net/sctp/stream_sched.c

   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 /* First Come First Serve (a.k.a. FIFO)
  23  * RFC DRAFT ndata Section 3.1
  24  */
  25 static int sctp_sched_fcfs_set(struct sctp_stream *stream, __u16 sid,
  26                                __u16 value, gfp_t gfp)
  27 {
  28         return 0;
  29 }
  30
  31 static int sctp_sched_fcfs_get(struct sctp_stream *stream, __u16 sid,
  32                                __u16 *value)
  33 {
  34         *value = 0;
  35         return 0;
  36 }
  37
  38 static int sctp_sched_fcfs_init(struct sctp_stream *stream)
  39 {
  40         return 0;
  41 }
  42
  43 static int sctp_sched_fcfs_init_sid(struct sctp_stream *stream, __u16 sid,
  44                                     gfp_t gfp)
  45 {
  46         return 0;
  47 }
  48
  49 static void sctp_sched_fcfs_free_sid(struct sctp_stream *stream, __u16 sid)
  50 {
  51 }
  52
  53 static void sctp_sched_fcfs_enqueue(struct sctp_outq *q,
  54                                     struct sctp_datamsg *msg)
  55 {
  56 }
  57
  58 static struct sctp_chunk *sctp_sched_fcfs_dequeue(struct sctp_outq *q)
  59 {
  60         struct sctp_stream *stream = &q->asoc->stream;
  61         struct sctp_chunk *ch = NULL;
  62         struct list_head *entry;
  63
  64         if (list_empty(&q->out_chunk_list))
  65                 goto out;
  66
  67         if (stream->out_curr) {
  68                 ch = list_entry(stream->out_curr->ext->outq.next,
  69                                 struct sctp_chunk, stream_list);
  70         } else {
  71                 entry = q->out_chunk_list.next;
  72                 ch = list_entry(entry, struct sctp_chunk, list);
  73         }
  74
  75         sctp_sched_dequeue_common(q, ch);
  76
  77 out:
  78         return ch;
  79 }
  80
  81 static void sctp_sched_fcfs_dequeue_done(struct sctp_outq *q,
  82                                          struct sctp_chunk *chunk)
  83 {
  84 }
  85
  86 static void sctp_sched_fcfs_sched_all(struct sctp_stream *stream)
  87 {
  88 }
  89
  90 static void sctp_sched_fcfs_unsched_all(struct sctp_stream *stream)
  91 {
  92 }
  93
  94 static struct sctp_sched_ops sctp_sched_fcfs = {
  95         .set = sctp_sched_fcfs_set,
  96         .get = sctp_sched_fcfs_get,
  97         .init = sctp_sched_fcfs_init,
  98         .init_sid = sctp_sched_fcfs_init_sid,
  99         .free_sid = sctp_sched_fcfs_free_sid,
 100         .enqueue = sctp_sched_fcfs_enqueue,
 101         .dequeue = sctp_sched_fcfs_dequeue,
 102         .dequeue_done = sctp_sched_fcfs_dequeue_done,
 103         .sched_all = sctp_sched_fcfs_sched_all,
 104         .unsched_all = sctp_sched_fcfs_unsched_all,
 105 };
 106
 107 static void sctp_sched_ops_fcfs_init(void)
 108 {
 109         sctp_sched_ops_register(SCTP_SS_FCFS, &sctp_sched_fcfs);
 110 }
 111
 112 /* API to other parts of the stack */
 113
 114 static struct sctp_sched_ops *sctp_sched_ops[SCTP_SS_MAX + 1];
 115
 116 void sctp_sched_ops_register(enum sctp_sched_type sched,
 117                              struct sctp_sched_ops *sched_ops)
 118 {
 119         sctp_sched_ops[sched] = sched_ops;
 120 }
 121
 122 void sctp_sched_ops_init(void)
 123 {
 124         sctp_sched_ops_fcfs_init();
 125         sctp_sched_ops_prio_init();
 126         sctp_sched_ops_rr_init();
 127         sctp_sched_ops_fc_init();
 128 }
 129
 130 static void sctp_sched_free_sched(struct sctp_stream *stream)
 131 {
 132         struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
 133         struct sctp_stream_out_ext *soute;
 134         int i;
 135
 136         sched->unsched_all(stream);
 137         for (i = 0; i < stream->outcnt; i++) {
 138                 soute = SCTP_SO(stream, i)->ext;
 139                 if (!soute)
 140                         continue;
 141                 sched->free_sid(stream, i);
 142                 /* Give the next scheduler a clean slate. */
 143                 memset_after(soute, 0, outq);
 144         }
 145 }
 146
 147 int sctp_sched_set_sched(struct sctp_association *asoc,
 148                          enum sctp_sched_type sched)
 149 {
 150         struct sctp_sched_ops *n = sctp_sched_ops[sched];
 151         struct sctp_sched_ops *old = asoc->outqueue.sched;
