net: sched: RED: Introduce an ECN nodrop mode

[linux-2.6-microblaze.git] / net / sched / sch_red.c

diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index d4ce111..3ef0a4f 100644 (file)
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -48,7 +48,7 @@ struct red_sched_data {
        struct Qdisc            *qdisc;
 };
 
-static const u32 red_supported_flags = TC_RED_HISTORIC_FLAGS;
+static const u32 red_supported_flags = TC_RED_HISTORIC_FLAGS | TC_RED_NODROP;
 
 static inline int red_use_ecn(struct red_sched_data *q)
 {
@@ -60,6 +60,11 @@ static inline int red_use_harddrop(struct red_sched_data *q)
        return q->flags & TC_RED_HARDDROP;
 }
 
+static int red_use_nodrop(struct red_sched_data *q)
+{
+       return q->flags & TC_RED_NODROP;
+}
+
 static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
                       struct sk_buff **to_free)
 {
@@ -80,23 +85,36 @@ static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 
        case RED_PROB_MARK:
                qdisc_qstats_overlimit(sch);
-               if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
+               if (!red_use_ecn(q)) {
                        q->stats.prob_drop++;
                        goto congestion_drop;
                }
 
-               q->stats.prob_mark++;
+               if (INET_ECN_set_ce(skb)) {
+                       q->stats.prob_mark++;
+               } else if (!red_use_nodrop(q)) {
+                       q->stats.prob_drop++;
+                       goto congestion_drop;
+               }
+
+               /* Non-ECT packet in ECN nodrop mode: queue it. */
                break;
 
        case RED_HARD_MARK:
                qdisc_qstats_overlimit(sch);
-               if (red_use_harddrop(q) || !red_use_ecn(q) ||
-                   !INET_ECN_set_ce(skb)) {
+               if (red_use_harddrop(q) || !red_use_ecn(q)) {
+                       q->stats.forced_drop++;
+                       goto congestion_drop;
+               }
+
+               if (INET_ECN_set_ce(skb)) {
+                       q->stats.forced_mark++;
+               } else if (!red_use_nodrop(q)) {
                        q->stats.forced_drop++;
                        goto congestion_drop;
                }
 
-               q->stats.forced_mark++;
+               /* Non-ECT packet in ECN nodrop mode: queue it. */
                break;
        }
 
@@ -171,6 +189,7 @@ static int red_offload(struct Qdisc *sch, bool enable)
                opt.set.limit = q->limit;
                opt.set.is_ecn = red_use_ecn(q);
                opt.set.is_harddrop = red_use_harddrop(q);
+               opt.set.is_nodrop = red_use_nodrop(q);
                opt.set.qstats = &sch->qstats;
        } else {
                opt.command = TC_RED_DESTROY;