net/sched/sch_mq.c

   1 /*
   2  * net/sched/sch_mq.c           Classful multiqueue dummy scheduler
   3  *
   4  * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
   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/export.h>
  15 #include <linux/string.h>
  16 #include <linux/errno.h>
  17 #include <linux/skbuff.h>
  18 #include <net/netlink.h>
  19 #include <net/pkt_cls.h>
  20 #include <net/pkt_sched.h>
  21 #include <net/sch_generic.h>
  22
  23 struct mq_sched {
  24         struct Qdisc            **qdiscs;
  25 };
  26
  27 static int mq_offload(struct Qdisc *sch, enum tc_mq_command cmd)
  28 {
  29         struct net_device *dev = qdisc_dev(sch);
  30         struct tc_mq_qopt_offload opt = {
  31                 .command = cmd,
  32                 .handle = sch->handle,
  33         };
  34
  35         if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
  36                 return -EOPNOTSUPP;
  37
  38         return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_MQ, &opt);
  39 }
  40
  41 static int mq_offload_stats(struct Qdisc *sch)
  42 {
  43         struct tc_mq_qopt_offload opt = {
  44                 .command = TC_MQ_STATS,
  45                 .handle = sch->handle,
  46                 .stats = {
  47                         .bstats = &sch->bstats,
  48                         .qstats = &sch->qstats,
  49                 },
  50         };
  51
  52         return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_MQ, &opt);
  53 }
  54
  55 static void mq_destroy(struct Qdisc *sch)
  56 {
  57         struct net_device *dev = qdisc_dev(sch);
  58         struct mq_sched *priv = qdisc_priv(sch);
  59         unsigned int ntx;
  60
  61         mq_offload(sch, TC_MQ_DESTROY);
  62
  63         if (!priv->qdiscs)
  64                 return;
  65         for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++)
  66                 qdisc_put(priv->qdiscs[ntx]);
  67         kfree(priv->qdiscs);
  68 }
  69
  70 static int mq_init(struct Qdisc *sch, struct nlattr *opt,
  71                    struct netlink_ext_ack *extack)
  72 {
  73         struct net_device *dev = qdisc_dev(sch);
  74         struct mq_sched *priv = qdisc_priv(sch);
  75         struct netdev_queue *dev_queue;
  76         struct Qdisc *qdisc;
  77         unsigned int ntx;
  78
  79         if (sch->parent != TC_H_ROOT)
  80                 return -EOPNOTSUPP;
  81
  82         if (!netif_is_multiqueue(dev))
  83                 return -EOPNOTSUPP;
  84
  85         /* pre-allocate qdiscs, attachment can't fail */
  86         priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
  87                                GFP_KERNEL);
  88         if (!priv->qdiscs)
  89                 return -ENOMEM;
  90
  91         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
  92                 dev_queue = netdev_get_tx_queue(dev, ntx);
  93                 qdisc = qdisc_create_dflt(dev_queue, get_default_qdisc_ops(dev, ntx),
  94                                           TC_H_MAKE(TC_H_MAJ(sch->handle),
  95                                                     TC_H_MIN(ntx + 1)),
  96                                           extack);
  97                 if (!qdisc)
  98                         return -ENOMEM;
  99                 priv->qdiscs[ntx] = qdisc;
 100                 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
 101         }
 102
 103         sch->flags |= TCQ_F_MQROOT;
 104
 105         mq_offload(sch, TC_MQ_CREATE);
 106         return 0;
 107 }
 108
 109 static void mq_attach(struct Qdisc *sch)
 110 {
 111         struct net_device *dev = qdisc_dev(sch);
 112         struct mq_sched *priv = qdisc_priv(sch);
 113         struct Qdisc *qdisc, *old;
 114         unsigned int ntx;
 115
 116         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
 117                 qdisc = priv->qdiscs[ntx];
 118                 old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
 119                 if (old)
 120                         qdisc_put(old);
 121 #ifdef CONFIG_NET_SCHED
 122                 if (ntx < dev->real_num_tx_queues)
 123                         qdisc_hash_add(qdisc, false);
 124 #endif
 125
 126         }
 127         kfree(priv->qdiscs);
 128         priv->qdiscs = NULL;
 129 }
 130
 131 static int mq_dump(struct Qdisc *sch, struct sk_buff *skb)
 132 {
 133         struct net_device *dev = qdisc_dev(sch);
 134         struct Qdisc *qdisc;
 135         unsigned int ntx;
 136         __u32 qlen = 0;
 137
 138         sch->q.qlen = 0;
 139         memset(&sch->bstats, 0, sizeof(sch->bstats));
 140         memset(&sch->qstats, 0, sizeof(sch->qstats));
 141
 142         /* MQ supports lockless qdiscs. However, statistics accounting needs
 143          * to account for all, none, or a mix of locked and unlocked child
 144          * qdiscs. Percpu stats are added to counters in-band and locking
 145          * qdisc totals are added at end.
