Received-SPF: pass (google.com: domain of linux-wireless+bounces-2290-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Message-ID: <590fe2823d934af997c515640733eb8889b0560f.camel@sipsolutions.net>
Subject: Re: [PATCH wireless v2] nl80211/cfg80211: add nla_policy for S1G
 band
From: Johannes Berg <johannes@sipsolutions.net>
To: Jeff Johnson <quic_jjohnson@quicinc.com>, Lin Ma <linma@zju.edu.cn>, 
 davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
 pabeni@redhat.com,  linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
  linux-kernel@vger.kernel.org, kvalo@kernel.org
Date: Sat, 20 Jan 2024 21:27:19 +0100
In-Reply-To: <9e1db7f3-fd18-4b3b-a912-3cf6efd96fed@quicinc.com>
References: <20240119151201.8670-1-linma@zju.edu.cn>
	 <9e1db7f3-fd18-4b3b-a912-3cf6efd96fed@quicinc.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.50.3 (3.50.3-1.fc39) 
Precedence: bulk
MIME-Version: 1.0

On Fri, 2024-01-19 at 15:47 -0800, Jeff Johnson wrote:
> > --- a/net/wireless/nl80211.c
> > +++ b/net/wireless/nl80211.c
> > @@ -911,6 +911,7 @@ nl80211_match_band_rssi_policy[NUM_NL80211_BANDS] =
=3D {
> >  	[NL80211_BAND_5GHZ] =3D { .type =3D NLA_S32 },
> >  	[NL80211_BAND_6GHZ] =3D { .type =3D NLA_S32 },
> >  	[NL80211_BAND_60GHZ] =3D { .type =3D NLA_S32 },
> > +	[NL80211_BAND_S1GHZ] =3D { .type =3D NLA_S32 },
> >  	[NL80211_BAND_LC]    =3D { .type =3D NLA_S32 },
> >  };
> > =20
> something is really suspicious since the NL80211_BAND_* enums are
> *value* enums, not attribute ID enums, and hence they should never be
> used in an nla_policy.

Yeah, that's what it looks like first, but then they do get used
anyway...

> what is actually using these as attribute IDs, noting that
> NL80211_BAND_2GHZ =3D=3D 0 and hence cannot be used as an attribute ID

Ohh. Good catch!

> seems the logic that introduced this policy needs to be revisited.
>=20

Let's just remove it?

commit 1e1b11b6a1111cd9e8af1fd6ccda270a9fa3eacf
Author: vamsi krishna <vamsin@codeaurora.org>
Date:   Fri Feb 1 18:34:51 2019 +0530

    nl80211/cfg80211: Specify band specific min RSSI thresholds with sched =
scan


As far as I can tell nothing is using that in the first place ...
Certainly not in the kernel, nor wpa_s, nor anything else I could find
really ...

We can't completely revert it since we need the attribute number to stay
allocated, but that's all we cannot remove.

johannes