On Mon, Oct 08, 2012 at 11:01:30PM +0200, Felix Fietkau wrote:
> On 2012-10-08 9:01 PM, Luis R. Rodriguez wrote:
> > 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.
> OK, I'll extend the commit log and resend without the stable-Cc.
Great in that case please feel free to add:
Acked-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxxxxxxxx>
Thanks!
Luis
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