diff mbox series

[net,1/2] mlxsw: spectrum_qdisc: Ignore grafting of invisible FIFO

Message ID 4f352657f275209e1923975f71641a00d5fdb046.1578333529.git.petrm@mellanox.com
State Accepted
Delegated to: David Miller
Headers show
Series When ungrafting from PRIO, replace child with FIFO | expand

Commit Message

Petr Machata Jan. 6, 2020, 6:01 p.m. UTC 
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 <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c | 7 +++++++
 1 file changed, 7 insertions(+)
diff mbox series

Patch

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.
 	 */