net/sched/sch_mqprio.c - third_party/linux - Git at Google

 /*
  * net/sched/sch_mqprio.c
  *
  * Copyright (c) 2010 John Fastabend <john.r.fastabend@intel.com>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * version 2 as published by the Free Software Foundation.
  */

 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/skbuff.h>
 #include <linux/module.h>
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
 #include <net/sch_generic.h>
 #include <net/pkt_cls.h>

 struct mqprio_sched {
 	struct Qdisc		**qdiscs;
 	u16 mode;
 	u16 shaper;
 	int hw_offload;
 	u32 flags;
 	u64 min_rate[TC_QOPT_MAX_QUEUE];
 	u64 max_rate[TC_QOPT_MAX_QUEUE];
 };

 static void mqprio_destroy(struct Qdisc *sch)
 {
 	struct net_device *dev = qdisc_dev(sch);
 	struct mqprio_sched *priv = qdisc_priv(sch);
 	unsigned int ntx;

 	if (priv->qdiscs) {
 		for (ntx = 0;
 		     ntx < dev->num_tx_queues && priv->qdiscs[ntx];
 		     ntx++)
 			qdisc_destroy(priv->qdiscs[ntx]);
 		kfree(priv->qdiscs);
 	}

 	if (priv->hw_offload && dev->netdev_ops->ndo_setup_tc) {
 		struct tc_mqprio_qopt_offload mqprio = { { 0 } };

 		switch (priv->mode) {
 		case TC_MQPRIO_MODE_DCB:
 		case TC_MQPRIO_MODE_CHANNEL:
 			dev->netdev_ops->ndo_setup_tc(dev,
 						      TC_SETUP_QDISC_MQPRIO,
 						      &mqprio);
 			break;
 		default:
 			return;
 		}
 	} else {
 		netdev_set_num_tc(dev, 0);
 	}
 }

 static int mqprio_parse_opt(struct net_device *dev, struct tc_mqprio_qopt *qopt)
 {
 	int i, j;

 	/* Verify num_tc is not out of max range */
 	if (qopt->num_tc > TC_MAX_QUEUE)
 		return -EINVAL;

 	/* Verify priority mapping uses valid tcs */
 	for (i = 0; i < TC_BITMASK + 1; i++) {
 		if (qopt->prio_tc_map[i] >= qopt->num_tc)
 			return -EINVAL;
 	}

 	/* Limit qopt->hw to maximum supported offload value.  Drivers have
 	 * the option of overriding this later if they don't support the a
 	 * given offload type.
 	 */
 	if (qopt->hw > TC_MQPRIO_HW_OFFLOAD_MAX)
 		qopt->hw = TC_MQPRIO_HW_OFFLOAD_MAX;

 	/* If hardware offload is requested we will leave it to the device
 	 * to either populate the queue counts itself or to validate the
 	 * provided queue counts.  If ndo_setup_tc is not present then
 	 * hardware doesn't support offload and we should return an error.
 	 */
 	if (qopt->hw)
 		return dev->netdev_ops->ndo_setup_tc ? 0 : -EINVAL;

 	for (i = 0; i < qopt->num_tc; i++) {
 		unsigned int last = qopt->offset[i] + qopt->count[i];

 		/* Verify the queue count is in tx range being equal to the
 		 * real_num_tx_queues indicates the last queue is in use.
 		 */
 		if (qopt->offset[i] >= dev->real_num_tx_queues ||
 		    !qopt->count[i] ||
 		    last > dev->real_num_tx_queues)
 			return -EINVAL;

 		/* Verify that the offset and counts do not overlap */
 		for (j = i + 1; j < qopt->num_tc; j++) {
 			if (last > qopt->offset[j])
 				return -EINVAL;
 		}
 	}

 	return 0;
 }

 static const struct nla_policy mqprio_policy[TCA_MQPRIO_MAX + 1] = {
 	[TCA_MQPRIO_MODE]	= { .len = sizeof(u16) },
 	[TCA_MQPRIO_SHAPER]	= { .len = sizeof(u16) },
 	[TCA_MQPRIO_MIN_RATE64]	= { .type = NLA_NESTED },
 	[TCA_MQPRIO_MAX_RATE64]	= { .type = NLA_NESTED },
 };

 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
 		      const struct nla_policy *policy, int len)
 {
 	int nested_len = nla_len(nla) - NLA_ALIGN(len);

 	if (nested_len >= nla_attr_size(0))
 		return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len),
 				 nested_len, policy, NULL);

 	memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
 	return 0;
 }

 static int mqprio_init(struct Qdisc *sch, struct nlattr *opt,
 		       struct netlink_ext_ack *extack)
 {
 	struct net_device *dev = qdisc_dev(sch);
 	struct mqprio_sched *priv = qdisc_priv(sch);
 	struct netdev_queue *dev_queue;
 	struct Qdisc *qdisc;
 	int i, err = -EOPNOTSUPP;
 	struct tc_mqprio_qopt *qopt = NULL;
 	struct nlattr *tb[TCA_MQPRIO_MAX + 1];
 	struct nlattr *attr;
 	int rem;
 	int len;

 	BUILD_BUG_ON(TC_MAX_QUEUE != TC_QOPT_MAX_QUEUE);
 	BUILD_BUG_ON(TC_BITMASK != TC_QOPT_BITMASK);

 	if (sch->parent != TC_H_ROOT)
 		return -EOPNOTSUPP;

 	if (!netif_is_multiqueue(dev))
 		return -EOPNOTSUPP;

