net/sched/sch_mqprio.c

   1 /*
   2  * net/sched/sch_mqprio.c
   3  *
   4  * Copyright (c) 2010 John Fastabend <john.r.fastabend@intel.com>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * version 2 as published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/slab.h>
  13 #include <linux/kernel.h>
  14 #include <linux/string.h>
  15 #include <linux/errno.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/module.h>
  18 #include <net/netlink.h>
  19 #include <net/pkt_sched.h>
  20 #include <net/sch_generic.h>
  21
  22 struct mqprio_sched {
  23         struct Qdisc            **qdiscs;
  24         int hw_owned;
  25 };
  26
  27 static void mqprio_destroy(struct Qdisc *sch)
  28 {
  29         struct net_device *dev = qdisc_dev(sch);
  30         struct mqprio_sched *priv = qdisc_priv(sch);
  31         struct tc_to_netdev tc = {.type = TC_SETUP_MQPRIO};
  32         unsigned int ntx;
  33
  34         if (priv->qdiscs) {
  35                 for (ntx = 0;
  36                      ntx < dev->num_tx_queues && priv->qdiscs[ntx];
  37                      ntx++)
  38                         qdisc_destroy(priv->qdiscs[ntx]);
  39                 kfree(priv->qdiscs);
  40         }
  41
  42         if (priv->hw_owned && dev->netdev_ops->ndo_setup_tc)
  43                 dev->netdev_ops->ndo_setup_tc(dev, sch->handle, 0, &tc);
  44         else
  45                 netdev_set_num_tc(dev, 0);
  46 }
  47
  48 static int mqprio_parse_opt(struct net_device *dev, struct tc_mqprio_qopt *qopt)
  49 {
  50         int i, j;
  51
  52         /* Verify num_tc is not out of max range */
  53         if (qopt->num_tc > TC_MAX_QUEUE)
  54                 return -EINVAL;
  55
  56         /* Verify priority mapping uses valid tcs */
  57         for (i = 0; i < TC_BITMASK + 1; i++) {
  58                 if (qopt->prio_tc_map[i] >= qopt->num_tc)
  59                         return -EINVAL;
  60         }
  61
  62         /* net_device does not support requested operation */
  63         if (qopt->hw && !dev->netdev_ops->ndo_setup_tc)
  64                 return -EINVAL;
  65
  66         /* if hw owned qcount and qoffset are taken from LLD so
  67          * no reason to verify them here
  68          */
  69         if (qopt->hw)
  70                 return 0;
  71
  72         for (i = 0; i < qopt->num_tc; i++) {
  73                 unsigned int last = qopt->offset[i] + qopt->count[i];
  74
  75                 /* Verify the queue count is in tx range being equal to the
  76                  * real_num_tx_queues indicates the last queue is in use.
  77                  */
  78                 if (qopt->offset[i] >= dev->real_num_tx_queues ||
  79                     !qopt->count[i] ||
  80                     last > dev->real_num_tx_queues)
  81                         return -EINVAL;
  82
  83                 /* Verify that the offset and counts do not overlap */
  84                 for (j = i + 1; j < qopt->num_tc; j++) {
  85                         if (last > qopt->offset[j])
  86                                 return -EINVAL;
  87                 }
  88         }
  89
  90         return 0;
  91 }
  92
  93 static int mqprio_init(struct Qdisc *sch, struct nlattr *opt)
  94 {
  95         struct net_device *dev = qdisc_dev(sch);
  96         struct mqprio_sched *priv = qdisc_priv(sch);
  97         struct netdev_queue *dev_queue;
  98         struct Qdisc *qdisc;
  99         int i, err = -EOPNOTSUPP;
 100         struct tc_mqprio_qopt *qopt = NULL;
 101
 102         BUILD_BUG_ON(TC_MAX_QUEUE != TC_QOPT_MAX_QUEUE);
 103         BUILD_BUG_ON(TC_BITMASK != TC_QOPT_BITMASK);
 104
 105         if (sch->parent != TC_H_ROOT)
 106                 return -EOPNOTSUPP;
 107
 108         if (!netif_is_multiqueue(dev))
 109                 return -EOPNOTSUPP;
 110
 111         if (!opt || nla_len(opt) < sizeof(*qopt))
 112                 return -EINVAL;
 113
 114         qopt = nla_data(opt);
 115         if (mqprio_parse_opt(dev, qopt))
 116                 return -EINVAL;
 117
 118         /* pre-allocate qdisc, attachment can't fail */
 119         priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
 120                                GFP_KERNEL);
 121         if (priv->qdiscs == NULL) {
 122                 err = -ENOMEM;
