[PATCH v5 0/4] net/sched: Load modules via alias

[Michal Koutný]

These modules may be loaded lazily without user's awareness and
control. Add respective aliases to modules and request them under these
aliases so that modprobe's blacklisting mechanism (through aliases)
works for them. (The same pattern exists e.g. for filesystem
modules.)

For example (before the change):
  $ tc filter add dev lo parent 10: protocol ip prio 10 handle 1: cgroup
  # cls_cgroup module is loaded despite a `blacklist cls_cgroup` entry
  # in /etc/modprobe.d/*.conf

After the change:
  $ tc filter add dev lo parent 10: protocol ip prio 10 handle 1: cgroup
  Error: TC classifier not found.
  We have an error talking to the kernel
  # explicit/acknowledged (privileged) action is needed
  $ modprobe cls_cgroup
  # blacklist entry won't apply to this direct modprobe, module is
  # loaded with awareness

A considered alternative was invoking `modprobe -b` always from
request_module(), however, dismissed as too intrusive and slightly
confusing in favor of the precedented aliases (the commit 7f78e0351394
("fs: Limit sys_mount to only request filesystem modules.").

User experience suffers in both alternatives. Its improvement is
orthogonal to blacklist honoring.

Changes from v1 (https://lore.kernel.org/r/20231121175640.9981-1-mkoutny@xxxxxxxx)
- Treat sch_ and act_ modules analogously to cls_

Changes from v2 (https://lore.kernel.org/r/20231206192752.18989-1-mkoutny@xxxxxxxx)
- reorganized commits (one generated commit + manual pre-/post- work)
- used alias names more fitting the existing net- aliases
- more info in commit messages and cover letter
- rebased on current master

Changes from v3 (https://lore.kernel.org/r/20240112180646.13232-1-mkoutny@xxxxxxxx)
- rebase on netdev/net-next/main
- correct aliases in cls_* modules (wrong sed)
- replace repeated prefix strings with a macro
- patch also request_module call in qdisc_set_default()

Changes from v4 (https://lore.kernel.org/r/20240123135242.11430-1-mkoutny@xxxxxxxx)
- update example in cover letter to existing module (cls_tcindex->cls_cgroup)
  - tested that ':-)
- remove __stringify in alias macro, net-cls-cgroup instead of net-cls-"cgroup"
- pass correct argument to request_module() (Simon)
- rebased on netdev-next/main

Michal Koutný (4):
  net/sched: Add helper macros with module names
  net/sched: Add module aliases for cls_,sch_,act_ modules
  net/sched: Load modules via their alias
  net/sched: Remove alias of sch_clsact

 include/net/act_api.h      | 2 ++
 include/net/pkt_cls.h      | 2 ++
 include/net/pkt_sched.h    | 2 ++
 net/sched/act_api.c        | 2 +-
 net/sched/act_bpf.c        | 1 +
 net/sched/act_connmark.c   | 1 +
 net/sched/act_csum.c       | 1 +
 net/sched/act_ct.c         | 1 +
 net/sched/act_ctinfo.c     | 1 +
 net/sched/act_gact.c       | 1 +
 net/sched/act_gate.c       | 1 +
 net/sched/act_ife.c        | 1 +
 net/sched/act_mirred.c     | 1 +
 net/sched/act_mpls.c       | 1 +
 net/sched/act_nat.c        | 1 +
 net/sched/act_pedit.c      | 1 +
 net/sched/act_police.c     | 1 +
 net/sched/act_sample.c     | 1 +
 net/sched/act_simple.c     | 1 +
 net/sched/act_skbedit.c    | 1 +
 net/sched/act_skbmod.c     | 1 +
 net/sched/act_tunnel_key.c | 1 +
 net/sched/act_vlan.c       | 1 +
 net/sched/cls_api.c        | 2 +-
 net/sched/cls_basic.c      | 1 +
 net/sched/cls_bpf.c        | 1 +
 net/sched/cls_cgroup.c     | 1 +
 net/sched/cls_flow.c       | 1 +
 net/sched/cls_flower.c     | 1 +
 net/sched/cls_fw.c         | 1 +
 net/sched/cls_matchall.c   | 1 +
 net/sched/cls_route.c      | 1 +
 net/sched/cls_u32.c        | 1 +
 net/sched/sch_api.c        | 4 ++--
 net/sched/sch_cake.c       | 1 +
 net/sched/sch_cbs.c        | 1 +
 net/sched/sch_choke.c      | 1 +
 net/sched/sch_codel.c      | 1 +
 net/sched/sch_drr.c        | 1 +
 net/sched/sch_etf.c        | 1 +
 net/sched/sch_ets.c        | 1 +
 net/sched/sch_fq.c         | 1 +
 net/sched/sch_fq_codel.c   | 1 +
 net/sched/sch_gred.c       | 1 +
 net/sched/sch_hfsc.c       | 1 +
 net/sched/sch_hhf.c        | 1 +
 net/sched/sch_htb.c        | 1 +
 net/sched/sch_ingress.c    | 3 ++-
 net/sched/sch_mqprio.c     | 1 +
 net/sched/sch_multiq.c     | 1 +
 net/sched/sch_netem.c      | 1 +
 net/sched/sch_pie.c        | 1 +
 net/sched/sch_plug.c       | 1 +
 net/sched/sch_prio.c       | 1 +
 net/sched/sch_qfq.c        | 1 +
 net/sched/sch_red.c        | 1 +
 net/sched/sch_sfb.c        | 1 +
 net/sched/sch_sfq.c        | 1 +
 net/sched/sch_skbprio.c    | 1 +
 net/sched/sch_taprio.c     | 1 +
 net/sched/sch_tbf.c        | 1 +
 61 files changed, 66 insertions(+), 5 deletions(-)


base-commit: 644c64318de0df5f4ea9f00e4b8cc262b343a93f
-- 
2.43.0