net: sched: report ndo_setup_tc failures via extack

Help end-users of the 'tc' command to see if the drivers ndo_setup_tc
function call fails. Troubleshooting when this happens is non-trivial
(see full process here[1]), and results in net_device getting assigned
the 'qdisc noop', which will drop all TX packets on the interface.

[1]: https://github.com/xdp-project/xdp-project/blob/master/areas/arm64/board_nxp_ls1088/nxp-board04-troubleshoot-qdisc.org

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Tested-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 55bd1429678f996a328f2be6fdb0b7e0de771168..11b683c45c2897cf52e3d0d599cbd4dcf9f2bf22 100644 (file)
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -735,8 +735,11 @@ static int tcf_block_offload_cmd(struct tcf_block *block,
        INIT_LIST_HEAD(&bo.cb_list);
 
        err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_BLOCK, &bo);
-       if (err < 0)
+       if (err < 0) {
+               if (err != -EOPNOTSUPP)
+                       NL_SET_ERR_MSG(extack, "Driver ndo_setup_tc failed");
                return err;
+       }
 
        return tcf_block_setup(block, &bo);
 }