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From:   Janusz Dziedzic <janusz.dziedzic@gmail.com>
Date:   Tue, 16 Nov 2021 14:58:09 +0100
Message-ID: <CAFED-j=i9wuN4JuiF4z2q5qbrhrLL_Php7pi6mpniMUeHHFUPA@mail.gmail.com>
Subject: Re: [PATCH mac80211-next] cfg80211: schedule offchan_cac_abort_wk in cfg80211_radar_event
To:     Lorenzo Bianconi <lorenzo@kernel.org>
Cc:     Johannes Berg <johannes@sipsolutions.net>,
        Felix Fietkau <nbd@nbd.name>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        lorenzo.bianconi@redhat.com, ryder.lee@mediatek.com,
        evelyn.tsai@mediatek.com, owen.peng@mediatek.com
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wt., 16 lis 2021 o 12:46 Lorenzo Bianconi <lorenzo@kernel.org> napisa=C5=82=
(a):
>
> If necessary schedule offchan_cac_abort_wk work in cfg80211_radar_event
> routine adding offchan parameter to cfg80211_radar_event signature.
> Rename cfg80211_radar_event in __cfg80211_radar_event and introduce
> the two following inline helpers:
> - cfg80211_radar_event
> - cfg80211_offchan_radar_event
> Doing so the drv will not need to run cfg80211_offchan_cac_abort() after
> radar detection on the offchannel chain.
>
> Tested-by: Owen Peng <owen.peng@mediatek.com>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  include/net/cfg80211.h | 24 +++++++++++++++++++++---
>  net/wireless/mlme.c    | 16 ++++++++++------
>  net/wireless/trace.h   | 11 +++++++----
>  3 files changed, 38 insertions(+), 13 deletions(-)
>

BTW, if we don't have user for this yet, maybe we should change name
offchannel -> background.
In ETSI spec
https://www.etsi.org/deliver/etsi_en/301800_301899/301893/02.01.01_60/en_30=
1893v020101p.pdf
we have off-channel CAC defined little bit different:

"Off-Channel CAC is performed by a number of non-continuous checks
spread over a period in time. This period, which is required to
determine the presence of radar signals, is defined as the Off-Channel
CAC Time."

And:
"Minimum Off-Channel CAC Time 6 minutes (see note 2) Maximum
Off-Channel CAC Time 4 hours (see note 2)"

So, your implementation simple run "background CAC" - use one (or
more) chain for that.

