1 /* 2 * Copyright (c) 2008, Intel Corporation. 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms and conditions of the GNU General Public License, 6 * version 2, as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 11 * more details. 12 * 13 * You should have received a copy of the GNU General Public License along with 14 * this program; if not, see <http://www.gnu.org/licenses/>. 15 * 16 * Author: Alexander Duyck <alexander.h.duyck@intel.com> 17 */ 18 19 #include <linux/module.h> 20 #include <linux/slab.h> 21 #include <linux/types.h> 22 #include <linux/kernel.h> 23 #include <linux/string.h> 24 #include <linux/errno.h> 25 #include <linux/skbuff.h> 26 #include <net/netlink.h> 27 #include <net/pkt_sched.h> 28 #include <net/pkt_cls.h> 29 30 struct multiq_sched_data { 31 u16 bands; 32 u16 max_bands; 33 u16 curband; 34 struct tcf_proto __rcu *filter_list; 35 struct Qdisc **queues; 36 }; 37 38 39 static struct Qdisc * 40 multiq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) 41 { 42 struct multiq_sched_data *q = qdisc_priv(sch); 43 u32 band; 44 struct tcf_result res; 45 struct tcf_proto *fl = rcu_dereference_bh(q->filter_list); 46 int err; 47 48 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 49 err = tc_classify(skb, fl, &res, false); 50 #ifdef CONFIG_NET_CLS_ACT 51 switch (err) { 52 case TC_ACT_STOLEN: 53 case TC_ACT_QUEUED: 54 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 55 case TC_ACT_SHOT: 56 return NULL; 57 } 58 #endif 59 band = skb_get_queue_mapping(skb); 60 61 if (band >= q->bands) 62 return q->queues[0]; 63 64 return q->queues[band]; 65 } 66 67 static int 68 multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch, 69 struct sk_buff **to_free) 70 { 71 struct Qdisc *qdisc; 72 int ret; 73 74 qdisc = multiq_classify(skb, sch, &ret); 75 #ifdef CONFIG_NET_CLS_ACT 76 if (qdisc == NULL) { 77 78 if (ret & __NET_XMIT_BYPASS) 79 qdisc_qstats_drop(sch); 80 __qdisc_drop(skb, to_free); 81 return ret; 82 } 83 #endif 84 85 ret = qdisc_enqueue(skb, qdisc, to_free); 86 if (ret == NET_XMIT_SUCCESS) { 87 sch->q.qlen++; 88 return NET_XMIT_SUCCESS; 89 } 90 if (net_xmit_drop_count(ret)) 91 qdisc_qstats_drop(sch); 92 return ret; 93 } 94 95 static struct sk_buff *multiq_dequeue(struct Qdisc *sch) 96 { 97 struct multiq_sched_data *q = qdisc_priv(sch); 98 struct Qdisc *qdisc; 99 struct sk_buff *skb; 100 int band; 101 102 for (band = 0; band < q->bands; band++) { 103 /* cycle through bands to ensure fairness */ 104 q->curband++; 105 if (q->curband >= q->bands) 106 q->curband = 0; 107 108 /* Check that target subqueue is available before 109 * pulling an skb to avoid head-of-line blocking. 110 */ 111 if (!netif_xmit_stopped( 112 netdev_get_tx_queue(qdisc_dev(sch), q->curband))) { 113 qdisc = q->queues[q->curband]; 114 skb = qdisc->dequeue(qdisc); 115 if (skb) { 116 qdisc_bstats_update(sch, skb); 117 sch->q.qlen--; 118 return skb; 119 } 120 } 121 } 122 return NULL; 123 124 } 125 126 static struct sk_buff *multiq_peek(struct Qdisc *sch) 127 { 128 struct multiq_sched_data *q = qdisc_priv(sch); 129 unsigned int curband = q->curband; 130 struct Qdisc *qdisc; 131 struct sk_buff *skb; 132 int band; 133 134 for (band = 0; band < q->bands; band++) { 135 /* cycle through bands to ensure fairness */ 136 curband++; 137 if (curband >= q->bands) 138 curband = 0; 139 140 /* Check that target subqueue is available before 141 * pulling an skb to avoid head-of-line blocking. 