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 == NULL)
  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, default_qdisc_ops,
  61                                           TC_H_MAKE(TC_H_MAJ(sch->handle),
  62                                                     TC_H_MIN(ntx + 1)));
  63                 if (qdisc == NULL)
  64                         goto err;
  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 err:
  73         mq_destroy(sch);
  74         return -ENOMEM;
  75 }
  76
  77 static void mq_attach(struct Qdisc *sch)
  78 {
  79         struct net_device *dev = qdisc_dev(sch);
  80         struct mq_sched *priv = qdisc_priv(sch);
  81         struct Qdisc *qdisc, *old;
  82         unsigned int ntx;
  83
  84         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
  85                 qdisc = priv->qdiscs[ntx];
  86                 old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
  87                 if (old)
  88                         qdisc_destroy(old);
  89 #ifdef CONFIG_NET_SCHED
  90                 if (ntx < dev->real_num_tx_queues)
  91                         qdisc_list_add(qdisc);
  92 #endif
  93
  94         }
  95         kfree(priv->qdiscs);
  96         priv->qdiscs = NULL;
  97 }
  98
  99 static int mq_dump(struct Qdisc *sch, struct sk_buff *skb)
 100 {
 101         struct net_device *dev = qdisc_dev(sch);
 102         struct Qdisc *qdisc;
 103         unsigned int ntx;
 104
 105         sch->q.qlen = 0;
 106         memset(&sch->bstats, 0, sizeof(sch->bstats));
 107         memset(&sch->qstats, 0, sizeof(sch->qstats));
 108
 109         for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
 110                 qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
 111                 spin_lock_bh(qdisc_lock(qdisc));
 112                 sch->q.qlen             += qdisc->q.qlen;
 113                 sch->bstats.bytes       += qdisc->bstats.bytes;
 114                 sch->bstats.packets     += qdisc->bstats.packets;
 115                 sch->qstats.backlog     += qdisc->qstats.backlog;
 116                 sch->qstats.drops       += qdisc->qstats.drops;
 117                 sch->qstats.requeues    += qdisc->qstats.requeues;
 118                 sch->qstats.overlimits  += qdisc->qstats.overlimits;
 119                 spin_unlock_bh(qdisc_lock(qdisc));
 120         }
 121         return 0;
 122 }
 123
 124 static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl)
 125 {
 126         struct net_device *dev = qdisc_dev(sch);
 127         unsigned long ntx = cl - 1;
 128
 129         if (ntx >= dev->num_tx_queues)
 130                 return NULL;
 131         return netdev_get_tx_queue(dev, ntx);
 132 }
 133
 134 static struct netdev_queue *mq_select_queue(struct Qdisc *sch,
 135                                             struct tcmsg *tcm)
 136 {
 137         unsigned int ntx = TC_H_MIN(tcm->tcm_parent);
 138         struct netdev_queue *dev_queue = mq_queue_get(sch, ntx);
 139
 140         if (!dev_queue) {
 141                 struct net_device *dev = qdisc_dev(sch);
 142
 143                 return netdev_get_tx_queue(dev, 0);
 144         }
 145         return dev_queue;
 146 }
 147
 148 static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
 149                     struct Qdisc **old)
 150 {
 151         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 152         struct net_device *dev = qdisc_dev(sch);
 153
 154         if (dev->flags & IFF_UP)
 155                 dev_deactivate(dev);
 156
 157         *old = dev_graft_qdisc(dev_queue, new);
 158         if (new)
 159                 new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
 160         if (dev->flags & IFF_UP)
 161                 dev_activate(dev);
 162         return 0;
 163 }
 164
 165 static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl)
 166 {
 167         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 168
 169         return dev_queue->qdisc_sleeping;
 170 }
 171
 172 static unsigned long mq_get(struct Qdisc *sch, u32 classid)
 173 {
 174         unsigned int ntx = TC_H_MIN(classid);
 175
 176         if (!mq_queue_get(sch, ntx))
 177                 return 0;
 178         return ntx;
 179 }
 180
 181 static void mq_put(struct Qdisc *sch, unsigned long cl)
 182 {
 183 }
 184
 185 static int mq_dump_class(struct Qdisc *sch, unsigned long cl,
 186                          struct sk_buff *skb, struct tcmsg *tcm)
 187 {
 188         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 189
 190         tcm->tcm_parent = TC_H_ROOT;
 191         tcm->tcm_handle |= TC_H_MIN(cl);
 192         tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
 193         return 0;
 194 }
 195
 196 static int mq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 197                                struct gnet_dump *d)
 198 {
 199         struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 200
 201         sch = dev_queue->qdisc_sleeping;
 202         if (gnet_stats_copy_basic(d, NULL, &sch->bstats) < 0 ||
 203             gnet_stats_copy_queue(d, NULL, &sch->qstats, sch->q.qlen) < 0)
 204                 return -1;
 205         return 0;
 206 }
 207
 208 static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 209 {
 210         struct net_device *dev = qdisc_dev(sch);
 211         unsigned int ntx;
 212
 213         if (arg->stop)
 214                 return;
 215
 216         arg->count = arg->skip;
 217         for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) {
 218                 if (arg->fn(sch, ntx + 1, arg) < 0) {
 219                         arg->stop = 1;
 220                         break;
 221                 }
 222                 arg->count++;
 223         }
 224 }
 225
 226 static const struct Qdisc_class_ops mq_class_ops = {
 227         .select_queue   = mq_select_queue,
 228         .graft          = mq_graft,
 229         .leaf           = mq_leaf,
 230         .get            = mq_get,
 231         .put            = mq_put,
 232         .walk           = mq_walk,
 233         .dump           = mq_dump_class,
 234         .dump_stats     = mq_dump_class_stats,
 235 };
 236
 237 struct Qdisc_ops mq_qdisc_ops __read_mostly = {
 238         .cl_ops         = &mq_class_ops,
 239         .id             = "mq",
 240         .priv_size      = sizeof(struct mq_sched),
 241         .init           = mq_init,
 242         .destroy        = mq_destroy,
 243         .attach         = mq_attach,
 244         .dump           = mq_dump,
 245         .owner          = THIS_MODULE,
 246 };