 123                 goto err;
 124         }
 125
 126         for (i = 0; i < dev->num_tx_queues; i++) {
 127                 dev_queue = netdev_get_tx_queue(dev, i);
 128                 qdisc = qdisc_create_dflt(dev_queue,
 129                                           get_default_qdisc_ops(dev, i),
 130                                           TC_H_MAKE(TC_H_MAJ(sch->handle),
 131                                                     TC_H_MIN(i + 1)));
 132                 if (qdisc == NULL) {
 133                         err = -ENOMEM;
 134                         goto err;
 135                 }
 136                 priv->qdiscs[i] = qdisc;
 137                 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
 138         }
 139
 140         /* If the mqprio options indicate that hardware should own
 141          * the queue mapping then run ndo_setup_tc otherwise use the
 142          * supplied and verified mapping
 143          */
 144         if (qopt->hw) {
 145                 struct tc_to_netdev tc = {.type = TC_SETUP_MQPRIO,
 146                                           { .tc = qopt->num_tc }};
 147
 148                 priv->hw_owned = 1;
 149                 err = dev->netdev_ops->ndo_setup_tc(dev, sch->handle, 0, &tc);
 150                 if (err)
 151                         goto err;
 152         } else {
 153                 netdev_set_num_tc(dev, qopt->num_tc);
 154                 for (i = 0; i < qopt->num_tc; i++)
 155                         netdev_set_tc_queue(dev, i,
 156                                             qopt->count[i], qopt->offset[i]);
 157         }
 158
 159         /* Always use supplied priority mappings */
 160         for (i = 0; i < TC_BITMASK + 1; i++)
 161                 netdev_set_prio_tc_map(dev, i, qopt->prio_tc_map[i]);
 162
 163         sch->flags |= TCQ_F_MQROOT;
 164         return 0;
 165
 166 err:
 167         mqprio_destroy(sch);
 168         return err;
 169 }
 170
 171 static void mqprio_attach(struct Qdisc *sch)
 172 {
 173         struct net_device *dev = qdisc_dev(sch);
 174         struct mqprio_sched *priv = qdisc_priv(sch);
 175         struct Qdisc *qdisc, *old;
 176         unsigned int ntx;
 177
 178         /* Attach underlying qdisc */
 179         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
 180                 qdisc = priv->qdiscs[ntx];
 181                 old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
 182                 if (old)
 183                         qdisc_destroy(old);
 184                 if (ntx < dev->real_num_tx_queues)
 185                         qdisc_list_add(qdisc);
 186         }
 187         kfree(priv->qdiscs);
 188         priv->qdiscs = NULL;
 189 }
 190
 191 static struct netdev_queue *mqprio_queue_get(struct Qdisc *sch,
 192                                              unsigned long cl)
 193 {
 194         struct net_device *dev = qdisc_dev(sch);
 195         unsigned long ntx = cl - 1 - netdev_get_num_tc(dev);
 196
 197         if (ntx >= dev->num_tx_queues)
 198                 return NULL;
 199         return netdev_get_tx_queue(dev, ntx);
 200 }
 201
 202 static int mqprio_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
 203                     struct Qdisc **old)
 204 {
 205         struct net_device *dev = qdisc_dev(sch);
 206         struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 207
 208         if (!dev_queue)
 209                 return -EINVAL;
 210
 211         if (dev->flags & IFF_UP)
 212                 dev_deactivate(dev);
 213
 214         *old = dev_graft_qdisc(dev_queue, new);
 215
 216         if (new)
 217                 new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
 218
 219         if (dev->flags & IFF_UP)
 220                 dev_activate(dev);
 221
 222         return 0;
 223 }
 224
 225 static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 226 {
 227         struct net_device *dev = qdisc_dev(sch);
 228         struct mqprio_sched *priv = qdisc_priv(sch);
 229         unsigned char *b = skb_tail_pointer(skb);
 230         struct tc_mqprio_qopt opt = { 0 };
 231         struct Qdisc *qdisc;
 232         unsigned int i;
 233
 234         sch->q.qlen = 0;
 235         memset(&sch->bstats, 0, sizeof(sch->bstats));
 236         memset(&sch->qstats, 0, sizeof(sch->qstats));
