sch_htb: Add extack messages for EOPNOTSUPP errors

In order to make the "Operation not supported" message clearer to the
user, add extack messages explaining why exactly adding offloaded HTB
could be not supported in each case.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index cf1d45db4e84ba0795c4a78c54893ac85203a3af..9267922ea9c375dc555e8c17f9d9e9a90721330a 100644 (file)
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1084,11 +1084,15 @@ static int htb_init(struct Qdisc *sch, struct nlattr *opt,
        offload = nla_get_flag(tb[TCA_HTB_OFFLOAD]);
 
        if (offload) {
-               if (sch->parent != TC_H_ROOT)
+               if (sch->parent != TC_H_ROOT) {
+                       NL_SET_ERR_MSG(extack, "HTB must be the root qdisc to use offload");
                        return -EOPNOTSUPP;
+               }
 
-               if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
+               if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) {
+                       NL_SET_ERR_MSG(extack, "hw-tc-offload ethtool feature flag must be on");
                        return -EOPNOTSUPP;
+               }
 
                q->num_direct_qdiscs = dev->real_num_tx_queues;
                q->direct_qdiscs = kcalloc(q->num_direct_qdiscs,