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cbq: remove TCA_CBQ_OVL_STRATEGY support
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since initial revision of cbq in 2004 iproute 2 has never implemented
support for TCA_CBQ_OVL_STRATEGY, which is what needs to be set to
activate the class->drop() call (TC_CBQ_OVL_DROP strategy must be
set by userspace value must be set by userspace).

David Miller says:
   It seems really safe to kill this thing off, flag an error if someone
   tries to set the attribute, and therefore kill off all of the
   non-default cbq_ovl_*() functions.

A followup commit can then remove all .drop qdisc methods since this
removed the only caller.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Florian Westphal authored and David S. Miller committed Jun 9, 2016
1 parent 76e48f9 commit c3498d3
Showing 1 changed file with 6 additions and 160 deletions.
166 changes: 6 additions & 160 deletions net/sched/sch_cbq.c
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Original file line number Diff line number Diff line change
Expand Up @@ -80,7 +80,6 @@ struct cbq_class {
unsigned char priority; /* class priority */
unsigned char priority2; /* priority to be used after overlimit */
unsigned char ewma_log; /* time constant for idle time calculation */
unsigned char ovl_strategy;
#ifdef CONFIG_NET_CLS_ACT
unsigned char police;
#endif
Expand All @@ -94,10 +93,6 @@ struct cbq_class {
u32 avpkt;
struct qdisc_rate_table *R_tab;

/* Overlimit strategy parameters */
void (*overlimit)(struct cbq_class *cl);
psched_tdiff_t penalty;

/* General scheduler (WRR) parameters */
long allot;
long quantum; /* Allotment per WRR round */
Expand Down Expand Up @@ -402,11 +397,8 @@ cbq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
return ret;
}

/* Overlimit actions */

/* TC_CBQ_OVL_CLASSIC: (default) penalize leaf class by adding offtime */

static void cbq_ovl_classic(struct cbq_class *cl)
/* Overlimit action: penalize leaf class by adding offtime */
static void cbq_overlimit(struct cbq_class *cl)
{
struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
psched_tdiff_t delay = cl->undertime - q->now;
Expand Down Expand Up @@ -456,99 +448,6 @@ static void cbq_ovl_classic(struct cbq_class *cl)
}
}

/* TC_CBQ_OVL_RCLASSIC: penalize by offtime classes in hierarchy, when
* they go overlimit
*/

static void cbq_ovl_rclassic(struct cbq_class *cl)
{
struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
struct cbq_class *this = cl;

do {
if (cl->level > q->toplevel) {
cl = NULL;
break;
}
} while ((cl = cl->borrow) != NULL);

if (cl == NULL)
cl = this;
cbq_ovl_classic(cl);
}

/* TC_CBQ_OVL_DELAY: delay until it will go to underlimit */

static void cbq_ovl_delay(struct cbq_class *cl)
{
struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
psched_tdiff_t delay = cl->undertime - q->now;

if (test_bit(__QDISC_STATE_DEACTIVATED,
&qdisc_root_sleeping(cl->qdisc)->state))
return;

if (!cl->delayed) {
psched_time_t sched = q->now;
ktime_t expires;

delay += cl->offtime;
if (cl->avgidle < 0)
delay -= (-cl->avgidle) - ((-cl->avgidle) >> cl->ewma_log);
if (cl->avgidle < cl->minidle)
cl->avgidle = cl->minidle;
cl->undertime = q->now + delay;

if (delay > 0) {
sched += delay + cl->penalty;
cl->penalized = sched;
cl->cpriority = TC_CBQ_MAXPRIO;
q->pmask |= (1<<TC_CBQ_MAXPRIO);

expires = ns_to_ktime(PSCHED_TICKS2NS(sched));
if (hrtimer_try_to_cancel(&q->delay_timer) &&
ktime_to_ns(ktime_sub(
hrtimer_get_expires(&q->delay_timer),
expires)) > 0)
hrtimer_set_expires(&q->delay_timer, expires);
hrtimer_restart(&q->delay_timer);
cl->delayed = 1;
cl->xstats.overactions++;
return;
}
delay = 1;
}
if (q->wd_expires == 0 || q->wd_expires > delay)
q->wd_expires = delay;
}

/* TC_CBQ_OVL_LOWPRIO: penalize class by lowering its priority band */

static void cbq_ovl_lowprio(struct cbq_class *cl)
{
struct cbq_sched_data *q = qdisc_priv(cl->qdisc);

cl->penalized = q->now + cl->penalty;

if (cl->cpriority != cl->priority2) {
cl->cpriority = cl->priority2;
q->pmask |= (1<<cl->cpriority);
cl->xstats.overactions++;
}
cbq_ovl_classic(cl);
}

