1 /* SCTP kernel implementation 2 * (C) Copyright Red Hat Inc. 2017 3 * 4 * This file is part of the SCTP kernel implementation 5 * 6 * These functions manipulate sctp stream queue/scheduling. 7 * 8 * This SCTP implementation is free software; 9 * you can redistribute it and/or modify it under the terms of 10 * the GNU General Public License as published by 11 * the Free Software Foundation; either version 2, or (at your option) 12 * any later version. 13 * 14 * This SCTP implementation is distributed in the hope that it 15 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 16 * ************************ 17 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 18 * See the GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with GNU CC; see the file COPYING. If not, see 22 * <http://www.gnu.org/licenses/>. 23 * 24 * Please send any bug reports or fixes you make to the 25 * email addresched(es): 26 * lksctp developers <linux-sctp@vger.kernel.org> 27 * 28 * Written or modified by: 29 * Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> 30 */ 31 32 #include <linux/list.h> 33 #include <net/sctp/sctp.h> 34 #include <net/sctp/sm.h> 35 #include <net/sctp/stream_sched.h> 36 37 /* Priority handling 38 * RFC DRAFT ndata section 3.4 39 */ 40 41 static void sctp_sched_prio_unsched_all(struct sctp_stream *stream); 42 43 static struct sctp_stream_priorities *sctp_sched_prio_new_head( 44 struct sctp_stream *stream, int prio, gfp_t gfp) 45 { 46 struct sctp_stream_priorities *p; 47 48 p = kmalloc(sizeof(*p), gfp); 49 if (!p) 50 return NULL; 51 52 INIT_LIST_HEAD(&p->prio_sched); 53 INIT_LIST_HEAD(&p->active); 54 p->next = NULL; 55 p->prio = prio; 56 57 return p; 58 } 59 60 static struct sctp_stream_priorities *sctp_sched_prio_get_head( 61 struct sctp_stream *stream, int prio, gfp_t gfp) 62 { 63 struct sctp_stream_priorities *p; 64 int i; 65 66 /* Look into scheduled priorities first, as they are sorted and 67 * we can find it fast IF it's scheduled. 68 */ 69 list_for_each_entry(p, &stream->prio_list, prio_sched) { 70 if (p->prio == prio) 71 return p; 72 if (p->prio > prio) 73 break; 74 } 75 76 /* No luck. So we search on all streams now. */ 77 for (i = 0; i < stream->outcnt; i++) { 78 if (!stream->out[i].ext) 79 continue; 80 81 p = stream->out[i].ext->prio_head; 82 if (!p) 83 /* Means all other streams won't be initialized 84 * as well. 85 */ 86 break; 87 if (p->prio == prio) 88 return p; 89 } 90 91 /* If not even there, allocate a new one. */ 92 return sctp_sched_prio_new_head(stream, prio, gfp); 93 } 94 95 static void sctp_sched_prio_next_stream(struct sctp_stream_priorities *p) 96 { 97 struct list_head *pos; 98 99 pos = p->next->prio_list.next; 100 if (pos == &p->active) 101 pos = pos->next; 102 p->next = list_entry(pos, struct sctp_stream_out_ext, prio_list); 103 } 104 105 static bool sctp_sched_prio_unsched(struct sctp_stream_out_ext *soute) 106 { 107 bool scheduled = false; 108 109 if (!list_empty(&soute->prio_list)) { 110 struct sctp_stream_priorities *prio_head = soute->prio_head; 111 112 /* Scheduled */ 113 scheduled = true; 114 115 if (prio_head->next == soute) 116 /* Try to move to the next stream */ 117 sctp_sched_prio_next_stream(prio_head); 118 119 list_del_init(&soute->prio_list); 120 121 /* Also unsched the priority if this was the