1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * net/sched/sch_mq.c Classful multiqueue dummy scheduler 4 * 5 * Copyright (c) 2009 Patrick McHardy <kaber@trash.net> 6 */ 7 8 #include <linux/types.h> 9 #include <linux/slab.h> 10 #include <linux/kernel.h> 11 #include <linux/export.h> 12 #include <linux/string.h> 13 #include <linux/errno.h> 14 #include <linux/skbuff.h> 15 #include <net/netlink.h> 16 #include <net/pkt_cls.h> 17 #include <net/pkt_sched.h> 18 #include <net/sch_generic.h> 19 20 struct mq_sched { 21 struct Qdisc **qdiscs; 22 }; 23 24 static int mq_offload(struct Qdisc *sch, enum tc_mq_command cmd) 25 { 26 struct net_device *dev = qdisc_dev(sch); 27 struct tc_mq_qopt_offload opt = { 28 .command = cmd, 29 .handle = sch->handle, 30 }; 31 32 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) 33 return -EOPNOTSUPP; 34 35 return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_MQ, &opt); 36 } 37 38 static int mq_offload_stats(struct Qdisc *sch) 39 { 40 struct tc_mq_qopt_offload opt = { 41 .command = TC_MQ_STATS, 42 .handle = sch->handle, 43 .stats = { 44 .bstats = &sch->bstats, 45 .qstats = &sch->qstats, 46 }, 47 }; 48 49 return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_MQ, &opt); 50 } 51 52 static void mq_destroy(struct Qdisc *sch) 53 { 54 struct net_device *dev = qdisc_dev(sch); 55 struct mq_sched *priv = qdisc_priv(sch); 56 unsigned int ntx; 57 58 mq_offload(sch, TC_MQ_DESTROY); 59 60 if (!priv->qdiscs) 61 return; 62 for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++) 63 qdisc_put(priv->qdiscs[ntx]); 64 kfree(priv->qdiscs); 65 } 66 67 static int mq_init(struct Qdisc *sch, struct nlattr *opt, 68 struct netlink_ext_ack *extack) 69 { 70 struct net_device *dev = qdisc_dev(sch); 71 struct mq_sched *priv = qdisc_priv(sch); 72 struct netdev_queue *dev_queue; 73 struct Qdisc *qdisc; 74 unsigned int ntx; 75 76 if (sch->parent != TC_H_ROOT) 77 return -EOPNOTSUPP; 78 79 if (!netif_is_multiqueue(dev)) 80 return -EOPNOTSUPP; 81 82 /* pre-allocate qdiscs, attachment can't fail */ 83 priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]), 84 GFP_KERNEL); 85 if (!priv->qdiscs) 86 return -ENOMEM; 87 88 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { 89 dev_queue = netdev_get_tx_queue(dev, ntx); 90 qdisc = qdisc_create_dflt(dev_queue, get_default_qdisc_ops(dev, ntx), 91 TC_H_MAKE(TC_H_MAJ(sch->handle), 92 TC_H_MIN(ntx + 1)), 93 extack); 94 if (!qdisc) 95 return -ENOMEM; 96 priv->qdiscs[ntx] = qdisc; 97 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT; 98 } 99 100 sch->flags |= TCQ_F_MQROOT; 101 102 mq_offload(sch, TC_MQ_CREATE); 103 return 0; 104 } 105 106 static void mq_attach(struct Qdisc *sch) 107 { 108 struct net_device *dev = qdisc_dev(sch); 109 struct mq_sched *priv = qdisc_priv(sch); 110 struct Qdisc *qdisc, *old; 111 unsigned int ntx; 112 113 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { 114 qdisc = priv->qdiscs[ntx]; 115 old = dev_graft_qdisc(qdisc->dev_queue, qdisc); 116 if (old) 117 qdisc_put(old); 118 #ifdef CONFIG_NET_SCHED 119 if (ntx < dev->real_num_tx_queues) 120 qdisc_hash_add(qdisc, false); 121 #endif 122 123 } 124 kfree(priv->qdiscs); 125 priv->qdiscs = NULL; 126 } 127 128 static int mq_dump(struct Qdisc *sch, struct sk_buff *skb) 129 { 130 struct net_device *dev = qdisc_dev(sch); 131 struct Qdisc *qdisc; 132 unsigned int ntx; 133 __u32 qlen = 0; 134 135 sch->q.qlen = 0; 136 memset(&sch->bstats, 0, sizeof(sch->bstats)); 137 memset(&sch->qstats, 0, sizeof(sch->qstats)); 138 139 /* MQ supports lockless qdiscs. However, statistics accounting needs 140 * to account for all, none, or a mix of locked and unlocked child 141 * qdiscs. Percpu stats are added to counters in-band and locking 142 * qdisc totals are added at end. 143 */ 144 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { 145 qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping; 146 spin_lock_bh(qdisc_lock(qdisc)); 147 148 if (qdisc_is_percpu_stats(qdisc)) { 149 qlen = qdisc_qlen_sum(qdisc); 