Commit 6aeaf262 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'sched-A-couple-of-fixes-for-sch_cake' 



Toke Høiland-Jørgensen says:

====================
sched: A couple of fixes for sch_cake

This series contains a couple of fixes for diffserv handling in sch_cake that
provide a nice speedup (with a somewhat pedantic nit fix tacked on to the end).

Not quite sure about whether this should go to stable; it does provide a nice
speedup, but it's not strictly a fix in the "correctness" sense. I lean towards
including this in stable as well, since our most important consumer of that
(OpenWrt) is likely to backport the series anyway.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 1ae71d99 3f608f0c

net/sched/sch_cake.c

+41 −17
Original line number Diff line number Diff line
@@ -1551,32 +1551,51 @@ static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free) 
	return idx + (tin << 16);

}



static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)

static u8 cake_handle_diffserv(struct sk_buff *skb, bool wash)

{

	int wlen = skb_network_offset(skb);

	const int offset = skb_network_offset(skb);

	u16 *buf, buf_;

	u8 dscp;



	switch (tc_skb_protocol(skb)) {

	case htons(ETH_P_IP):

		wlen += sizeof(struct iphdr);

		buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);

		if (unlikely(!buf))

			return 0;



		/* ToS is in the second byte of iphdr */

		dscp = ipv4_get_dsfield((struct iphdr *)buf) >> 2;



		if (wash && dscp) {

			const int wlen = offset + sizeof(struct iphdr);



			if (!pskb_may_pull(skb, wlen) ||

			    skb_try_make_writable(skb, wlen))

				return 0;



		dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2;

		if (wash && dscp)

			ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0);

		}



		return dscp;



	case htons(ETH_P_IPV6):

		wlen += sizeof(struct ipv6hdr);

		buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);

		if (unlikely(!buf))

			return 0;



		/* Traffic class is in the first and second bytes of ipv6hdr */

		dscp = ipv6_get_dsfield((struct ipv6hdr *)buf) >> 2;



		if (wash && dscp) {

			const int wlen = offset + sizeof(struct ipv6hdr);



			if (!pskb_may_pull(skb, wlen) ||

			    skb_try_make_writable(skb, wlen))

				return 0;



		dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;

		if (wash && dscp)

			ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0);

		}



		return dscp;



	case htons(ETH_P_ARP):
@@ -1593,14 +1612,17 @@ static struct cake_tin_data *cake_select_tin(struct Qdisc *sch, 
{

	struct cake_sched_data *q = qdisc_priv(sch);

	u32 tin, mark;

	bool wash;

	u8 dscp;



	/* Tin selection: Default to diffserv-based selection, allow overriding

	 * using firewall marks or skb->priority.

	 * using firewall marks or skb->priority. Call DSCP parsing early if

	 * wash is enabled, otherwise defer to below to skip unneeded parsing.

	 */

	dscp = cake_handle_diffserv(skb,

				    q->rate_flags & CAKE_FLAG_WASH);

	mark = (skb->mark & q->fwmark_mask) >> q->fwmark_shft;

	wash = !!(q->rate_flags & CAKE_FLAG_WASH);

	if (wash)

		dscp = cake_handle_diffserv(skb, wash);



	if (q->tin_mode == CAKE_DIFFSERV_BESTEFFORT)

		tin = 0;
@@ -1614,6 +1636,8 @@ static struct cake_tin_data *cake_select_tin(struct Qdisc *sch, 
		tin = q->tin_order[TC_H_MIN(skb->priority) - 1];



	else {

		if (!wash)

			dscp = cake_handle_diffserv(skb, wash);

		tin = q->tin_index[dscp];



		if (unlikely(tin >= q->tin_cnt))
@@ -2691,7 +2715,7 @@ static int cake_init(struct Qdisc *sch, struct nlattr *opt, 
	qdisc_watchdog_init(&q->watchdog, sch);



	if (opt) {

		int err = cake_change(sch, opt, extack);

		err = cake_change(sch, opt, extack);



		if (err)

			return err;

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