[LEDE-DEV] [PATCH v2] mac80211: backport calculate-min-channel-width fix

Koen Vandeputte koen.vandeputte at ncentric.com
Fri Jan 20 03:40:33 PST 2017

compiled & tested on cns3xxx

Signed-off-by: Koen Vandeputte <koen.vandeputte at ncentric.com>
 ...211-calculate-min-channel-width-correctly.patch | 53 ++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 package/kernel/mac80211/patches/354-mac80211-calculate-min-channel-width-correctly.patch

diff --git a/package/kernel/mac80211/patches/354-mac80211-calculate-min-channel-width-correctly.patch b/package/kernel/mac80211/patches/354-mac80211-calculate-min-channel-width-correctly.patch
new file mode 100644
index 0000000..4567b02
--- /dev/null
+++ b/package/kernel/mac80211/patches/354-mac80211-calculate-min-channel-width-correctly.patch
@@ -0,0 +1,53 @@
+From: Johannes Berg <johannes.berg at intel.com>
+Date: Fri, 7 Oct 2016 12:23:49 +0200
+Subject: [PATCH] mac80211: calculate min channel width correctly
+In the current minimum chandef code there's an issue in that the
+recalculation can happen after rate control is initialized for a
+station that has a wider bandwidth than the current chanctx, and
+then rate control can immediately start using those higher rates
+which could cause problems.
+Observe that first of all that this problem is because we don't
+take non-associated and non-uploaded stations into account. The
+restriction to non-associated is quite pointless and is one of
+the causes for the problem described above, since the rate init
+will happen before the station is set to associated; no frames
+could actually be sent until associated, but the rate table can
+already contain higher rates and that might cause problems.
+Also, rejecting non-uploaded stations is wrong, since the rate
+control can select higher rates for those as well.
+Secondly, it's then necessary to recalculate the minimal config
+before initializing rate control, so that when rate control is
+initialized, the higher rates are already available. This can be
+done easily by adding the necessary function call in rate init.
+Change-Id: Ib9bc02d34797078db55459d196993f39dcd43070
+Signed-off-by: Johannes Berg <johannes.berg at intel.com>
+--- a/net/mac80211/chan.c
++++ b/net/mac80211/chan.c
+@@ -231,9 +231,6 @@ ieee80211_get_max_required_bw(struct iee
+ 		    !(sta->sdata->bss && sta->sdata->bss == sdata->bss))
+ 			continue;
+-		if (!sta->uploaded || !test_sta_flag(sta, WLAN_STA_ASSOC))
+-			continue;
+ 		max_bw = max(max_bw, ieee80211_get_sta_bw(&sta->sta));
+ 	}
+ 	rcu_read_unlock();
+--- a/net/mac80211/rate.c
++++ b/net/mac80211/rate.c
+@@ -40,6 +40,8 @@ void rate_control_rate_init(struct sta_i
+ 	ieee80211_sta_set_rx_nss(sta);
++	ieee80211_recalc_min_chandef(sta->sdata);
+ 	if (!ref)
+ 		return;

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