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From:   Tom Psyborg <pozega.tomislav@gmail.com>
Date:   Wed, 15 Jan 2020 17:04:04 +0100
Message-ID: <CAKR_QVJkVSCuzZWgOxxmkffTYG3pgX4ZX_vvw-6Th5=tvs7ovg@mail.gmail.com>
Subject: Re: [PATCH] cfg80211: Fix regulatory data is reset in case all phys
 have disconnected
To:     Orr Mazor <orr.mazor@tandemg.com>
Cc:     Johannes Berg <johannes@sipsolutions.net>,
        "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
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On 15/01/2020, Orr Mazor <orr.mazor@tandemg.com> wrote:
> In case no one is occupying a wiphy, all past regulatory data will be lost
> as a result of reset to world reg domain.
>
> This includes any channel that is currently in NOP time as well as
> in AVAILABLE state.
>
> This means that after detecting a radar on a channel the user might be
> able to simply reset hostapd and get back to that channel,
> this is a major issue.
>
> To solve this I have added a check before doing any resets.
>
> If the user (for example: hostapd) asks for a regdomain and we are
> already in that regdomain, than we shouldn't reset that regdomain in case
> of wiphy disconnection (for example: hostapd reset or killed).
>
> That way the regulatory data will be saved as long as we are
> in the same regdomain.
>
> Since in that case we will anyway get back to the same regdomain
> the only difference is we will now save the regulatory data,
> won't lose it, and as a result won't get back to a channel that a radar
> was detected on until NOP will be finished, as should be.
>
> Signed-off-by: Orr Mazor <Orr.Mazor@tandemg.com>
> ---
>  net/wireless/reg.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/net/wireless/reg.c b/net/wireless/reg.c
> index d18cc05061a0..5049c487950b 100644
> --- a/net/wireless/reg.c
> +++ b/net/wireless/reg.c
> @@ -3180,6 +3180,16 @@ static void restore_regulatory_settings(bool
> reset_user, bool cached)
>  	}
>  	spin_unlock(&reg_indoor_lock);
>
> +	/* If the user asks for a regdomain and we are
> +	 * already in that regdomain, than we shouldn't reset
> +	 * the regdomain in the case of wiphy disconnection.
> +	 */
> +	if (cached && !reset_user &&
> +	    (!IS_ERR_OR_NULL(cfg80211_user_regdom)) &&
> +	    (!regdom_changes(cfg80211_user_regdom->alpha2))) {
> +		return;
> +	}
> +
>  	reset_regdomains(true, &world_regdom);
>  	restore_alpha2(alpha2, reset_user);
>
> --
> 2.17.1
>
>

Which device have you tested this on?