 	/* make certain can allocate enough classids to handle queues */
 	if (dev->num_tx_queues >= TC_H_MIN_PRIORITY)
 		return -ENOMEM;

 	if (!opt || nla_len(opt) < sizeof(*qopt))
 		return -EINVAL;

 	qopt = nla_data(opt);
 	if (mqprio_parse_opt(dev, qopt))
 		return -EINVAL;

 	len = nla_len(opt) - NLA_ALIGN(sizeof(*qopt));
 	if (len > 0) {
 		err = parse_attr(tb, TCA_MQPRIO_MAX, opt, mqprio_policy,
 				 sizeof(*qopt));
 		if (err < 0)
 			return err;

 		if (!qopt->hw)
 			return -EINVAL;

 		if (tb[TCA_MQPRIO_MODE]) {
 			priv->flags |= TC_MQPRIO_F_MODE;
 			priv->mode = *(u16 *)nla_data(tb[TCA_MQPRIO_MODE]);
 		}

 		if (tb[TCA_MQPRIO_SHAPER]) {
 			priv->flags |= TC_MQPRIO_F_SHAPER;
 			priv->shaper = *(u16 *)nla_data(tb[TCA_MQPRIO_SHAPER]);
 		}

 		if (tb[TCA_MQPRIO_MIN_RATE64]) {
 			if (priv->shaper != TC_MQPRIO_SHAPER_BW_RATE)
 				return -EINVAL;
 			i = 0;
 			nla_for_each_nested(attr, tb[TCA_MQPRIO_MIN_RATE64],
 					    rem) {
 				if (nla_type(attr) != TCA_MQPRIO_MIN_RATE64)
 					return -EINVAL;
 				if (i >= qopt->num_tc)
 					break;
 				priv->min_rate[i] = *(u64 *)nla_data(attr);
 				i++;
 			}
 			priv->flags |= TC_MQPRIO_F_MIN_RATE;
 		}

 		if (tb[TCA_MQPRIO_MAX_RATE64]) {
 			if (priv->shaper != TC_MQPRIO_SHAPER_BW_RATE)
 				return -EINVAL;
 			i = 0;
 			nla_for_each_nested(attr, tb[TCA_MQPRIO_MAX_RATE64],
 					    rem) {
 				if (nla_type(attr) != TCA_MQPRIO_MAX_RATE64)
 					return -EINVAL;
 				if (i >= qopt->num_tc)
 					break;
 				priv->max_rate[i] = *(u64 *)nla_data(attr);
 				i++;
 			}
 			priv->flags |= TC_MQPRIO_F_MAX_RATE;
 		}
 	}

 	/* pre-allocate qdisc, attachment can't fail */
 	priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
 			       GFP_KERNEL);
 	if (!priv->qdiscs)
 		return -ENOMEM;

 	for (i = 0; i < dev->num_tx_queues; i++) {
 		dev_queue = netdev_get_tx_queue(dev, i);
 		qdisc = qdisc_create_dflt(dev_queue,
 					  get_default_qdisc_ops(dev, i),
 					  TC_H_MAKE(TC_H_MAJ(sch->handle),
 						    TC_H_MIN(i + 1)), extack);
 		if (!qdisc)
 			return -ENOMEM;

 		priv->qdiscs[i] = qdisc;
 		qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
 	}

 	/* If the mqprio options indicate that hardware should own
 	 * the queue mapping then run ndo_setup_tc otherwise use the
 	 * supplied and verified mapping
 	 */
 	if (qopt->hw) {
 		struct tc_mqprio_qopt_offload mqprio = {.qopt = *qopt};

 		switch (priv->mode) {
 		case TC_MQPRIO_MODE_DCB:
 			if (priv->shaper != TC_MQPRIO_SHAPER_DCB)
 				return -EINVAL;
 			break;
 		case TC_MQPRIO_MODE_CHANNEL:
 			mqprio.flags = priv->flags;
 			if (priv->flags & TC_MQPRIO_F_MODE)
 				mqprio.mode = priv->mode;
 			if (priv->flags & TC_MQPRIO_F_SHAPER)
 				mqprio.shaper = priv->shaper;
 			if (priv->flags & TC_MQPRIO_F_MIN_RATE)
 				for (i = 0; i < mqprio.qopt.num_tc; i++)
 					mqprio.min_rate[i] = priv->min_rate[i];
 			if (priv->flags & TC_MQPRIO_F_MAX_RATE)
 				for (i = 0; i < mqprio.qopt.num_tc; i++)
 					mqprio.max_rate[i] = priv->max_rate[i];
 			break;
 		default:
 			return -EINVAL;
 		}
 		err = dev->netdev_ops->ndo_setup_tc(dev,
 						    TC_SETUP_QDISC_MQPRIO,
 						    &mqprio);
 		if (err)
 			return err;

 		priv->hw_offload = mqprio.qopt.hw;
 	} else {
 		netdev_set_num_tc(dev, qopt->num_tc);
 		for (i = 0; i < qopt->num_tc; i++)
 			netdev_set_tc_queue(dev, i,
 					    qopt->count[i], qopt->offset[i]);
 	}

 	/* Always use supplied priority mappings */
 	for (i = 0; i < TC_BITMASK + 1; i++)
 		netdev_set_prio_tc_map(dev, i, qopt->prio_tc_map[i]);

 	sch->flags |= TCQ_F_MQROOT;
 	return 0;
 }

 static void mqprio_attach(struct Qdisc *sch)
 {
 	struct net_device *dev = qdisc_dev(sch);
 	struct mqprio_sched *priv = qdisc_priv(sch);
 	struct Qdisc *qdisc, *old;
 	unsigned int ntx;

 	/* Attach underlying qdisc */
 	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
 		qdisc = priv->qdiscs[ntx];
 		old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
 		if (old)
 			qdisc_destroy(old);
 		if (ntx < dev->real_num_tx_queues)
 			qdisc_hash_add(qdisc, false);
 	}
 	kfree(priv->qdiscs);
 	priv->qdiscs = NULL;
 }

 static struct netdev_queue *mqprio_queue_get(struct Qdisc *sch,
 					     unsigned long cl)
 {
 	struct net_device *dev = qdisc_dev(sch);
 	unsigned long ntx = cl - 1;

 	if (ntx >= dev->num_tx_queues)
 		return NULL;
 	return netdev_get_tx_queue(dev, ntx);
 }

 static int mqprio_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
 			struct Qdisc **old, struct netlink_ext_ack *extack)
 {
 	struct net_device *dev = qdisc_dev(sch);
 	struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);

 	if (!dev_queue)
 		return -EINVAL;

 	if (dev->flags & IFF_UP)
 		dev_deactivate(dev);

