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_offload;
  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         unsigned int ntx;
  32
  33         if (priv->qdiscs) {
  34                 for (ntx = 0;
  35                      ntx < dev->num_tx_queues && priv->qdiscs[ntx];
  36                      ntx++)
  37                         qdisc_destroy(priv->qdiscs[ntx]);
  38                 kfree(priv->qdiscs);
  39         }
  40
  41         if (priv->hw_offload && dev->netdev_ops->ndo_setup_tc) {
  42                 struct tc_mqprio_qopt offload = { 0 };
  43                 struct tc_to_netdev tc = { { .mqprio = &offload } };
  44
  45                 dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_MQPRIO,
  46                                               sch->handle, 0, 0, &tc);
  47         } else {
  48                 netdev_set_num_tc(dev, 0);
  49         }
  50 }
  51
  52 static int mqprio_parse_opt(struct net_device *dev, struct tc_mqprio_qopt *qopt)
  53 {
  54         int i, j;
  55
  56         /* Verify num_tc is not out of max range */
  57         if (qopt->num_tc > TC_MAX_QUEUE)
  58                 return -EINVAL;
  59
  60         /* Verify priority mapping uses valid tcs */
  61         for (i = 0; i < TC_BITMASK + 1; i++) {
  62                 if (qopt->prio_tc_map[i] >= qopt->num_tc)
  63                         return -EINVAL;
  64         }
  65
  66         /* Limit qopt->hw to maximum supported offload value.  Drivers have
  67          * the option of overriding this later if they don't support the a
  68          * given offload type.
  69          */
  70         if (qopt->hw > TC_MQPRIO_HW_OFFLOAD_MAX)
  71                 qopt->hw = TC_MQPRIO_HW_OFFLOAD_MAX;
  72
  73         /* If hardware offload is requested we will leave it to the device
  74          * to either populate the queue counts itself or to validate the
  75          * provided queue counts.  If ndo_setup_tc is not present then
  76          * hardware doesn't support offload and we should return an error.
  77          */
  78         if (qopt->hw)
  79                 return dev->netdev_ops->ndo_setup_tc ? 0 : -EINVAL;
  80
  81         for (i = 0; i < qopt->num_tc; i++) {
  82                 unsigned int last = qopt->offset[i] + qopt->count[i];
  83
  84                 /* Verify the queue count is in tx range being equal to the
  85                  * real_num_tx_queues indicates the last queue is in use.
  86                  */
  87                 if (qopt->offset[i] >= dev->real_num_tx_queues ||
  88                     !qopt->count[i] ||
  89                     last > dev->real_num_tx_queues)
  90                         return -EINVAL;
  91
  92                 /* Verify that the offset and counts do not overlap */
  93                 for (j = i + 1; j < qopt->num_tc; j++) {
  94                         if (last > qopt->offset[j])
  95                                 return -EINVAL;
  96                 }
  97         }
  98
  99         return 0;
 100 }
 101
 102 static int mqprio_init(struct Qdisc *sch, struct nlattr *opt)
 103 {
 104         struct net_device *dev = qdisc_dev(sch);
 105         struct mqprio_sched *priv = qdisc_priv(sch);
 106         struct netdev_queue *dev_queue;
 107         struct Qdisc *qdisc;
 108         int i, err = -EOPNOTSUPP;
 109         struct tc_mqprio_qopt *qopt = NULL;
 110
 111         BUILD_BUG_ON(TC_MAX_QUEUE != TC_QOPT_MAX_QUEUE);
 112         BUILD_BUG_ON(TC_BITMASK != TC_QOPT_BITMASK);
 113
 114         if (sch->parent != TC_H_ROOT)
 115                 return -EOPNOTSUPP;
 116
 117         if (!netif_is_multiqueue(dev))
 118                 return -EOPNOTSUPP;
 119
 120         if (!opt || nla_len(opt) < sizeof(*qopt))
 121                 return -EINVAL;
 122
 123         qopt = nla_data(opt);
 124         if (mqprio_parse_opt(dev, qopt))
 125                 return -EINVAL;
 126
 127         /* pre-allocate qdisc, attachment can't fail */
 128         priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
 129                                GFP_KERNEL);
 130         if (!priv->qdiscs)
 131                 return -ENOMEM;
 132
 133         for (i = 0; i < dev->num_tx_queues; i++) {
