Subject: Re: net-sched 07/06: sch_htb: remove write-only qdisc filter_cnt

From: Jarek Poplawski <[email-masked]>
Date: Fri, 4 Jul 2008 16:29:38 +0200

On Fri, Jul 04, 2008 at 02:20:03PM +0200, Patrick McHardy wrote:

> commit 50ed378778be0c8d435163122827cf513882a707
> Author: Patrick McHardy <[email-masked]>
> Date:   Fri Jul 4 14:18:03 2008 +0200
> 
>     net-sched: sch_htb: remove write-only qdisc filter_cnt
>     
>     The filter_cnt is supposed to count filter references to a class.
>     Since the qdisc can't be the target of a filter, it doesn't need
>     a filter_cnt. In fact the counter is never decreased since cls_api
>     considers a return value of zero a failure and doesn't unbind again.
>     
>     Signed-off-by: Patrick McHardy <[email-masked]>

...plus, of course, it's never checked. Good point and good patch (IMHO).

Regards,
Jarek P.

> 
> diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
> index 128a5ab..ee8b4ff 100644
> --- a/net/sched/sch_htb.c
> +++ b/net/sched/sch_htb.c
> @@ -159,7 +159,6 @@ struct htb_sched {
>  
>  	/* filters for qdisc itself */
>  	struct tcf_proto *filter_list;
> -	int filter_cnt;
>  
>  	int rate2quantum;	/* quant = rate / rate2quantum */
>  	psched_time_t now;	/* cached dequeue time */
> @@ -1484,7 +1483,6 @@ static struct tcf_proto **htb_find_tcf(struct Qdisc *sch, unsigned long arg)
>  static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent,
>  				     u32 classid)
>  {
> -	struct htb_sched *q = qdisc_priv(sch);
>  	struct htb_class *cl = htb_find(classid, sch);
>  
>  	/*if (cl && !cl->level) return 0;
> @@ -1498,20 +1496,15 @@ static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent,
>  	 */
>  	if (cl)
>  		cl->filter_cnt++;
> -	else
> -		q->filter_cnt++;
>  	return (unsigned long)cl;
>  }
>  
>  static void htb_unbind_filter(struct Qdisc *sch, unsigned long arg)
>  {
> -	struct htb_sched *q = qdisc_priv(sch);
>  	struct htb_class *cl = (struct htb_class *)arg;
>  
>  	if (cl)
>  		cl->filter_cnt--;
> -	else
> -		q->filter_cnt--;
>  }
>  
>  static void htb_walk(struct Qdisc *sch, struct qdisc_walker *arg)