Re: [Patch net] net_sched: walk through all child classes in tc_bind_tclass()

[David Miller <davem@davemloft.net>]

From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Thu, 23 Jan 2020 17:27:08 -0800

> In a complex TC class hierarchy like this:
> 
> tc qdisc add dev eth0 root handle 1:0 cbq bandwidth 100Mbit         \
>   avpkt 1000 cell 8
> tc class add dev eth0 parent 1:0 classid 1:1 cbq bandwidth 100Mbit  \
>   rate 6Mbit weight 0.6Mbit prio 8 allot 1514 cell 8 maxburst 20      \
>   avpkt 1000 bounded
> 
> tc filter add dev eth0 parent 1:0 protocol ip prio 1 u32 match ip \
>   sport 80 0xffff flowid 1:3
> tc filter add dev eth0 parent 1:0 protocol ip prio 1 u32 match ip \
>   sport 25 0xffff flowid 1:4
> 
> tc class add dev eth0 parent 1:1 classid 1:3 cbq bandwidth 100Mbit  \
>   rate 5Mbit weight 0.5Mbit prio 5 allot 1514 cell 8 maxburst 20      \
>   avpkt 1000
> tc class add dev eth0 parent 1:1 classid 1:4 cbq bandwidth 100Mbit  \
>   rate 3Mbit weight 0.3Mbit prio 5 allot 1514 cell 8 maxburst 20      \
>   avpkt 1000
> 
> where filters are installed on qdisc 1:0, so we can't merely
> search from class 1:1 when creating class 1:3 and class 1:4. We have
> to walk through all the child classes of the direct parent qdisc.
> Otherwise we would miss filters those need reverse binding.
> 
> Fixes: 07d79fc7d94e ("net_sched: add reverse binding for tc class")
> Cc: Jamal Hadi Salim <jhs@mojatatu.com>
> Cc: Jiri Pirko <jiri@resnulli.us>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

Applied and queued up for -stable.