142 */ 143 if (!netif_xmit_stopped( 144 netdev_get_tx_queue(qdisc_dev(sch), curband))) { 145 qdisc = q->queues[curband]; 146 skb = qdisc->ops->peek(qdisc); 147 if (skb) 148 return skb; 149 } 150 } 151 return NULL; 152 153 } 154 155 static void 156 multiq_reset(struct Qdisc *sch) 157 { 158 u16 band; 159 struct multiq_sched_data *q = qdisc_priv(sch); 160 161 for (band = 0; band < q->bands; band++) 162 qdisc_reset(q->queues[band]); 163 sch->q.qlen = 0; 164 q->curband = 0; 165 } 166 167 static void 168 multiq_destroy(struct Qdisc *sch) 169 { 170 int band; 171 struct multiq_sched_data *q = qdisc_priv(sch); 172 173 tcf_destroy_chain(&q->filter_list); 174 for (band = 0; band < q->bands; band++) 175 qdisc_destroy(q->queues[band]); 176 177 kfree(q->queues); 178 } 179 180 static int multiq_tune(struct Qdisc *sch, struct nlattr *opt) 181 { 182 struct multiq_sched_data *q = qdisc_priv(sch); 183 struct tc_multiq_qopt *qopt; 184 int i; 185 186 if (!netif_is_multiqueue(qdisc_dev(sch))) 187 return -EOPNOTSUPP; 188 if (nla_len(opt) < sizeof(*qopt)) 189 return -EINVAL; 190 191 qopt = nla_data(opt); 192 193 qopt->bands = qdisc_dev(sch)->real_num_tx_queues; 194 195 sch_tree_lock(sch); 196 q->bands = qopt->bands; 197 for (i = q->bands; i < q->max_bands; i++) { 198 if (q->queues[i] != &noop_qdisc) { 199 struct Qdisc *child = q->queues[i]; 200 q->queues[i] = &noop_qdisc; 201 qdisc_tree_reduce_backlog(child, child->q.qlen, 202 child->qstats.backlog); 203 qdisc_destroy(child); 204 } 205 } 206 207 sch_tree_unlock(sch); 208 209 for (i = 0; i < q->bands; i++) { 210 if (q->queues[i] == &noop_qdisc) { 211 struct Qdisc *child, *old; 212 child = qdisc_create_dflt(sch->dev_queue, 213 &pfifo_qdisc_ops, 214 TC_H_MAKE(sch->handle, 215 i + 1)); 216 if (child) { 217 sch_tree_lock(sch); 218 old = q->queues[i]; 219 q->queues[i] = child; 220 if (child != &noop_qdisc) 221 qdisc_hash_add(child, true); 222 223 if (old != &noop_qdisc) { 224 qdisc_tree_reduce_backlog(old, 225 old->q.qlen, 226 old->qstats.backlog); 227 qdisc_destroy(old); 228 } 229 sch_tree_unlock(sch); 230 } 231 } 232 } 233 return 0; 234 } 235 236 static int multiq_init(struct Qdisc *sch, struct nlattr *opt) 237 { 238 struct multiq_sched_data *q = qdisc_priv(sch); 239 int i, err; 240 241 q->queues = NULL; 242 243 if (opt == NULL) 244 return -EINVAL; 245 246 q->max_bands = qdisc_dev(sch)->num_tx_queues; 247 248 q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL); 249 if (!q->queues) 250 return -ENOBUFS; 251 for (i = 0; i < q->max_bands; i++) 252 q->queues[i] = &noop_qdisc; 253 254 err = multiq_tune(sch, opt); 255 256 if (err) 257 kfree(q->queues); 258 259 return err; 260 } 261 262 static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb) 263 { 264 struct multiq_sched_data *q = qdisc_priv(sch); 265 unsigned char *b = skb_tail_pointer(skb); 266 struct tc_multiq_qopt opt; 267 268 opt.bands = q->bands; 269 opt.max_bands = q->max_bands; 270 271 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 272 goto nla_put_failure; 273 274 return skb->len; 275 276 nla_put_failure: 277 nlmsg_trim(skb, b); 278 return -1; 279 } 280 281 static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 282 struct Qdisc **old) 283 { 284 