net: sched: drop all special handling of tx_queue_len == 0

Those were all workarounds for the formerly double meaning of
tx_queue_len, which broke scheduling algorithms if untreated.

Now that all in-tree drivers have been converted away from setting
tx_queue_len = 0, it should be safe to drop these workarounds for
categorically broken setups.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index f1acb0f..cf4b0f8 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1048,11 +1048,9 @@
 
 	if (tb[TCA_HTB_DIRECT_QLEN])
 		q->direct_qlen = nla_get_u32(tb[TCA_HTB_DIRECT_QLEN]);
-	else {
+	else
 		q->direct_qlen = qdisc_dev(sch)->tx_queue_len;
-		if (q->direct_qlen < 2)	/* some devices have zero tx_queue_len */
-			q->direct_qlen = 2;
-	}
+
 	if ((q->rate2quantum = gopt->rate2quantum) < 1)
 		q->rate2quantum = 1;
 	q->defcls = gopt->defcls;