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, &pfifo_fast_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         }
 136
 137         /* If the mqprio options indicate that hardware should own
 138          * the queue mapping then run ndo_setup_tc otherwise use the
 139          * supplied and verified mapping
 140          */
 141         if (qopt->hw) {
 142                 priv->hw_owned = 1;
 143                 err = dev->netdev_ops->ndo_setup_tc(dev, qopt->num_tc);
 144                 if (err)
 145                         goto err;
 146         } else {
 147                 netdev_set_num_tc(dev, qopt->num_tc);
 148                 for (i = 0; i < qopt->num_tc; i++)
 149                         netdev_set_tc_queue(dev, i,
 150                                             qopt->count[i], qopt->offset[i]);
 151         }
 152
 153         /* Always use supplied priority mappings */
 154         for (i = 0; i < TC_BITMASK + 1; i++)
 155                 netdev_set_prio_tc_map(dev, i, qopt->prio_tc_map[i]);
 156
 157         sch->flags |= TCQ_F_MQROOT;
 158         return 0;
 159
 160 err:
 161         mqprio_destroy(sch);
 162         return err;
 163 }
 164
 165 static void mqprio_attach(struct Qdisc *sch)
 166 {
 167         struct net_device *dev = qdisc_dev(sch);
 168         struct mqprio_sched *priv = qdisc_priv(sch);
 169         struct Qdisc *qdisc;
 170         unsigned int ntx;
 171
 172         /* Attach underlying qdisc */
 173         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
 174                 qdisc = priv->qdiscs[ntx];
 175                 qdisc = dev_graft_qdisc(qdisc->dev_queue, qdisc);
 176                 if (qdisc)
 177                         qdisc_destroy(qdisc);
 178         }
 179         kfree(priv->qdiscs);
 180         priv->qdiscs = NULL;
 181 }
 182
 183 static struct netdev_queue *mqprio_queue_get(struct Qdisc *sch,
 184                                              unsigned long cl)
 185 {
 186         struct net_device *dev = qdisc_dev(sch);
 187         unsigned long ntx = cl - 1 - netdev_get_num_tc(dev);
 188
 189         if (ntx >= dev->num_tx_queues)
 190                 return NULL;
 191         return netdev_get_tx_queue(dev, ntx);
 192 }
 193
 194 static int mqprio_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
 195                     struct Qdisc **old)
 196 {
 197         struct net_device *dev = qdisc_dev(sch);
 198         struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 199
 200         if (!dev_queue)
 201                 return -EINVAL;
 202
 203         if (dev->flags & IFF_UP)
 204                 dev_deactivate(dev);
 205
 206         *old = dev_graft_qdisc(dev_queue, new);
 207
 208         if (dev->flags & IFF_UP)
 209                 dev_activate(dev);
 210
 211         return 0;
 212 }
 213
 214 static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 215 {
 216         struct net_device *dev = qdisc_dev(sch);
 217         struct mqprio_sched *priv = qdisc_priv(sch);
 218         unsigned char *b = skb_tail_pointer(skb);
 219         struct tc_mqprio_qopt opt = { 0 };
 220         struct Qdisc *qdisc;
 221         unsigned int i;
 222
 223         sch->q.qlen = 0;
 224         memset(&sch->bstats, 0, sizeof(sch->bstats));
 225         memset(&sch->qstats, 0, sizeof(sch->qstats));
 226
 227         for (i = 0; i < dev->num_tx_queues; i++) {
 228                 qdisc = netdev_get_tx_queue(dev, i)->qdisc;
 229                 spin_lock_bh(qdisc_lock(qdisc));
 230                 sch->q.qlen             += qdisc->q.qlen;
 231                 sch->bstats.bytes       += qdisc->bstats.bytes;
 232                 sch->bstats.packets     += qdisc->bstats.packets;
 233                 sch->qstats.qlen        += qdisc->qstats.qlen;
 234                 sch->qstats.backlog     += qdisc->qstats.backlog;
 235                 sch->qstats.drops       += qdisc->qstats.drops;
 236                 sch->qstats.requeues    += qdisc->qstats.requeues;
 237                 sch->qstats.overlimits  += qdisc->qstats.overlimits;
 238                 spin_unlock_bh(qdisc_lock(qdisc));
 239         }
 240
 241         opt.num_tc = netdev_get_num_tc(dev);
 242         memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map));
 243         opt.hw = priv->hw_owned;
 244
 245         for (i = 0; i < netdev_get_num_tc(dev); i++) {
 246                 opt.count[i] = dev->tc_to_txq[i].count;
 247                 opt.offset[i] = dev->tc_to_txq[i].offset;
 248         }
 249
 250         NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 251
 252         return skb->len;
 253 nla_put_failure:
 254         nlmsg_trim(skb, b);
 255         return -1;
 256 }
 257
 258 static struct Qdisc *mqprio_leaf(struct Qdisc *sch, unsigned long cl)
 259 {
 260         struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 261
 262         if (!dev_queue)
 263                 return NULL;
 264
 265         return dev_queue->qdisc_sleeping;
 266 }
 267
 268 static unsigned long mqprio_get(struct Qdisc *sch, u32 classid)
 269 {
 270         struct net_device *dev = qdisc_dev(sch);
 271         unsigned int ntx = TC_H_MIN(classid);
 272
 273         if (ntx > dev->num_tx_queues + netdev_get_num_tc(dev))
 274                 return 0;
 275         return ntx;
 276 }
 277
 278 static void mqprio_put(struct Qdisc *sch, unsigned long cl)
 279 {
 280 }
 281
 282 static int mqprio_dump_class(struct Qdisc *sch, unsigned long cl,
 283                          struct sk_buff *skb, struct tcmsg *tcm)
 284 {