 152         struct sctp_datamsg *msg = NULL;
 153         struct sctp_chunk *ch;
 154         int i, ret = 0;
 155
 156         if (old == n)
 157                 return ret;
 158
 159         if (sched > SCTP_SS_MAX)
 160                 return -EINVAL;
 161
 162         if (old)
 163                 sctp_sched_free_sched(&asoc->stream);
 164
 165         asoc->outqueue.sched = n;
 166         n->init(&asoc->stream);
 167         for (i = 0; i < asoc->stream.outcnt; i++) {
 168                 if (!SCTP_SO(&asoc->stream, i)->ext)
 169                         continue;
 170
 171                 ret = n->init_sid(&asoc->stream, i, GFP_ATOMIC);
 172                 if (ret)
 173                         goto err;
 174         }
 175
 176         /* We have to requeue all chunks already queued. */
 177         list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
 178                 if (ch->msg == msg)
 179                         continue;
 180                 msg = ch->msg;
 181                 n->enqueue(&asoc->outqueue, msg);
 182         }
 183
 184         return ret;
 185
 186 err:
 187         sctp_sched_free_sched(&asoc->stream);
 188         asoc->outqueue.sched = &sctp_sched_fcfs; /* Always safe */
 189
 190         return ret;
 191 }
 192
 193 int sctp_sched_get_sched(struct sctp_association *asoc)
 194 {
 195         int i;
 196
 197         for (i = 0; i <= SCTP_SS_MAX; i++)
 198                 if (asoc->outqueue.sched == sctp_sched_ops[i])
 199                         return i;
 200
 201         return 0;
 202 }
 203
 204 int sctp_sched_set_value(struct sctp_association *asoc, __u16 sid,
 205                          __u16 value, gfp_t gfp)
 206 {
 207         if (sid >= asoc->stream.outcnt)
 208                 return -EINVAL;
 209
 210         if (!SCTP_SO(&asoc->stream, sid)->ext) {
 211                 int ret;
 212
 213                 ret = sctp_stream_init_ext(&asoc->stream, sid);
 214                 if (ret)
 215                         return ret;
 216         }
 217
 218         return asoc->outqueue.sched->set(&asoc->stream, sid, value, gfp);
 219 }
 220
 221 int sctp_sched_get_value(struct sctp_association *asoc, __u16 sid,
 222                          __u16 *value)
 223 {
 224         if (sid >= asoc->stream.outcnt)
 225                 return -EINVAL;
 226
 227         if (!SCTP_SO(&asoc->stream, sid)->ext)
 228                 return 0;
 229
 230         return asoc->outqueue.sched->get(&asoc->stream, sid, value);
 231 }
 232
 233 void sctp_sched_dequeue_done(struct sctp_outq *q, struct sctp_chunk *ch)
 234 {
 235         if (!list_is_last(&ch->frag_list, &ch->msg->chunks) &&
 236             !q->asoc->peer.intl_capable) {
 237                 struct sctp_stream_out *sout;
 238                 __u16 sid;
 239
 240                 /* datamsg is not finish, so save it as current one,
 241                  * in case application switch scheduler or a higher
 242                  * priority stream comes in.
 243                  */
 244                 sid = sctp_chunk_stream_no(ch);
 245                 sout = SCTP_SO(&q->asoc->stream, sid);
 246                 q->asoc->stream.out_curr = sout;
 247                 return;
 248         }
 249
 250         q->asoc->stream.out_curr = NULL;
 251         q->sched->dequeue_done(q, ch);
 252 }
 253
 254 /* Auxiliary functions for the schedulers */
 255 void sctp_sched_dequeue_common(struct sctp_outq *q, struct sctp_chunk *ch)
 256 {
 257         list_del_init(&ch->list);
 258         list_del_init(&ch->stream_list);
 259         q->out_qlen -= ch->skb->len;
 260 }
 261
 262 int sctp_sched_init_sid(struct sctp_stream *stream, __u16 sid, gfp_t gfp)
 263 {
 264         struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
 265         struct sctp_stream_out_ext *ext = SCTP_SO(stream, sid)->ext;
 266
 267         INIT_LIST_HEAD(&ext->outq);
 268         return sched->init_sid(stream, sid, gfp);
 269 }
 270
 271 struct sctp_sched_ops *sctp_sched_ops_from_stream(struct sctp_stream *stream)
 272 {
 273         struct sctp_association *asoc;
 274
 275         asoc = container_of(stream, struct sctp_association, stream);
 276
 277         return asoc->outqueue.sched;
 278 }