pkt_sched: sch_hfsc: sch_htb: Add non-work-conserving warning handler.

Patrick McHardy <kaber@trash.net> suggested:
> How about making this flag and the warning message (in a out-of-line
> function) globally available? Other qdiscs (f.i. HFSC) can't deal with
> inner non-work-conserving qdiscs as well.

This patch uses qdisc->flags field of "suspected" child qdisc.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 0fc4a18..3200979 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -444,6 +444,17 @@
 }
 EXPORT_SYMBOL(qdisc_calculate_pkt_len);
 
+void qdisc_warn_nonwc(char *txt, struct Qdisc *qdisc)
+{
+	if (!(qdisc->flags & TCQ_F_WARN_NONWC)) {
+		printk(KERN_WARNING
+		       "%s: %s qdisc %X: is non-work-conserving?\n",
+		       txt, qdisc->ops->id, qdisc->handle >> 16);
+		qdisc->flags |= TCQ_F_WARN_NONWC;
+	}
+}
+EXPORT_SYMBOL(qdisc_warn_nonwc);
+
 static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
 {
 	struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,