// 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 <[email protected]>
*
* Written or modified by:
* Marcelo Ricardo Leitner <[email protected]>
*/
#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);
}
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