Re: [PATCH net v5 4/5] amt: make pre-query report drops visible

[netdev-bot+sashiko]

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 says DEV_STATS_INC() is applied only to
  amt_dev_xmit()'s counters: "The device is LLTX, so amt_dev_xmit() can…

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amt: make pre-query report drops visible

This patch adds a debug message when an amt gateway drops an IGMP or MLD
report because the relay's Membership Query has not arrived yet. It also
stops amt_dev_xmit() from counting reports it forwarded as tx_dropped.
Finally, it switches the device's tx_dropped and tx_errors updates to
DEV_STATS_INC().

> The device is LLTX, so amt_dev_xmit() can run on several CPUs at once;
> use DEV_STATS_INC() for its tx_dropped and tx_errors updates so
> concurrent increments are not lost.

[Severity: Low]
This isn't a bug, but does this paragraph cover the whole diff?

It describes the DEV_STATS_INC() change as limited to amt_dev_xmit().
Only two of the converted sites are in that function. The patch also
converts every other tx_errors and tx_dropped increment in
drivers/net/amt.c:

  amt_send_discovery()      (three tx_errors sites)
  amt_send_request()        (three tx_errors sites)
  amt_send_igmp_gq()        (tx_dropped)
  amt_build_mld_gq()        (tx_errors)
  amt_send_mld_gq()         (tx_dropped)
  amt_send_advertisement()  (three tx_errors sites)

These run from the gateway workqueue and the relay receive path, not
from ndo_start_xmit.

The extra conversions look correct and are needed. DEV_STATS_INC() does
atomic_long_inc() on the same storage as dev->stats.tx_errors and
dev->stats.tx_dropped. A plain ++ left on either field could overwrite
an atomic increment from amt_dev_xmit().

Could the commit message mention these conversions and give that reason?

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Sashiko AI review · https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20261105125010.1107546-1-omar%40blockcast.net