 	*old = dev_graft_qdisc(dev_queue, new);

 	if (new)
 		new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;

 	if (dev->flags & IFF_UP)
 		dev_activate(dev);

 	return 0;
 }

 static int dump_rates(struct mqprio_sched *priv,
 		      struct tc_mqprio_qopt *opt, struct sk_buff *skb)
 {
 	struct nlattr *nest;
 	int i;

 	if (priv->flags & TC_MQPRIO_F_MIN_RATE) {
 		nest = nla_nest_start(skb, TCA_MQPRIO_MIN_RATE64);
 		if (!nest)
 			goto nla_put_failure;

 		for (i = 0; i < opt->num_tc; i++) {
 			if (nla_put(skb, TCA_MQPRIO_MIN_RATE64,
 				    sizeof(priv->min_rate[i]),
 				    &priv->min_rate[i]))
 				goto nla_put_failure;
 		}
 		nla_nest_end(skb, nest);
 	}

 	if (priv->flags & TC_MQPRIO_F_MAX_RATE) {
 		nest = nla_nest_start(skb, TCA_MQPRIO_MAX_RATE64);
 		if (!nest)
 			goto nla_put_failure;

 		for (i = 0; i < opt->num_tc; i++) {
 			if (nla_put(skb, TCA_MQPRIO_MAX_RATE64,
 				    sizeof(priv->max_rate[i]),
 				    &priv->max_rate[i]))
 				goto nla_put_failure;
 		}
 		nla_nest_end(skb, nest);
 	}
 	return 0;

 nla_put_failure:
 	nla_nest_cancel(skb, nest);
 	return -1;
 }

 static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct net_device *dev = qdisc_dev(sch);
 	struct mqprio_sched *priv = qdisc_priv(sch);
 	struct nlattr *nla = (struct nlattr *)skb_tail_pointer(skb);
 	struct tc_mqprio_qopt opt = { 0 };
 	struct Qdisc *qdisc;
 	unsigned int ntx, tc;

 	sch->q.qlen = 0;
 	memset(&sch->bstats, 0, sizeof(sch->bstats));
 	memset(&sch->qstats, 0, sizeof(sch->qstats));

 	/* MQ supports lockless qdiscs. However, statistics accounting needs
 	 * to account for all, none, or a mix of locked and unlocked child
 	 * qdiscs. Percpu stats are added to counters in-band and locking
 	 * qdisc totals are added at end.
 	 */
 	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
 		qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
 		spin_lock_bh(qdisc_lock(qdisc));

 		if (qdisc_is_percpu_stats(qdisc)) {
 			__u32 qlen = qdisc_qlen_sum(qdisc);

 			__gnet_stats_copy_basic(NULL, &sch->bstats,
 						qdisc->cpu_bstats,
 						&qdisc->bstats);
 			__gnet_stats_copy_queue(&sch->qstats,
 						qdisc->cpu_qstats,
 						&qdisc->qstats, qlen);
 		} else {
 			sch->q.qlen		+= qdisc->q.qlen;
 			sch->bstats.bytes	+= qdisc->bstats.bytes;
 			sch->bstats.packets	+= qdisc->bstats.packets;
 			sch->qstats.backlog	+= qdisc->qstats.backlog;
 			sch->qstats.drops	+= qdisc->qstats.drops;
 			sch->qstats.requeues	+= qdisc->qstats.requeues;
 			sch->qstats.overlimits	+= qdisc->qstats.overlimits;
 		}

 		spin_unlock_bh(qdisc_lock(qdisc));
 	}

 	opt.num_tc = netdev_get_num_tc(dev);
 	memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map));
 	opt.hw = priv->hw_offload;

 	for (tc = 0; tc < netdev_get_num_tc(dev); tc++) {
 		opt.count[tc] = dev->tc_to_txq[tc].count;
 		opt.offset[tc] = dev->tc_to_txq[tc].offset;
 	}

 	if (nla_put(skb, TCA_OPTIONS, NLA_ALIGN(sizeof(opt)), &opt))
 		goto nla_put_failure;

 	if ((priv->flags & TC_MQPRIO_F_MODE) &&
 	    nla_put_u16(skb, TCA_MQPRIO_MODE, priv->mode))
 		goto nla_put_failure;

 	if ((priv->flags & TC_MQPRIO_F_SHAPER) &&
 	    nla_put_u16(skb, TCA_MQPRIO_SHAPER, priv->shaper))
 		goto nla_put_failure;

 	if ((priv->flags & TC_MQPRIO_F_MIN_RATE ||
 	     priv->flags & TC_MQPRIO_F_MAX_RATE) &&
 	    (dump_rates(priv, &opt, skb) != 0))
 		goto nla_put_failure;

 	return nla_nest_end(skb, nla);
 nla_put_failure:
 	nlmsg_trim(skb, nla);
 	return -1;
 }

 static struct Qdisc *mqprio_leaf(struct Qdisc *sch, unsigned long cl)
 {
 	struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);

 	if (!dev_queue)
 		return NULL;

 	return dev_queue->qdisc_sleeping;
 }

 static unsigned long mqprio_find(struct Qdisc *sch, u32 classid)
 {
 	struct net_device *dev = qdisc_dev(sch);
 	unsigned int ntx = TC_H_MIN(classid);

 	/* There are essentially two regions here that have valid classid
 	 * values. The first region will have a classid value of 1 through
 	 * num_tx_queues. All of these are backed by actual Qdiscs.
 	 */
 	if (ntx < TC_H_MIN_PRIORITY)
 		return (ntx <= dev->num_tx_queues) ? ntx : 0;

