LXR linux/net/sctp/stream_sched

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* SCTP kernel implementation
   3 * (C) Copyright Red Hat Inc. 2017
   4 *
   5 * This file is part of the SCTP kernel implementation
   6 *
   7 * These functions manipulate sctp stream queue/scheduling.
   8 *
   9 * Please send any bug reports or fixes you make to the
  10 * email addresched(es):
  11 *    lksctp developers <linux-sctp@vger.kernel.org>
  12 *
  13 * Written or modified by:
  14 *    Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
  15 */
  16
  17#include <linux/list.h>
  18#include <net/sctp/sctp.h>
  19#include <net/sctp/sm.h>
  20#include <net/sctp/stream_sched.h>
  21
  22/* Priority handling
  23 * RFC DRAFT ndata section 3.2
  24 */
  25static void sctp_sched_rr_unsched_all(struct sctp_stream *stream);
  26
  27static void sctp_sched_rr_next_stream(struct sctp_stream *stream)
  28{
  29        struct list_head *pos;
  30
  31        pos = stream->rr_next->rr_list.next;
  32        if (pos == &stream->rr_list)
  33                pos = pos->next;
  34        stream->rr_next = list_entry(pos, struct sctp_stream_out_ext, rr_list);
  35}
  36
  37static void sctp_sched_rr_unsched(struct sctp_stream *stream,
  38                                  struct sctp_stream_out_ext *soute)
  39{
  40        if (stream->rr_next == soute)
  41                /* Try to move to the next stream */
  42                sctp_sched_rr_next_stream(stream);
  43
  44        list_del_init(&soute->rr_list);
  45
  46        /* If we have no other stream queued, clear next */
  47        if (list_empty(&stream->rr_list))
  48                stream->rr_next = NULL;
  49}
  50
  51static void sctp_sched_rr_sched(struct sctp_stream *stream,
  52                                struct sctp_stream_out_ext *soute)
  53{
  54        if (!list_empty(&soute->rr_list))
  55                /* Already scheduled. */
  56                return;
  57
  58        /* Schedule the stream */
  59        list_add_tail(&soute->rr_list, &stream->rr_list);
  60
  61        if (!stream->rr_next)
  62                stream->rr_next = soute;
  63}
  64
  65static int sctp_sched_rr_set(struct sctp_stream *stream, __u16 sid,
  66                             __u16 prio, gfp_t gfp)
  67{
  68        return 0;
  69}
  70
  71static int sctp_sched_rr_get(struct sctp_stream *stream, __u16 sid,
  72                             __u16 *value)
  73{
  74        return 0;
  75}
  76
  77static int sctp_sched_rr_init(struct sctp_stream *stream)
  78{
  79        INIT_LIST_HEAD(&stream->rr_list);
  80        stream->rr_next = NULL;
  81
  82        return 0;
  83}
  84
  85static int sctp_sched_rr_init_sid(struct sctp_stream *stream, __u16 sid,
  86                                  gfp_t gfp)
  87{
  88        INIT_LIST_HEAD(&SCTP_SO(stream, sid)->ext->rr_list);
  89
  90        return 0;
  91}
  92
  93static void sctp_sched_rr_free(struct sctp_stream *stream)
  94{
  95        sctp_sched_rr_unsched_all(stream);
  96}
  97
  98static void sctp_sched_rr_enqueue(struct sctp_outq *q,
  99                                  struct sctp_datamsg *msg)
 100{
 101        struct sctp_stream *stream;
 102        struct sctp_chunk *ch;
 103        __u16 sid;
 104
 105        ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list);
 106        sid = sctp_chunk_stream_no(ch);
 107        stream = &q->asoc->stream;
 108        sctp_sched_rr_sched(stream, SCTP_SO(stream, sid)->ext);
 109}
 110
 111static struct sctp_chunk *sctp_sched_rr_dequeue(struct sctp_outq *q)
 112{
 113        struct sctp_stream *stream = &q->asoc->stream;
 114        struct sctp_stream_out_ext *soute;
 115        struct sctp_chunk *ch = NULL;
 116
 117        /* Bail out quickly if queue is empty */
 118        if (list_empty(&q->out_chunk_list))
 119                goto out;
 120
 121        /* Find which chunk is next */
 122        if (stream->out_curr)
 123                soute = stream->out_curr->ext;
 124        else
 125                soute = stream->rr_next;
 126        ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list);
 127
 128        sctp_sched_dequeue_common(q, ch);
 129
 130out:
 131        return ch;
 132}
 133
 134static void sctp_sched_rr_dequeue_done(struct sctp_outq *q,
 135                                       struct sctp_chunk *ch)
 136{
 137        struct sctp_stream_out_ext *soute;
 138        __u16 sid;
 139
 140        /* Last chunk on that msg, move to the next stream */
 141        sid = sctp_chunk_stream_no(ch);
 142        soute = SCTP_SO(&q->asoc->stream, sid)->ext;
 143
 144        sctp_sched_rr_next_stream(&q->asoc->stream);
 145
 146        if (list_empty(&soute->outq))
 147                sctp_sched_rr_unsched(&q->asoc->stream, soute);
 148}
 149
 150static void sctp_sched_rr_sched_all(struct sctp_stream *stream)
 151{
 152        struct sctp_association *asoc;
 153        struct sctp_stream_out_ext *soute;
 154        struct sctp_chunk *ch;
 155
 156        asoc = container_of(stream, struct sctp_association, stream);
 157        list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
 158                __u16 sid;
 159
 160                sid = sctp_chunk_stream_no(ch);
 161                soute = SCTP_SO(stream, sid)->ext;
 162                if (soute)
 163                        sctp_sched_rr_sched(stream, soute);
 164        }
 165}
 166
 167static void sctp_sched_rr_unsched_all(struct sctp_stream *stream)
 168{
 169        struct sctp_stream_out_ext *soute, *tmp;
 170
 171        list_for_each_entry_safe(soute, tmp, &stream->rr_list, rr_list)
 172                sctp_sched_rr_unsched(stream, soute);
 173}
 174
 175static struct sctp_sched_ops sctp_sched_rr = {
 176        .set = sctp_sched_rr_set,
 177        .get = sctp_sched_rr_get,
 178        .init = sctp_sched_rr_init,
 179        .init_sid = sctp_sched_rr_init_sid,
 180        .free = sctp_sched_rr_free,
 181        .enqueue = sctp_sched_rr_enqueue,
 182        .dequeue = sctp_sched_rr_dequeue,
 183        .dequeue_done = sctp_sched_rr_dequeue_done,
 184        .sched_all = sctp_sched_rr_sched_all,
 185        .unsched_all = sctp_sched_rr_unsched_all,
 186};
 187
 188void sctp_sched_ops_rr_init(void)
 189{
 190        sctp_sched_ops_register(SCTP_SS_RR, &sctp_sched_rr);
 191}
 192