+/*
+ * Check if data is still being extracted from the buffers for a specific
+ * stream. Consumer data lock MUST be acquired before calling this function.
+ *
+ * Return 0 if the traced data are still getting read else 1 meaning that the
+ * data is available for trace viewer reading.
+ */
+int lttng_kconsumer_data_available(struct lttng_consumer_stream *stream)
+{
+ int ret;
+
+ assert(stream);
+
+ /*
+ * Try to lock the stream mutex. On failure, we know that the stream is
+ * being used else where hence there is data still being extracted.
+ */
+ ret = pthread_mutex_trylock(&stream->lock);
+ if (ret == EBUSY) {
+ goto data_not_available;
+ }
+ /* The stream is now locked so we can do our ustctl calls */
+
+ ret = kernctl_get_next_subbuf(stream->wait_fd);
+ if (ret == 0) {
+ /* There is still data so let's put back this subbuffer. */
+ ret = kernctl_put_subbuf(stream->wait_fd);
+ assert(ret == 0);
+ pthread_mutex_unlock(&stream->lock);
+ goto data_not_available;
+ }
+
+ /* Data is available to be read for this stream. */
+ pthread_mutex_unlock(&stream->lock);
+ return 1;
+
+data_not_available:
+ return 0;
+}