 	/* The second region represents the hardware traffic classes. These
 	 * are represented by classid values of TC_H_MIN_PRIORITY through
 	 * TC_H_MIN_PRIORITY + netdev_get_num_tc - 1
 	 */
 	return ((ntx - TC_H_MIN_PRIORITY) < netdev_get_num_tc(dev)) ? ntx : 0;
 }

 static int mqprio_dump_class(struct Qdisc *sch, unsigned long cl,
 			 struct sk_buff *skb, struct tcmsg *tcm)
 {
 	if (cl < TC_H_MIN_PRIORITY) {
 		struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 		struct net_device *dev = qdisc_dev(sch);
 		int tc = netdev_txq_to_tc(dev, cl - 1);

 		tcm->tcm_parent = (tc < 0) ? 0 :
 			TC_H_MAKE(TC_H_MAJ(sch->handle),
 				  TC_H_MIN(tc + TC_H_MIN_PRIORITY));
 		tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
 	} else {
 		tcm->tcm_parent = TC_H_ROOT;
 		tcm->tcm_info = 0;
 	}
 	tcm->tcm_handle |= TC_H_MIN(cl);
 	return 0;
 }

 static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 				   struct gnet_dump *d)
 	__releases(d->lock)
 	__acquires(d->lock)
 {
 	if (cl >= TC_H_MIN_PRIORITY) {
 		int i;
 		__u32 qlen = 0;
 		struct gnet_stats_queue qstats = {0};
 		struct gnet_stats_basic_packed bstats = {0};
 		struct net_device *dev = qdisc_dev(sch);
 		struct netdev_tc_txq tc = dev->tc_to_txq[cl & TC_BITMASK];

 		/* Drop lock here it will be reclaimed before touching
 		 * statistics this is required because the d->lock we
 		 * hold here is the look on dev_queue->qdisc_sleeping
 		 * also acquired below.
 		 */
 		if (d->lock)
 			spin_unlock_bh(d->lock);

 		for (i = tc.offset; i < tc.offset + tc.count; i++) {
 			struct netdev_queue *q = netdev_get_tx_queue(dev, i);
 			struct Qdisc *qdisc = rtnl_dereference(q->qdisc);
 			struct gnet_stats_basic_cpu __percpu *cpu_bstats = NULL;
 			struct gnet_stats_queue __percpu *cpu_qstats = NULL;

 			spin_lock_bh(qdisc_lock(qdisc));
 			if (qdisc_is_percpu_stats(qdisc)) {
 				cpu_bstats = qdisc->cpu_bstats;
 				cpu_qstats = qdisc->cpu_qstats;
 			}

 			qlen = qdisc_qlen_sum(qdisc);
 			__gnet_stats_copy_basic(NULL, &sch->bstats,
 						cpu_bstats, &qdisc->bstats);
 			__gnet_stats_copy_queue(&sch->qstats,
 						cpu_qstats,
 						&qdisc->qstats,
 						qlen);
 			spin_unlock_bh(qdisc_lock(qdisc));
 		}

 		/* Reclaim root sleeping lock before completing stats */
 		if (d->lock)
 			spin_lock_bh(d->lock);
 		if (gnet_stats_copy_basic(NULL, d, NULL, &bstats) < 0 ||
 		    gnet_stats_copy_queue(d, NULL, &qstats, qlen) < 0)
 			return -1;
 	} else {
 		struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);

 		sch = dev_queue->qdisc_sleeping;
 		if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
 					  d, NULL, &sch->bstats) < 0 ||
 		    gnet_stats_copy_queue(d, NULL,
 					  &sch->qstats, sch->q.qlen) < 0)
 			return -1;
 	}
 	return 0;
 }

 static void mqprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 {
 	struct net_device *dev = qdisc_dev(sch);
 	unsigned long ntx;

 	if (arg->stop)
 		return;

 	/* Walk hierarchy with a virtual class per tc */
 	arg->count = arg->skip;
 	for (ntx = arg->skip; ntx < netdev_get_num_tc(dev); ntx++) {
 		if (arg->fn(sch, ntx + TC_H_MIN_PRIORITY, arg) < 0) {
 			arg->stop = 1;
 			return;
 		}
 		arg->count++;
 	}

 	/* Pad the values and skip over unused traffic classes */
 	if (ntx < TC_MAX_QUEUE) {
 		arg->count = TC_MAX_QUEUE;
 		ntx = TC_MAX_QUEUE;
 	}

 	/* Reset offset, sort out remaining per-queue qdiscs */
 	for (ntx -= TC_MAX_QUEUE; ntx < dev->num_tx_queues; ntx++) {
 		if (arg->fn(sch, ntx + 1, arg) < 0) {
 			arg->stop = 1;
 			return;
 		}
 		arg->count++;
 	}
 }

 static struct netdev_queue *mqprio_select_queue(struct Qdisc *sch,
 						struct tcmsg *tcm)
 {
 	return mqprio_queue_get(sch, TC_H_MIN(tcm->tcm_parent));
 }

 static const struct Qdisc_class_ops mqprio_class_ops = {
 	.graft		= mqprio_graft,
 	.leaf		= mqprio_leaf,
 	.find		= mqprio_find,
 	.walk		= mqprio_walk,
 	.dump		= mqprio_dump_class,
 	.dump_stats	= mqprio_dump_class_stats,
 	.select_queue	= mqprio_select_queue,
 };

 static struct Qdisc_ops mqprio_qdisc_ops __read_mostly = {
 	.cl_ops		= &mqprio_class_ops,
 	.id		= "mqprio",
 	.priv_size	= sizeof(struct mqprio_sched),
 	.init		= mqprio_init,
 	.destroy	= mqprio_destroy,
 	.attach		= mqprio_attach,
 	.dump		= mqprio_dump,
 	.owner		= THIS_MODULE,
 };

 static int __init mqprio_module_init(void)
 {
 	return register_qdisc(&mqprio_qdisc_ops);
 }

 static void __exit mqprio_module_exit(void)
 {
 	unregister_qdisc(&mqprio_qdisc_ops);
 }

 module_init(mqprio_module_init);
 module_exit(mqprio_module_exit);

