net/sched: taprio: don't overwrite "sch" variable in taprio_dump_class_stats()

In taprio_dump_class_stats() we don't need a reference to the root Qdisc
once we get the reference to the child corresponding to this traffic
class, so it's okay to overwrite "sch". But in a future patch we will
need the root Qdisc too, so create a dedicated "child" pointer variable
to hold the child reference. This also makes the code adhere to a more
conventional coding style.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_taprio.c

@@ -2388,10 +2388,10 @@ static int taprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 	__acquires(d->lock)
 {
 	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);
+	struct Qdisc *child = dev_queue->qdisc_sleeping;
 
-	sch = dev_queue->qdisc_sleeping;
-	if (gnet_stats_copy_basic(d, NULL, &sch->bstats, true) < 0 ||
-	    qdisc_qstats_copy(d, sch) < 0)
+	if (gnet_stats_copy_basic(d, NULL, &child->bstats, true) < 0 ||
+	    qdisc_qstats_copy(d, child) < 0)
 		return -1;
 	return 0;
 }