On 1/5/26 3:04 PM, Xin Long wrote:

+/* Create and register new streams for sending or receiving. */
+static struct quic_stream *quic_stream_create(struct quic_stream_table *streams,
+					      s64 max_stream_id, bool send, bool is_serv)
+{
+	struct quic_stream_limits *limits = &streams->send;
+	struct quic_stream *stream = NULL;
+	gfp_t gfp = GFP_KERNEL_ACCOUNT;
+	s64 stream_id;
+
+	if (!send) {
+		limits = &streams->recv;
+		gfp = GFP_ATOMIC | __GFP_ACCOUNT;
+	}
+	stream_id = limits->next_bidi_stream_id;
+	if (quic_stream_id_uni(max_stream_id))
+		stream_id = limits->next_uni_stream_id;
+
+	/* rfc9000#section-2.1: A stream ID that is used out of order results in all streams
+	 * of that type with lower-numbered stream IDs also being opened.
+	 */
+	while (stream_id <= max_stream_id) {
+		stream = kzalloc(sizeof(*stream), gfp);
+		if (!stream)
+			return NULL;

Do you need to release the allocated ids in case of failure? It would be
sourprising to find some ids allocated when this call fails/returns NULL.

+
+		stream->id = stream_id;
+		if (quic_stream_id_uni(stream_id)) {
+			if (send) {
+				stream->send.max_bytes = limits->max_stream_data_uni;
+			} else {
+				stream->recv.max_bytes = limits->max_stream_data_uni;
+				stream->recv.window = stream->recv.max_bytes;
+			}
+			/* Streams must be opened sequentially. Update the next stream ID so the
+			 * correct starting point is known if an out-of-order open is requested.
+			 */
+			limits->next_uni_stream_id = stream_id + QUIC_STREAM_ID_STEP;
+			limits->streams_uni++;
+
+			quic_stream_add(streams, stream);
+			stream_id += QUIC_STREAM_ID_STEP;
+			continue;
+		}
+
+		if (quic_stream_id_local(stream_id, is_serv)) {
+			stream->send.max_bytes = streams->send.max_stream_data_bidi_remote;
+			stream->recv.max_bytes = streams->recv.max_stream_data_bidi_local;
+		} else {
+			stream->send.max_bytes = streams->send.max_stream_data_bidi_local;
+			stream->recv.max_bytes = streams->recv.max_stream_data_bidi_remote;
+		}
+		stream->recv.window = stream->recv.max_bytes;
+
+		limits->next_bidi_stream_id = stream_id + QUIC_STREAM_ID_STEP;
+		limits->streams_bidi++;
+
+		quic_stream_add(streams, stream);
+		stream_id += QUIC_STREAM_ID_STEP;
+	}
+	return stream;
+}
+
+/* Check if a send or receive stream ID is already closed. */
+static bool quic_stream_id_closed(struct quic_stream_table *streams, s64 stream_id, bool send)
+{
+	struct quic_stream_limits *limits = send ? &streams->send : &streams->recv;
+
+	if (quic_stream_id_uni(stream_id))
+		return stream_id < limits->next_uni_stream_id;
+	return stream_id < limits->next_bidi_stream_id;

I can't recall if I mentioned the following in a past review... it looks
like the above assumes wrap around are not possible, which is realistic
given the u64 counters - it would require > 100y on a server allocating
4G ids per second.

But it would be nice to explcitly document such assumption somewhere.

+}
+
+/* Check if a stream ID would exceed local (recv) or peer (send) limits. */
+bool quic_stream_id_exceeds(struct quic_stream_table *streams, s64 stream_id, bool send)
+{
+	u64 nstreams;
+
+	if (!send) {
+		if (quic_stream_id_uni(stream_id))
+			return stream_id > streams->recv.max_uni_stream_id;
+		return stream_id > streams->recv.max_bidi_stream_id;
+	}
+
+	if (quic_stream_id_uni(stream_id)) {
+		if (stream_id > streams->send.max_uni_stream_id)
+			return true;
+		stream_id -= streams->send.next_uni_stream_id;
+		nstreams = quic_stream_id_to_streams(stream_id);

It's not clear to me why send streams only have this additional check.

+		return nstreams + streams->send.streams_uni > streams->send.max_streams_uni;

Possibly it would be more consistent

max_uni_stream_id -> max_stream_ids_uni

(no strong preferences)

+	}
+
+	if (stream_id > streams->send.max_bidi_stream_id)
+		return true;
+	stream_id -= streams->send.next_bidi_stream_id;
+	nstreams = quic_stream_id_to_streams(stream_id);
+	return nstreams + streams->send.streams_bidi > streams->send.max_streams_bidi;
+}

[...]

+/* Get or create a receive stream by ID. Requires sock lock held. */
+struct quic_stream *quic_stream_recv_get(struct quic_stream_table *streams, s64 stream_id,
+					 bool is_serv)
+{
+	struct quic_stream *stream;
+
+	if (!quic_stream_id_valid(stream_id, is_serv, false))
+		return ERR_PTR(-EINVAL);
+
+	stream = quic_stream_find(streams, stream_id);
+	if (stream)
+		return stream;
+
+	if (quic_stream_id_local(stream_id, is_serv)) {
+		if (quic_stream_id_closed(streams, stream_id, true))
+			return ERR_PTR(-ENOSTR);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (quic_stream_id_closed(streams, stream_id, false))
+		return ERR_PTR(-ENOSTR);
+
+	if (quic_stream_id_exceeds(streams, stream_id, false))
+		return ERR_PTR(-EAGAIN);
+
+	stream = quic_stream_create(streams, stream_id, false, is_serv);
+	if (!stream)
+		return ERR_PTR(-ENOSTR);
+	if (quic_stream_id_valid(stream_id, is_serv, true))
+		streams->send.active_stream_id = stream_id;

This function is really similar to quic_stream_send_get(), I think it
should be easy factor out a common helper (and possibly use directly
such helper with no send/recv wrapper).

/P