Subject: Re: [next-queue PATCH v5 4/5] net/sched: Add support for HW offloading for CBS

From: Jiri Pirko <[email-masked]>
Date: Wed, 11 Oct 2017 09:07:51 +0200

Wed, Oct 11, 2017 at 02:43:59AM CEST, [email-masked] wrote:
>This adds support for offloading the CBS algorithm to the controller,
>if supported.

Oh, so you have it as a separate patch, yet some bits left in the
previous one...

>
>Signed-off-by: Vinicius Costa Gomes <[email-masked]>
>---
> net/sched/sch_cbs.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 81 insertions(+), 11 deletions(-)
>
>diff --git a/net/sched/sch_cbs.c b/net/sched/sch_cbs.c
>index 5e1f72df1abd..2812bac4092b 100644
>--- a/net/sched/sch_cbs.c
>+++ b/net/sched/sch_cbs.c
>@@ -69,6 +69,7 @@
> 
> struct cbs_sched_data {
> 	bool offload;
>+	int queue;
> 	s64 port_rate; /* in bytes/s */
> 	s64 last; /* timestamp in ns */
> 	s64 credits; /* in bytes */
>@@ -81,6 +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);
>@@ -179,6 +185,11 @@ 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);
>@@ -190,14 +201,37 @@ static const struct nla_policy cbs_policy[TCA_CBS_MAX + 1] = {
> 	[TCA_CBS_PARMS]	= { .len = sizeof(struct tc_cbs_qopt) },
> };
> 
>+static void disable_cbs_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;
>+
>+	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);

Hmm, you have separete helper for disable, yet you have enable spread
over cbs_change. Please push the enable code into enable_cbs_offload.
While you are at it, change the names to cbs_ to maintain the qdisc
prefix in function names: cbs_offload_enable/cbs_offload_disable

>+}
>+
> 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 tc_cbs_qopt_offload cbs = { };
> 	struct nlattr *tb[TCA_CBS_MAX + 1];
>-	struct ethtool_link_ksettings ecmd;
>+	const struct net_device_ops *ops;
> 	struct tc_cbs_qopt *qopt;
>-	s64 link_speed;
> 	int err;
> 
> 	err = nla_parse_nested(tb, TCA_CBS_MAX, opt, cbs_policy, NULL);
>@@ -209,18 +243,48 @@ static int cbs_change(struct Qdisc *sch, struct nlattr *opt)
> 
> 	qopt = nla_data(tb[TCA_CBS_PARMS]);
> 
>-	if (qopt->offload)
>-		return -EOPNOTSUPP;
>+	q->enqueue = cbs_enqueue_offload;
>+	q->dequeue = cbs_dequeue_offload;
> 
>-	if (!__ethtool_get_link_ksettings(dev, &ecmd))
>-		link_speed = ecmd.base.speed;
>-	else
>-		link_speed = SPEED_1000;
>+	if (!qopt->offload) {
>+		struct ethtool_link_ksettings ecmd;
>+		s64 link_speed;
> 
>-	q->port_rate = link_speed * 1000 * BYTES_PER_KBIT;
>+		if (!__ethtool_get_link_ksettings(dev, &ecmd))
>+			link_speed = ecmd.base.speed;
>+		else
>+			link_speed = SPEED_1000;
> 
>-	q->enqueue = cbs_enqueue_soft;
>-	q->dequeue = cbs_dequeue_soft;
>+		q->port_rate = link_speed * 1000 * BYTES_PER_KBIT;
>+
>+		q->enqueue = cbs_enqueue_soft;
>+		q->dequeue = cbs_dequeue_soft;
>+
>+		disable_cbs_offload(dev, q);
>+
>+		err = 0;
>+		goto done;
>+	}
>+
>+	cbs.queue = q->queue;
>+
>+	cbs.enable = 1;
>+	cbs.hicredit = qopt->hicredit;
>+	cbs.locredit = qopt->locredit;
>+	cbs.idleslope = qopt->idleslope;
>+	cbs.sendslope = qopt->sendslope;
>+
>+	ops = dev->netdev_ops;
>+
>+	err = -EOPNOTSUPP;
>+	if (!ops->ndo_setup_tc)
>+		goto done;
>+
>+	err = ops->ndo_setup_tc(dev, TC_SETUP_CBS, &cbs);
>+
>+done:
>+	if (err < 0)
>+		return err;
> 
> 	q->hicredit = qopt->hicredit;
> 	q->locredit = qopt->locredit;
>@@ -234,10 +298,13 @@ 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);
>+
> 	qdisc_watchdog_init(&q->watchdog, sch);
> 
> 	return cbs_change(sch, opt);
>@@ -246,8 +313,11 @@ 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);
>+
>+	disable_cbs_offload(dev, q);
> }
> 
> static int cbs_dump(struct Qdisc *sch, struct sk_buff *skb)
>-- 
>2.14.2
>