 285         struct net_device *dev = qdisc_dev(sch);
 286
 287         if (cl <= netdev_get_num_tc(dev)) {
 288                 tcm->tcm_parent = TC_H_ROOT;
 289                 tcm->tcm_info = 0;
 290         } else {
 291                 int i;
 292                 struct netdev_queue *dev_queue;
 293
 294                 dev_queue = mqprio_queue_get(sch, cl);
 295                 tcm->tcm_parent = 0;
 296                 for (i = 0; i < netdev_get_num_tc(dev); i++) {
 297                         struct netdev_tc_txq tc = dev->tc_to_txq[i];
 298                         int q_idx = cl - netdev_get_num_tc(dev);
 299
 300                         if (q_idx > tc.offset &&
 301                             q_idx <= tc.offset + tc.count) {
 302                                 tcm->tcm_parent =
 303                                         TC_H_MAKE(TC_H_MAJ(sch->handle),
 304                                                   TC_H_MIN(i + 1));
 305                                 break;
 306                         }
 307                 }
 308                 tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
 309         }
 310         tcm->tcm_handle |= TC_H_MIN(cl);
 311         return 0;
 312 }
 313
 314 static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 315                                    struct gnet_dump *d)
 316         __releases(d->lock)
 317         __acquires(d->lock)
 318 {
 319         struct net_device *dev = qdisc_dev(sch);
 320
 321         if (cl <= netdev_get_num_tc(dev)) {
 322                 int i;
 323                 struct Qdisc *qdisc;
 324                 struct gnet_stats_queue qstats = {0};
 325                 struct gnet_stats_basic_packed bstats = {0};
 326                 struct netdev_tc_txq tc = dev->tc_to_txq[cl - 1];
 327
 328                 /* Drop lock here it will be reclaimed before touching
 329                  * statistics this is required because the d->lock we
 330                  * hold here is the look on dev_queue->qdisc_sleeping
 331                  * also acquired below.
 332                  */
 333                 spin_unlock_bh(d->lock);
 334
 335                 for (i = tc.offset; i < tc.offset + tc.count; i++) {
 336                         qdisc = netdev_get_tx_queue(dev, i)->qdisc;
 337                         spin_lock_bh(qdisc_lock(qdisc));
 338                         bstats.bytes      += qdisc->bstats.bytes;
 339                         bstats.packets    += qdisc->bstats.packets;
 340                         qstats.qlen       += qdisc->qstats.qlen;
 341                         qstats.backlog    += qdisc->qstats.backlog;
 342                         qstats.drops      += qdisc->qstats.drops;
 343                         qstats.requeues   += qdisc->qstats.requeues;
 344                         qstats.overlimits += qdisc->qstats.overlimits;
 345                         spin_unlock_bh(qdisc_lock(qdisc));
 346                 }
 347                 /* Reclaim root sleeping lock before completing stats */
 348                 spin_lock_bh(d->lock);
 349                 if (gnet_stats_copy_basic(d, &bstats) < 0 ||
 350                     gnet_stats_copy_queue(d, &qstats) < 0)
 351                         return -1;
 352         } else {
 353                 struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 354
 355                 sch = dev_queue->qdisc_sleeping;
 356                 sch->qstats.qlen = sch->q.qlen;
 357                 if (gnet_stats_copy_basic(d, &sch->bstats) < 0 ||
 358                     gnet_stats_copy_queue(d, &sch->qstats) < 0)
 359                         return -1;
 360         }
 361         return 0;
 362 }
 363
 364 static void mqprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 365 {
 366         struct net_device *dev = qdisc_dev(sch);
 367         unsigned long ntx;
 368
 369         if (arg->stop)
 370                 return;
 371
 372         /* Walk hierarchy with a virtual class per tc */
 373         arg->count = arg->skip;
 374         for (ntx = arg->skip;
 375              ntx < dev->num_tx_queues + netdev_get_num_tc(dev);
 376              ntx++) {
 377                 if (arg->fn(sch, ntx + 1, arg) < 0) {
 378                         arg->stop = 1;
 379                         break;
 380                 }
 381                 arg->count++;
 382         }
 383 }
 384
 385 static const struct Qdisc_class_ops mqprio_class_ops = {
 386         .graft          = mqprio_graft,
 387         .leaf           = mqprio_leaf,
 388         .get            = mqprio_get,
 389         .put            = mqprio_put,
 390         .walk           = mqprio_walk,
 391         .dump           = mqprio_dump_class,
 392         .dump_stats     = mqprio_dump_class_stats,
 393 };
 394
 395 static struct Qdisc_ops mqprio_qdisc_ops __read_mostly = {
 396         .cl_ops         = &mqprio_class_ops,
 397         .id             = "mqprio",
 398         .priv_size      = sizeof(struct mqprio_sched),
 399         .init           = mqprio_init,
 400         .destroy        = mqprio_destroy,
 401         .attach         = mqprio_attach,
 402         .dump           = mqprio_dump,
 403         .owner          = THIS_MODULE,
 404 };
 405
 406 static int __init mqprio_module_init(void)
 407 {
 408         return register_qdisc(&mqprio_qdisc_ops);
 409 }
 410
 411 static void __exit mqprio_module_exit(void)
 412 {
 413         unregister_qdisc(&mqprio_qdisc_ops);
 414 }
 415
 416 module_init(mqprio_module_init);
 417 module_exit(mqprio_module_exit);
 418
 419 MODULE_LICENSE("GPL");