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/string.h> 15 #include <linux/errno.h> 16 #include <linux/skbuff.h> 17 #include <net/netlink.h> 18 #include <net/pkt_sched.h> 19 20 struct mq_sched { 21 struct Qdisc **qdiscs; 22 }; 23 24 static void mq_destroy(struct Qdisc *sch) 25 { 26 struct net_device *dev = qdisc_dev(sch); 27 struct mq_sched *priv = qdisc_priv(sch); 28 unsigned int ntx; 29 30 if (!priv->qdiscs) 31 return; 32 for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++) 33 qdisc_destroy(priv->qdiscs[ntx]); 34 kfree(priv->qdiscs); 35 } 36 37 static int mq_init(struct Qdisc *sch, struct nlattr *opt) 38 { 39 struct net_device *dev = qdisc_dev(sch); 40 struct mq_sched *priv = qdisc_priv(sch); 41 struct netdev_queue *dev_queue; 42 struct Qdisc *qdisc; 43 unsigned int ntx; 44 45 if (sch->parent != TC_H_ROOT) 46 return -EOPNOTSUPP; 47 48 if (!netif_is_multiqueue(dev)) 49 return -EOPNOTSUPP; 50 51 /* pre-allocate qdiscs, attachment can't fail */ 52 priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]), 53 GFP_KERNEL); 54 if (priv->qdiscs == NULL) 55 return -ENOMEM; 56 57 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { 58 dev_queue = netdev_get_tx_queue(dev, ntx); 59 qdisc = qdisc_create_dflt(dev_queue, &pfifo_fast_ops, 60 TC_H_MAKE(TC_H_MAJ(sch->handle), 61 TC_H_MIN(ntx + 1))); 62 if (qdisc == NULL) 63 goto err; 64 qdisc->flags |= TCQ_F_CAN_BYPASS; 65 priv->qdiscs[ntx] = qdisc; 66 } 67 68 sch->flags |= TCQ_F_MQROOT; 69 return 0; 70 71 err: 72 mq_destroy(sch); 73 return -ENOMEM; 74 } 75 76 static void mq_attach(struct Qdisc *sch) 77 { 78 struct net_device *dev = qdisc_dev(sch); 79 struct mq_sched *priv = qdisc_priv(sch); 80 struct Qdisc *qdisc; 81 unsigned int ntx; 82 83 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { 84 qdisc = priv->qdiscs[ntx]; 85 qdisc = dev_graft_qdisc(qdisc->dev_queue, qdisc); 86 if (qdisc) 87 qdisc_destroy(qdisc); 88 } 89 kfree(priv->qdiscs); 90 priv->qdiscs = NULL; 91 } 92 93 static int mq_dump(struct Qdisc *sch, struct sk_buff *skb) 94 { 95 struct net_device *dev = qdisc_dev(sch); 96 struct Qdisc *qdisc; 97 unsigned int ntx; 98 99 sch->q.qlen = 0; 100 memset(&sch->bstats, 0, sizeof(sch->bstats)); 101 memset(&sch->qstats, 0, sizeof(sch->qstats)); 102 103 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { 104 qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping; 105 spin_lock_bh(qdisc_lock(qdisc)); 106 sch->q.qlen += qdisc->q.qlen; 107 sch->bstats.bytes += qdisc->bstats.bytes; 108 sch->bstats.packets += qdisc->bstats.packets; 109 sch->qstats.qlen += qdisc->qstats.qlen; 110 sch->qstats.backlog += qdisc->qstats.backlog; 111 sch->qstats.drops += qdisc->qstats.drops; 112 sch->qstats.requeues += qdisc->qstats.requeues; 113 sch->qstats.overlimits += qdisc->qstats.overlimits; 114 spin_unlock_bh(qdisc_lock(qdisc)); 115 } 116 return 0; 117 } 118 119 static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl) 120 { 121 struct net_device *dev = qdisc_dev(sch); 122 unsigned long ntx = cl - 1; 123 124 if (ntx >= dev->num_tx_queues) 125 return NULL; 126 return netdev_get_tx_queue(dev, ntx); 127 } 128 129 static struct netdev_queue *mq_select_queue(struct Qdisc *sch, 130 struct tcmsg *tcm) 131 { 132 unsigned int ntx = TC_H_MIN(tcm->tcm_parent); 133 struct netdev_queue *dev_queue = mq_queue_get(sch, ntx); 134 135 if (!dev_queue) { 136 struct net_device *dev = qdisc_dev(sch); 137 138 return netdev_get_tx_queue(dev, 0); 139 } 140 return dev_queue; 141 } 142 143 static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new, 144 struct Qdisc **old) 145 { 146 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 147 struct net_device *dev = qdisc_dev(sch); 148 149 if (dev->flags & IFF_UP) 150 dev_deactivate(dev); 151 152 *old = dev_graft_qdisc(dev_queue, new); 153 154 if (dev->flags & IFF_UP) 155 dev_activate(dev); 156 return 0; 157 } 158 159 static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl) 160 { 161 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 162 163 return dev_queue->qdisc_sleeping; 164 } 165 166 static unsigned long mq_get(struct Qdisc *sch, u32 classid) 167 { 168 unsigned int ntx = TC_H_MIN(classid); 169 170 if (!mq_queue_get(sch, ntx)) 171 return 0; 172 return ntx; 173 } 174 175 static void mq_put(struct Qdisc *sch, unsigned long cl) 176 { 177 } 178 179 static int mq_dump_class(struct Qdisc *sch, unsigned long cl, 180 struct sk_buff *skb, struct tcmsg *tcm) 181 { 182 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 183 184 tcm->tcm_parent = TC_H_ROOT; 185 tcm->tcm_handle |= TC_H_MIN(cl); 186 tcm->tcm_info = dev_queue->qdisc_sleeping->handle; 187 return 0; 188 } 189 190 static int mq_dump_class_stats(struct Qdisc *sch, unsigned long cl, 191 struct gnet_dump *d) 192 { 193 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 194 195 sch = dev_queue->qdisc_sleeping; 196 sch->qstats.qlen = sch->q.qlen; 197 if (gnet_stats_copy_basic(d, &sch->bstats) < 0 || 198 gnet_stats_copy_queue(d, &sch->qstats) < 0) 199 return -1; 200 return 0; 201 } 202 203 static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg) 204 { 205 struct net_device *dev = qdisc_dev(sch); 206 unsigned int ntx; 207 208 if (arg->stop) 209 return; 210 211 arg->count = arg->skip; 212 for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) { 213 if (arg->fn(sch, ntx + 1, arg) < 0) { 214 arg->stop = 1; 215 break; 216 } 217 arg->count++; 218 } 219 } 220 221 static const struct Qdisc_class_ops mq_class_ops = { 222 .select_queue = mq_select_queue, 223 .graft = mq_graft, 224 .leaf = mq_leaf, 225 .get = mq_get, 226 .put = mq_put, 227 .walk = mq_walk, 228 .dump = mq_dump_class, 229 .dump_stats = mq_dump_class_stats, 230 }; 231 232 struct Qdisc_ops mq_qdisc_ops __read_mostly = { 233 .cl_ops = &mq_class_ops, 234 .id = "mq", 235 .priv_size = sizeof(struct mq_sched), 236 .init = mq_init, 237 .destroy = mq_destroy, 238 .attach = mq_attach, 239 .dump = mq_dump, 240 .owner = THIS_MODULE, 241 }; 242