struct multiq_sched_data *q = qdisc_priv(sch); 285 unsigned long band = arg - 1; 286 287 if (new == NULL) 288 new = &noop_qdisc; 289 290 *old = qdisc_replace(sch, new, &q->queues[band]); 291 return 0; 292 } 293 294 static struct Qdisc * 295 multiq_leaf(struct Qdisc *sch, unsigned long arg) 296 { 297 struct multiq_sched_data *q = qdisc_priv(sch); 298 unsigned long band = arg - 1; 299 300 return q->queues[band]; 301 } 302 303 static unsigned long multiq_get(struct Qdisc *sch, u32 classid) 304 { 305 struct multiq_sched_data *q = qdisc_priv(sch); 306 unsigned long band = TC_H_MIN(classid); 307 308 if (band - 1 >= q->bands) 309 return 0; 310 return band; 311 } 312 313 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent, 314 u32 classid) 315 { 316 return multiq_get(sch, classid); 317 } 318 319 320 static void multiq_put(struct Qdisc *q, unsigned long cl) 321 { 322 } 323 324 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl, 325 struct sk_buff *skb, struct tcmsg *tcm) 326 { 327 struct multiq_sched_data *q = qdisc_priv(sch); 328 329 tcm->tcm_handle |= TC_H_MIN(cl); 330 tcm->tcm_info = q->queues[cl - 1]->handle; 331 return 0; 332 } 333 334 static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl, 335 struct gnet_dump *d) 336 { 337 struct multiq_sched_data *q = qdisc_priv(sch); 338 struct Qdisc *cl_q; 339 340 cl_q = q->queues[cl - 1]; 341 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), 342 d, NULL, &cl_q->bstats) < 0 || 343 gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0) 344 return -1; 345 346 return 0; 347 } 348 349 static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg) 350 { 351 struct multiq_sched_data *q = qdisc_priv(sch); 352 int band; 353 354 if (arg->stop) 355 return; 356 357 for (band = 0; band < q->bands; band++) { 358 if (arg->count < arg->skip) { 359 arg->count++; 360 continue; 361 } 362 if (arg->fn(sch, band + 1, arg) < 0) { 363 arg->stop = 1; 364 break; 365 } 366 arg->count++; 367 } 368 } 369 370 static struct tcf_proto __rcu **multiq_find_tcf(struct Qdisc *sch, 371 unsigned long cl) 372 { 373 struct multiq_sched_data *q = qdisc_priv(sch); 374 375 if (cl) 376 return NULL; 377 return &q->filter_list; 378 } 379 380 static const struct Qdisc_class_ops multiq_class_ops = { 381 .graft = multiq_graft, 382 .leaf = multiq_leaf, 383 .get = multiq_get, 384 .put = multiq_put, 385 .walk = multiq_walk, 386 .tcf_chain = multiq_find_tcf, 387 .bind_tcf = multiq_bind, 388 .unbind_tcf = multiq_put, 389 .dump = multiq_dump_class, 390 .dump_stats = multiq_dump_class_stats, 391 }; 392 393 static struct Qdisc_ops multiq_qdisc_ops __read_mostly = { 394 .next = NULL, 395 .cl_ops = &multiq_class_ops, 396 .id = "multiq", 397 .priv_size = sizeof(struct multiq_sched_data), 398 .enqueue = multiq_enqueue, 399 .dequeue = multiq_dequeue, 400 .peek = multiq_peek, 401 .init = multiq_init, 402 .reset = multiq_reset, 403 .destroy = multiq_destroy, 404 .change = multiq_tune, 405 .dump = multiq_dump, 406 .owner = THIS_MODULE, 407 }; 408 409 static int __init multiq_module_init(void) 410 { 411 return register_qdisc(&multiq_qdisc_ops); 412 } 413 414 static void __exit multiq_module_exit(void) 415 { 416 unregister_qdisc(&multiq_qdisc_ops); 417 } 418 419 module_init(multiq_module_init) 420 module_exit(multiq_module_exit) 421 422 MODULE_LICENSE("GPL"); 423