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net_sched: Add qdisc __NET_XMIT_STOLEN flag
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Patrick McHardy <kaber@trash.net> noticed:
"The other problem that affects all qdiscs supporting actions is
TC_ACT_QUEUED/TC_ACT_STOLEN getting mapped to NET_XMIT_SUCCESS
even though the packet is not queued, corrupting upper qdiscs'
qlen counters."

and later explained:
"The reason why it translates it at all seems to be to not increase
the drops counter. Within a single qdisc this could be avoided by
other means easily, upper qdiscs would still increase the counter
when we return anything besides NET_XMIT_SUCCESS though.

This means we need a new NET_XMIT return value to indicate this to
the upper qdiscs. So I'd suggest to introduce NET_XMIT_STOLEN,
return that to upper qdiscs and translate it to NET_XMIT_SUCCESS
in dev_queue_xmit, similar to NET_XMIT_BYPASS."

David Miller <davem@davemloft.net> noticed:
"Maybe these NET_XMIT_* values being passed around should be a set of
bits. They could be composed of base meanings, combined with specific
attributes.

So you could say "NET_XMIT_DROP | __NET_XMIT_NO_DROP_COUNT"

The attributes get masked out by the top-level ->enqueue() caller,
such that the base meanings are the only thing that make their
way up into the stack. If it's only about communication within the
qdisc tree, let's simply code it that way."

This patch is trying to realize these ideas.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jarek Poplawski authored and David S. Miller committed Aug 5, 2008
1 parent 6e583ce commit 378a2f0
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Showing 12 changed files with 68 additions and 34 deletions.
1 change: 1 addition & 0 deletions include/linux/netdevice.h
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,7 @@ struct wireless_dev;
#define NET_XMIT_BYPASS 4 /* packet does not leave via dequeue;
(TC use only - dev_queue_xmit
returns this as NET_XMIT_SUCCESS) */
#define NET_XMIT_MASK 0xFFFF /* qdisc flags in net/sch_generic.h */

/* Backlog congestion levels */
#define NET_RX_SUCCESS 0 /* keep 'em coming, baby */
Expand Down
14 changes: 13 additions & 1 deletion include/net/sch_generic.h
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Original file line number Diff line number Diff line change
Expand Up @@ -343,6 +343,18 @@ static inline unsigned int qdisc_pkt_len(struct sk_buff *skb)
return qdisc_skb_cb(skb)->pkt_len;
}

#ifdef CONFIG_NET_CLS_ACT
/* additional qdisc xmit flags */
enum net_xmit_qdisc_t {
__NET_XMIT_STOLEN = 0x00010000,
};

#define net_xmit_drop_count(e) ((e) & __NET_XMIT_STOLEN ? 0 : 1)

#else
#define net_xmit_drop_count(e) (1)
#endif

static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
#ifdef CONFIG_NET_SCHED
Expand All @@ -355,7 +367,7 @@ static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
static inline int qdisc_enqueue_root(struct sk_buff *skb, struct Qdisc *sch)
{
qdisc_skb_cb(skb)->pkt_len = skb->len;
return qdisc_enqueue(skb, sch);
return qdisc_enqueue(skb, sch) & NET_XMIT_MASK;
}

static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
Expand Down
12 changes: 7 additions & 5 deletions net/sched/sch_atm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -415,7 +415,7 @@ static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
kfree_skb(skb);
return NET_XMIT_SUCCESS;
return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
kfree_skb(skb);
goto drop;
Expand All @@ -432,9 +432,11 @@ static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
ret = qdisc_enqueue(skb, flow->q);
if (ret != 0) {
drop: __maybe_unused
sch->qstats.drops++;
if (flow)
flow->qstats.drops++;
if (net_xmit_drop_count(ret)) {
sch->qstats.drops++;
if (flow)
flow->qstats.drops++;
}
return ret;
}
sch->bstats.bytes += qdisc_pkt_len(skb);
Expand Down Expand Up @@ -530,7 +532,7 @@ static int atm_tc_requeue(struct sk_buff *skb, struct Qdisc *sch)
if (!ret) {
sch->q.qlen++;
sch->qstats.requeues++;
} else {
} else if (net_xmit_drop_count(ret)) {
sch->qstats.drops++;
p->link.qstats.drops++;
}
Expand Down
23 changes: 15 additions & 8 deletions net/sched/sch_cbq.c
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Original file line number Diff line number Diff line change
Expand Up @@ -256,7 +256,7 @@ cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
switch (result) {
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
*qerr = NET_XMIT_SUCCESS;
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return NULL;
case TC_ACT_RECLASSIFY:
Expand Down Expand Up @@ -397,9 +397,11 @@ cbq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
return ret;
}

