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From: Thomas Pedersen <thomas@eero.com>
Date: Mon, 5 Dec 2016 09:59:45 -0800
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Subject: Re: [PATCH] mac80211: Remove invalid flag operations in mesh TSF synchronization
To: Masashi Honma <masashi.honma@gmail.com>
Cc: Bob Copeland <me@bobcopeland.com>,
        Johannes Berg <johannes@sipsolutions.net>,
        linux-wireless@vger.kernel.org
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On Fri, Dec 2, 2016 at 10:59 PM, Masashi Honma <masashi.honma@gmail.com> wrote:
> On 2016/12/03 06:13, Bob Copeland wrote:
>>
>> On Fri, Dec 02, 2016 at 12:07:18PM -0800, Thomas Pedersen wrote:
>
>
> # Rejected by linux wireless ML. This is resubmission.
>
> thomas and Bob, Thanks for comments.
>
>> 802.11-2012 13.13.2.2.3:
>> The mesh STA checks if the transmitter of the Beacon frame or Probe
>> Response frame is in the
>> process of the TBTT adjustment (see 13.13.4.4.3).
>
> There are two functionalities.
>
> 1) 13.13.2.2 Neighbor offset synchronization method
> 2) 13.13.4.4 TBTT adjustment
>
> The ifmsh->adjusting_tbtt flag implements "TBTT Adjusting field" in the
> Mesh Configuration field.
>
> The flag is updated by 2).
> 13.13.4.4.3 TBTT scanning and adjustment procedures:
> The mesh STA shall set the TBTT Adjusting field in the Mesh
> Configuration element to 1 in order to announce that the TBTT
> adjustment procedure is ongoing.
>
> And the flag is refered by 1) as you said.
>
>
> The purpose of the flag is to prevent 1) while 2) is ongoing.
>
> In other words, 1) has only read access authority to the flag. However,
> previous code updated the flag in 1). In addition, there is no code for
> 2). So I just remove the invalid accessing codes.

I don't think 1) has read only access to that flag. A TSF adjust will
by definition move the TBTT as well.

-- 
thomas