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