[PATCHv2 net-next 14/15] net: sch: sch_cbs: add extack support

[Alexander Aring]

This patch adds extack support for the cbs qdisc implementation by
adding NL_SET_ERR_MSG in validation of user input.
Also it serves to illustrate a use case of how the infrastructure ops
api changes are to be used by individual qdiscs.

Cc: David Ahern <dsah...@gmail.com>
Signed-off-by: Alexander Aring <ar...@mojatatu.com>
---
 net/sched/sch_cbs.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/net/sched/sch_cbs.c b/net/sched/sch_cbs.c
index 8bf6e163d29c..6d09ffd2371e 100644
--- a/net/sched/sch_cbs.c
+++ b/net/sched/sch_cbs.c
@@ -219,14 +219,17 @@ static void cbs_disable_offload(struct net_device *dev,
 }
 
 static int cbs_enable_offload(struct net_device *dev, struct cbs_sched_data *q,
-                             const struct tc_cbs_qopt *opt)
+                             const struct tc_cbs_qopt *opt,
+                             struct netlink_ext_ack *extack)
 {
        const struct net_device_ops *ops = dev->netdev_ops;
        struct tc_cbs_qopt_offload cbs = { };
        int err;
 
-       if (!ops->ndo_setup_tc)
+       if (!ops->ndo_setup_tc) {
+               NL_SET_ERR_MSG(extack, "Specified device does support cbs 
offload");
                return -EOPNOTSUPP;
+       }
 
        cbs.queue = q->queue;
 
@@ -237,8 +240,10 @@ static int cbs_enable_offload(struct net_device *dev, 
struct cbs_sched_data *q,
        cbs.sendslope = opt->sendslope;
 
        err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_CBS, &cbs);
-       if (err < 0)
+       if (err < 0) {
+               NL_SET_ERR_MSG(extack, "Specified device failed to setup cbs 
hardware offload");
                return err;
+       }
 
        q->enqueue = cbs_enqueue_offload;
        q->dequeue = cbs_dequeue_offload;
@@ -255,12 +260,14 @@ static int cbs_change(struct Qdisc *sch, struct nlattr 
*opt,
        struct tc_cbs_qopt *qopt;
        int err;
 
-       err = nla_parse_nested(tb, TCA_CBS_MAX, opt, cbs_policy, NULL);
+       err = nla_parse_nested(tb, TCA_CBS_MAX, opt, cbs_policy, extack);
        if (err < 0)
                return err;
 
-       if (!tb[TCA_CBS_PARMS])
+       if (!tb[TCA_CBS_PARMS]) {
+               NL_SET_ERR_MSG(extack, "Missing CBS parameter which are 
mandatory");
                return -EINVAL;
+       }
 
        qopt = nla_data(tb[TCA_CBS_PARMS]);
 
@@ -277,7 +284,7 @@ static int cbs_change(struct Qdisc *sch, struct nlattr *opt,
 
                cbs_disable_offload(dev, q);
        } else {
-               err = cbs_enable_offload(dev, q, qopt);
+               err = cbs_enable_offload(dev, q, qopt, extack);
                if (err < 0)
                        return err;
        }
@@ -298,8 +305,10 @@ static int cbs_init(struct Qdisc *sch, struct nlattr *opt,
        struct cbs_sched_data *q = qdisc_priv(sch);
        struct net_device *dev = qdisc_dev(sch);
 
-       if (!opt)
+       if (!opt) {
+               NL_SET_ERR_MSG(extack, "Missing CBS qdisc options  which are 
mandatory");
                return -EINVAL;
+       }
 
        q->queue = sch->dev_queue - netdev_get_tx_queue(dev, 0);
 
-- 
2.11.0