 MODULE_LICENSE("GPL");
	/*
	* net/sched/sch_mqprio.c
	*
	* Copyright (c) 2010 John Fastabend <john.r.fastabend@intel.com>
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* version 2 as published by the Free Software Foundation.
	*/

	#include <linux/types.h>
	#include <linux/slab.h>
	#include <linux/kernel.h>
	#include <linux/string.h>
	#include <linux/errno.h>
	#include <linux/skbuff.h>
	#include <linux/module.h>
	#include <net/netlink.h>
	#include <net/pkt_sched.h>
	#include <net/sch_generic.h>
	#include <net/pkt_cls.h>

	struct mqprio_sched {
	struct Qdisc **qdiscs;
	u16 mode;
	u16 shaper;
	int hw_offload;
	u32 flags;
	u64 min_rate[TC_QOPT_MAX_QUEUE];
	u64 max_rate[TC_QOPT_MAX_QUEUE];
	};

	static void mqprio_destroy(struct Qdisc *sch)
	{
	struct net_device *dev = qdisc_dev(sch);
	struct mqprio_sched *priv = qdisc_priv(sch);
	unsigned int ntx;

	if (priv->qdiscs) {
	for (ntx = 0;
	ntx < dev->num_tx_queues && priv->qdiscs[ntx];
	ntx++)
	qdisc_destroy(priv->qdiscs[ntx]);
	kfree(priv->qdiscs);
	}

	if (priv->hw_offload && dev->netdev_ops->ndo_setup_tc) {
	struct tc_mqprio_qopt_offload mqprio = { { 0 } };

	switch (priv->mode) {
	case TC_MQPRIO_MODE_DCB:
	case TC_MQPRIO_MODE_CHANNEL:
	dev->netdev_ops->ndo_setup_tc(dev,
	TC_SETUP_QDISC_MQPRIO,
	&mqprio);
	break;
	default:
	return;
	}
	} else {
	netdev_set_num_tc(dev, 0);
	}
	}

	static int mqprio_parse_opt(struct net_device dev, struct tc_mqprio_qopt qopt)
	{
	int i, j;

	/* Verify num_tc is not out of max range */
	if (qopt->num_tc > TC_MAX_QUEUE)
	return -EINVAL;

	/* Verify priority mapping uses valid tcs */
	for (i = 0; i < TC_BITMASK + 1; i++) {
	if (qopt->prio_tc_map[i] >= qopt->num_tc)
	return -EINVAL;
	}

	/* Limit qopt->hw to maximum supported offload value. Drivers have
	* the option of overriding this later if they don't support the a
	* given offload type.
	*/
	if (qopt->hw > TC_MQPRIO_HW_OFFLOAD_MAX)
	qopt->hw = TC_MQPRIO_HW_OFFLOAD_MAX;

	/* If hardware offload is requested we will leave it to the device
	* to either populate the queue counts itself or to validate the
	* provided queue counts. If ndo_setup_tc is not present then
	* hardware doesn't support offload and we should return an error.
	*/
	if (qopt->hw)
	return dev->netdev_ops->ndo_setup_tc ? 0 : -EINVAL;

	for (i = 0; i < qopt->num_tc; i++) {
	unsigned int last = qopt->offset[i] + qopt->count[i];

	/* Verify the queue count is in tx range being equal to the
	* real_num_tx_queues indicates the last queue is in use.
	*/
	if (qopt->offset[i] >= dev->real_num_tx_queues \|\|
	!qopt->count[i] \|\|
	last > dev->real_num_tx_queues)
	return -EINVAL;

	/* Verify that the offset and counts do not overlap */
	for (j = i + 1; j < qopt->num_tc; j++) {
	if (last > qopt->offset[j])
	return -EINVAL;
	}
	}

	return 0;
	}

	static const struct nla_policy mqprio_policy[TCA_MQPRIO_MAX + 1] = {
	[TCA_MQPRIO_MODE] = { .len = sizeof(u16) },
	[TCA_MQPRIO_SHAPER] = { .len = sizeof(u16) },
	[TCA_MQPRIO_MIN_RATE64] = { .type = NLA_NESTED },
	[TCA_MQPRIO_MAX_RATE64] = { .type = NLA_NESTED },
	};

	static int parse_attr(struct nlattr tb[], int maxtype, struct nlattr nla,
	const struct nla_policy *policy, int len)
	{
	int nested_len = nla_len(nla) - NLA_ALIGN(len);

	if (nested_len >= nla_attr_size(0))
	return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len),
	nested_len, policy, NULL);

	memset(tb, 0, sizeof(struct nlattr ) (maxtype + 1));
	return 0;
	}

	static int mqprio_init(struct Qdisc sch, struct nlattr opt,
	struct netlink_ext_ack *extack)
	{
	struct net_device *dev = qdisc_dev(sch);
	struct mqprio_sched *priv = qdisc_priv(sch);
	struct netdev_queue *dev_queue;
	struct Qdisc *qdisc;
	int i, err = -EOPNOTSUPP;
	struct tc_mqprio_qopt *qopt = NULL;
	struct nlattr *tb[TCA_MQPRIO_MAX + 1];
	struct nlattr *attr;
	int rem;
	int len;

	BUILD_BUG_ON(TC_MAX_QUEUE != TC_QOPT_MAX_QUEUE);
	BUILD_BUG_ON(TC_BITMASK != TC_QOPT_BITMASK);

	if (sch->parent != TC_H_ROOT)
	return -EOPNOTSUPP;

	if (!netif_is_multiqueue(dev))
	return -EOPNOTSUPP;

