[PATCH] net: sched: avoid duplicates in classes dump

This is a follow up of commit ea3274695353 ("net: sched: avoid
duplicates in qdisc dump") which has fixed the issue only for the qdisc
dump.

The duplicate printing also occurs when dumping the classes via
  tc class show dev eth0

Fixes: 59cc1f61f09c ("net: sched: convert qdisc linked list to hashtable")
Signed-off-by: Maximilian Heyne <redacted>
---
 net/sched/sch_api.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index e2e4353db8a7..f87d07736a14 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c

@@ -2168,7 +2168,7 @@ static int tc_dump_tclass_qdisc(struct Qdisc *q, struct sk_buff *skb,
 
 static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb,
 			       struct tcmsg *tcm, struct netlink_callback *cb,
-			       int *t_p, int s_t)
+			       int *t_p, int s_t, bool recur)
 {
 	struct Qdisc *q;
 	int b;

@@ -2179,7 +2179,7 @@ static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb,
 	if (tc_dump_tclass_qdisc(root, skb, tcm, cb, t_p, s_t) < 0)
 		return -1;
 
-	if (!qdisc_dev(root))
+	if (!qdisc_dev(root) || !recur)
 		return 0;
 
 	if (tcm->tcm_parent) {

@@ -2214,13 +2214,13 @@ static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
 	s_t = cb->args[0];
 	t = 0;
 
-	if (tc_dump_tclass_root(dev->qdisc, skb, tcm, cb, &t, s_t) < 0)
+	if (tc_dump_tclass_root(dev->qdisc, skb, tcm, cb, &t, s_t, true) < 0)
 		goto done;
 
 	dev_queue = dev_ingress_queue(dev);
 	if (dev_queue &&
 	    tc_dump_tclass_root(dev_queue->qdisc_sleeping, skb, tcm, cb,
-				&t, s_t) < 0)
+				&t, s_t, false) < 0)
 		goto done;
 
 done:

-- 
2.16.6




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On Thu, Mar 4, 2021 at 6:44 AM Maximilian Heyne [off-list ref] wrote:

This is a follow up of commit ea3274695353 ("net: sched: avoid
duplicates in qdisc dump") which has fixed the issue only for the qdisc
dump.

The duplicate printing also occurs when dumping the classes via
  tc class show dev eth0

Fixes: 59cc1f61f09c ("net: sched: convert qdisc linked list to hashtable")
Signed-off-by: Maximilian Heyne <redacted>

Seems reasonable. If you can show the difference of tc class dump
before and after this patch in your changelog, it would be helpful to
understand the bug here.

Thanks.

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Thu, 4 Mar 2021 14:43:17 +0000 you wrote:

This is a follow up of commit ea3274695353 ("net: sched: avoid
duplicates in qdisc dump") which has fixed the issue only for the qdisc
dump.

The duplicate printing also occurs when dumping the classes via
  tc class show dev eth0

[...]

Here is the summary with links:
  - net: sched: avoid duplicates in classes dump
    https://git.kernel.org/netdev/net/c/bfc256056358

You are awesome, thank you!
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