Commit 8c95eca0 authored by Toke Høiland-Jørgensen's avatar Toke Høiland-Jørgensen Committed by David S. Miller
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sch_cake: don't call diffserv parsing code when it is not needed 



As a further optimisation of the diffserv parsing codepath, we can skip it
entirely if CAKE is configured to neither use diffserv-based
classification, nor to zero out the diffserv bits.

Fixes: c87b4ecd ("sch_cake: Make sure we can write the IP header before changing DSCP bits")
Signed-off-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9208d286

net/sched/sch_cake.c

+9 −4
Original line number Diff line number Diff line
@@ -1551,7 +1551,7 @@ 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)

{

	const int offset = skb_network_offset(skb);

	u16 *buf, buf_;
@@ -1612,14 +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;
@@ -1633,6 +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))

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