Date:   Tue, 24 Jan 2023 15:09:52 +0100
From:   Lorenzo Bianconi <lorenzo@kernel.org>
To:     Nicolas Cavallari <nicolas.cavallari@green-communications.fr>
Cc:     Johannes Berg <johannes@sipsolutions.net>,
        Rameshkumar Sundaram <quic_ramess@quicinc.com>,
        ath11k@lists.infradead.org, linux-wireless@vger.kernel.org
Subject: Re: [PATCH 1/2] nl80211: add support to enable/disable bss color
 collision detection
Message-ID: <Y8/msHegwheXGWze@lore-desk>
References: <20221226083328.29051-1-quic_ramess@quicinc.com>
 <20221226083328.29051-2-quic_ramess@quicinc.com>
 <74c57dc34af10537f98f5bb9b6ce80e5676e09b0.camel@sipsolutions.net>
 <1609a645-3e23-7e37-9aa1-94f970e481e2@green-communications.fr>
 <Y8q5Z98S3pODD77W@lore-desk>
 <eac1cf31-518f-6542-24c6-69e6c059f3c9@green-communications.fr>
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> Hi Lorenzo,
>=20
> On 20/01/2023 16:55, Lorenzo Bianconi wrote:
> > I agree, I think we can ratelimit netlink messages sent by the kernel to
> > userspace (e.g. to hostapd), I would say every 500ms is ok.
> > I guess we can move cfg80211_obss_color_collision_notify() in a dedicat=
ed
> > delayed_work so we can grab wdev mutex (cfg80211_obss_color_collision_n=
otify is
> > currently running in interrupt context).
> > To give an idea, what do you think about patch below? (please note it i=
s just
> > compiled tested so far).
>=20
> The patch does not work, the fix appears easy:
> > +void ieee80211_color_collision_detection_work(struct work_struct *work)
> > +{
> > +	struct delayed_work *delayed_work =3D to_delayed_work(work);
> > +	struct ieee80211_link_data *link =3D
> > +		container_of(delayed_work, struct ieee80211_link_data,
> > +			     dfs_cac_timer_work);
>=20
> This should probably be color_collision_detect_work.

Yep, sorry. It is just a copy paste issue :)
I will share a new version.

Regards,
Lorenzo

>=20
> > +	struct ieee80211_sub_if_data *sdata =3D link->sdata;
> > +
> > +	sdata_lock(sdata);
>=20
> It crashed here, link is NULL.
>=20
> > +	cfg80211_obss_color_collision_notify(sdata->dev, link->color_bitmap,
> > +					     GFP_KERNEL);
> > +	sdata_unlock(sdata);
> > +}
> Will test the fixed version later.

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