From 3971a535b839489e4ea31796cc086e6ce616318c Mon Sep 17 00:00:00 2001 From: Petr Machata Date: Mon, 6 Jan 2020 18:01:55 +0000 Subject: mlxsw: spectrum_qdisc: Ignore grafting of invisible FIFO The following patch will change PRIO to replace a removed Qdisc with an invisible FIFO, instead of NOOP. mlxsw will see this replacement due to the graft message that is generated. But because FIFO does not issue its own REPLACE message, when the graft operation takes place, the Qdisc that mlxsw tracks under the indicated band is still the old one. The child handle (0:0) therefore does not match, and mlxsw rejects the graft operation, which leads to an extack message: Warning: Offloading graft operation failed. Fix by ignoring the invisible children in the PRIO graft handler. The DESTROY message of the removed Qdisc is going to follow shortly and handle the removal. Fixes: 32dc5efc6cb4 ("mlxsw: spectrum: qdiscs: prio: Handle graft command") Signed-off-by: Petr Machata Acked-by: Jiri Pirko Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c index 68cc6737d45c..46d43cfd04e9 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c @@ -651,6 +651,13 @@ mlxsw_sp_qdisc_prio_graft(struct mlxsw_sp_port *mlxsw_sp_port, mlxsw_sp_port->tclass_qdiscs[tclass_num].handle == p->child_handle) return 0; + if (!p->child_handle) { + /* This is an invisible FIFO replacing the original Qdisc. + * Ignore it--the original Qdisc's destroy will follow. + */ + return 0; + } + /* See if the grafted qdisc is already offloaded on any tclass. If so, * unoffload it. */ -- cgit v1.2.3 From 240ce7f6428ff5188b9eedc066e1e4d645b8635f Mon Sep 17 00:00:00 2001 From: Petr Machata Date: Mon, 6 Jan 2020 18:01:56 +0000 Subject: net: sch_prio: When ungrafting, replace with FIFO When a child Qdisc is removed from one of the PRIO Qdisc's bands, it is replaced unconditionally by a NOOP qdisc. As a result, any traffic hitting that band gets dropped. That is incorrect--no Qdisc was explicitly added when PRIO was created, and after removal, none should have to be added either. Fix PRIO by first attempting to create a default Qdisc and only falling back to noop when that fails. This pattern of attempting to create an invisible FIFO, using NOOP only as a fallback, is also seen in other Qdiscs. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Petr Machata Acked-by: Jiri Pirko Signed-off-by: David S. Miller --- net/sched/sch_prio.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c index 18b884cfdfe8..647941702f9f 100644 --- a/net/sched/sch_prio.c +++ b/net/sched/sch_prio.c @@ -292,8 +292,14 @@ static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, struct tc_prio_qopt_offload graft_offload; unsigned long band = arg - 1; - if (new == NULL) - new = &noop_qdisc; + if (!new) { + new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, + TC_H_MAKE(sch->handle, arg), extack); + if (!new) + new = &noop_qdisc; + else + qdisc_hash_add(new, true); + } *old = qdisc_replace(sch, new, &q->queues[band]); -- cgit v1.2.3