From: Eric Dumazet <eduma...@google.com>
Date: Thu, 28 Feb 2019 12:55:43 -0800
> In the series fc8b81a5981f ("Merge branch 'lockless-qdisc-series'")
> John made the assumption that the data path had no need to read
> the qdisc qlen (number of packets in the qdisc).
>
> It is true when pfifo_fast is used as the root qdisc, or as direct MQ/MQPRIO
> children.
>
> But pfifo_fast can be used as leaf in class full qdiscs, and existing
> logic needs to access the child qlen in an efficient way.
...
I'm going to let this sit a bit for review...
