Re: [PATCH wireless-next] wifi: brcmfmac: msgbuf: count tx status only for the current flowring

["Kordian Chmielewski (mlody1212)" <kudzo51@gmail.com>]

Hi Andre,

I have now run it on a BCM43684 (firmware 17.10.188.75) as an access
point, with the logic of your 4/4 and this patch ported to my tree (its
tx status path is the BCA one, with the flowid and generation kept per
pktid), plus counters for the test. The AP sent a client a 150 Mbit/s
UDP stream while the client was deauthenticated 60 times.

In 62 flowring deletes, 2130 frames were out when the delete request was
sent. The tx status of every one of them came before the delete
response, none came after it, and outstanding_tx never went below zero.
Here too the host saw every status before the delete response, as in
your BCM4377 trace, and the generation check did not trigger.

To see the case itself, I then held back the tx status of a flowring
being deleted for 3 s in the driver, so the host handled the delete
response first and the new flowring of the reconnected client got the
same flowid. With the generation check, all 531 such statuses came for
a reused flowid and left its counter alone: at each of the 15 deletes it
matched the frames still out. With the generation check turned off, the
counter of the new flowring was wrong at 14 of 15 deletes, by 787 frames
in total, and went below zero.

One wording fix in the patch: "This happens whatever order the firmware
sends the two messages in" is too strong, it should say "This can
happen". Without holding a status back I have not seen it.

Kordian