On 06/15/2018 03:27 AM, Konstantin Khlebnikov wrote:
> When blackhole is used on top of classful qdisc like hfsc it breaks
> qlen and backlog counters because packets are disappear without notice.
>
> In HFSC non-zero qlen while all classes are inactive triggers warning:
> WARNING: ... at net/sched/sch_hfsc.c:1393 hfsc_dequeue+0xba4/0xe90 [sch_hfsc]
> and schedules watchdog work endlessly.
>
> This patch return __NET_XMIT_BYPASS in addition to NET_XMIT_SUCCESS,
> this flag tells upper layer: this packet is gone and isn't queued.
>
> Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
> ---
> net/sched/sch_blackhole.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/sched/sch_blackhole.c b/net/sched/sch_blackhole.c
> index c98a61e980ba..9c4c2bb547d7 100644
> --- a/net/sched/sch_blackhole.c
> +++ b/net/sched/sch_blackhole.c
> @@ -21,7 +21,7 @@ static int blackhole_enqueue(struct sk_buff *skb, struct
> Qdisc *sch,
> struct sk_buff **to_free)
> {
> qdisc_drop(skb, sch, to_free);
> - return NET_XMIT_SUCCESS;
> + return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
Why do not we use instead :
return qdisc_drop(skb, sch, to_free);
Although noop_enqueue() seems to use :
return NET_XMIT_CN;
Oh well.