 134                 dev_queue = netdev_get_tx_queue(dev, i);
 135                 qdisc = qdisc_create_dflt(dev_queue,
 136                                           get_default_qdisc_ops(dev, i),
 137                                           TC_H_MAKE(TC_H_MAJ(sch->handle),
 138                                                     TC_H_MIN(i + 1)));
 139                 if (!qdisc)
 140                         return -ENOMEM;
 141
 142                 priv->qdiscs[i] = qdisc;
 143                 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
 144         }
 145
 146         /* If the mqprio options indicate that hardware should own
 147          * the queue mapping then run ndo_setup_tc otherwise use the
 148          * supplied and verified mapping
 149          */
 150         if (qopt->hw) {
 151                 struct tc_mqprio_qopt offload = *qopt;
 152                 struct tc_to_netdev tc = { { .mqprio = &offload } };
 153
 154                 err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_MQPRIO,
 155                                                     sch->handle, 0, 0, &tc);
 156                 if (err)
 157                         return err;
 158
 159                 priv->hw_offload = offload.hw;
 160         } else {
 161                 netdev_set_num_tc(dev, qopt->num_tc);
 162                 for (i = 0; i < qopt->num_tc; i++)
 163                         netdev_set_tc_queue(dev, i,
 164                                             qopt->count[i], qopt->offset[i]);
 165         }
 166
 167         /* Always use supplied priority mappings */
 168         for (i = 0; i < TC_BITMASK + 1; i++)
 169                 netdev_set_prio_tc_map(dev, i, qopt->prio_tc_map[i]);
 170
 171         sch->flags |= TCQ_F_MQROOT;
 172         return 0;
 173 }
 174
 175 static void mqprio_attach(struct Qdisc *sch)
 176 {
 177         struct net_device *dev = qdisc_dev(sch);
 178         struct mqprio_sched *priv = qdisc_priv(sch);
 179         struct Qdisc *qdisc, *old;
 180         unsigned int ntx;
 181
 182         /* Attach underlying qdisc */
 183         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
 184                 qdisc = priv->qdiscs[ntx];
 185                 old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
 186                 if (old)
 187                         qdisc_destroy(old);
 188                 if (ntx < dev->real_num_tx_queues)
 189                         qdisc_hash_add(qdisc, false);
 190         }
 191         kfree(priv->qdiscs);
 192         priv->qdiscs = NULL;
 193 }
 194
 195 static struct netdev_queue *mqprio_queue_get(struct Qdisc *sch,
 196                                              unsigned long cl)
 197 {
 198         struct net_device *dev = qdisc_dev(sch);
 199         unsigned long ntx = cl - 1 - netdev_get_num_tc(dev);
 200
 201         if (ntx >= dev->num_tx_queues)
 202                 return NULL;
 203         return netdev_get_tx_queue(dev, ntx);
 204 }
 205
 206 static int mqprio_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
 207                     struct Qdisc **old)
 208 {
 209         struct net_device *dev = qdisc_dev(sch);
 210         struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 211
 212         if (!dev_queue)
 213                 return -EINVAL;
 214
 215         if (dev->flags & IFF_UP)
 216                 dev_deactivate(dev);
 217
 218         *old = dev_graft_qdisc(dev_queue, new);
 219
 220         if (new)
 221                 new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
 222
 223         if (dev->flags & IFF_UP)
 224                 dev_activate(dev);
 225
 226         return 0;
 227 }
 228
 229 static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 230 {
 231         struct net_device *dev = qdisc_dev(sch);
 232         struct mqprio_sched *priv = qdisc_priv(sch);
 233         unsigned char *b = skb_tail_pointer(skb);
 234         struct tc_mqprio_qopt opt = { 0 };
 235         struct Qdisc *qdisc;
 236         unsigned int i;
 237
 238         sch->q.qlen = 0;
 239         memset(&sch->bstats, 0, sizeof(sch->bstats));
 240         memset(&sch->qstats, 0, sizeof(sch->qstats));
 241
 242         for (i = 0; i < dev->num_tx_queues; i++) {