	/* make certain can allocate enough classids to handle queues */
	if (dev->num_tx_queues >= TC_H_MIN_PRIORITY)
	return -ENOMEM;

	if (!opt \|\| nla_len(opt) < sizeof(*qopt))
	return -EINVAL;

	qopt = nla_data(opt);
	if (mqprio_parse_opt(dev, qopt))
	return -EINVAL;

	len = nla_len(opt) - NLA_ALIGN(sizeof(*qopt));
	if (len > 0) {
	err = parse_attr(tb, TCA_MQPRIO_MAX, opt, mqprio_policy,
	sizeof(*qopt));
	if (err < 0)
	return err;

	if (!qopt->hw)
	return -EINVAL;

	if (tb[TCA_MQPRIO_MODE]) {
	priv->flags \|= TC_MQPRIO_F_MODE;
	priv->mode = (u16 )nla_data(tb[TCA_MQPRIO_MODE]);
	}

	if (tb[TCA_MQPRIO_SHAPER]) {
	priv->flags \|= TC_MQPRIO_F_SHAPER;
	priv->shaper = (u16 )nla_data(tb[TCA_MQPRIO_SHAPER]);
	}

	if (tb[TCA_MQPRIO_MIN_RATE64]) {
	if (priv->shaper != TC_MQPRIO_SHAPER_BW_RATE)
	return -EINVAL;
	i = 0;
	nla_for_each_nested(attr, tb[TCA_MQPRIO_MIN_RATE64],
	rem) {
	if (nla_type(attr) != TCA_MQPRIO_MIN_RATE64)
	return -EINVAL;
	if (i >= qopt->num_tc)
	break;
	priv->min_rate[i] = (u64 )nla_data(attr);
	i++;
	}
	priv->flags \|= TC_MQPRIO_F_MIN_RATE;
	}

	if (tb[TCA_MQPRIO_MAX_RATE64]) {
	if (priv->shaper != TC_MQPRIO_SHAPER_BW_RATE)
	return -EINVAL;
	i = 0;
	nla_for_each_nested(attr, tb[TCA_MQPRIO_MAX_RATE64],
	rem) {
	if (nla_type(attr) != TCA_MQPRIO_MAX_RATE64)
	return -EINVAL;
	if (i >= qopt->num_tc)
	break;
	priv->max_rate[i] = (u64 )nla_data(attr);
	i++;
	}
	priv->flags \|= TC_MQPRIO_F_MAX_RATE;
	}
	}

	/* pre-allocate qdisc, attachment can't fail */
	priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
	GFP_KERNEL);
	if (!priv->qdiscs)
	return -ENOMEM;

	for (i = 0; i < dev->num_tx_queues; i++) {
	dev_queue = netdev_get_tx_queue(dev, i);
	qdisc = qdisc_create_dflt(dev_queue,
	get_default_qdisc_ops(dev, i),
	TC_H_MAKE(TC_H_MAJ(sch->handle),
	TC_H_MIN(i + 1)), extack);
	if (!qdisc)
	return -ENOMEM;

	priv->qdiscs[i] = qdisc;
	qdisc->flags \|= TCQ_F_ONETXQUEUE \| TCQ_F_NOPARENT;
	}

	/* If the mqprio options indicate that hardware should own
	* the queue mapping then run ndo_setup_tc otherwise use the
	* supplied and verified mapping
	*/
	if (qopt->hw) {
	struct tc_mqprio_qopt_offload mqprio = {.qopt = *qopt};

	switch (priv->mode) {
	case TC_MQPRIO_MODE_DCB:
	if (priv->shaper != TC_MQPRIO_SHAPER_DCB)
	return -EINVAL;
	break;
	case TC_MQPRIO_MODE_CHANNEL:
	mqprio.flags = priv->flags;
	if (priv->flags & TC_MQPRIO_F_MODE)
	mqprio.mode = priv->mode;
	if (priv->flags & TC_MQPRIO_F_SHAPER)
	mqprio.shaper = priv->shaper;
	if (priv->flags & TC_MQPRIO_F_MIN_RATE)
	for (i = 0; i < mqprio.qopt.num_tc; i++)
	mqprio.min_rate[i] = priv->min_rate[i];
	if (priv->flags & TC_MQPRIO_F_MAX_RATE)
	for (i = 0; i < mqprio.qopt.num_tc; i++)
	mqprio.max_rate[i] = priv->max_rate[i];
	break;
	default:
	return -EINVAL;
	}
	err = dev->netdev_ops->ndo_setup_tc(dev,
	TC_SETUP_QDISC_MQPRIO,
	&mqprio);
	if (err)
	return err;

	priv->hw_offload = mqprio.qopt.hw;
	} else {
	netdev_set_num_tc(dev, qopt->num_tc);
	for (i = 0; i < qopt->num_tc; i++)
	netdev_set_tc_queue(dev, i,
	qopt->count[i], qopt->offset[i]);
	}

	/* Always use supplied priority mappings */
	for (i = 0; i < TC_BITMASK + 1; i++)
	netdev_set_prio_tc_map(dev, i, qopt->prio_tc_map[i]);

	sch->flags \|= TCQ_F_MQROOT;
	return 0;
	}

	static void mqprio_attach(struct Qdisc *sch)
	{
	struct net_device *dev = qdisc_dev(sch);
	struct mqprio_sched *priv = qdisc_priv(sch);
	struct Qdisc qdisc, old;
	unsigned int ntx;

	/* Attach underlying qdisc */
	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
	qdisc = priv->qdiscs[ntx];
	old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
	if (old)
	qdisc_destroy(old);
	if (ntx < dev->real_num_tx_queues)
	qdisc_hash_add(qdisc, false);
	}
	kfree(priv->qdiscs);
	priv->qdiscs = NULL;
	}

	static struct netdev_queue mqprio_queue_get(struct Qdisc sch,
	unsigned long cl)
	{
	struct net_device *dev = qdisc_dev(sch);
	unsigned long ntx = cl - 1;

	if (ntx >= dev->num_tx_queues)
	return NULL;
	return netdev_get_tx_queue(dev, ntx);
	}

	static int mqprio_graft(struct Qdisc sch, unsigned long cl, struct Qdisc new,
	struct Qdisc *old, struct netlink_ext_ack extack)
	{
	struct net_device *dev = qdisc_dev(sch);
	struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);

	if (!dev_queue)
	return -EINVAL;

	if (dev->flags & IFF_UP)
	dev_deactivate(dev);

