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Commit 3b3ae880 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

net: sched: consolidate tc_classify{,_compat} 



For classifiers getting invoked via tc_classify(), we always need an
extra function call into tc_classify_compat(), as both are being
exported as symbols and tc_classify() itself doesn't do much except
handling of reclassifications when tp->classify() returned with
TC_ACT_RECLASSIFY.

CBQ and ATM are the only qdiscs that directly call into tc_classify_compat(),
all others use tc_classify(). When tc actions are being configured
out in the kernel, tc_classify() effectively does nothing besides
delegating.

We could spare this layer and consolidate both functions. pktgen on
single CPU constantly pushing skbs directly into the netif_receive_skb()
path with a dummy classifier on ingress qdisc attached, improves
slightly from 22.3Mpps to 23.1Mpps.

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fe218823

include/net/pkt_sched.h

+1 −3
Original line number Diff line number Diff line
@@ -110,10 +110,8 @@ static inline void qdisc_run(struct Qdisc *q) 
		__qdisc_run(q);

}



int tc_classify_compat(struct sk_buff *skb, const struct tcf_proto *tp,

		       struct tcf_result *res);

int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,

		struct tcf_result *res);

		struct tcf_result *res, bool compat_mode);



static inline __be16 tc_skb_protocol(const struct sk_buff *skb)

{

net/core/dev.c

+1 −1
Original line number Diff line number Diff line
@@ -3657,7 +3657,7 @@ static inline struct sk_buff *handle_ing(struct sk_buff *skb, 
	skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_INGRESS);

	qdisc_bstats_cpu_update(cl->q, skb);



	switch (tc_classify(skb, cl, &cl_res)) {

	switch (tc_classify(skb, cl, &cl_res, false)) {

	case TC_ACT_OK:

	case TC_ACT_RECLASSIFY:

		skb->tc_index = TC_H_MIN(cl_res.classid);

net/sched/sch_api.c

+25 −30
Original line number Diff line number Diff line
@@ -1806,51 +1806,46 @@ static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb) 
 * to this qdisc, (optionally) tests for protocol and asks

 * specific classifiers.

 */

int tc_classify_compat(struct sk_buff *skb, const struct tcf_proto *tp,

		       struct tcf_result *res)

int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,

		struct tcf_result *res, bool compat_mode)

{

	__be16 protocol = tc_skb_protocol(skb);

	int err;

#ifdef CONFIG_NET_CLS_ACT

	const struct tcf_proto *old_tp = tp;

	int limit = 0;



reclassify:

#endif

	for (; tp; tp = rcu_dereference_bh(tp->next)) {

		int err;



		if (tp->protocol != protocol &&

		    tp->protocol != htons(ETH_P_ALL))

			continue;

		err = tp->classify(skb, tp, res);



		err = tp->classify(skb, tp, res);

#ifdef CONFIG_NET_CLS_ACT

		if (unlikely(err == TC_ACT_RECLASSIFY &&

			     !compat_mode))

			goto reset;

#endif

		if (err >= 0)

			return err;

	}

	return -1;

}

EXPORT_SYMBOL(tc_classify_compat);



int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,

		struct tcf_result *res)

{

	int err = 0;

#ifdef CONFIG_NET_CLS_ACT

	const struct tcf_proto *otp = tp;

	int limit = 0;

reclassify:

#endif



	err = tc_classify_compat(skb, tp, res);

	return -1;

#ifdef CONFIG_NET_CLS_ACT

	if (err == TC_ACT_RECLASSIFY) {

		tp = otp;



reset:

	if (unlikely(limit++ >= MAX_REC_LOOP)) {

			net_notice_ratelimited("%s: packet reclassify loop rule prio %u protocol %02x\n",

					       tp->q->ops->id,

					       tp->prio & 0xffff,

					       ntohs(tp->protocol));

		net_notice_ratelimited("%s: reclassify loop, rule prio %u, "

				       "protocol %02x\n", tp->q->ops->id,

				       tp->prio & 0xffff, ntohs(tp->protocol));

		return TC_ACT_SHOT;

	}



	tp = old_tp;

	goto reclassify;

	}

#endif

	return err;

}

EXPORT_SYMBOL(tc_classify);

net/sched/sch_atm.c

+1 −1
Original line number Diff line number Diff line
@@ -375,7 +375,7 @@ static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch) 
		list_for_each_entry(flow, &p->flows, list) {

			fl = rcu_dereference_bh(flow->filter_list);

			if (fl) {

				result = tc_classify_compat(skb, fl, &res);

				result = tc_classify(skb, fl, &res, true);

				if (result < 0)

					continue;

				flow = (struct atm_flow_data *)res.class;

net/sched/sch_cbq.c

+1 −1
Original line number Diff line number Diff line
@@ -240,7 +240,7 @@ cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) 
		/*

		 * Step 2+n. Apply classifier.

		 */

		result = tc_classify_compat(skb, fl, &res);

		result = tc_classify(skb, fl, &res, true);

		if (!fl || result < 0)

			goto fallback;