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Subject: Re: [PATCH-v3 1/2] wireless:  Support assoc-at-ms timer in sta-info
From:   Johannes Berg <johannes@sipsolutions.net>
To:     greearb@candelatech.com, linux-wireless@vger.kernel.org
Date:   Fri, 14 Jun 2019 15:38:19 +0200
In-Reply-To: <20190415172123.6532-1-greearb@candelatech.com> (sfid-20190415_192129_410858_A3814220)
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On Mon, 2019-04-15 at 10:21 -0700, greearb@candelatech.com wrote:
> From: Ben Greear <greearb@candelatech.com>
> 
> Report time stamp of when sta became associated.

I guess that makes sense.

> Signed-off-by: Ben Greear <greearb@candelatech.com>
> ---
>  include/net/cfg80211.h       | 2 ++
>  include/uapi/linux/nl80211.h | 2 ++
>  net/wireless/nl80211.c       | 1 +
>  3 files changed, 5 insertions(+)
> 
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index f49eb1464b7a..a3ad78b9d9f4 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -1268,6 +1268,7 @@ struct cfg80211_tid_stats {
>   *	indicate the relevant values in this struct for them
>   * @connected_time: time(in secs) since a station is last connected
>   * @inactive_time: time since last station activity (tx/rx) in milliseconds
> + * @assoc_at_ms: time in ms of the last association

I think the "_at_ms" doesn't really make sense. "time in ms" also
doesn't make sense as documentation. I think you need to say what should
be assigned here.

Also, you're actually using ktime_get_real() for this, which again
doesn't make much sense. For exposing an absolute time, I think we're
better off with CLOCK_BOOTTIME like we use elsewhere:

 * @boottime_ns: CLOCK_BOOTTIME timestamp the frame was received at, this is
 *      needed only for beacons and probe responses that update the scan cache.


> + * @NL80211_STA_INFO_ASSOC_AT_MS: Timestamp of last association

_ASSOC_TIMESTAMP or something would make more sense too as the attribute
name, and clearly the documentation needs to spell out the semantics
here too.

johannes