[PATCH net-next 07/14] net: sched: gred: support reporting stats from offloads

[Jakub Kicinski]

Allow drivers which offload GRED to report back statistics.  Since
A lot of GRED stats is fairly ad hoc in nature pass to drivers the
standard struct gnet_stats_basic/gnet_stats_queue pairs, and
untangle the values in the core.

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
Reviewed-by: John Hurley <john.hur...@netronome.com>
---
 include/net/pkt_cls.h |  8 ++++++++
 net/sched/sch_gred.c  | 47 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index c9198797aaed..d0e9a8091426 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -871,6 +871,7 @@ struct tc_red_qopt_offload {
 enum tc_gred_command {
        TC_GRED_REPLACE,
        TC_GRED_DESTROY,
+       TC_GRED_STATS,
 };
 
 struct tc_gred_vq_qopt_offload_params {
@@ -895,12 +896,19 @@ struct tc_gred_qopt_offload_params {
        struct tc_gred_vq_qopt_offload_params tab[MAX_DPs];
 };
 
+struct tc_gred_qopt_offload_stats {
+       struct gnet_stats_basic_packed bstats[MAX_DPs];
+       struct gnet_stats_queue qstats[MAX_DPs];
+       struct red_stats *xstats[MAX_DPs];
+};
+
 struct tc_gred_qopt_offload {
        enum tc_gred_command command;
        u32 handle;
        u32 parent;
        union {
                struct tc_gred_qopt_offload_params set;
+               struct tc_gred_qopt_offload_stats stats;
        };
 };
 
diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
index 908c9d1dfdf8..234afbf9115b 100644
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -354,6 +354,50 @@ static void gred_offload(struct Qdisc *sch, enum 
tc_gred_command command)
        dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_GRED, &opt);
 }
 
+static int gred_offload_dump_stats(struct Qdisc *sch)
+{
+       struct gred_sched *table = qdisc_priv(sch);
+       struct tc_gred_qopt_offload *hw_stats;
+       unsigned int i;
+       int ret;
+
+       hw_stats = kzalloc(sizeof(*hw_stats), GFP_KERNEL);
+       if (!hw_stats)
+               return -ENOMEM;
+
+       hw_stats->command = TC_GRED_STATS;
+       hw_stats->handle = sch->handle;
+       hw_stats->parent = sch->parent;
+
+       for (i = 0; i < MAX_DPs; i++)
+               if (table->tab[i])
+                       hw_stats->stats.xstats[i] = &table->tab[i]->stats;
+
+       ret = qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_GRED, hw_stats);
+       /* Even if driver returns failure adjust the stats - in case offload
+        * ended but driver still wants to adjust the values.
+        */
+       for (i = 0; i < MAX_DPs; i++) {
+               if (!table->tab[i])
+                       continue;
+               table->tab[i]->packetsin += hw_stats->stats.bstats[i].packets;
+               table->tab[i]->bytesin += hw_stats->stats.bstats[i].bytes;
+               table->tab[i]->backlog += hw_stats->stats.qstats[i].backlog;
+
+               _bstats_update(&sch->bstats,
+                              hw_stats->stats.bstats[i].bytes,
+                              hw_stats->stats.bstats[i].packets);
+               sch->qstats.qlen += hw_stats->stats.qstats[i].qlen;
+               sch->qstats.backlog += hw_stats->stats.qstats[i].backlog;
+               sch->qstats.drops += hw_stats->stats.qstats[i].drops;
+               sch->qstats.requeues += hw_stats->stats.qstats[i].requeues;
+               sch->qstats.overlimits += hw_stats->stats.qstats[i].overlimits;
+       }
+
+       kfree(hw_stats);
+       return ret;
+}
+
 static inline void gred_destroy_vq(struct gred_sched_data *q)
 {
        kfree(q);
@@ -725,6 +769,9 @@ static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
                .flags  = table->red_flags,
        };
 
+       if (gred_offload_dump_stats(sch))
+               goto nla_put_failure;
+
        opts = nla_nest_start(skb, TCA_OPTIONS);
        if (opts == NULL)
                goto nla_put_failure;
-- 
2.17.1