Since commit 
9776d32537d2 ("net: Move call_fib_rule_notifiers up in
fib_nl_newrule") it is possible to forbid the installation of
unsupported FIB rules.
Have mlxsw return an error for non-default FIB rules in addition to the
existing extack message.
Example:
# ip rule add from 198.51.100.1 table 10
Error: mlxsw_spectrum: FIB rules not supported.
Note that offload is only aborted when non-default FIB rules are already
installed and merely replayed during module initialization.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 
        switch (info->family) {
        case AF_INET:
                if (!fib4_rule_default(rule) && !rule->l3mdev)
-                       err = -1;
+                       err = -EOPNOTSUPP;
                break;
        case AF_INET6:
                if (!fib6_rule_default(rule) && !rule->l3mdev)
-                       err = -1;
+                       err = -EOPNOTSUPP;
                break;
        case RTNL_FAMILY_IPMR:
                if (!ipmr_rule_default(rule) && !rule->l3mdev)
-                       err = -1;
+                       err = -EOPNOTSUPP;
                break;
        case RTNL_FAMILY_IP6MR:
                if (!ip6mr_rule_default(rule) && !rule->l3mdev)
-                       err = -1;
+                       err = -EOPNOTSUPP;
                break;
        }
 
        if (err < 0)
-               NL_SET_ERR_MSG_MOD(extack, "FIB rules not supported. Aborting offload");
+               NL_SET_ERR_MSG_MOD(extack, "FIB rules not supported");
 
        return err;
 }
        case FIB_EVENT_RULE_DEL:
                err = mlxsw_sp_router_fib_rule_event(event, info,
                                                     router->mlxsw_sp);
-               if (!err)
-                       return NOTIFY_DONE;
+               if (!err || info->extack)
+                       return notifier_from_errno(err);
        }
 
        fib_work = kzalloc(sizeof(*fib_work), GFP_ATOMIC);