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