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>

1 files changed, 9 insertions, 2 deletions

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index f4eb365f7dcd..d0a6321c302e 100644
--- a/include/net/sch_generic.h
+++ b/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);
 }