 243                 qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
 244                 spin_lock_bh(qdisc_lock(qdisc));
 245                 sch->q.qlen             += qdisc->q.qlen;
 246                 sch->bstats.bytes       += qdisc->bstats.bytes;
 247                 sch->bstats.packets     += qdisc->bstats.packets;
 248                 sch->qstats.backlog     += qdisc->qstats.backlog;
 249                 sch->qstats.drops       += qdisc->qstats.drops;
 250                 sch->qstats.requeues    += qdisc->qstats.requeues;
 251                 sch->qstats.overlimits  += qdisc->qstats.overlimits;
 252                 spin_unlock_bh(qdisc_lock(qdisc));
 253         }
 254
 255         opt.num_tc = netdev_get_num_tc(dev);
 256         memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map));
 257         opt.hw = priv->hw_offload;
 258
 259         for (i = 0; i < netdev_get_num_tc(dev); i++) {
 260                 opt.count[i] = dev->tc_to_txq[i].count;
 261                 opt.offset[i] = dev->tc_to_txq[i].offset;
 262         }
 263
 264         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 265                 goto nla_put_failure;
 266
 267         return skb->len;
 268 nla_put_failure:
 269         nlmsg_trim(skb, b);
 270         return -1;
 271 }
 272
 273 static struct Qdisc *mqprio_leaf(struct Qdisc *sch, unsigned long cl)
 274 {
 275         struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 276
 277         if (!dev_queue)
 278                 return NULL;
 279
 280         return dev_queue->qdisc_sleeping;
 281 }
 282
 283 static unsigned long mqprio_get(struct Qdisc *sch, u32 classid)
 284 {
 285         struct net_device *dev = qdisc_dev(sch);
 286         unsigned int ntx = TC_H_MIN(classid);
 287
 288         if (ntx > dev->num_tx_queues + netdev_get_num_tc(dev))
 289                 return 0;
 290         return ntx;
 291 }
 292
 293 static void mqprio_put(struct Qdisc *sch, unsigned long cl)
 294 {
 295 }
 296
 297 static int mqprio_dump_class(struct Qdisc *sch, unsigned long cl,
 298                          struct sk_buff *skb, struct tcmsg *tcm)
 299 {
 300         struct net_device *dev = qdisc_dev(sch);
 301
 302         if (cl <= netdev_get_num_tc(dev)) {
 303                 tcm->tcm_parent = TC_H_ROOT;
 304                 tcm->tcm_info = 0;
 305         } else {
 306                 int i;
 307                 struct netdev_queue *dev_queue;
 308
 309                 dev_queue = mqprio_queue_get(sch, cl);
 310                 tcm->tcm_parent = 0;
 311                 for (i = 0; i < netdev_get_num_tc(dev); i++) {
 312                         struct netdev_tc_txq tc = dev->tc_to_txq[i];
 313                         int q_idx = cl - netdev_get_num_tc(dev);
 314
 315                         if (q_idx > tc.offset &&
 316                             q_idx <= tc.offset + tc.count) {
 317                                 tcm->tcm_parent =
 318                                         TC_H_MAKE(TC_H_MAJ(sch->handle),
 319                                                   TC_H_MIN(i + 1));
 320                                 break;
 321                         }
 322                 }
 323                 tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
 324         }
 325         tcm->tcm_handle |= TC_H_MIN(cl);
 326         return 0;
 327 }
 328
 329 static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 330                                    struct gnet_dump *d)
 331         __releases(d->lock)
 332         __acquires(d->lock)
 333 {
 334         struct net_device *dev = qdisc_dev(sch);
 335
 336         if (cl <= netdev_get_num_tc(dev)) {
 337                 int i;
 338                 __u32 qlen = 0;
 339                 struct Qdisc *qdisc;
 340                 struct gnet_stats_queue qstats = {0};
 341                 struct gnet_stats_basic_packed bstats = {0};
 342                 struct netdev_tc_txq tc = dev->tc_to_txq[cl - 1];
 343
 344                 /* Drop lock here it will be reclaimed before touching
 345                  * statistics this is required because the d->lock we
 346                  * hold here is the look on dev_queue->qdisc_sleeping
 347                  * also acquired below.
