diff --git a/src/quic_stream.c b/src/quic_stream.c
index da86e04ff9..727636b06a 100644
--- a/src/quic_stream.c
+++ b/src/quic_stream.c
@@ -17,6 +17,34 @@ DECLARE_STATIC_POOL(pool_head_quic_stream_buf, "qc_stream_buf",
                     sizeof(struct qc_stream_buf));
 
 
+static void qc_stream_buf_free(struct qc_stream_desc *stream,
+                               struct qc_stream_buf **stream_buf)
+{
+	struct quic_conn *qc = stream->qc;
+	struct buffer *buf = &(*stream_buf)->buf;
+
+	LIST_DEL_INIT(&(*stream_buf)->list);
+	if (*stream_buf == stream->buf) {
+		/* current buf must always be last entry in buflist */
+		BUG_ON(!LIST_ISEMPTY(&stream->buf_list));
+		stream->buf = NULL;
+	}
+
+	b_free(buf);
+	offer_buffers(NULL, 1);
+	pool_free(pool_head_quic_stream_buf, *stream_buf);
+	*stream_buf = NULL;
+
+	/* notify MUX about available buffers. */
+	--qc->stream_buf_count;
+	if (qc->mux_state == QC_MUX_READY) {
+		if (qc->qcc->flags & QC_CF_CONN_FULL) {
+			qc->qcc->flags &= ~QC_CF_CONN_FULL;
+			tasklet_wakeup(qc->qcc->wait_event.tasklet);
+		}
+	}
+}
+
 /* Allocate a new stream descriptor with id <id>. The caller is responsible to
  * store the stream in the appropriate tree. -1 special value must be used for
  * a CRYPTO data stream, the type being ignored.
@@ -92,7 +120,6 @@ int qc_stream_desc_ack(struct qc_stream_desc **stream, size_t offset, size_t len
 {
 	struct qc_stream_desc *s = *stream;
 	struct qc_stream_buf *stream_buf;
-	struct quic_conn *qc = s->qc;
 	struct buffer *buf;
 	size_t diff;
 
@@ -110,39 +137,17 @@ int qc_stream_desc_ack(struct qc_stream_desc **stream, size_t offset, size_t len
 	s->ack_offset += diff;
 	b_del(buf, diff);
 
-	/* nothing more to do if buf still not empty. */
-	if (b_data(buf))
-		return diff;
+	/* Free oldest buffer if all data acknowledged. */
+	if (!b_data(buf)) {
+		qc_stream_buf_free(s, &stream_buf);
 
-	/* buf is empty and can now be freed. Do not forget to reset current
-	 * buf ptr if we were working on it.
-	 */
-	LIST_DELETE(&stream_buf->list);
-	if (stream_buf == s->buf) {
-		/* current buf must always be last entry in buflist */
-		BUG_ON(!LIST_ISEMPTY(&s->buf_list));
-		s->buf = NULL;
-	}
-
-	b_free(buf);
-	pool_free(pool_head_quic_stream_buf, stream_buf);
-	offer_buffers(NULL, 1);
-
-	/* notify MUX about available buffers. */
-	--qc->stream_buf_count;
-	if (qc->mux_state == QC_MUX_READY) {
-		if (qc->qcc->flags & QC_CF_CONN_FULL) {
-			qc->qcc->flags &= ~QC_CF_CONN_FULL;
-			tasklet_wakeup(qc->qcc->wait_event.tasklet);
+		/* Free stream instance if already released and no buffers left. */
+		if (s->release && LIST_ISEMPTY(&s->buf_list)) {
+			qc_stream_desc_free(s, 0);
+			*stream = NULL;
 		}
 	}
 
-	/* Free stream instance if already released and no buffers left. */
-	if (s->release && LIST_ISEMPTY(&s->buf_list)) {
-		qc_stream_desc_free(s, 0);
-		*stream = NULL;
-	}
-
 	return diff;
 }