last stream */ 122 if (list_empty(&prio_head->active)) { 123 list_del_init(&prio_head->prio_sched); 124 /* If there is no stream left, clear next */ 125 prio_head->next = NULL; 126 } 127 } 128 129 return scheduled; 130 } 131 132 static void sctp_sched_prio_sched(struct sctp_stream *stream, 133 struct sctp_stream_out_ext *soute) 134 { 135 struct sctp_stream_priorities *prio, *prio_head; 136 137 prio_head = soute->prio_head; 138 139 /* Nothing to do if already scheduled */ 140 if (!list_empty(&soute->prio_list)) 141 return; 142 143 /* Schedule the stream. If there is a next, we schedule the new 144 * one before it, so it's the last in round robin order. 145 * If there isn't, we also have to schedule the priority. 146 */ 147 if (prio_head->next) { 148 list_add(&soute->prio_list, prio_head->next->prio_list.prev); 149 return; 150 } 151 152 list_add(&soute->prio_list, &prio_head->active); 153 prio_head->next = soute; 154 155 list_for_each_entry(prio, &stream->prio_list, prio_sched) { 156 if (prio->prio > prio_head->prio) { 157 list_add(&prio_head->prio_sched, prio->prio_sched.prev); 158 return; 159 } 160 } 161 162 list_add_tail(&prio_head->prio_sched, &stream->prio_list); 163 } 164 165 static int sctp_sched_prio_set(struct sctp_stream *stream, __u16 sid, 166 __u16 prio, gfp_t gfp) 167 { 168 struct sctp_stream_out *sout = &stream->out[sid]; 169 struct sctp_stream_out_ext *soute = sout->ext; 170 struct sctp_stream_priorities *prio_head, *old; 171 bool reschedule = false; 172 int i; 173 174 prio_head = sctp_sched_prio_get_head(stream, prio, gfp); 175 if (!prio_head) 176 return -ENOMEM; 177 178 reschedule = sctp_sched_prio_unsched(soute); 179 old = soute->prio_head; 180 soute->prio_head = prio_head; 181 if (reschedule) 182 sctp_sched_prio_sched(stream, soute); 183 184 if (!old) 185 /* Happens when we set the priority for the first time */ 186 return 0; 187 188 for (i = 0; i < stream->outcnt; i++) { 189 soute = stream->out[i].ext; 190 if (soute && soute->prio_head == old) 191 /* It's still in use, nothing else to do here. */ 192 return 0; 193 } 194 195 /* No hits, we are good to free it. */ 196 kfree(old); 197 198 return 0; 199 } 200 201 static int sctp_sched_prio_get(struct sctp_stream *stream, __u16 sid, 202 __u16 *value) 203 { 204 *value = stream->out[sid].ext->prio_head->prio; 205 return 0; 206 } 207 208 static int sctp_sched_prio_init(struct sctp_stream *stream) 209 { 210 INIT_LIST_HEAD(&stream->prio_list); 211 212 return 0; 213 } 214 215 static int sctp_sched_prio_init_sid(struct sctp_stream *stream, __u16 sid, 216 gfp_t gfp) 217 { 218 INIT_LIST_HEAD(&stream->out[sid].ext->prio_list); 219 return sctp_sched_prio_set(stream, sid, 0, gfp); 220 } 221 222 static void sctp_sched_prio_free(struct sctp_stream *stream) 223 { 224 struct sctp_stream_priorities *prio, *n; 225 LIST_HEAD(list); 226 int i; 227 228 /* As we don't keep a list of priorities, to avoid multiple 229 * frees we have to do it in 3 steps: 230 * 1. unsched everyone, so the lists are free to use in 2. 