150 __gnet_stats_copy_basic(NULL, &sch->bstats, 151 qdisc->cpu_bstats, 152 &qdisc->bstats); 153 __gnet_stats_copy_queue(&sch->qstats, 154 qdisc->cpu_qstats, 155 &qdisc->qstats, qlen); 156 sch->q.qlen += qlen; 157 } else { 158 sch->q.qlen += qdisc->q.qlen; 159 sch->bstats.bytes += qdisc->bstats.bytes; 160 sch->bstats.packets += qdisc->bstats.packets; 161 sch->qstats.qlen += qdisc->qstats.qlen; 162 sch->qstats.backlog += qdisc->qstats.backlog; 163 sch->qstats.drops += qdisc->qstats.drops; 164 sch->qstats.requeues += qdisc->qstats.requeues; 165 sch->qstats.overlimits += qdisc->qstats.overlimits; 166 } 167 168 spin_unlock_bh(qdisc_lock(qdisc)); 169 } 170 171 return mq_offload_stats(sch); 172 } 173 174 static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl) 175 { 176 struct net_device *dev = qdisc_dev(sch); 177 unsigned long ntx = cl - 1; 178 179 if (ntx >= dev->num_tx_queues) 180 return NULL; 181 return netdev_get_tx_queue(dev, ntx); 182 } 183 184 static struct netdev_queue *mq_select_queue(struct Qdisc *sch, 185 struct tcmsg *tcm) 186 { 187 return mq_queue_get(sch, TC_H_MIN(tcm->tcm_parent)); 188 } 189 190 static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new, 191 struct Qdisc **old, struct netlink_ext_ack *extack) 192 { 193 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 194 struct tc_mq_qopt_offload graft_offload; 195 struct net_device *dev = qdisc_dev(sch); 196 197 if (dev->flags & IFF_UP) 198 dev_deactivate(dev); 199 200 *old = dev_graft_qdisc(dev_queue, new); 201 if (new) 202 new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT; 203 if (dev->flags & IFF_UP) 204 dev_activate(dev); 205 206 graft_offload.handle = sch->handle; 207 graft_offload.graft_params.queue = cl - 1; 208 graft_offload.graft_params.child_handle = new ? new->handle : 0; 209 graft_offload.command = TC_MQ_GRAFT; 210 211 qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, *old, 212 TC_SETUP_QDISC_MQ, &graft_offload, extack); 213 return 0; 214 } 215 216 static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl) 217 { 218 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 219 220 return dev_queue->qdisc_sleeping; 221 } 222 223 static unsigned long mq_find(struct Qdisc *sch, u32 classid) 224 { 225 unsigned int ntx = TC_H_MIN(classid); 226 227 if (!mq_queue_get(sch, ntx)) 228 return 0; 229 return ntx; 230 } 231 232 static int mq_dump_class(struct Qdisc *sch, unsigned long cl, 233 struct sk_buff *skb, struct tcmsg *tcm) 234 { 235 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 236 237 tcm->tcm_parent = TC_H_ROOT; 238 tcm->tcm_handle |= TC_H_MIN(cl); 239 tcm->tcm_info = dev_queue->qdisc_sleeping->handle; 240 return 0; 241 } 242 243 static int mq_dump_class_stats(struct Qdisc *sch, unsigned long cl, 244 struct gnet_dump *d) 245 { 246 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 247 248 sch = dev_queue->qdisc_sleeping; 249 if (gnet_stats_copy_basic(&sch->running, d, sch->cpu_bstats, 250 &sch->bstats) < 0 || 251 qdisc_qstats_copy(d, sch) < 0) 252 return -1; 253 return 0; 254 } 255 256 static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg) 257 { 258 struct net_device *dev = qdisc_dev(sch); 259 unsigned int ntx; 260 261 if (arg->stop) 262 return; 263 264 arg->count = arg->skip; 265 for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) { 266 if (arg->fn(sch, ntx + 1, arg) < 0) { 267 arg->stop = 1; 268 break; 269 } 270 arg->count++; 271 } 272 } 273 274 static const struct Qdisc_class_ops mq_class_ops = { 275 .select_queue = mq_select_queue, 276 .graft = mq_graft, 277 .leaf = mq_leaf, 278 .find = mq_find, 279 .walk = mq_walk, 280 .dump = mq_dump_class, 281 .dump_stats = mq_dump_class_stats, 282 }; 283 284 struct Qdisc_ops mq_qdisc_ops __read_mostly = { 285 .cl_ops = &mq_class_ops, 286 .id = "mq", 287 .priv_size = sizeof(struct mq_sched), 288 .init = mq_init, 289 .destroy = mq_destroy, 290 .attach = mq_attach, 291 .change_real_num_tx = mq_change_real_num_tx, 292 .dump = mq_dump, 293 .owner = THIS_MODULE, 294 }; 295