sch->qstats.drops++;
cbq_mark_toplevel(q, cl);
cl->qstats.drops++;
if (net_xmit_drop_count(ret)) {
sch->qstats.drops++;
cbq_mark_toplevel(q, cl);
cl->qstats.drops++;
}
return ret;
}

Expand Down Expand Up @@ -430,8 +432,10 @@ cbq_requeue(struct sk_buff *skb, struct Qdisc *sch)
cbq_activate_class(cl);
return 0;
}
sch->qstats.drops++;
cl->qstats.drops++;
if (net_xmit_drop_count(ret)) {
sch->qstats.drops++;
cl->qstats.drops++;
}
return ret;
}

Expand Down Expand Up @@ -664,21 +668,24 @@ static int cbq_reshape_fail(struct sk_buff *skb, struct Qdisc *child)
q->rx_class = NULL;

if (cl && (cl = cbq_reclassify(skb, cl)) != NULL) {
int ret;

cbq_mark_toplevel(q, cl);

q->rx_class = cl;
cl->q->__parent = sch;

if (qdisc_enqueue(skb, cl->q) == 0) {
ret = qdisc_enqueue(skb, cl->q);
if (ret == NET_XMIT_SUCCESS) {
sch->q.qlen++;
sch->bstats.packets++;
sch->bstats.bytes += qdisc_pkt_len(skb);
if (!cl->next_alive)
cbq_activate_class(cl);
return 0;
}
sch->qstats.drops++;
if (net_xmit_drop_count(ret))
sch->qstats.drops++;
return 0;
}

Expand Down
8 changes: 5 additions & 3 deletions net/sched/sch_dsmark.c
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Original file line number Diff line number Diff line change
Expand Up @@ -236,7 +236,7 @@ static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
kfree_skb(skb);
return NET_XMIT_SUCCESS;
return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;

case TC_ACT_SHOT:
goto drop;
Expand All @@ -254,7 +254,8 @@ static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)

err = qdisc_enqueue(skb, p->q);
if (err != NET_XMIT_SUCCESS) {
sch->qstats.drops++;
if (net_xmit_drop_count(err))
sch->qstats.drops++;
return err;
}

Expand Down Expand Up @@ -321,7 +322,8 @@ static int dsmark_requeue(struct sk_buff *skb, struct Qdisc *sch)

err = p->q->ops->requeue(skb, p->q);
if (err != NET_XMIT_SUCCESS) {
sch->qstats.drops++;
if (net_xmit_drop_count(err))
sch->qstats.drops++;
return err;
}

Expand Down
8 changes: 5 additions & 3 deletions net/sched/sch_hfsc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1166,7 +1166,7 @@ hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
switch (result) {
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
*qerr = NET_XMIT_SUCCESS;
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return NULL;
}
Expand Down Expand Up @@ -1586,8 +1586,10 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch)

err = qdisc_enqueue(skb, cl->qdisc);
if (unlikely(err != NET_XMIT_SUCCESS)) {
cl->qstats.drops++;
sch->qstats.drops++;
if (net_xmit_drop_count(err)) {
cl->qstats.drops++;
sch->qstats.drops++;
}
return err;
}

