net_sched: add u64 rate to psched_ratecfg_precompute()

Add an extra u64 rate parameter to psched_ratecfg_precompute()
so that some qdisc can opt-in for 64bit rates in the future,
to overcome the ~34 Gbits limit.

psched_ratecfg_getrate() reports a legacy structure to
tc utility, so if actual rate is above the 32bit rate field,
cap it to the 34Gbit limit.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sch_generic.h

@@ -702,13 +702,20 @@ static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
 }
 
 void psched_ratecfg_precompute(struct psched_ratecfg *r,
-			       const struct tc_ratespec *conf);
+			       const struct tc_ratespec *conf,
+			       u64 rate64);
 
 static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
 					  const struct psched_ratecfg *r)
 {
 	memset(res, 0, sizeof(*res));
-	res->rate = r->rate_bytes_ps;
+
+	/* legacy struct tc_ratespec has a 32bit @rate field
+	 * Qdisc using 64bit rate should add new attributes
+	 * in order to maintain compatibility.
+	 */
+	res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
+
 	res->overhead = r->overhead;
 	res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
 }

net/sched/act_police.c

@@ -231,14 +231,14 @@ override:
 	}
 	if (R_tab) {
 		police->rate_present = true;
-		psched_ratecfg_precompute(&police->rate, &R_tab->rate);
+		psched_ratecfg_precompute(&police->rate, &R_tab->rate, 0);
 		qdisc_put_rtab(R_tab);
 	} else {
 		police->rate_present = false;
 	}
 	if (P_tab) {
 		police->peak_present = true;
-		psched_ratecfg_precompute(&police->peak, &P_tab->rate);
+		psched_ratecfg_precompute(&police->peak, &P_tab->rate, 0);
 		qdisc_put_rtab(P_tab);
 	} else {
 		police->peak_present = false;

net/sched/sch_generic.c

@@ -910,11 +910,12 @@ void dev_shutdown(struct net_device *dev)
 }
 
 void psched_ratecfg_precompute(struct psched_ratecfg *r,
-			       const struct tc_ratespec *conf)
+			       const struct tc_ratespec *conf,
+			       u64 rate64)
 {
 	memset(r, 0, sizeof(*r));
 	r->overhead = conf->overhead;
-	r->rate_bytes_ps = conf->rate;
+	r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
 	r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
 	r->mult = 1;
 	/*

net/sched/sch_htb.c

@@ -1491,8 +1491,8 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
 			cl->prio = TC_HTB_NUMPRIO - 1;
 	}
 
-	psched_ratecfg_precompute(&cl->rate, &hopt->rate);
-	psched_ratecfg_precompute(&cl->ceil, &hopt->ceil);
+	psched_ratecfg_precompute(&cl->rate, &hopt->rate, 0);
+	psched_ratecfg_precompute(&cl->ceil, &hopt->ceil, 0);
 
 	cl->buffer = PSCHED_TICKS2NS(hopt->buffer);
 	cl->cbuffer = PSCHED_TICKS2NS(hopt->cbuffer);

net/sched/sch_tbf.c

@@ -341,9 +341,9 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt)
 	q->tokens = q->buffer;
 	q->ptokens = q->mtu;
 
-	psched_ratecfg_precompute(&q->rate, &rtab->rate);
+	psched_ratecfg_precompute(&q->rate, &rtab->rate, 0);
 	if (ptab) {
-		psched_ratecfg_precompute(&q->peak, &ptab->rate);
+		psched_ratecfg_precompute(&q->peak, &ptab->rate, 0);
 		q->peak_present = true;
 	} else {
 		q->peak_present = false;