 237
 238         for (i = 0; i < dev->num_tx_queues; i++) {
 239                 qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
 240                 spin_lock_bh(qdisc_lock(qdisc));
 241                 sch->q.qlen             += qdisc->q.qlen;
 242                 sch->bstats.bytes       += qdisc->bstats.bytes;
 243                 sch->bstats.packets     += qdisc->bstats.packets;
 244                 sch->qstats.backlog     += qdisc->qstats.backlog;
 245                 sch->qstats.drops       += qdisc->qstats.drops;
 246                 sch->qstats.requeues    += qdisc->qstats.requeues;
 247                 sch->qstats.overlimits  += qdisc->qstats.overlimits;
 248                 spin_unlock_bh(qdisc_lock(qdisc));
 249         }
 250
 251         opt.num_tc = netdev_get_num_tc(dev);
 252         memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map));
 253         opt.hw = priv->hw_owned;
 254
 255         for (i = 0; i < netdev_get_num_tc(dev); i++) {
 256                 opt.count[i] = dev->tc_to_txq[i].count;
 257                 opt.offset[i] = dev->tc_to_txq[i].offset;
 258         }
 259
 260         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 261                 goto nla_put_failure;
 262
 263         return skb->len;
 264 nla_put_failure:
 265         nlmsg_trim(skb, b);
 266         return -1;
 267 }
 268
 269 static struct Qdisc *mqprio_leaf(struct Qdisc *sch, unsigned long cl)
 270 {
 271         struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 272
 273         if (!dev_queue)
 274                 return NULL;
 275
 276         return dev_queue->qdisc_sleeping;
 277 }
 278
 279 static unsigned long mqprio_get(struct Qdisc *sch, u32 classid)
 280 {
 281         struct net_device *dev = qdisc_dev(sch);
 282         unsigned int ntx = TC_H_MIN(classid);
 283
 284         if (ntx > dev->num_tx_queues + netdev_get_num_tc(dev))
 285                 return 0;
 286         return ntx;
 287 }
 288
 289 static void mqprio_put(struct Qdisc *sch, unsigned long cl)
 290 {
 291 }
 292
 293 static int mqprio_dump_class(struct Qdisc *sch, unsigned long cl,
 294                          struct sk_buff *skb, struct tcmsg *tcm)
 295 {
 296         struct net_device *dev = qdisc_dev(sch);
 297
 298         if (cl <= netdev_get_num_tc(dev)) {
 299                 tcm->tcm_parent = TC_H_ROOT;
 300                 tcm->tcm_info = 0;
 301         } else {
 302                 int i;
 303                 struct netdev_queue *dev_queue;
 304
 305                 dev_queue = mqprio_queue_get(sch, cl);
 306                 tcm->tcm_parent = 0;
 307                 for (i = 0; i < netdev_get_num_tc(dev); i++) {
 308                         struct netdev_tc_txq tc = dev->tc_to_txq[i];
 309                         int q_idx = cl - netdev_get_num_tc(dev);
 310
 311                         if (q_idx > tc.offset &&
 312                             q_idx <= tc.offset + tc.count) {
 313                                 tcm->tcm_parent =
 314                                         TC_H_MAKE(TC_H_MAJ(sch->handle),
 315                                                   TC_H_MIN(i + 1));
 316                                 break;
 317                         }
 318                 }
 319                 tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
 320         }
 321         tcm->tcm_handle |= TC_H_MIN(cl);
 322         return 0;
 323 }
 324
 325 static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 326                                    struct gnet_dump *d)
 327         __releases(d->lock)
 328         __acquires(d->lock)
 329 {
 330         struct net_device *dev = qdisc_dev(sch);
 331
 332         if (cl <= netdev_get_num_tc(dev)) {
 333                 int i;
 334                 __u32 qlen = 0;
 335                 struct Qdisc *qdisc;
 336                 struct gnet_stats_queue qstats = {0};
 337                 struct gnet_stats_basic_packed bstats = {0};
 338                 struct netdev_tc_txq tc = dev->tc_to_txq[cl - 1];
 339
 340                 /* Drop lock here it will be reclaimed before touching
 341                  * statistics this is required because the d->lock we
 342                  * hold here is the look on dev_queue->qdisc_sleeping
 343                  * also acquired below.