BR
Janusz


> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index 362da9f6bf39..a887086cb103 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -7605,15 +7605,33 @@ void cfg80211_cqm_txe_notify(struct net_device *d=
ev, const u8 *peer,
>  void cfg80211_cqm_beacon_loss_notify(struct net_device *dev, gfp_t gfp);
>
>  /**
> - * cfg80211_radar_event - radar detection event
> + * __cfg80211_radar_event - radar detection event
>   * @wiphy: the wiphy
>   * @chandef: chandef for the current channel
> + * @offchan: the radar has been detected on the offchannel chain
>   * @gfp: context flags
>   *
>   * This function is called when a radar is detected on the current chane=
nl.
>   */
> -void cfg80211_radar_event(struct wiphy *wiphy,
> -                         struct cfg80211_chan_def *chandef, gfp_t gfp);
> +void __cfg80211_radar_event(struct wiphy *wiphy,
> +                           struct cfg80211_chan_def *chandef,
> +                           bool offchan, gfp_t gfp);
> +
> +static inline void
> +cfg80211_radar_event(struct wiphy *wiphy,
> +                    struct cfg80211_chan_def *chandef,
> +                    gfp_t gfp)
> +{
> +       __cfg80211_radar_event(wiphy, chandef, false, gfp);
> +}
> +
> +static inline void
> +cfg80211_offchan_radar_event(struct wiphy *wiphy,
> +                            struct cfg80211_chan_def *chandef,
> +                            gfp_t gfp)
> +{
> +       __cfg80211_radar_event(wiphy, chandef, true, gfp);
> +}
>
>  /**
>   * cfg80211_sta_opmode_change_notify - STA's ht/vht operation mode chang=
e event
> diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
> index ac2e5e732d94..450be1ec70b8 100644
> --- a/net/wireless/mlme.c
> +++ b/net/wireless/mlme.c
> @@ -905,13 +905,13 @@ void cfg80211_dfs_channels_update_work(struct work_=
struct *work)
>  }
>
>
> -void cfg80211_radar_event(struct wiphy *wiphy,
> -                         struct cfg80211_chan_def *chandef,
> -                         gfp_t gfp)
> +void __cfg80211_radar_event(struct wiphy *wiphy,
> +                           struct cfg80211_chan_def *chandef,
> +                           bool offchan, gfp_t gfp)
>  {
>         struct cfg80211_registered_device *rdev =3D wiphy_to_rdev(wiphy);
>
> -       trace_cfg80211_radar_event(wiphy, chandef);
> +       trace_cfg80211_radar_event(wiphy, chandef, offchan);
>
>         /* only set the chandef supplied channel to unavailable, in
>          * case the radar is detected on only one of multiple channels
> @@ -919,6 +919,9 @@ void cfg80211_radar_event(struct wiphy *wiphy,
>          */
>         cfg80211_set_dfs_state(wiphy, chandef, NL80211_DFS_UNAVAILABLE);
>
> +       if (offchan)
> +               queue_work(cfg80211_wq, &rdev->offchan_cac_abort_wk);
> +
>         cfg80211_sched_dfs_chan_update(rdev);
>
>         nl80211_radar_notify(rdev, chandef, NL80211_RADAR_DETECTED, NULL,=
 gfp);
> @@ -926,7 +929,7 @@ void cfg80211_radar_event(struct wiphy *wiphy,
>         memcpy(&rdev->radar_chandef, chandef, sizeof(struct cfg80211_chan=
_def));
>         queue_work(cfg80211_wq, &rdev->propagate_radar_detect_wk);
>  }
> -EXPORT_SYMBOL(cfg80211_radar_event);
> +EXPORT_SYMBOL(__cfg80211_radar_event);
>
>  void cfg80211_cac_event(struct net_device *netdev,
>                         const struct cfg80211_chan_def *chandef,
> @@ -998,7 +1001,8 @@ __cfg80211_offchan_cac_event(struct cfg80211_registe=
red_device *rdev,
>                 rdev->offchan_radar_wdev =3D NULL;
>                 break;
>         case NL80211_RADAR_CAC_ABORTED:
> -               cancel_delayed_work(&rdev->offchan_cac_done_wk);
> +               if (!cancel_delayed_work(&rdev->offchan_cac_done_wk))
> +                       return;
>                 wdev =3D rdev->offchan_radar_wdev;
>                 rdev->offchan_radar_wdev =3D NULL;
>                 break;
> diff --git a/net/wireless/trace.h b/net/wireless/trace.h
> index 0b27eaa14a18..e854d52db1a6 100644
> --- a/net/wireless/trace.h
> +++ b/net/wireless/trace.h
> @@ -3053,18 +3053,21 @@ TRACE_EVENT(cfg80211_ch_switch_started_notify,
>  );
>
>  TRACE_EVENT(cfg80211_radar_event,
> -       TP_PROTO(struct wiphy *wiphy, struct cfg80211_chan_def *chandef),
> -       TP_ARGS(wiphy, chandef),
> +       TP_PROTO(struct wiphy *wiphy, struct cfg80211_chan_def *chandef,
> +                bool offchan),
> +       TP_ARGS(wiphy, chandef, offchan),
>         TP_STRUCT__entry(
>                 WIPHY_ENTRY
>                 CHAN_DEF_ENTRY
> +               __field(bool, offchan)
>         ),
>         TP_fast_assign(
>                 WIPHY_ASSIGN;
>                 CHAN_DEF_ASSIGN(chandef);
> +               __entry->offchan =3D offchan;
>         ),
> -       TP_printk(WIPHY_PR_FMT ", " CHAN_DEF_PR_FMT,
> -                 WIPHY_PR_ARG, CHAN_DEF_PR_ARG)
> +       TP_printk(WIPHY_PR_FMT ", " CHAN_DEF_PR_FMT ", offchan %d",
> +                 WIPHY_PR_ARG, CHAN_DEF_PR_ARG, __entry->offchan)
>  );
>
>  TRACE_EVENT(cfg80211_cac_event,
> --
> 2.31.1
>


--=20
Janusz Dziedzic