Hi all,

These are fixes for ingress and clsact Qdiscs:

[1,2/6]: ingress and clsact Qdiscs should only be created under ffff:fff1
  [3/6]: Under ffff:fff1, only create ingress and clsact Qdiscs (for now,
         at least)
  [4/6]: After creating ingress and clsact Qdiscs under ffff:fff1, do not
         graft them again to anywhere else (e.g. as the inner Qdisc of a
         TBF Qdisc)
  [5/6]: Prepare for [6/6], do not reuse that for-loop in qdisc_graft()
         for ingress and clsact Qdiscs
  [6/6]: Fix use-after-free [a] in mini_qdisc_pair_swap()

Please review (especially [6/6]), thanks!  Other tasks, including:

  - prohibiting sch_ingress, sch_clsact etc. in default_qdisc
  - more cleanups for qdisc_graft()

Will be done in separate patches.

[a] https://syzkaller.appspot.com/bug?extid=b53a9c0d1ea4ad62da8b

Thanks,
Peilin Ye (6):
  net/sched: sch_ingress: Only create under TC_H_INGRESS
  net/sched: sch_clsact: Only create under TC_H_CLSACT
  net/sched: Reserve TC_H_INGRESS (TC_H_CLSACT) for ingress (clsact)
    Qdiscs
  net/sched: Prohibit regrafting ingress or clsact Qdiscs
  net/sched: Refactor qdisc_graft() for ingress and clsact Qdiscs
  net/sched: qdisc_destroy() old ingress and clsact Qdiscs before
    grafting

 include/net/sch_generic.h |  8 ++++++
 net/sched/sch_api.c       | 54 +++++++++++++++++++++++++++++----------
 net/sched/sch_generic.c   | 14 +++++++---
 net/sched/sch_ingress.c   | 10 ++++++--
 4 files changed, 67 insertions(+), 19 deletions(-)

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2.20.1