On Sat, Oct 06, 2012 at 02:40:54PM +0200, Felix Fietkau wrote:
> A few places touch chan->max_power based on updated tx power rules, but
> forget to do the same to chan->max_reg_power.
>
> Signed-off-by: Felix Fietkau <nbd@xxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> net/wireless/reg.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/net/wireless/reg.c b/net/wireless/reg.c
> index 3b8cbbc..bcc7d7e 100644
> --- a/net/wireless/reg.c
> +++ b/net/wireless/reg.c
> @@ -908,7 +908,7 @@ static void handle_channel(struct wiphy *wiphy,
> map_regdom_flags(reg_rule->flags) | bw_flags;
> chan->max_antenna_gain = chan->orig_mag =
> (int) MBI_TO_DBI(power_rule->max_antenna_gain);
> - chan->max_power = chan->orig_mpwr =
> + chan->max_reg_power = chan->max_power = chan->orig_mpwr =
> (int) MBM_TO_DBM(power_rule->max_eirp);
> return;
> }
> @@ -1331,7 +1331,8 @@ static void handle_channel_custom(struct wiphy *wiphy,
>
> chan->flags |= map_regdom_flags(reg_rule->flags) | bw_flags;
> chan->max_antenna_gain = (int) MBI_TO_DBI(power_rule->max_antenna_gain);
> - chan->max_power = (int) MBM_TO_DBM(power_rule->max_eirp);
> + chan->max_reg_power = chan->max_power =
> + (int) MBM_TO_DBM(power_rule->max_eirp);
This looks good to me, good catch! The commit log could use some love,
given that this is a stable patch it is worthy to describe the
consequences of not applying this patch. Can you describe what you
observed that makes this a critical patch? The only piece of code
that uses max_reg_power in cfg80211, mac80211 or drivers is on
net/wireless/reg.c and drivers/net/wireless/mwifiex/cfg80211.c.
In either case the issue the code you are patching is for code
that deals with drivers that have a custom regulatory domain
in which orig_mpwr would have been initialized to a non-zero value
upon registration. In such cases we could only potenially run into
an issue on this piece of code on handle_channel():
chan->max_reg_power = (int) MBM_TO_DBM(power_rule->max_eirp);
if (chan->orig_mpwr) {
/*
* Devices that have their own custom regulatory domain
* but also use WIPHY_FLAG_STRICT_REGULATORY will follow the
* passed country IE power settings.
*/
if (initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE &&
wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY &&
wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY)
chan->max_power = chan->max_reg_power;
else
chan->max_power = min(chan->orig_mpwr,
chan->max_reg_power);
} else
chan->max_power = chan->max_reg_power;
The issue would happen if orig_mpwr is non zero (custom) and
then max_reg_power would not have been initialized. This runs
when you change a regulatory domain on a card with a custom
regulatory domain and this would be an issue if max_reg_power
would not be initialized. This however does not happen due to
the first line above.
So I agree with this patch but do not see the requirement for
it to go in as a stable fix to older stable kernels.
Luis
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