl->seq1;
__atomic_add_fetch(&impl->seq, 1, __ATOMIC_SEQ_CST);
if (impl->io_control)
process_control(impl, &impl->io_control->sequence);
@ -1143,12 +1143,13 @@ int pw_stream_set_active(struct pw_stream *stream, bool active)
int pw_stream_get_time(struct pw_stream *stream, struct pw_time *time)
{
struct stream *impl = SPA_CONTAINER_OF(stream, struct stream, this);
uint32_t seq;
uintptr_t seq1, seq2;
do {
seq = impl->seq2;
seq1 = __atomic_load_n(&impl->seq, __ATOMIC_SEQ_CST);
*time = impl->time;
} while (impl->seq1 != seq);
seq2 = __atomic_load_n(&impl->seq, __ATOMIC_SEQ_CST);
} while (seq1 != seq2 || seq1 & 1);
if (impl->direction == SPA_DIRECTION_INPUT)
time->queued = (int64_t)(time->queued - impl->dequeued.outcount);