Subject: [PATCH 1/3] net/sched: netem: use extack

From: Stephen Hemminger <[email-masked]>
Date: Wed, 31 Jan 2024 19:45:58 -0800

The error handling in netem predates introduction of extack,
and was mostly using pr_info(). Use extack to put errors in
result rather than console log.

Signed-off-by: Stephen Hemminger <[email-masked]>
---
 net/sched/sch_netem.c | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index fa678eb88528..7c37a69aba0e 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -782,15 +782,18 @@ static void dist_free(struct disttable *d)
  * signed 16 bit values.
  */
 
-static int get_dist_table(struct disttable **tbl, const struct nlattr *attr)
+static int get_dist_table(struct disttable **tbl, const struct nlattr *attr,
+			  struct netlink_ext_ack *extack)
 {
 	size_t n = nla_len(attr)/sizeof(__s16);
 	const __s16 *data = nla_data(attr);
 	struct disttable *d;
 	int i;
 
-	if (!n || n > NETEM_DIST_MAX)
+	if (!n || n > NETEM_DIST_MAX) {
+		NL_SET_ERR_MSG_FMT_MOD(extack, "invalid distribution table size: %zu", n);
 		return -EINVAL;
+	}
 
 	d = kvmalloc(struct_size(d, table, n), GFP_KERNEL);
 	if (!d)
@@ -865,7 +868,8 @@ static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
 		q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
 }
 
-static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
+static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr,
+			struct netlink_ext_ack *extack)
 {
 	const struct nlattr *la;
 	int rem;
@@ -878,7 +882,7 @@ static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
 			const struct tc_netem_gimodel *gi = nla_data(la);
 
 			if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
-				pr_info("netem: incorrect gi model size\n");
+				NL_SET_ERR_MSG_MOD(extack, "incorrect GI model size");
 				return -EINVAL;
 			}
 
@@ -897,7 +901,7 @@ static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
 			const struct tc_netem_gemodel *ge = nla_data(la);
 
 			if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
-				pr_info("netem: incorrect ge model size\n");
+				NL_SET_ERR_MSG_MOD(extack, "incorrect GE model size");
 				return -EINVAL;
 			}
 
@@ -911,7 +915,7 @@ static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
 		}
 
 		default:
-			pr_info("netem: unknown loss type %u\n", type);
+			NL_SET_ERR_MSG_FMT_MOD(extack, "unknown loss type: %u", type);
 			return -EINVAL;
 		}
 	}
@@ -934,12 +938,13 @@ static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
 };
 
 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
-		      const struct nla_policy *policy, int len)
+		      const struct nla_policy *policy, int len,
+		      struct netlink_ext_ack *extack)
 {
 	int nested_len = nla_len(nla) - NLA_ALIGN(len);
 
 	if (nested_len < 0) {
-		pr_info("netem: invalid attributes len %d\n", nested_len);
+		NL_SET_ERR_MSG_MOD(extack, "invalid nested attribute length");
 		return -EINVAL;
 	}
 
@@ -966,18 +971,18 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt,
 	int ret;
 
 	qopt = nla_data(opt);
-	ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
+	ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt), extack);
 	if (ret < 0)
 		return ret;
 
 	if (tb[TCA_NETEM_DELAY_DIST]) {
-		ret = get_dist_table(&delay_dist, tb[TCA_NETEM_DELAY_DIST]);
+		ret = get_dist_table(&delay_dist, tb[TCA_NETEM_DELAY_DIST], extack);
 		if (ret)
 			goto table_free;
 	}
 
 	if (tb[TCA_NETEM_SLOT_DIST]) {
-		ret = get_dist_table(&slot_dist, tb[TCA_NETEM_SLOT_DIST]);
+		ret = get_dist_table(&slot_dist, tb[TCA_NETEM_SLOT_DIST], extack);
 		if (ret)
 			goto table_free;
 	}
@@ -988,7 +993,7 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt,
 	old_loss_model = q->loss_model;
 
 	if (tb[TCA_NETEM_LOSS]) {
-		ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
+		ret = get_loss_clg(q, tb[TCA_NETEM_LOSS], extack);
 		if (ret) {
 			q->loss_model = old_loss_model;
 			q->clg = old_clg;
@@ -1068,18 +1073,16 @@ static int netem_init(struct Qdisc *sch, struct nlattr *opt,
 		      struct netlink_ext_ack *extack)
 {
 	struct netem_sched_data *q = qdisc_priv(sch);
-	int ret;
 
 	qdisc_watchdog_init(&q->watchdog, sch);
 
-	if (!opt)
+	if (!opt) {
+		NL_SET_ERR_MSG_MOD(extack, "Netem missing required parameters");
 		return -EINVAL;
+	}
 
 	q->loss_model = CLG_RANDOM;
-	ret = netem_change(sch, opt, extack);
-	if (ret)
-		pr_info("netem: change failed\n");
-	return ret;
+	return netem_change(sch, opt, extack);
 }
 
 static void netem_destroy(struct Qdisc *sch)
-- 
2.43.0