1 files changed, 319 insertions, 0 deletions
diff --git a/net/sctp/stream_sched_prio.c b/net/sctp/stream_sched_prio.c
new file mode 100644
index 0000000000..4d4d9da331
--- /dev/null
+++ b/net/sctp/stream_sched_prio.c
@@ -0,0 +1,319 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* SCTP kernel implementation
+ * (C) Copyright Red Hat Inc. 2017
+ *
+ * This file is part of the SCTP kernel implementation
+ *
+ * These functions manipulate sctp stream queue/scheduling.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email addresched(es):
+ *    lksctp developers <linux-sctp@vger.kernel.org>
+ *
+ * Written or modified by:
+ *    Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
+ */
+
+#include <linux/list.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+#include <net/sctp/stream_sched.h>
+
+/* Priority handling
+ * RFC DRAFT ndata section 3.4
+ */
+
+static void sctp_sched_prio_unsched_all(struct sctp_stream *stream);
+
+static struct sctp_stream_priorities *sctp_sched_prio_head_get(struct sctp_stream_priorities *p)
+{
+	p->users++;
+	return p;
+}
+
+static void sctp_sched_prio_head_put(struct sctp_stream_priorities *p)
+{
+	if (p && --p->users == 0)
+		kfree(p);
+}
+
+static struct sctp_stream_priorities *sctp_sched_prio_new_head(
+			struct sctp_stream *stream, int prio, gfp_t gfp)
+{
+	struct sctp_stream_priorities *p;
+
+	p = kmalloc(sizeof(*p), gfp);
+	if (!p)
+		return NULL;
+
+	INIT_LIST_HEAD(&p->prio_sched);
+	INIT_LIST_HEAD(&p->active);
+	p->next = NULL;
+	p->prio = prio;
+	p->users = 1;
+
+	return p;
+}
+
+static struct sctp_stream_priorities *sctp_sched_prio_get_head(
+			struct sctp_stream *stream, int prio, gfp_t gfp)
+{
+	struct sctp_stream_priorities *p;
+	int i;
+
+	/* Look into scheduled priorities first, as they are sorted and
+	 * we can find it fast IF it's scheduled.
+	 */
+	list_for_each_entry(p, &stream->prio_list, prio_sched) {
+		if (p->prio == prio)
+			return sctp_sched_prio_head_get(p);
+		if (p->prio > prio)
+			break;
+	}
+
+	/* No luck. So we search on all streams now. */
+	for (i = 0; i < stream->outcnt; i++) {
+		if (!SCTP_SO(stream, i)->ext)
+			continue;
+
+		p = SCTP_SO(stream, i)->ext->prio_head;
+		if (!p)
+			/* Means all other streams won't be initialized
+			 * as well.
+			 */
+			break;
+		if (p->prio == prio)
+			return sctp_sched_prio_head_get(p);
+	}
+
+	/* If not even there, allocate a new one. */
+	return sctp_sched_prio_new_head(stream, prio, gfp);
+}
+
+static void sctp_sched_prio_next_stream(struct sctp_stream_priorities *p)
+{
+	struct list_head *pos;
+
+	pos = p->next->prio_list.next;
+	if (pos == &p->active)
+		pos = pos->next;
+	p->next = list_entry(pos, struct sctp_stream_out_ext, prio_list);
+}
+
+static bool sctp_sched_prio_unsched(struct sctp_stream_out_ext *soute)
+{
+	bool scheduled = false;
+
+	if (!list_empty(&soute->prio_list)) {
+		struct sctp_stream_priorities *prio_head = soute->prio_head;
+
+		/* Scheduled */
+		scheduled = true;
+
+		if (prio_head->next == soute)
+			/* Try to move to the next stream */
+			sctp_sched_prio_next_stream(prio_head);
+
+		list_del_init(&soute->prio_list);
+
+		/* Also unsched the priority if this was the last stream */
+		if (list_empty(&prio_head->active)) {
+			list_del_init(&prio_head->prio_sched);
+			/* If there is no stream left, clear next */
+			prio_head->next = NULL;
+		}
+	}
+
+	return scheduled;
+}
+
+static void sctp_sched_prio_sched(struct sctp_stream *stream,
+				  struct sctp_stream_out_ext *soute)
+{
+	struct sctp_stream_priorities *prio, *prio_head;
+
+	prio_head = soute->prio_head;
+
+	/* Nothing to do if already scheduled */
+	if (!list_empty(&soute->prio_list))
+		return;
+
+	/* Schedule the stream. If there is a next, we schedule the new
+	 * one before it, so it's the last in round robin order.
+	 * If there isn't, we also have to schedule the priority.
