Subject: Re: Kernel 2.4.25 + VLAN + CBQ disc broken ?

From: Patrick McHardy <[email-masked]>
Date: Tue, 23 Mar 2004 23:56:37 +0100

Gianfranco Delli Carri wrote:
> Greetigs,
> 
> seems that in a 2.4.25 kernel, with VLAN configured, if you try tu use CBQ disc on VLAN subIf no more traffic can be passed. (NO ARP, NO IP)
> 
> Just after: 
> /sbin/tc qdisc add dev eth1.10 root handle 1 cbq bandwidth 100Mbit avpkt 1000 cell 8
> 
> traffic was dropped.
> 
> Seems that in the same server enviroment the CBQ disc attached to the untagged interface can work without problems.

Please try this patch.

Dave, the txqueuelen=0 fix for pfifo_fast apparently didn't went in
2.4, this is the patch from 2.6, it applies with minor offset.

Best regards
Patrick
ChangeSet 1.1561.2.5, 2004/02/18 13:18:53-08:00, [email-masked]

	[PKTSCHED]: Use queue limit of 1 when tx_queue_len is zero.

# This patch includes the following deltas:
#	           ChangeSet	1.1561.2.4 -> 1.1561.2.5
#	net/sched/sch_fifo.c	1.7     -> 1.8    
#	net/sched/sch_gred.c	1.13    -> 1.14   
#

 sch_fifo.c |    6 ++++--
 sch_gred.c |    2 +-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff -Nru a/net/sched/sch_fifo.c b/net/sched/sch_fifo.c
--- a/net/sched/sch_fifo.c	Wed Feb 18 18:09:39 2004
+++ b/net/sched/sch_fifo.c	Wed Feb 18 18:09:39 2004
@@ -141,10 +141,12 @@
 	struct fifo_sched_data *q = (void*)sch->data;
 
 	if (opt == NULL) {
+		unsigned int limit = sch->dev->tx_queue_len ? : 1;
+
 		if (sch->ops == &bfifo_qdisc_ops)
-			q->limit = sch->dev->tx_queue_len*sch->dev->mtu;
+			q->limit = limit*sch->dev->mtu;
 		else	
-			q->limit = sch->dev->tx_queue_len;
+			q->limit = limit;
 	} else {
 		struct tc_fifo_qopt *ctl = RTA_DATA(opt);
 		if (opt->rta_len < RTA_LENGTH(sizeof(*ctl)))
diff -Nru a/net/sched/sch_gred.c b/net/sched/sch_gred.c
--- a/net/sched/sch_gred.c	Wed Feb 18 18:09:39 2004
+++ b/net/sched/sch_gred.c	Wed Feb 18 18:09:39 2004
@@ -110,7 +110,7 @@
 	unsigned long	qave=0;	
 	int i=0;
 
-	if (!t->initd && skb_queue_len(&sch->q) < sch->dev->tx_queue_len) {
+	if (!t->initd && skb_queue_len(&sch->q) < (sch->dev->tx_queue_len ? : 1)) {
 		D2PRINTK("NO GRED Queues setup yet! Enqueued anyway\n");
 		goto do_enqueue;
 	}