net: sch: api: add extack support in qdisc_get_rtab

This patch adds extack support for the function qdisc_get_rtab which is
a common used function in the tc subsystem. Callers which are interested
in the receiving error can assign extack to get a more detailed
information why qdisc_get_rtab failed.

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>

include/net/pkt_sched.h

@@ -101,7 +101,8 @@ void qdisc_hash_del(struct Qdisc *q);
 struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle);
 struct Qdisc *qdisc_lookup_class(struct net_device *dev, u32 handle);
 struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
-					struct nlattr *tab);
+					struct nlattr *tab,
+					struct netlink_ext_ack *extack);
 void qdisc_put_rtab(struct qdisc_rate_table *tab);
 void qdisc_put_stab(struct qdisc_size_table *tab);
 void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc);

net/sched/act_police.c

@@ -118,13 +118,13 @@ static int tcf_act_police_init(struct net *net, struct nlattr *nla,
 	police = to_police(*a);
 	if (parm->rate.rate) {
 		err = -ENOMEM;
-		R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE]);
+		R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE], NULL);
 		if (R_tab == NULL)
 			goto failure;
 
 		if (parm->peakrate.rate) {
 			P_tab = qdisc_get_rtab(&parm->peakrate,
-					       tb[TCA_POLICE_PEAKRATE]);
+					       tb[TCA_POLICE_PEAKRATE], NULL);
 			if (P_tab == NULL)
 				goto failure;
 		}

net/sched/sch_api.c

@@ -393,13 +393,16 @@ static __u8 __detect_linklayer(struct tc_ratespec *r, __u32 *rtab)
 static struct qdisc_rate_table *qdisc_rtab_list;
 
 struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
-					struct nlattr *tab)
+					struct nlattr *tab,
+					struct netlink_ext_ack *extack)
 {
 	struct qdisc_rate_table *rtab;
 
 	if (tab == NULL || r->rate == 0 || r->cell_log == 0 ||
-	    nla_len(tab) != TC_RTAB_SIZE)
+	    nla_len(tab) != TC_RTAB_SIZE) {
+		NL_SET_ERR_MSG(extack, "Invalid rate table parameters for searching");
 		return NULL;
+	}
 
 	for (rtab = qdisc_rtab_list; rtab; rtab = rtab->next) {
 		if (!memcmp(&rtab->rate, r, sizeof(struct tc_ratespec)) &&
@@ -418,6 +421,8 @@ struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
 			r->linklayer = __detect_linklayer(r, rtab->data);
 		rtab->next = qdisc_rtab_list;
 		qdisc_rtab_list = rtab;
+	} else {
+		NL_SET_ERR_MSG(extack, "Failed to allocate new qdisc rate table");
 	}
 	return rtab;
 }

net/sched/sch_cbq.c

@@ -1156,7 +1156,7 @@ static int cbq_init(struct Qdisc *sch, struct nlattr *opt,
 
 	r = nla_data(tb[TCA_CBQ_RATE]);
 
-	q->link.R_tab = qdisc_get_rtab(r, tb[TCA_CBQ_RTAB]);
+	q->link.R_tab = qdisc_get_rtab(r, tb[TCA_CBQ_RTAB], extack);
 	if (!q->link.R_tab)
 		return -EINVAL;
 
@@ -1484,7 +1484,7 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **t
 
 		if (tb[TCA_CBQ_RATE]) {
 			rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]),
-					      tb[TCA_CBQ_RTAB]);
+					      tb[TCA_CBQ_RTAB], extack);
 			if (rtab == NULL)
 				return -EINVAL;
 		}
@@ -1537,7 +1537,8 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **t
 	if (!tb[TCA_CBQ_WRROPT] || !tb[TCA_CBQ_RATE] || !tb[TCA_CBQ_LSSOPT])
 		return -EINVAL;
 
-	rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]), tb[TCA_CBQ_RTAB]);
+	rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]), tb[TCA_CBQ_RTAB],
+			      extack);
 	if (rtab == NULL)
 		return -EINVAL;
 

net/sched/sch_htb.c

@@ -1357,10 +1357,12 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
 
 	/* Keeping backward compatible with rate_table based iproute2 tc */
 	if (hopt->rate.linklayer == TC_LINKLAYER_UNAWARE)
-		qdisc_put_rtab(qdisc_get_rtab(&hopt->rate, tb[TCA_HTB_RTAB]));
+		qdisc_put_rtab(qdisc_get_rtab(&hopt->rate, tb[TCA_HTB_RTAB],
+					      NULL));
 
 	if (hopt->ceil.linklayer == TC_LINKLAYER_UNAWARE)
-		qdisc_put_rtab(qdisc_get_rtab(&hopt->ceil, tb[TCA_HTB_CTAB]));
+		qdisc_put_rtab(qdisc_get_rtab(&hopt->ceil, tb[TCA_HTB_CTAB],
+					      NULL));
 
 	if (!cl) {		/* new class */
 		struct Qdisc *new_q;

net/sched/sch_tbf.c

@@ -327,11 +327,13 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt,
 	qopt = nla_data(tb[TCA_TBF_PARMS]);
 	if (qopt->rate.linklayer == TC_LINKLAYER_UNAWARE)
 		qdisc_put_rtab(qdisc_get_rtab(&qopt->rate,
-					      tb[TCA_TBF_RTAB]));
+					      tb[TCA_TBF_RTAB],
+					      NULL));
 
 	if (qopt->peakrate.linklayer == TC_LINKLAYER_UNAWARE)
 			qdisc_put_rtab(qdisc_get_rtab(&qopt->peakrate,
-						      tb[TCA_TBF_PTAB]));
+						      tb[TCA_TBF_PTAB],
+						      NULL));
 
 	buffer = min_t(u64, PSCHED_TICKS2NS(qopt->buffer), ~0U);
 	mtu = min_t(u64, PSCHED_TICKS2NS(qopt->mtu), ~0U);