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Commit 990e35ec authored by Vinicius Costa Gomes's avatar Vinicius Costa Gomes Committed by David S. Miller
Browse files

cbs: Add support for the graft function 



This will allow to install a child qdisc under cbs. The main use case
is to install ETF (Earliest TxTime First) qdisc under cbs, so there's
another level of control for time-sensitive traffic.

Signed-off-by: default avatarVinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 336a443b

net/sched/sch_cbs.c

+125 −9
Original line number Diff line number Diff line
@@ -78,18 +78,42 @@ struct cbs_sched_data { 
	s64 sendslope; /* in bytes/s */

	s64 idleslope; /* in bytes/s */

	struct qdisc_watchdog watchdog;

	int (*enqueue)(struct sk_buff *skb, struct Qdisc *sch);

	int (*enqueue)(struct sk_buff *skb, struct Qdisc *sch,

		       struct sk_buff **to_free);

	struct sk_buff *(*dequeue)(struct Qdisc *sch);

	struct Qdisc *qdisc;

};



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

static int cbs_child_enqueue(struct sk_buff *skb, struct Qdisc *sch,

			     struct Qdisc *child,

			     struct sk_buff **to_free)

{

	int err;



	err = child->ops->enqueue(skb, child, to_free);

	if (err != NET_XMIT_SUCCESS)

		return err;



	qdisc_qstats_backlog_inc(sch, skb);

	sch->q.qlen++;



	return NET_XMIT_SUCCESS;

}



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

			       struct sk_buff **to_free)

{

	return qdisc_enqueue_tail(skb, sch);

	struct cbs_sched_data *q = qdisc_priv(sch);

	struct Qdisc *qdisc = q->qdisc;



	return cbs_child_enqueue(skb, sch, qdisc, to_free);

}



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

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

			    struct sk_buff **to_free)

{

	struct cbs_sched_data *q = qdisc_priv(sch);

	struct Qdisc *qdisc = q->qdisc;



	if (sch->q.qlen == 0 && q->credits > 0) {

		/* We need to stop accumulating credits when there's
@@ -99,7 +123,7 @@ static int cbs_enqueue_soft(struct sk_buff *skb, struct Qdisc *sch) 
		q->last = ktime_get_ns();

	}



	return qdisc_enqueue_tail(skb, sch);

	return cbs_child_enqueue(skb, sch, qdisc, to_free);

}



static int cbs_enqueue(struct sk_buff *skb, struct Qdisc *sch,
@@ -107,7 +131,7 @@ static int cbs_enqueue(struct sk_buff *skb, struct Qdisc *sch, 
{

	struct cbs_sched_data *q = qdisc_priv(sch);



	return q->enqueue(skb, sch);

	return q->enqueue(skb, sch, to_free);

}



/* timediff is in ns, slope is in bytes/s */
@@ -132,9 +156,25 @@ static s64 credits_from_len(unsigned int len, s64 slope, s64 port_rate) 
	return div64_s64(len * slope, port_rate);

}



static struct sk_buff *cbs_child_dequeue(struct Qdisc *sch, struct Qdisc *child)

{

	struct sk_buff *skb;



	skb = child->ops->dequeue(child);

	if (!skb)

		return NULL;



	qdisc_qstats_backlog_dec(sch, skb);

	qdisc_bstats_update(sch, skb);

	sch->q.qlen--;



	return skb;

}



static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch)

{

	struct cbs_sched_data *q = qdisc_priv(sch);

	struct Qdisc *qdisc = q->qdisc;

	s64 now = ktime_get_ns();

	struct sk_buff *skb;

	s64 credits;
@@ -157,8 +197,7 @@ static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch) 
			return NULL;

		}

	}



	skb = qdisc_dequeue_head(sch);

	skb = cbs_child_dequeue(sch, qdisc);

	if (!skb)

		return NULL;
@@ -178,7 +217,10 @@ static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch) 


static struct sk_buff *cbs_dequeue_offload(struct Qdisc *sch)

{

	return qdisc_dequeue_head(sch);

	struct cbs_sched_data *q = qdisc_priv(sch);

	struct Qdisc *qdisc = q->qdisc;



	return cbs_child_dequeue(sch, qdisc);

}



static struct sk_buff *cbs_dequeue(struct Qdisc *sch)
@@ -310,6 +352,13 @@ static int cbs_init(struct Qdisc *sch, struct nlattr *opt, 
		return -EINVAL;

	}



	q->qdisc = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,

				     sch->handle, extack);

	if (!q->qdisc)

		return -ENOMEM;



	qdisc_hash_add(q->qdisc, false);



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



	q->enqueue = cbs_enqueue_soft;
@@ -328,6 +377,9 @@ static void cbs_destroy(struct Qdisc *sch) 
	qdisc_watchdog_cancel(&q->watchdog);



	cbs_disable_offload(dev, q);



	if (q->qdisc)

		qdisc_destroy(q->qdisc);

}



static int cbs_dump(struct Qdisc *sch, struct sk_buff *skb)
@@ -356,8 +408,72 @@ static int cbs_dump(struct Qdisc *sch, struct sk_buff *skb) 
	return -1;

}



static int cbs_dump_class(struct Qdisc *sch, unsigned long cl,

			  struct sk_buff *skb, struct tcmsg *tcm)

{

	struct cbs_sched_data *q = qdisc_priv(sch);



	if (cl != 1 || !q->qdisc)	/* only one class */

		return -ENOENT;



	tcm->tcm_handle |= TC_H_MIN(1);

	tcm->tcm_info = q->qdisc->handle;



	return 0;

}



static int cbs_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,

		     struct Qdisc **old, struct netlink_ext_ack *extack)

{

	struct cbs_sched_data *q = qdisc_priv(sch);



	if (!new) {

		new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,

					sch->handle, NULL);

		if (!new)

			new = &noop_qdisc;

	}



	*old = qdisc_replace(sch, new, &q->qdisc);

	return 0;

}



static struct Qdisc *cbs_leaf(struct Qdisc *sch, unsigned long arg)

{

	struct cbs_sched_data *q = qdisc_priv(sch);



	return q->qdisc;

}



static unsigned long cbs_find(struct Qdisc *sch, u32 classid)

{

	return 1;

}



static void cbs_walk(struct Qdisc *sch, struct qdisc_walker *walker)

{

	if (!walker->stop) {

		if (walker->count >= walker->skip) {

			if (walker->fn(sch, 1, walker) < 0) {

				walker->stop = 1;

				return;

			}

		}

		walker->count++;

	}

}



static const struct Qdisc_class_ops cbs_class_ops = {

	.graft		=	cbs_graft,

	.leaf		=	cbs_leaf,

	.find		=	cbs_find,

	.walk		=	cbs_walk,

	.dump		=	cbs_dump_class,

};



static struct Qdisc_ops cbs_qdisc_ops __read_mostly = {

	.id		=	"cbs",

	.cl_ops		=	&cbs_class_ops,

	.priv_size	=	sizeof(struct cbs_sched_data),

	.enqueue	=	cbs_enqueue,

	.dequeue	=	cbs_dequeue,