net: sch: sch_drr: add extack support

This patch adds extack support for the drr 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 <dsahern@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c
index bf638ce57c50eae22de1452e4c112724311d8f50..e0b0cf8a993933b06adeeec8798b44fbe9e9cb90 100644 (file)
--- a/net/sched/sch_drr.c
+++ b/net/sched/sch_drr.c
@@ -74,17 +74,21 @@ static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
        u32 quantum;
        int err;
 
-       if (!opt)
+       if (!opt) {
+               NL_SET_ERR_MSG(extack, "DRR options are required for this operation");
                return -EINVAL;
+       }
 
-       err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy, NULL);
+       err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy, extack);
        if (err < 0)
                return err;
 
        if (tb[TCA_DRR_QUANTUM]) {
                quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]);
-               if (quantum == 0)
+               if (quantum == 0) {
+                       NL_SET_ERR_MSG(extack, "Specified DRR quantum cannot be zero");
                        return -EINVAL;
+               }
        } else
                quantum = psched_mtu(qdisc_dev(sch));
 
@@ -95,8 +99,10 @@ static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
                                                    NULL,
                                                    qdisc_root_sleeping_running(sch),
                                                    tca[TCA_RATE]);
-                       if (err)
+                       if (err) {
+                               NL_SET_ERR_MSG(extack, "Failed to replace estimator");
                                return err;
+                       }
                }
 
                sch_tree_lock(sch);
@@ -127,6 +133,7 @@ static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
                                            qdisc_root_sleeping_running(sch),
                                            tca[TCA_RATE]);
                if (err) {
+                       NL_SET_ERR_MSG(extack, "Failed to replace estimator");
                        qdisc_destroy(cl->qdisc);
                        kfree(cl);
                        return err;
@@ -179,8 +186,10 @@ static struct tcf_block *drr_tcf_block(struct Qdisc *sch, unsigned long cl,
 {
        struct drr_sched *q = qdisc_priv(sch);
 
-       if (cl)
+       if (cl) {
+               NL_SET_ERR_MSG(extack, "DRR classid must be zero");
                return NULL;
+       }
 
        return q->block;
 }