[RFC take2] pkt_sched: gen_estimator: Dont report fake rate estimators

[Eric Dumazet <eric.dumazet@gmail.com>]

Here is second attempt to make this change, thanks Jarek !

This is indeed less intrusive !

[RFC] pkt_sched: gen_estimator: Dont report fake rate estimators

We currently send TCA_STATS_RATE_EST elements to netlink users, even if no estimator
is running.

# tc -s -d qdisc
qdisc pfifo_fast 0: dev eth0 root bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
 Sent 112833764978 bytes 1495081739 pkt (dropped 0, overlimits 0 requeues 0)
 rate 0bit 0pps backlog 0b 0p requeues 0

User has no way to tell if the "rate 0bit 0pps" is a real estimation, or a fake
one (because no estimator is active)

After this patch, tc command output is :
$ tc -s -d qdisc
qdisc pfifo_fast 0: dev eth0 root bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
 Sent 561075 bytes 1196 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0

We add a parameter to gnet_stats_copy_rate_est() function so that
it can use gen_estimator_active(bstats, r), as suggested by Jarek.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---
 include/net/gen_stats.h |    1 +
 net/core/gen_stats.c    |    7 ++++++-
 net/sched/act_api.c     |    2 +-
 net/sched/sch_api.c     |    2 +-
 net/sched/sch_cbq.c     |    2 +-
 net/sched/sch_drr.c     |    2 +-
 net/sched/sch_hfsc.c    |    2 +-
 net/sched/sch_htb.c     |    2 +-
 8 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
index c148855..a0800e6 100644
--- a/include/net/gen_stats.h
+++ b/include/net/gen_stats.h
@@ -30,6 +30,7 @@ extern int gnet_stats_start_copy_compat(struct sk_buff *skb, int type,
 extern int gnet_stats_copy_basic(struct gnet_dump *d,
 				 struct gnet_stats_basic_packed *b);
 extern int gnet_stats_copy_rate_est(struct gnet_dump *d,
+				    const struct gnet_stats_basic_packed *bstats,
 				    struct gnet_stats_rate_est *r);
 extern int gnet_stats_copy_queue(struct gnet_dump *d,
 				 struct gnet_stats_queue *q);
diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c
index 8569310..6f9513e 100644
--- a/net/core/gen_stats.c
+++ b/net/core/gen_stats.c
@@ -136,8 +136,13 @@ gnet_stats_copy_basic(struct gnet_dump *d, struct gnet_stats_basic_packed *b)
  * if the room in the socket buffer was not sufficient.
  */
 int
-gnet_stats_copy_rate_est(struct gnet_dump *d, struct gnet_stats_rate_est *r)
+gnet_stats_copy_rate_est(struct gnet_dump *d,
+			 const struct gnet_stats_basic_packed *bstats,
+			 struct gnet_stats_rate_est *r)
 {
+	if (!gen_estimator_active(bstats, r))
+		return 0;
+
 	if (d->compat_tc_stats) {
 		d->tc_stats.bps = r->bps;
 		d->tc_stats.pps = r->pps;
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 2dfb3e7..2b0d5ee 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -618,7 +618,7 @@ int tcf_action_copy_stats(struct sk_buff *skb, struct tc_action *a,
 			goto errout;
 
 	if (gnet_stats_copy_basic(&d, &h->tcf_bstats) < 0 ||
-	    gnet_stats_copy_rate_est(&d, &h->tcf_rate_est) < 0 ||
+	    gnet_stats_copy_rate_est(&d, &h->tcf_bstats, &h->tcf_rate_est) < 0 ||
 	    gnet_stats_copy_queue(&d, &h->tcf_qstats) < 0)
 		goto errout;
 
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 903e418..1acfd29 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1179,7 +1179,7 @@ static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
 		goto nla_put_failure;
 
 	if (gnet_stats_copy_basic(&d, &q->bstats) < 0 ||
-	    gnet_stats_copy_rate_est(&d, &q->rate_est) < 0 ||
+	    gnet_stats_copy_rate_est(&d, &q->bstats, &q->rate_est) < 0 ||
 	    gnet_stats_copy_queue(&d, &q->qstats) < 0)
 		goto nla_put_failure;
 
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 5b132c4..3846d65 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -1609,7 +1609,7 @@ cbq_dump_class_stats(struct Qdisc *sch, unsigned long arg,
 		cl->xstats.undertime = cl->undertime - q->now;
 
 	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
-	    gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
+	    gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
 	    gnet_stats_copy_queue(d, &cl->qstats) < 0)
 		return -1;
 
diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c
index 5a888af..a65604f 100644
--- a/net/sched/sch_drr.c
+++ b/net/sched/sch_drr.c
@@ -280,7 +280,7 @@ static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
 	}
 
 	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
-	    gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
+	    gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
 	    gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
 		return -1;
 
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 2c5c76b..b38b39c 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1375,7 +1375,7 @@ hfsc_dump_class_stats(struct Qdisc *sch, unsigned long arg,
 	xstats.rtwork  = cl->cl_cumul;
 
 	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
-	    gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
+	    gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
 	    gnet_stats_copy_queue(d, &cl->qstats) < 0)
 		return -1;
 
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 85acab9..8352fa3 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1105,7 +1105,7 @@ htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d)
 	cl->xstats.ctokens = cl->ctokens;
 
 	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
-	    gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
+	    gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
 	    gnet_stats_copy_queue(d, &cl->qstats) < 0)
 		return -1;