[NET_SCHED]: Use nla_nest_start/nla_nest_end

Use nla_nest_start/nla_nest_end for dumping nested attributes.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c
index aaa32a2..19c0007 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -605,8 +605,7 @@
 {
 	struct atm_qdisc_data *p = qdisc_priv(sch);
 	struct atm_flow_data *flow = (struct atm_flow_data *)cl;
-	unsigned char *b = skb_tail_pointer(skb);
-	struct nlattr *nla;
+	struct nlattr *nest;
 
 	pr_debug("atm_tc_dump_class(sch %p,[qdisc %p],flow %p,skb %p,tcm %p)\n",
 		sch, p, flow, skb, tcm);
@@ -614,8 +613,11 @@
 		return -EINVAL;
 	tcm->tcm_handle = flow->classid;
 	tcm->tcm_info = flow->q->handle;
-	nla = (struct nlattr *)b;
-	NLA_PUT(skb, TCA_OPTIONS, 0, NULL);
+
+	nest = nla_nest_start(skb, TCA_OPTIONS);
+	if (nest == NULL)
+		goto nla_put_failure;
+
 	NLA_PUT(skb, TCA_ATM_HDR, flow->hdr_len, flow->hdr);
 	if (flow->vcc) {
 		struct sockaddr_atmpvc pvc;
@@ -636,11 +638,12 @@
 
 		NLA_PUT(skb, TCA_ATM_EXCESS, sizeof(zero), &zero);
 	}
-	nla->nla_len = skb_tail_pointer(skb) - b;
+
+	nla_nest_end(skb, nest);
 	return skb->len;
 
 nla_put_failure:
-	nlmsg_trim(skb, b);
+	nla_nest_cancel(skb, nest);
 	return -1;
 }
 static int