 348                  */
 349                 if (d->lock)
 350                         spin_unlock_bh(d->lock);
 351
 352                 for (i = tc.offset; i < tc.offset + tc.count; i++) {
 353                         struct netdev_queue *q = netdev_get_tx_queue(dev, i);
 354
 355                         qdisc = rtnl_dereference(q->qdisc);
 356                         spin_lock_bh(qdisc_lock(qdisc));
 357                         qlen              += qdisc->q.qlen;
 358                         bstats.bytes      += qdisc->bstats.bytes;
 359                         bstats.packets    += qdisc->bstats.packets;
 360                         qstats.backlog    += qdisc->qstats.backlog;
 361                         qstats.drops      += qdisc->qstats.drops;
 362                         qstats.requeues   += qdisc->qstats.requeues;
 363                         qstats.overlimits += qdisc->qstats.overlimits;
 364                         spin_unlock_bh(qdisc_lock(qdisc));
 365                 }
 366                 /* Reclaim root sleeping lock before completing stats */
 367                 if (d->lock)
 368                         spin_lock_bh(d->lock);
 369                 if (gnet_stats_copy_basic(NULL, d, NULL, &bstats) < 0 ||
 370                     gnet_stats_copy_queue(d, NULL, &qstats, qlen) < 0)
 371                         return -1;
 372         } else {
 373                 struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 374
 375                 sch = dev_queue->qdisc_sleeping;
 376                 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
 377                                           d, NULL, &sch->bstats) < 0 ||
 378                     gnet_stats_copy_queue(d, NULL,
 379                                           &sch->qstats, sch->q.qlen) < 0)
 380                         return -1;
 381         }
 382         return 0;
 383 }
 384
 385 static void mqprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 386 {
 387         struct net_device *dev = qdisc_dev(sch);
 388         unsigned long ntx;
 389
 390         if (arg->stop)
 391                 return;
 392
 393         /* Walk hierarchy with a virtual class per tc */
 394         arg->count = arg->skip;
 395         for (ntx = arg->skip;
 396              ntx < dev->num_tx_queues + netdev_get_num_tc(dev);
 397              ntx++) {
 398                 if (arg->fn(sch, ntx + 1, arg) < 0) {
 399                         arg->stop = 1;
 400                         break;
 401                 }
 402                 arg->count++;
 403         }
 404 }
 405
 406 static const struct Qdisc_class_ops mqprio_class_ops = {
 407         .graft          = mqprio_graft,
 408         .leaf           = mqprio_leaf,
 409         .get            = mqprio_get,
 410         .put            = mqprio_put,
 411         .walk           = mqprio_walk,
 412         .dump           = mqprio_dump_class,
 413         .dump_stats     = mqprio_dump_class_stats,
 414 };
 415
 416 static struct Qdisc_ops mqprio_qdisc_ops __read_mostly = {
 417         .cl_ops         = &mqprio_class_ops,
 418         .id             = "mqprio",
 419         .priv_size      = sizeof(struct mqprio_sched),
 420         .init           = mqprio_init,
 421         .destroy        = mqprio_destroy,
 422         .attach         = mqprio_attach,
 423         .dump           = mqprio_dump,
 424         .owner          = THIS_MODULE,
 425 };
 426
 427 static int __init mqprio_module_init(void)
 428 {
 429         return register_qdisc(&mqprio_qdisc_ops);
 430 }
 431
 432 static void __exit mqprio_module_exit(void)
 433 {
 434         unregister_qdisc(&mqprio_qdisc_ops);
 435 }
 436
 437 module_init(mqprio_module_init);
 438 module_exit(mqprio_module_exit);
 439
 440 MODULE_LICENSE("GPL");