Expand Down
18 changes: 11 additions & 7 deletions net/sched/sch_htb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -221,7 +221,7 @@ static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch,
switch (result) {
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
*qerr = NET_XMIT_SUCCESS;
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return NULL;
}
Expand Down Expand Up @@ -572,9 +572,11 @@ static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
kfree_skb(skb);
return ret;
#endif
} else if (qdisc_enqueue(skb, cl->un.leaf.q) != NET_XMIT_SUCCESS) {
sch->qstats.drops++;
cl->qstats.drops++;
} else if ((ret = qdisc_enqueue(skb, cl->un.leaf.q)) != NET_XMIT_SUCCESS) {
if (net_xmit_drop_count(ret)) {
sch->qstats.drops++;
cl->qstats.drops++;
}
return NET_XMIT_DROP;
} else {
cl->bstats.packets +=
Expand Down Expand Up @@ -615,10 +617,12 @@ static int htb_requeue(struct sk_buff *skb, struct Qdisc *sch)
kfree_skb(skb);
return ret;
#endif
} else if (cl->un.leaf.q->ops->requeue(skb, cl->un.leaf.q) !=
} else if ((ret = cl->un.leaf.q->ops->requeue(skb, cl->un.leaf.q)) !=
NET_XMIT_SUCCESS) {
sch->qstats.drops++;
cl->qstats.drops++;
if (net_xmit_drop_count(ret)) {
sch->qstats.drops++;
cl->qstats.drops++;
}
return NET_XMIT_DROP;
} else
htb_activate(q, cl);
Expand Down
3 changes: 2 additions & 1 deletion net/sched/sch_netem.c
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Original file line number Diff line number Diff line change
Expand Up @@ -240,8 +240,9 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
sch->q.qlen++;
sch->bstats.bytes += qdisc_pkt_len(skb);
sch->bstats.packets++;
} else
} else if (net_xmit_drop_count(ret)) {
sch->qstats.drops++;
}

pr_debug("netem: enqueue ret %d\n", ret);
return ret;
Expand Down
8 changes: 5 additions & 3 deletions net/sched/sch_prio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,7 @@ prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
switch (err) {
case TC_ACT_STOLEN:
case TC_ACT_QUEUED:
*qerr = NET_XMIT_SUCCESS;
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return NULL;
}
Expand Down Expand Up @@ -88,7 +88,8 @@ prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
sch->q.qlen++;
return NET_XMIT_SUCCESS;
}
sch->qstats.drops++;
if (net_xmit_drop_count(ret))
sch->qstats.drops++;
return ret;
}

Expand All @@ -114,7 +115,8 @@ prio_requeue(struct sk_buff *skb, struct Qdisc* sch)
sch->qstats.requeues++;
return 0;
}
sch->qstats.drops++;
if (net_xmit_drop_count(ret))
sch->qstats.drops++;
return NET_XMIT_DROP;
}

Expand Down
2 changes: 1 addition & 1 deletion net/sched/sch_red.c
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Original file line number Diff line number Diff line change
Expand Up @@ -97,7 +97,7 @@ static int red_enqueue(struct sk_buff *skb, struct Qdisc* sch)
sch->bstats.bytes += qdisc_pkt_len(skb);
sch->bstats.packets++;
sch->q.qlen++;
} else {
} else if (net_xmit_drop_count(ret)) {
q->stats.pdrop++;
sch->qstats.drops++;
}
Expand Down
2 changes: 1 addition & 1 deletion net/sched/sch_sfq.c
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Original file line number Diff line number Diff line change
Expand Up @@ -178,7 +178,7 @@ static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
switch (result) {
case TC_ACT_STOLEN:
case TC_ACT_QUEUED:
*qerr = NET_XMIT_SUCCESS;
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return 0;
}
Expand Down
3 changes: 2 additions & 1 deletion net/sched/sch_tbf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -135,7 +135,8 @@ static int tbf_enqueue(struct sk_buff *skb, struct Qdisc* sch)

ret = qdisc_enqueue(skb, q->qdisc);
if (ret != 0) {
sch->qstats.drops++;
if (net_xmit_drop_count(ret))
sch->qstats.drops++;
return ret;
}

Expand Down

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