	*old = dev_graft_qdisc(dev_queue, new);

	if (new)
	new->flags \|= TCQ_F_ONETXQUEUE \| TCQ_F_NOPARENT;

	if (dev->flags & IFF_UP)
	dev_activate(dev);

	return 0;
	}

	static int dump_rates(struct mqprio_sched *priv,
	struct tc_mqprio_qopt opt, struct sk_buff skb)
	{
	struct nlattr *nest;
	int i;

	if (priv->flags & TC_MQPRIO_F_MIN_RATE) {
	nest = nla_nest_start(skb, TCA_MQPRIO_MIN_RATE64);
	if (!nest)
	goto nla_put_failure;

	for (i = 0; i < opt->num_tc; i++) {
	if (nla_put(skb, TCA_MQPRIO_MIN_RATE64,
	sizeof(priv->min_rate[i]),
	&priv->min_rate[i]))
	goto nla_put_failure;
	}
	nla_nest_end(skb, nest);
	}

	if (priv->flags & TC_MQPRIO_F_MAX_RATE) {
	nest = nla_nest_start(skb, TCA_MQPRIO_MAX_RATE64);
	if (!nest)
	goto nla_put_failure;

	for (i = 0; i < opt->num_tc; i++) {
	if (nla_put(skb, TCA_MQPRIO_MAX_RATE64,
	sizeof(priv->max_rate[i]),
	&priv->max_rate[i]))
	goto nla_put_failure;
	}
	nla_nest_end(skb, nest);
	}
	return 0;

	nla_put_failure:
	nla_nest_cancel(skb, nest);
	return -1;
	}

	static int mqprio_dump(struct Qdisc sch, struct sk_buff skb)
	{
	struct net_device *dev = qdisc_dev(sch);
	struct mqprio_sched *priv = qdisc_priv(sch);
	struct nlattr nla = (struct nlattr )skb_tail_pointer(skb);
	struct tc_mqprio_qopt opt = { 0 };
	struct Qdisc *qdisc;
	unsigned int ntx, tc;

	sch->q.qlen = 0;
	memset(&sch->bstats, 0, sizeof(sch->bstats));
	memset(&sch->qstats, 0, sizeof(sch->qstats));

	/* MQ supports lockless qdiscs. However, statistics accounting needs
	* to account for all, none, or a mix of locked and unlocked child
	* qdiscs. Percpu stats are added to counters in-band and locking
	* qdisc totals are added at end.
	*/
	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
	qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
	spin_lock_bh(qdisc_lock(qdisc));

	if (qdisc_is_percpu_stats(qdisc)) {
	__u32 qlen = qdisc_qlen_sum(qdisc);

	__gnet_stats_copy_basic(NULL, &sch->bstats,
	qdisc->cpu_bstats,
	&qdisc->bstats);
	__gnet_stats_copy_queue(&sch->qstats,
	qdisc->cpu_qstats,
	&qdisc->qstats, qlen);
	} else {
	sch->q.qlen += qdisc->q.qlen;
	sch->bstats.bytes += qdisc->bstats.bytes;
	sch->bstats.packets += qdisc->bstats.packets;
	sch->qstats.backlog += qdisc->qstats.backlog;
	sch->qstats.drops += qdisc->qstats.drops;
	sch->qstats.requeues += qdisc->qstats.requeues;
	sch->qstats.overlimits += qdisc->qstats.overlimits;
	}

	spin_unlock_bh(qdisc_lock(qdisc));
	}

	opt.num_tc = netdev_get_num_tc(dev);
	memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map));
	opt.hw = priv->hw_offload;

	for (tc = 0; tc < netdev_get_num_tc(dev); tc++) {
	opt.count[tc] = dev->tc_to_txq[tc].count;
	opt.offset[tc] = dev->tc_to_txq[tc].offset;
	}

	if (nla_put(skb, TCA_OPTIONS, NLA_ALIGN(sizeof(opt)), &opt))
	goto nla_put_failure;

	if ((priv->flags & TC_MQPRIO_F_MODE) &&
	nla_put_u16(skb, TCA_MQPRIO_MODE, priv->mode))
	goto nla_put_failure;

	if ((priv->flags & TC_MQPRIO_F_SHAPER) &&
	nla_put_u16(skb, TCA_MQPRIO_SHAPER, priv->shaper))
	goto nla_put_failure;

	if ((priv->flags & TC_MQPRIO_F_MIN_RATE \|\|
	priv->flags & TC_MQPRIO_F_MAX_RATE) &&
	(dump_rates(priv, &opt, skb) != 0))
	goto nla_put_failure;

	return nla_nest_end(skb, nla);
	nla_put_failure:
	nlmsg_trim(skb, nla);
	return -1;
	}

	static struct Qdisc mqprio_leaf(struct Qdisc sch, unsigned long cl)
	{
	struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);

	if (!dev_queue)
	return NULL;

	return dev_queue->qdisc_sleeping;
	}

	static unsigned long mqprio_find(struct Qdisc *sch, u32 classid)
	{
	struct net_device *dev = qdisc_dev(sch);
	unsigned int ntx = TC_H_MIN(classid);

	/* There are essentially two regions here that have valid classid
	* values. The first region will have a classid value of 1 through
	* num_tx_queues. All of these are backed by actual Qdiscs.
	*/
	if (ntx < TC_H_MIN_PRIORITY)
	return (ntx <= dev->num_tx_queues) ? ntx : 0;

