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_sched.h>
  20
  21 struct mq_sched {
  22         struct Qdisc            **qdiscs;
  23 };
  24
  25 static void mq_destroy(struct Qdisc *sch)
  26 {
  27         struct net_device *dev = qdisc_dev(sch);
  28         struct mq_sched *priv = qdisc_priv(sch);
  29         unsigned int ntx;
  30
  31         if (!priv->qdiscs)
  32                 return;
  33         for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++)
  34                 qdisc_destroy(priv->qdiscs[ntx]);
  35         kfree(priv->qdiscs);
  36 }
  37
  38 static int mq_init(struct Qdisc *sch, struct nlattr *opt)
  39 {
  40         struct net_device *dev = qdisc_dev(sch);
  41         struct mq_sched *priv = qdisc_priv(sch);
  42         struct netdev_queue *dev_queue;
  43         struct Qdisc *qdisc;
  44         unsigned int ntx;
  45
  46         if (sch->parent != TC_H_ROOT)
  47                 return -EOPNOTSUPP;
  48
  49         if (!netif_is_multiqueue(dev))
  50                 return -EOPNOTSUPP;
  51
  52         /* pre-allocate qdiscs, attachment can't fail */
  53         priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
  54                                GFP_KERNEL);
  55         if (!priv->qdiscs)
  56                 return -ENOMEM;
  57
  58         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
  59                 dev_queue = netdev_get_tx_queue(dev, ntx);
  60                 qdisc = qdisc_create_dflt(dev_queue, get_default_qdisc_ops(dev, ntx),
  61                                           TC_H_MAKE(TC_H_MAJ(sch->handle),
  62                                                     TC_H_MIN(ntx + 1)));
  63                 if (!qdisc)
  64                         return -ENOMEM;
  65                 priv->qdiscs[ntx] = qdisc;
  66                 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
  67         }
  68
  69         sch->flags |= TCQ_F_MQROOT;
  70         return 0;
  71 }
  72
  73 static void mq_attach(struct Qdisc *sch)
  74 {
  75         struct net_device *dev = qdisc_dev(sch);
  76         struct mq_sched *priv = qdisc_priv(sch);
  77         struct Qdisc *qdisc, *old;
  78         unsigned int ntx;
  79
  80         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
  81                 qdisc = priv->qdiscs[ntx];
  82                 old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
  83                 if (old)
  84                         qdisc_destroy(old);
  85 #ifdef CONFIG_NET_SCHED
  86                 if (ntx < dev->real_num_tx_queues)
  87                         qdisc_hash_add(qdisc, false);
  88 #endif
  89
  90         }
  91         kfree(priv->qdiscs);
  92         priv->qdiscs = NULL;
  93 }
  94
  95 static int mq_dump(struct Qdisc *sch, struct sk_buff *skb)
  96 {
  97         struct net_device *dev = qdisc_dev(sch);
  98         struct Qdisc *qdisc;
  99         unsigned int ntx;
 100
 101         sch->q.qlen = 0;
 102         memset(&sch->bstats, 0, sizeof(sch->bstats));
 103         memset(&sch->qstats, 0, sizeof(sch->qstats));
 104
 105         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
 106                 qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
 107                 spin_lock_bh(qdisc_lock(qdisc));
 108                 sch->q.qlen             += qdisc->q.qlen;
 109                 sch->bstats.bytes       += qdisc->bstats.bytes;
 110                 sch->bstats.packets     += qdisc->bstats.packets;
 111                 sch->qstats.backlog     += qdisc->qstats.backlog;
 112                 sch->qstats.drops       += qdisc->qstats.drops;
 113                 sch->qstats.requeues    += qdisc->qstats.requeues;
 114                 sch->qstats.overlimits  += qdisc->qstats.overlimits;
 115                 spin_unlock_bh(qdisc_lock(qdisc));
 116         }
 117         return 0;
 118 }
 119
 120 static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl)
 121 {
 122         struct net_device *dev = qdisc_dev(sch);
 123         unsigned long ntx = cl - 1;
 124
 125         if (ntx >= dev->num_tx_queues)
 126                 return NULL;
 127         return netdev_get_tx_queue(dev, ntx);
 128 }
 129
 130 static struct netdev_queue *mq_select_queue(struct Qdisc *sch,
 131                                             struct tcmsg *tcm)
 132 {
 133         return mq_queue_get(sch, TC_H_MIN(tcm->tcm_parent));
 134 }
 135
 136 static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
 137                     struct Qdisc **old)
 138 {
 139         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 140         struct net_device *dev = qdisc_dev(sch);
 141
 142         if (dev->flags & IFF_UP)
 143                 dev_deactivate(dev);
 144
 145         *old = dev_graft_qdisc(dev_queue, new);
 146         if (new)
 147                 new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
 148         if (dev->flags & IFF_UP)
 149                 dev_activate(dev);
 150         return 0;
 151 }
 152
 153 static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl)
 154 {
 155         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 156
 157         return dev_queue->qdisc_sleeping;
 158 }
 159
 160 static unsigned long mq_find(struct Qdisc *sch, u32 classid)
 161 {
 162         unsigned int ntx = TC_H_MIN(classid);
 163
 164         if (!mq_queue_get(sch, ntx))
 165                 return 0;
 166         return ntx;
 167 }
 168
 169 static int mq_dump_class(struct Qdisc *sch, unsigned long cl,
 170                          struct sk_buff *skb, struct tcmsg *tcm)
 171 {
 172         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 173
 174         tcm->tcm_parent = TC_H_ROOT;
 175         tcm->tcm_handle |= TC_H_MIN(cl);
 176         tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
 177         return 0;
 178 }
 179
 180 static int mq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 181                                struct gnet_dump *d)
 182 {
 183         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 184
 185         sch = dev_queue->qdisc_sleeping;
 186         if (gnet_stats_copy_basic(&sch->running, d, NULL, &sch->bstats) < 0 ||
 187             gnet_stats_copy_queue(d, NULL, &sch->qstats, sch->q.qlen) < 0)
 188                 return -1;
 189         return 0;
 190 }
 191
 192 static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 193 {
 194         struct net_device *dev = qdisc_dev(sch);
 195         unsigned int ntx;
 196
 197         if (arg->stop)
 198                 return;
 199
 200         arg->count = arg->skip;
 201         for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) {
 202                 if (arg->fn(sch, ntx + 1, arg) < 0) {
 203                         arg->stop = 1;
 204                         break;
 205                 }
 206                 arg->count++;
 207         }
 208 }
 209
 210 static const struct Qdisc_class_ops mq_class_ops = {
 211         .select_queue   = mq_select_queue,
 212         .graft          = mq_graft,
 213         .leaf           = mq_leaf,
 214         .find           = mq_find,
 215         .walk           = mq_walk,
 216         .dump           = mq_dump_class,
 217         .dump_stats     = mq_dump_class_stats,
 218 };
 219
 220 struct Qdisc_ops mq_qdisc_ops __read_mostly = {
 221         .cl_ops         = &mq_class_ops,
 222         .id             = "mq",
 223         .priv_size      = sizeof(struct mq_sched),
 224         .init           = mq_init,
 225         .destroy        = mq_destroy,
 226         .attach         = mq_attach,
 227         .dump           = mq_dump,
 228         .owner          = THIS_MODULE,
 229 };