# \[PATCH net-next 1/9\] net: sch\_tbf: Add a graft command

- From: Ido Schimmel \<hidden\>
- Date: 2021-10-19 08:08:17 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/10/11213823
- Thread: https://ratatoskr.run/netdev/2021/10/11213821/t.md

```text
From: Petr Machata <petrm@nvidia.com>

As another qdisc is linked to the TBF, the latter should issue an event to
give drivers a chance to react to the grafting. In other qdiscs, this event
is called GRAFT, so follow suit with TBF as well.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
---
 include/net/pkt_cls.h |  2 ++
 net/sched/sch_tbf.c   | 16 ++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 4a5833108083..193f88ebf629 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -977,6 +977,7 @@ enum tc_tbf_command {
 	TC_TBF_REPLACE,
 	TC_TBF_DESTROY,
 	TC_TBF_STATS,
+	TC_TBF_GRAFT,
 };
 
 struct tc_tbf_qopt_offload_replace_params {
@@ -992,6 +993,7 @@ struct tc_tbf_qopt_offload {
 	union {
 		struct tc_tbf_qopt_offload_replace_params replace_params;
 		struct tc_qopt_offload_stats stats;
+		u32 child_handle;
 	};
 };
 
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 78e79029dc63..72102277449e 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -184,6 +184,20 @@ static int tbf_offload_dump(struct Qdisc *sch)
 	return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_TBF, &qopt);
 }
 
+static void tbf_offload_graft(struct Qdisc *sch, struct Qdisc *new,
+			      struct Qdisc *old, struct netlink_ext_ack *extack)
+{
+	struct tc_tbf_qopt_offload graft_offload = {
+		.handle		= sch->handle,
+		.parent		= sch->parent,
+		.child_handle	= new->handle,
+		.command	= TC_TBF_GRAFT,
+	};
+
+	qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old,
+				   TC_SETUP_QDISC_TBF, &graft_offload, extack);
+}
+
 /* GSO packet is too big, segment it so that tbf can transmit
  * each segment in time
  */
@@ -547,6 +561,8 @@ static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 		new = &noop_qdisc;
 
 	*old = qdisc_replace(sch, new, &q->qdisc);
+
+	tbf_offload_graft(sch, new, *old, extack);
 	return 0;
 }
 
-- 
2.31.1

```