 146          */
 147         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
 148                 qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
 149                 spin_lock_bh(qdisc_lock(qdisc));
 150
 151                 if (qdisc_is_percpu_stats(qdisc)) {
 152                         qlen = qdisc_qlen_sum(qdisc);
 153                         __gnet_stats_copy_basic(NULL, &sch->bstats,
 154                                                 qdisc->cpu_bstats,
 155                                                 &qdisc->bstats);
 156                         __gnet_stats_copy_queue(&sch->qstats,
 157                                                 qdisc->cpu_qstats,
 158                                                 &qdisc->qstats, qlen);
 159                 } else {
 160                         sch->q.qlen             += qdisc->q.qlen;
 161                         sch->bstats.bytes       += qdisc->bstats.bytes;
 162                         sch->bstats.packets     += qdisc->bstats.packets;
 163                         sch->qstats.qlen        += qdisc->qstats.qlen;
 164                         sch->qstats.backlog     += qdisc->qstats.backlog;
 165                         sch->qstats.drops       += qdisc->qstats.drops;
 166                         sch->qstats.requeues    += qdisc->qstats.requeues;
 167                         sch->qstats.overlimits  += qdisc->qstats.overlimits;
 168                 }
 169
 170                 spin_unlock_bh(qdisc_lock(qdisc));
 171         }
 172
 173         return mq_offload_stats(sch);
 174 }
 175
 176 static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl)
 177 {
 178         struct net_device *dev = qdisc_dev(sch);
 179         unsigned long ntx = cl - 1;
 180
 181         if (ntx >= dev->num_tx_queues)
 182                 return NULL;
 183         return netdev_get_tx_queue(dev, ntx);
 184 }
 185
 186 static struct netdev_queue *mq_select_queue(struct Qdisc *sch,
 187                                             struct tcmsg *tcm)
 188 {
 189         return mq_queue_get(sch, TC_H_MIN(tcm->tcm_parent));
 190 }
 191
 192 static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
 193                     struct Qdisc **old, struct netlink_ext_ack *extack)
 194 {
 195         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 196         struct tc_mq_qopt_offload graft_offload;
 197         struct net_device *dev = qdisc_dev(sch);
 198
 199         if (dev->flags & IFF_UP)
 200                 dev_deactivate(dev);
 201
 202         *old = dev_graft_qdisc(dev_queue, new);
 203         if (new)
 204                 new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
 205         if (dev->flags & IFF_UP)
 206                 dev_activate(dev);
 207
 208         graft_offload.handle = sch->handle;
 209         graft_offload.graft_params.queue = cl - 1;
 210         graft_offload.graft_params.child_handle = new ? new->handle : 0;
 211         graft_offload.command = TC_MQ_GRAFT;
 212
 213         qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, *old,
 214                                    TC_SETUP_QDISC_MQ, &graft_offload, extack);
 215         return 0;
 216 }
 217
 218 static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl)
 219 {
 220         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 221
 222         return dev_queue->qdisc_sleeping;
 223 }
 224
 225 static unsigned long mq_find(struct Qdisc *sch, u32 classid)
 226 {
 227         unsigned int ntx = TC_H_MIN(classid);
 228
 229         if (!mq_queue_get(sch, ntx))
 230                 return 0;
 231         return ntx;
 232 }
 233
 234 static int mq_dump_class(struct Qdisc *sch, unsigned long cl,
 235                          struct sk_buff *skb, struct tcmsg *tcm)
 236 {
 237         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 238
 239         tcm->tcm_parent = TC_H_ROOT;
 240         tcm->tcm_handle |= TC_H_MIN(cl);
 241         tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
 242         return 0;
 243 }
 244
 245 static int mq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 246                                struct gnet_dump *d)
 247 {
 248         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 249
 250         sch = dev_queue->qdisc_sleeping;
 251         if (gnet_stats_copy_basic(&sch->running, d, NULL, &sch->bstats) < 0 ||
 252             qdisc_qstats_copy(d, sch) < 0)
 253                 return -1;
 254         return 0;
 255 }
 256
 257 static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 258 {
 259         struct net_device *dev = qdisc_dev(sch);
 260         unsigned int ntx;
 261
 262         if (arg->stop)
 263                 return;
 264
 265         arg->count = arg->skip;
 266         for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) {
 267                 if (arg->fn(sch, ntx + 1, arg) < 0) {
 268                         arg->stop = 1;
 269                         break;
 270                 }
 271                 arg->count++;
 272         }
 273 }
 274
 275 static const struct Qdisc_class_ops mq_class_ops = {
 276         .select_queue   = mq_select_queue,
 277         .graft          = mq_graft,
 278         .leaf           = mq_leaf,
 279         .find           = mq_find,
 280         .walk           = mq_walk,
 281         .dump           = mq_dump_class,
 282         .dump_stats     = mq_dump_class_stats,
 283 };
 284
 285 struct Qdisc_ops mq_qdisc_ops __read_mostly = {
 286         .cl_ops         = &mq_class_ops,
 287         .id             = "mq",
 288         .priv_size      = sizeof(struct mq_sched),
 289         .init           = mq_init,
 290         .destroy        = mq_destroy,
 291         .attach         = mq_attach,
 292         .dump           = mq_dump,
 293         .owner          = THIS_MODULE,
 294 };