Thread (20 messages) flat view 20 messages, 3 authors, 2023-02-20

Re: [PATCH net-next 08/12] net/sched: mqprio: add an extack message to mqprio_parse_opt()

From: Ferenc Fejes <hidden>
Date: 2023-02-17 07:24:15
Also in: lkml

Hi Vladimir!

On Fri, 2023-02-17 at 01:21 +0200, Vladimir Oltean wrote:
Ferenc reports that a combination of poor iproute2 defaults and
obscure
cases where the kernel returns -EINVAL make it difficult to
understand
what is wrong with this command:

$ ip link add veth0 numtxqueues 8 numrxqueues 8 type veth peer name
veth1
$ tc qdisc add dev veth0 root mqprio num_tc 8 map 0 1 2 3 4 5 6 7 \
        queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7
RTNETLINK answers: Invalid argument

Hopefully with this patch, the cause is clearer:

Error: Device does not support hardware offload.
Much better, great improvement!
quoted hunk ↗ jump to hunk
This was rejected because iproute2 defaults to "hw 1" if the option
is
not specified.

Link:
https://patchwork.kernel.org/project/netdevbpf/patch/20230204135307.1036988-3-vladimir.oltean@nxp.com/#25215636
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 net/sched/sch_mqprio.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/sched/sch_mqprio.c b/net/sched/sch_mqprio.c
index 18eda5fade81..52cfc0ec2e23 100644
--- a/net/sched/sch_mqprio.c
+++ b/net/sched/sch_mqprio.c
@@ -134,8 +134,11 @@ static int mqprio_parse_opt(struct net_device
*dev, struct tc_mqprio_qopt *qopt,
        /* If ndo_setup_tc is not present then hardware doesn't
support offload
         * and we should return an error.
         */
-       if (qopt->hw && !dev->netdev_ops->ndo_setup_tc)
+       if (qopt->hw && !dev->netdev_ops->ndo_setup_tc) {
+               NL_SET_ERR_MSG(extack,
+                              "Device does not support hardware
offload");
                return -EINVAL;
+       }
 
        return 0;
 }
Thanks for doing this!

Best,
Ferenc
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