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Commit 3d0bd028 authored by Vinicius Costa Gomes's avatar Vinicius Costa Gomes Committed by Jeff Kirsher
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net/sched: Add support for HW offloading for CBS 



This adds support for offloading the CBS algorithm to the controller,
if supported. Drivers wanting to support CBS offload must implement
the .ndo_setup_tc callback and handle the TC_SETUP_CBS (introduced
here) type.

Signed-off-by: default avatarVinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: default avatarHenrik Austad <henrik@austad.us>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 585d763a

include/linux/netdevice.h

+1 −0
Original line number Diff line number Diff line
@@ -776,6 +776,7 @@ enum tc_setup_type { 
	TC_SETUP_CLSMATCHALL,

	TC_SETUP_CLSBPF,

	TC_SETUP_BLOCK,

	TC_SETUP_CBS,

};



/* These structures hold the attributes of xdp state that are being passed

include/net/pkt_sched.h

+9 −0
Original line number Diff line number Diff line
@@ -140,4 +140,13 @@ static inline struct net *qdisc_net(struct Qdisc *q) 
	return dev_net(q->dev_queue->dev);

}



struct tc_cbs_qopt_offload {

	u8 enable;

	s32 queue;

	s32 hicredit;

	s32 locredit;

	s32 idleslope;

	s32 sendslope;

};



#endif

net/sched/sch_cbs.c

+92 −12
Original line number Diff line number Diff line
@@ -68,6 +68,8 @@ 
#define BYTES_PER_KBIT (1000LL / 8)



struct cbs_sched_data {

	bool offload;

	int queue;

	s64 port_rate; /* in bytes/s */

	s64 last; /* timestamp in ns */

	s64 credits; /* in bytes */
@@ -80,6 +82,11 @@ struct cbs_sched_data { 
	struct sk_buff *(*dequeue)(struct Qdisc *sch);

};



static int cbs_enqueue_offload(struct sk_buff *skb, struct Qdisc *sch)

{

	return qdisc_enqueue_tail(skb, sch);

}



static int cbs_enqueue_soft(struct sk_buff *skb, struct Qdisc *sch)

{

	struct cbs_sched_data *q = qdisc_priv(sch);
@@ -169,6 +176,11 @@ static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch) 
	return skb;

}



static struct sk_buff *cbs_dequeue_offload(struct Qdisc *sch)

{

	return qdisc_dequeue_head(sch);

}



static struct sk_buff *cbs_dequeue(struct Qdisc *sch)

{

	struct cbs_sched_data *q = qdisc_priv(sch);
@@ -180,14 +192,66 @@ static const struct nla_policy cbs_policy[TCA_CBS_MAX + 1] = { 
	[TCA_CBS_PARMS]	= { .len = sizeof(struct tc_cbs_qopt) },

};



static void cbs_disable_offload(struct net_device *dev,

				struct cbs_sched_data *q)

{

	struct tc_cbs_qopt_offload cbs = { };

	const struct net_device_ops *ops;

	int err;



	if (!q->offload)

		return;



	q->enqueue = cbs_enqueue_soft;

	q->dequeue = cbs_dequeue_soft;



	ops = dev->netdev_ops;

	if (!ops->ndo_setup_tc)

		return;



	cbs.queue = q->queue;

	cbs.enable = 0;



	err = ops->ndo_setup_tc(dev, TC_SETUP_CBS, &cbs);

	if (err < 0)

		pr_warn("Couldn't disable CBS offload for queue %d\n",

			cbs.queue);

}



static int cbs_enable_offload(struct net_device *dev, struct cbs_sched_data *q,

			      const struct tc_cbs_qopt *opt)

