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: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vinicius Costa Gomes 2018-07-23 17:08:00 -07:00 committed by David S. Miller
parent 336a443bd9
commit 990e35ecba

View File

@ -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)
{
return qdisc_enqueue_tail(skb, sch);
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_soft(struct sk_buff *skb, struct Qdisc *sch)
static int cbs_enqueue_offload(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;
return cbs_child_enqueue(skb, sch, qdisc, to_free);
}
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 @@ nla_put_failure:
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,