net: sched: lock imbalance in hhf qdisc

hhf_change() takes the sch_tree_lock and releases it but misses the
error cases. Fix the missed case here.

To reproduce try a command like this,

# tc qdisc change dev p3p2 root hhf quantum 40960 non_hh_weight 300000

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_hhf.c

@@ -553,11 +553,6 @@ static int hhf_change(struct Qdisc *sch, struct nlattr *opt)
 	if (err < 0)
 		return err;
 
-	sch_tree_lock(sch);
-
-	if (tb[TCA_HHF_BACKLOG_LIMIT])
-		sch->limit = nla_get_u32(tb[TCA_HHF_BACKLOG_LIMIT]);
-
 	if (tb[TCA_HHF_QUANTUM])
 		new_quantum = nla_get_u32(tb[TCA_HHF_QUANTUM]);
 
@@ -567,6 +562,12 @@ static int hhf_change(struct Qdisc *sch, struct nlattr *opt)
 	non_hh_quantum = (u64)new_quantum * new_hhf_non_hh_weight;
 	if (non_hh_quantum > INT_MAX)
 		return -EINVAL;
+
+	sch_tree_lock(sch);
+
+	if (tb[TCA_HHF_BACKLOG_LIMIT])
+		sch->limit = nla_get_u32(tb[TCA_HHF_BACKLOG_LIMIT]);
+
 	q->quantum = new_quantum;
 	q->hhf_non_hh_weight = new_hhf_non_hh_weight;