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