Re: [PATCH net-next v7 1/4] net/sched: cake, fq_codel: return the classifier result to the caller

[netdev-bot+sashiko@kernel.org]

Thank you for your contribution! Sashiko AI review found more severe
issue(s) in other patches of this series. This mail is only an FYI, in case
you want to address the nit picks below when you respin.

Low priority / nit picks for your consideration:

- [Low] The commit message body opens with the heading "The Fix:", but
  the patch fixes nothing.

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net/sched: cake, fq_codel: return the classifier result to the caller

This commit changes the external classifier helpers in cake and fq_codel
so they no longer compute the flow hash. The cake helper now returns the
filter's flow/host overrides, and the fq_codel helper returns a 1-based
flow index or a request to hash. The enqueue callers then do the flow
selection themselves, in preparation for later accounting changes.

> The Fix:
> cake and fq_codel run an optional external classifier from their enqueue
> path and then compute the flow hash inside the helper.

[Severity: Low]
This isn't a bug, but is the "The Fix:" heading accurate here? Later in
the same message it says:

> This is preparation for the accounting changes that follow. Packet
> classification and flow selection are unchanged.

>From the diff, behaviour looks the same as before.

In cake, cake_tcf_classify() returns true for exactly the actions on which
the old cake_classify() returned 0 (SHOT, STOLEN, QUEUED, TRAP).
cake_enqueue() then calls cake_select_tin() and cake_hash() with the same
overrides that were used before.

In fq_codel, the old fq_codel_classify() returned 0 (drop) in three cases:
a terminal action, no filter match, and TC_H_MIN(res.classid) == 0. The
new version returns true in those same three cases. When it does not drop,
it hands back the same index or hash request as before.

Since this is a refactor and not a fix, could the heading be dropped or
reworded, for example to "Preparation:"? As written, backporters and stable
selection tooling might take it for a bug fix.

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Sashiko AI review · https://netdev-ai.bots.linux.dev/sashiko/#/patchset/QDISC-BA27.v7.r0.20261019115505%40mojatatu.com