	/* The second region represents the hardware traffic classes. These
	* are represented by classid values of TC_H_MIN_PRIORITY through
	* TC_H_MIN_PRIORITY + netdev_get_num_tc - 1
	*/
	return ((ntx - TC_H_MIN_PRIORITY) < netdev_get_num_tc(dev)) ? ntx : 0;
	}

	static int mqprio_dump_class(struct Qdisc *sch, unsigned long cl,
	struct sk_buff skb, struct tcmsg tcm)
	{
	if (cl < TC_H_MIN_PRIORITY) {
	struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
	struct net_device *dev = qdisc_dev(sch);
	int tc = netdev_txq_to_tc(dev, cl - 1);

	tcm->tcm_parent = (tc < 0) ? 0 :
	TC_H_MAKE(TC_H_MAJ(sch->handle),
	TC_H_MIN(tc + TC_H_MIN_PRIORITY));
	tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
	} else {
	tcm->tcm_parent = TC_H_ROOT;
	tcm->tcm_info = 0;
	}
	tcm->tcm_handle \|= TC_H_MIN(cl);
	return 0;
	}

	static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
	struct gnet_dump *d)
	__releases(d->lock)
	__acquires(d->lock)
	{
	if (cl >= TC_H_MIN_PRIORITY) {
	int i;
	__u32 qlen = 0;
	struct gnet_stats_queue qstats = {0};
	struct gnet_stats_basic_packed bstats = {0};
	struct net_device *dev = qdisc_dev(sch);
	struct netdev_tc_txq tc = dev->tc_to_txq[cl & TC_BITMASK];

	/* Drop lock here it will be reclaimed before touching
	* statistics this is required because the d->lock we
	* hold here is the look on dev_queue->qdisc_sleeping
	* also acquired below.
	*/
	if (d->lock)
	spin_unlock_bh(d->lock);

	for (i = tc.offset; i < tc.offset + tc.count; i++) {
	struct netdev_queue *q = netdev_get_tx_queue(dev, i);
	struct Qdisc *qdisc = rtnl_dereference(q->qdisc);
	struct gnet_stats_basic_cpu __percpu *cpu_bstats = NULL;
	struct gnet_stats_queue __percpu *cpu_qstats = NULL;

	spin_lock_bh(qdisc_lock(qdisc));
	if (qdisc_is_percpu_stats(qdisc)) {
	cpu_bstats = qdisc->cpu_bstats;
	cpu_qstats = qdisc->cpu_qstats;
	}

	qlen = qdisc_qlen_sum(qdisc);
	__gnet_stats_copy_basic(NULL, &sch->bstats,
	cpu_bstats, &qdisc->bstats);
	__gnet_stats_copy_queue(&sch->qstats,
	cpu_qstats,
	&qdisc->qstats,
	qlen);
	spin_unlock_bh(qdisc_lock(qdisc));
	}

	/* Reclaim root sleeping lock before completing stats */
	if (d->lock)
	spin_lock_bh(d->lock);
	if (gnet_stats_copy_basic(NULL, d, NULL, &bstats) < 0 \|\|
	gnet_stats_copy_queue(d, NULL, &qstats, qlen) < 0)
	return -1;
	} else {
	struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);

	sch = dev_queue->qdisc_sleeping;
	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
	d, NULL, &sch->bstats) < 0 \|\|
	gnet_stats_copy_queue(d, NULL,
	&sch->qstats, sch->q.qlen) < 0)
	return -1;
	}
	return 0;
	}

	static void mqprio_walk(struct Qdisc sch, struct qdisc_walker arg)
	{
	struct net_device *dev = qdisc_dev(sch);
	unsigned long ntx;

	if (arg->stop)
	return;

	/* Walk hierarchy with a virtual class per tc */
	arg->count = arg->skip;
	for (ntx = arg->skip; ntx < netdev_get_num_tc(dev); ntx++) {
	if (arg->fn(sch, ntx + TC_H_MIN_PRIORITY, arg) < 0) {
	arg->stop = 1;
	return;
	}
	arg->count++;
	}

	/* Pad the values and skip over unused traffic classes */
	if (ntx < TC_MAX_QUEUE) {
	arg->count = TC_MAX_QUEUE;
	ntx = TC_MAX_QUEUE;
	}

	/* Reset offset, sort out remaining per-queue qdiscs */
	for (ntx -= TC_MAX_QUEUE; ntx < dev->num_tx_queues; ntx++) {
	if (arg->fn(sch, ntx + 1, arg) < 0) {
	arg->stop = 1;
	return;
	}
	arg->count++;
	}
	}

	static struct netdev_queue mqprio_select_queue(struct Qdisc sch,
	struct tcmsg *tcm)
	{
	return mqprio_queue_get(sch, TC_H_MIN(tcm->tcm_parent));
	}

	static const struct Qdisc_class_ops mqprio_class_ops = {
	.graft = mqprio_graft,
	.leaf = mqprio_leaf,
	.find = mqprio_find,
	.walk = mqprio_walk,
	.dump = mqprio_dump_class,
	.dump_stats = mqprio_dump_class_stats,
	.select_queue = mqprio_select_queue,
	};

	static struct Qdisc_ops mqprio_qdisc_ops __read_mostly = {
	.cl_ops = &mqprio_class_ops,
	.id = "mqprio",
	.priv_size = sizeof(struct mqprio_sched),
	.init = mqprio_init,
	.destroy = mqprio_destroy,
	.attach = mqprio_attach,
	.dump = mqprio_dump,
	.owner = THIS_MODULE,
	};

	static int __init mqprio_module_init(void)
	{
	return register_qdisc(&mqprio_qdisc_ops);
	}

	static void __exit mqprio_module_exit(void)
	{
	unregister_qdisc(&mqprio_qdisc_ops);
	}

	module_init(mqprio_module_init);
	module_exit(mqprio_module_exit);

	MODULE_LICENSE("GPL");