+	 */
+	if (prio_head->next) {
+		list_add(&soute->prio_list, prio_head->next->prio_list.prev);
+		return;
+	}
+
+	list_add(&soute->prio_list, &prio_head->active);
+	prio_head->next = soute;
+
+	list_for_each_entry(prio, &stream->prio_list, prio_sched) {
+		if (prio->prio > prio_head->prio) {
+			list_add(&prio_head->prio_sched, prio->prio_sched.prev);
+			return;
+		}
+	}
+
+	list_add_tail(&prio_head->prio_sched, &stream->prio_list);
+}
+
+static int sctp_sched_prio_set(struct sctp_stream *stream, __u16 sid,
+			       __u16 prio, gfp_t gfp)
+{
+	struct sctp_stream_out *sout = SCTP_SO(stream, sid);
+	struct sctp_stream_out_ext *soute = sout->ext;
+	struct sctp_stream_priorities *prio_head, *old;
+	bool reschedule = false;
+
+	old = soute->prio_head;
+	if (old && old->prio == prio)
+		return 0;
+
+	prio_head = sctp_sched_prio_get_head(stream, prio, gfp);
+	if (!prio_head)
+		return -ENOMEM;
+
+	reschedule = sctp_sched_prio_unsched(soute);
+	soute->prio_head = prio_head;
+	if (reschedule)
+		sctp_sched_prio_sched(stream, soute);
+
+	sctp_sched_prio_head_put(old);
+	return 0;
+}
+
+static int sctp_sched_prio_get(struct sctp_stream *stream, __u16 sid,
+			       __u16 *value)
+{
+	*value = SCTP_SO(stream, sid)->ext->prio_head->prio;
+	return 0;
+}
+
+static int sctp_sched_prio_init(struct sctp_stream *stream)
+{
+	INIT_LIST_HEAD(&stream->prio_list);
+
+	return 0;
+}
+
+static int sctp_sched_prio_init_sid(struct sctp_stream *stream, __u16 sid,
+				    gfp_t gfp)
+{
+	INIT_LIST_HEAD(&SCTP_SO(stream, sid)->ext->prio_list);
+	return sctp_sched_prio_set(stream, sid, 0, gfp);
+}
+
+static void sctp_sched_prio_free_sid(struct sctp_stream *stream, __u16 sid)
+{
+	sctp_sched_prio_head_put(SCTP_SO(stream, sid)->ext->prio_head);
+	SCTP_SO(stream, sid)->ext->prio_head = NULL;
+}
+
+static void sctp_sched_prio_enqueue(struct sctp_outq *q,
+				    struct sctp_datamsg *msg)
+{
+	struct sctp_stream *stream;
+	struct sctp_chunk *ch;
+	__u16 sid;
+
+	ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list);
+	sid = sctp_chunk_stream_no(ch);
+	stream = &q->asoc->stream;
+	sctp_sched_prio_sched(stream, SCTP_SO(stream, sid)->ext);
+}
+
+static struct sctp_chunk *sctp_sched_prio_dequeue(struct sctp_outq *q)
+{
+	struct sctp_stream *stream = &q->asoc->stream;
+	struct sctp_stream_priorities *prio;
+	struct sctp_stream_out_ext *soute;
+	struct sctp_chunk *ch = NULL;
+
+	/* Bail out quickly if queue is empty */
+	if (list_empty(&q->out_chunk_list))
+		goto out;
+
+	/* Find which chunk is next. It's easy, it's either the current
+	 * one or the first chunk on the next active stream.
+	 */
+	if (stream->out_curr) {
+		soute = stream->out_curr->ext;
+	} else {
+		prio = list_entry(stream->prio_list.next,
+				  struct sctp_stream_priorities, prio_sched);
+		soute = prio->next;
+	}
+	ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list);
+	sctp_sched_dequeue_common(q, ch);
+
+out:
+	return ch;
+}
+
+static void sctp_sched_prio_dequeue_done(struct sctp_outq *q,
+					 struct sctp_chunk *ch)
+{
+	struct sctp_stream_priorities *prio;
+	struct sctp_stream_out_ext *soute;
+	__u16 sid;
+
+	/* Last chunk on that msg, move to the next stream on
+	 * this priority.
+	 */
+	sid = sctp_chunk_stream_no(ch);
+	soute = SCTP_SO(&q->asoc->stream, sid)->ext;
+	prio = soute->prio_head;
+
+	sctp_sched_prio_next_stream(prio);
+
+	if (list_empty(&soute->outq))
+		sctp_sched_prio_unsched(soute);
+}
+
+static void sctp_sched_prio_sched_all(struct sctp_stream *stream)
+{
+	struct sctp_association *asoc;
+	struct sctp_stream_out *sout;
+	struct sctp_chunk *ch;
+
+	asoc = container_of(stream, struct sctp_association, stream);
+	list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
+		__u16 sid;
+
+		sid = sctp_chunk_stream_no(ch);
+		sout = SCTP_SO(stream, sid);
+		if (sout->ext)
+			sctp_sched_prio_sched(stream, sout->ext);
+	}
+}
+
+static void sctp_sched_prio_unsched_all(struct sctp_stream *stream)
+{
+	struct sctp_stream_priorities *p, *tmp;
+	struct sctp_stream_out_ext *soute, *souttmp;
+
+	list_for_each_entry_safe(p, tmp, &stream->prio_list, prio_sched)
+		list_for_each_entry_safe(soute, souttmp, &p->active, prio_list)
+			sctp_sched_prio_unsched(soute);
+}
+
+static struct sctp_sched_ops sctp_sched_prio = {
+	.set = sctp_sched_prio_set,
+	.get = sctp_sched_prio_get,
+	.init = sctp_sched_prio_init,
+	.init_sid = sctp_sched_prio_init_sid,
+	.free_sid = sctp_sched_prio_free_sid,
+	.enqueue = sctp_sched_prio_enqueue,
+	.dequeue = sctp_sched_prio_dequeue,
+	.dequeue_done = sctp_sched_prio_dequeue_done,
+	.sched_all = sctp_sched_prio_sched_all,
+	.unsched_all = sctp_sched_prio_unsched_all,
+};
+
+void sctp_sched_ops_prio_init(void)
+{
+	sctp_sched_ops_register(SCTP_SS_PRIO, &sctp_sched_prio);
+}