 344                  */
 345                 if (d->lock)
 346                         spin_unlock_bh(d->lock);
 347
 348                 for (i = tc.offset; i < tc.offset + tc.count; i++) {
 349                         struct netdev_queue *q = netdev_get_tx_queue(dev, i);
 350
 351                         qdisc = rtnl_dereference(q->qdisc);
 352                         spin_lock_bh(qdisc_lock(qdisc));
 353                         qlen              += qdisc->q.qlen;
 354                         bstats.bytes      += qdisc->bstats.bytes;
 355                         bstats.packets    += qdisc->bstats.packets;
 356                         qstats.backlog    += qdisc->qstats.backlog;
 357                         qstats.drops      += qdisc->qstats.drops;
 358                         qstats.requeues   += qdisc->qstats.requeues;
 359                         qstats.overlimits += qdisc->qstats.overlimits;
 360                         spin_unlock_bh(qdisc_lock(qdisc));
 361                 }
 362                 /* Reclaim root sleeping lock before completing stats */
 363                 if (d->lock)
 364                         spin_lock_bh(d->lock);
 365                 if (gnet_stats_copy_basic(NULL, d, NULL, &bstats) < 0 ||
 366                     gnet_stats_copy_queue(d, NULL, &qstats, qlen) < 0)
 367                         return -1;
 368         } else {
 369                 struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 370
 371                 sch = dev_queue->qdisc_sleeping;
 372                 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
 373                                           d, NULL, &sch->bstats) < 0 ||
 374                     gnet_stats_copy_queue(d, NULL,
 375                                           &sch->qstats, sch->q.qlen) < 0)
 376                         return -1;
 377         }
 378         return 0;
 379 }
 380
 381 static void mqprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 382 {
 383         struct net_device *dev = qdisc_dev(sch);
 384         unsigned long ntx;
 385
 386         if (arg->stop)
 387                 return;
 388
 389         /* Walk hierarchy with a virtual class per tc */
 390         arg->count = arg->skip;
 391         for (ntx = arg->skip;
 392              ntx < dev->num_tx_queues + netdev_get_num_tc(dev);
 393              ntx++) {
 394                 if (arg->fn(sch, ntx + 1, arg) < 0) {
 395                         arg->stop = 1;
 396                         break;
 397                 }
 398                 arg->count++;
 399         }
 400 }
 401
 402 static const struct Qdisc_class_ops mqprio_class_ops = {
 403         .graft          = mqprio_graft,
 404         .leaf           = mqprio_leaf,
 405         .get            = mqprio_get,
 406         .put            = mqprio_put,
 407         .walk           = mqprio_walk,
 408         .dump           = mqprio_dump_class,
 409         .dump_stats     = mqprio_dump_class_stats,
 410 };
 411
 412 static struct Qdisc_ops mqprio_qdisc_ops __read_mostly = {
 413         .cl_ops         = &mqprio_class_ops,
 414         .id             = "mqprio",
 415         .priv_size      = sizeof(struct mqprio_sched),
 416         .init           = mqprio_init,
 417         .destroy        = mqprio_destroy,
 418         .attach         = mqprio_attach,
 419         .dump           = mqprio_dump,
 420         .owner          = THIS_MODULE,
 421 };
 422
 423 static int __init mqprio_module_init(void)
 424 {
 425         return register_qdisc(&mqprio_qdisc_ops);
 426 }
 427
 428 static void __exit mqprio_module_exit(void)
 429 {
 430         unregister_qdisc(&mqprio_qdisc_ops);
 431 }
 432
 433 module_init(mqprio_module_init);
 434 module_exit(mqprio_module_exit);
 435
 436 MODULE_LICENSE("GPL");