linux/net/sched/sch_mqprio.c
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   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
  22struct mqprio_sched {
  23        struct Qdisc            **qdiscs;
  24        int hw_owned;
  25};
  26
  27static 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
  47static 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
  92static 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
 160err:
 161        mqprio_destroy(sch);
 162        return err;
 163}
 164
 165static 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
 183static 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
 194static 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
 214static 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        if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 251                goto nla_put_failure;
 252
 253        return skb->len;
 254nla_put_failure:
 255        nlmsg_trim(skb, b);
 256        return -1;
 257}
 258
 259static struct Qdisc *mqprio_leaf(struct Qdisc *sch, unsigned long cl)
 260{
 261        struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 262
 263        if (!dev_queue)
 264                return NULL;
 265
 266        return dev_queue->qdisc_sleeping;
 267}
 268
 269static unsigned long mqprio_get(struct Qdisc *sch, u32 classid)
 270{
 271        struct net_device *dev = qdisc_dev(sch);
 272        unsigned int ntx = TC_H_MIN(classid);
 273
 274        if (ntx > dev->num_tx_queues + netdev_get_num_tc(dev))
 275                return 0;
 276        return ntx;
 277}
 278
 279static void mqprio_put(struct Qdisc *sch, unsigned long cl)
 280{
 281}
 282
 283static int mqprio_dump_class(struct Qdisc *sch, unsigned long cl,
 284                         struct sk_buff *skb, struct tcmsg *tcm)
 285{
 286        struct net_device *dev = qdisc_dev(sch);
 287
 288        if (cl <= netdev_get_num_tc(dev)) {
 289                tcm->tcm_parent = TC_H_ROOT;
 290                tcm->tcm_info = 0;
 291        } else {
 292                int i;
 293                struct netdev_queue *dev_queue;
 294
 295                dev_queue = mqprio_queue_get(sch, cl);
 296                tcm->tcm_parent = 0;
 297                for (i = 0; i < netdev_get_num_tc(dev); i++) {
 298                        struct netdev_tc_txq tc = dev->tc_to_txq[i];
 299                        int q_idx = cl - netdev_get_num_tc(dev);
 300
 301                        if (q_idx > tc.offset &&
 302                            q_idx <= tc.offset + tc.count) {
 303                                tcm->tcm_parent =
 304                                        TC_H_MAKE(TC_H_MAJ(sch->handle),
 305                                                  TC_H_MIN(i + 1));
 306                                break;
 307                        }
 308                }
 309                tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
 310        }
 311        tcm->tcm_handle |= TC_H_MIN(cl);
 312        return 0;
 313}
 314
 315static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 316                                   struct gnet_dump *d)
 317        __releases(d->lock)
 318        __acquires(d->lock)
 319{
 320        struct net_device *dev = qdisc_dev(sch);
 321
 322        if (cl <= netdev_get_num_tc(dev)) {
 323                int i;
 324                struct Qdisc *qdisc;
 325                struct gnet_stats_queue qstats = {0};
 326                struct gnet_stats_basic_packed bstats = {0};
 327                struct netdev_tc_txq tc = dev->tc_to_txq[cl - 1];
 328
 329                /* Drop lock here it will be reclaimed before touching
 330                 * statistics this is required because the d->lock we
 331                 * hold here is the look on dev_queue->qdisc_sleeping
 332                 * also acquired below.
 333                 */
 334                spin_unlock_bh(d->lock);
 335
 336                for (i = tc.offset; i < tc.offset + tc.count; i++) {
 337                        qdisc = netdev_get_tx_queue(dev, i)->qdisc;
 338                        spin_lock_bh(qdisc_lock(qdisc));
 339                        bstats.bytes      += qdisc->bstats.bytes;
 340                        bstats.packets    += qdisc->bstats.packets;
 341                        qstats.qlen       += qdisc->qstats.qlen;
 342                        qstats.backlog    += qdisc->qstats.backlog;
 343                        qstats.drops      += qdisc->qstats.drops;
 344                        qstats.requeues   += qdisc->qstats.requeues;
 345                        qstats.overlimits += qdisc->qstats.overlimits;
 346                        spin_unlock_bh(qdisc_lock(qdisc));
 347                }
 348                /* Reclaim root sleeping lock before completing stats */
 349                spin_lock_bh(d->lock);
 350                if (gnet_stats_copy_basic(d, &bstats) < 0 ||
 351                    gnet_stats_copy_queue(d, &qstats) < 0)
 352                        return -1;
 353        } else {
 354                struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 355
 356                sch = dev_queue->qdisc_sleeping;
 357                sch->qstats.qlen = sch->q.qlen;
 358                if (gnet_stats_copy_basic(d, &sch->bstats) < 0 ||
 359                    gnet_stats_copy_queue(d, &sch->qstats) < 0)
 360                        return -1;
 361        }
 362        return 0;
 363}
 364
 365static void mqprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 366{
 367        struct net_device *dev = qdisc_dev(sch);
 368        unsigned long ntx;
 369
 370        if (arg->stop)
 371                return;
 372
 373        /* Walk hierarchy with a virtual class per tc */
 374        arg->count = arg->skip;
 375        for (ntx = arg->skip;
 376             ntx < dev->num_tx_queues + netdev_get_num_tc(dev);
 377             ntx++) {
 378                if (arg->fn(sch, ntx + 1, arg) < 0) {
 379                        arg->stop = 1;
 380                        break;
 381                }
 382                arg->count++;
 383        }
 384}
 385
 386static const struct Qdisc_class_ops mqprio_class_ops = {
 387        .graft          = mqprio_graft,
 388        .leaf           = mqprio_leaf,
 389        .get            = mqprio_get,
 390        .put            = mqprio_put,
 391        .walk           = mqprio_walk,
 392        .dump           = mqprio_dump_class,
 393        .dump_stats     = mqprio_dump_class_stats,
 394};
 395
 396static struct Qdisc_ops mqprio_qdisc_ops __read_mostly = {
 397        .cl_ops         = &mqprio_class_ops,
 398        .id             = "mqprio",
 399        .priv_size      = sizeof(struct mqprio_sched),
 400        .init           = mqprio_init,
 401        .destroy        = mqprio_destroy,
 402        .attach         = mqprio_attach,
 403        .dump           = mqprio_dump,
 404        .owner          = THIS_MODULE,
 405};
 406
 407static int __init mqprio_module_init(void)
 408{
 409        return register_qdisc(&mqprio_qdisc_ops);
 410}
 411
 412static void __exit mqprio_module_exit(void)
 413{
 414        unregister_qdisc(&mqprio_qdisc_ops);
 415}
 416
 417module_init(mqprio_module_init);
 418module_exit(mqprio_module_exit);
 419
 420MODULE_LICENSE("GPL");
 421
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