{

	const struct net_device_ops *ops = dev->netdev_ops;

	struct tc_cbs_qopt_offload cbs = { };

	int err;



	if (!ops->ndo_setup_tc)

		return -EOPNOTSUPP;



	cbs.queue = q->queue;



	cbs.enable = 1;

	cbs.hicredit = opt->hicredit;

	cbs.locredit = opt->locredit;

	cbs.idleslope = opt->idleslope;

	cbs.sendslope = opt->sendslope;



	err = ops->ndo_setup_tc(dev, TC_SETUP_CBS, &cbs);

	if (err < 0)

		return err;



	q->enqueue = cbs_enqueue_offload;

	q->dequeue = cbs_dequeue_offload;



	return 0;

}



static int cbs_change(struct Qdisc *sch, struct nlattr *opt)

{

	struct cbs_sched_data *q = qdisc_priv(sch);

	struct net_device *dev = qdisc_dev(sch);

	struct nlattr *tb[TCA_CBS_MAX + 1];

	struct ethtool_link_ksettings ecmd;

	struct tc_cbs_qopt *qopt;

	s64 link_speed;

	int err;



	err = nla_parse_nested(tb, TCA_CBS_MAX, opt, cbs_policy, NULL);
@@ -199,8 +263,9 @@ static int cbs_change(struct Qdisc *sch, struct nlattr *opt) 


	qopt = nla_data(tb[TCA_CBS_PARMS]);



	if (qopt->offload)

		return -EOPNOTSUPP;

	if (!qopt->offload) {

		struct ethtool_link_ksettings ecmd;

		s64 link_speed;



		if (!__ethtool_get_link_ksettings(dev, &ecmd))

			link_speed = ecmd.base.speed;
@@ -209,13 +274,19 @@ static int cbs_change(struct Qdisc *sch, struct nlattr *opt) 


		q->port_rate = link_speed * 1000 * BYTES_PER_KBIT;



	q->enqueue = cbs_enqueue_soft;

	q->dequeue = cbs_dequeue_soft;

		cbs_disable_offload(dev, q);

	} else {

		err = cbs_enable_offload(dev, q, qopt);

		if (err < 0)

			return err;

	}



	/* Everything went OK, save the parameters used. */

	q->hicredit = qopt->hicredit;

	q->locredit = qopt->locredit;

	q->idleslope = qopt->idleslope * BYTES_PER_KBIT;

	q->sendslope = qopt->sendslope * BYTES_PER_KBIT;

	q->offload = qopt->offload;



	return 0;

}
@@ -223,10 +294,16 @@ static int cbs_change(struct Qdisc *sch, struct nlattr *opt) 
static int cbs_init(struct Qdisc *sch, struct nlattr *opt)

{

	struct cbs_sched_data *q = qdisc_priv(sch);

	struct net_device *dev = qdisc_dev(sch);



	if (!opt)

		return -EINVAL;



	q->queue = sch->dev_queue - netdev_get_tx_queue(dev, 0);



	q->enqueue = cbs_enqueue_soft;

	q->dequeue = cbs_dequeue_soft;



	qdisc_watchdog_init(&q->watchdog, sch);



	return cbs_change(sch, opt);
@@ -235,8 +312,11 @@ static int cbs_init(struct Qdisc *sch, struct nlattr *opt) 
static void cbs_destroy(struct Qdisc *sch)

{

	struct cbs_sched_data *q = qdisc_priv(sch);

	struct net_device *dev = qdisc_dev(sch);



	qdisc_watchdog_cancel(&q->watchdog);



	cbs_disable_offload(dev, q);

}



static int cbs_dump(struct Qdisc *sch, struct sk_buff *skb)
@@ -253,7 +333,7 @@ static int cbs_dump(struct Qdisc *sch, struct sk_buff *skb) 
	opt.locredit = q->locredit;

	opt.sendslope = div64_s64(q->sendslope, BYTES_PER_KBIT);

	opt.idleslope = div64_s64(q->idleslope, BYTES_PER_KBIT);

	opt.offload = 0;

	opt.offload = q->offload;



	if (nla_put(skb, TCA_CBS_PARMS, sizeof(opt), &opt))

		goto nla_put_failure;