231 * 2. build the list of the priorities 232 * 3. free the list 233 */ 234 sctp_sched_prio_unsched_all(stream); 235 for (i = 0; i < stream->outcnt; i++) { 236 if (!stream->out[i].ext) 237 continue; 238 prio = stream->out[i].ext->prio_head; 239 if (prio && list_empty(&prio->prio_sched)) 240 list_add(&prio->prio_sched, &list); 241 } 242 list_for_each_entry_safe(prio, n, &list, prio_sched) { 243 list_del_init(&prio->prio_sched); 244 kfree(prio); 245 } 246 } 247 248 static void sctp_sched_prio_enqueue(struct sctp_outq *q, 249 struct sctp_datamsg *msg) 250 { 251 struct sctp_stream *stream; 252 struct sctp_chunk *ch; 253 __u16 sid; 254 255 ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list); 256 sid = sctp_chunk_stream_no(ch); 257 stream = &q->asoc->stream; 258 sctp_sched_prio_sched(stream, stream->out[sid].ext); 259 } 260 261 static struct sctp_chunk *sctp_sched_prio_dequeue(struct sctp_outq *q) 262 { 263 struct sctp_stream *stream = &q->asoc->stream; 264 struct sctp_stream_priorities *prio; 265 struct sctp_stream_out_ext *soute; 266 struct sctp_chunk *ch = NULL; 267 268 /* Bail out quickly if queue is empty */ 269 if (list_empty(&q->out_chunk_list)) 270 goto out; 271 272 /* Find which chunk is next. It's easy, it's either the current 273 * one or the first chunk on the next active stream. 274 */ 275 if (stream->out_curr) { 276 soute = stream->out_curr->ext; 277 } else { 278 prio = list_entry(stream->prio_list.next, 279 struct sctp_stream_priorities, prio_sched); 280 soute = prio->next; 281 } 282 ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list); 283 sctp_sched_dequeue_common(q, ch); 284 285 out: 286 return ch; 287 } 288 289 static void sctp_sched_prio_dequeue_done(struct sctp_outq *q, 290 struct sctp_chunk *ch) 291 { 292 struct sctp_stream_priorities *prio; 293 struct sctp_stream_out_ext *soute; 294 __u16 sid; 295 296 /* Last chunk on that msg, move to the next stream on 297 * this priority. 298 */ 299 sid = sctp_chunk_stream_no(ch); 300 soute = q->asoc->stream.out[sid].ext; 301 prio = soute->prio_head; 302 303 sctp_sched_prio_next_stream(prio); 304 305 if (list_empty(&soute->outq)) 306 sctp_sched_prio_unsched(soute); 307 } 308 309 static void sctp_sched_prio_sched_all(struct sctp_stream *stream) 310 { 311 struct sctp_association *asoc; 312 struct sctp_stream_out *sout; 313 struct sctp_chunk *ch; 314 315 asoc = container_of(stream, struct sctp_association, stream); 316 list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) { 317 __u16 sid; 318 319 sid = sctp_chunk_stream_no(ch); 320 sout = &stream->out[sid]; 321 if (sout->ext) 322 sctp_sched_prio_sched(stream, sout->ext); 323 } 324 } 325 326 static void sctp_sched_prio_unsched_all(struct sctp_stream *stream) 327 { 328 struct sctp_stream_priorities *p, *tmp; 329 struct sctp_stream_out_ext *soute, *souttmp; 330 331 list_for_each_entry_safe(p, tmp, &stream->prio_list, prio_sched) 332 list_for_each_entry_safe(soute, souttmp, &p->active, prio_list) 333 sctp_sched_prio_unsched(soute); 334 } 335 336 static struct sctp_sched_ops sctp_sched_prio = { 337 .set = sctp_sched_prio_set, 338 .get = sctp_sched_prio_get, 339 .init = sctp_sched_prio_init, 340 .init_sid = sctp_sched_prio_init_sid, 341 .free = sctp_sched_prio_free, 342 .enqueue = sctp_sched_prio_enqueue, 343 .dequeue = sctp_sched_prio_dequeue, 344 .dequeue_done = sctp_sched_prio_dequeue_done, 345 .sched_all = sctp_sched_prio_sched_all, 346 .unsched_all = sctp_sched_prio_unsched_all, 347 }; 348 349 void sctp_sched_ops_prio_init(void) 350 { 351 sctp_sched_ops_register(SCTP_SS_PRIO, &sctp_sched_prio); 352 } 353