/* TC_CBQ_OVL_DROP: penalize class by dropping */

static void cbq_ovl_drop(struct cbq_class *cl)
{
if (cl->q->ops->drop)
if (cl->q->ops->drop(cl->q))
cl->qdisc->q.qlen--;
cl->xstats.overactions++;
cbq_ovl_classic(cl);
}

static psched_tdiff_t cbq_undelay_prio(struct cbq_sched_data *q, int prio,
psched_time_t now)
{
Expand Down Expand Up @@ -807,7 +706,7 @@ cbq_under_limit(struct cbq_class *cl)
cl = cl->borrow;
if (!cl) {
this_cl->qstats.overlimits++;
this_cl->overlimit(this_cl);
cbq_overlimit(this_cl);
return NULL;
}
if (cl->level > q->toplevel)
Expand Down Expand Up @@ -1280,35 +1179,6 @@ static int cbq_set_wrr(struct cbq_class *cl, struct tc_cbq_wrropt *wrr)
return 0;
}

static int cbq_set_overlimit(struct cbq_class *cl, struct tc_cbq_ovl *ovl)
{
switch (ovl->strategy) {
case TC_CBQ_OVL_CLASSIC:
cl->overlimit = cbq_ovl_classic;
break;
case TC_CBQ_OVL_DELAY:
cl->overlimit = cbq_ovl_delay;
break;
case TC_CBQ_OVL_LOWPRIO:
if (ovl->priority2 - 1 >= TC_CBQ_MAXPRIO ||
ovl->priority2 - 1 <= cl->priority)
return -EINVAL;
cl->priority2 = ovl->priority2 - 1;
cl->overlimit = cbq_ovl_lowprio;
break;
case TC_CBQ_OVL_DROP:
cl->overlimit = cbq_ovl_drop;
break;
case TC_CBQ_OVL_RCLASSIC:
cl->overlimit = cbq_ovl_rclassic;
break;
default:
return -EINVAL;
}
cl->penalty = ovl->penalty;
return 0;
}

#ifdef CONFIG_NET_CLS_ACT
static int cbq_set_police(struct cbq_class *cl, struct tc_cbq_police *p)
{
Expand Down Expand Up @@ -1375,8 +1245,6 @@ static int cbq_init(struct Qdisc *sch, struct nlattr *opt)
q->link.priority = TC_CBQ_MAXPRIO - 1;
q->link.priority2 = TC_CBQ_MAXPRIO - 1;
q->link.cpriority = TC_CBQ_MAXPRIO - 1;
q->link.ovl_strategy = TC_CBQ_OVL_CLASSIC;
q->link.overlimit = cbq_ovl_classic;
q->link.allot = psched_mtu(qdisc_dev(sch));
q->link.quantum = q->link.allot;
q->link.weight = q->link.R_tab->rate.rate;
Expand Down Expand Up @@ -1463,24 +1331,6 @@ static int cbq_dump_wrr(struct sk_buff *skb, struct cbq_class *cl)
return -1;
}

static int cbq_dump_ovl(struct sk_buff *skb, struct cbq_class *cl)
{
unsigned char *b = skb_tail_pointer(skb);
struct tc_cbq_ovl opt;

opt.strategy = cl->ovl_strategy;
opt.priority2 = cl->priority2 + 1;
opt.pad = 0;
opt.penalty = cl->penalty;
if (nla_put(skb, TCA_CBQ_OVL_STRATEGY, sizeof(opt), &opt))
goto nla_put_failure;
return skb->len;

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

static int cbq_dump_fopt(struct sk_buff *skb, struct cbq_class *cl)
{
unsigned char *b = skb_tail_pointer(skb);
Expand Down Expand Up @@ -1526,7 +1376,6 @@ static int cbq_dump_attr(struct sk_buff *skb, struct cbq_class *cl)
if (cbq_dump_lss(skb, cl) < 0 ||
cbq_dump_rate(skb, cl) < 0 ||
cbq_dump_wrr(skb, cl) < 0 ||
cbq_dump_ovl(skb, cl) < 0 ||
#ifdef CONFIG_NET_CLS_ACT
cbq_dump_police(skb, cl) < 0 ||
#endif
Expand Down Expand Up @@ -1736,6 +1585,9 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **t
if (err < 0)
return err;

if (tb[TCA_CBQ_OVL_STRATEGY])
return -EOPNOTSUPP;

if (cl) {
/* Check parent */
if (parentid) {
Expand Down Expand Up @@ -1784,9 +1636,6 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **t
cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
}

if (tb[TCA_CBQ_OVL_STRATEGY])
cbq_set_overlimit(cl, nla_data(tb[TCA_CBQ_OVL_STRATEGY]));

#ifdef CONFIG_NET_CLS_ACT
if (tb[TCA_CBQ_POLICE])
cbq_set_police(cl, nla_data(tb[TCA_CBQ_POLICE]));
Expand Down Expand Up @@ -1887,9 +1736,6 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **t
cl->maxidle = q->link.maxidle;
if (cl->avpkt == 0)
cl->avpkt = q->link.avpkt;
cl->overlimit = cbq_ovl_classic;
if (tb[TCA_CBQ_OVL_STRATEGY])
cbq_set_overlimit(cl, nla_data(tb[TCA_CBQ_OVL_STRATEGY]));
#ifdef CONFIG_NET_CLS_ACT
if (tb[TCA_CBQ_POLICE])
cbq_set_police(cl, nla_data(tb[TCA_CBQ_POLICE]));
Expand Down

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