[PATCH] mac80211: stop tx before doing hw config and rate update

[Rajkumar Manoharan <rmanohar@qca.qualcomm.com>]

The assumption is that during the hw config, transmission was
already stopped by mac80211. But during channel type change,
the mac80211 continue to transmit frames. The driver like ath9k
does chip reset while doing channel set. This could leads to
buffer overflow at driver side. And also after configuring the channel
and before calling rate updation, the frames are continued to xmit
with older rates. This patch ensures that the frames are always
xmitted with updated rates and avoid buffer overflow.

Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
---
 net/mac80211/ieee80211_i.h |    1 +
 net/mac80211/mlme.c        |   10 ++++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index c204cee..8db9f9a 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -670,6 +670,7 @@ enum queue_stop_reason {
 	IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
 	IEEE80211_QUEUE_STOP_REASON_SUSPEND,
 	IEEE80211_QUEUE_STOP_REASON_SKB_ADD,
+	IEEE80211_QUEUE_STOP_REASON_CHTYPE_CHANGE,
 };
 
 #ifdef CONFIG_MAC80211_LEDS
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 60a6f27..5b51390 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -232,6 +232,13 @@ static u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
 		WARN_ON(!ieee80211_set_channel_type(local, sdata, channel_type));
 	}
 
+	ieee80211_stop_queues_by_reason(&sdata->local->hw,
+			IEEE80211_QUEUE_STOP_REASON_CHTYPE_CHANGE);
+
+	/* flush out all packets */
+	synchronize_net();
+
+	drv_flush(local, false);
 	/* channel_type change automatically detected */
 	ieee80211_hw_config(local, 0);
 
@@ -245,6 +252,9 @@ static u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
 		rcu_read_unlock();
 	}
 
+	ieee80211_wake_queues_by_reason(&sdata->local->hw,
+			IEEE80211_QUEUE_STOP_REASON_CHTYPE_CHANGE);
+
 	ht_opmode = le16_to_cpu(hti->operation_mode);
 
 	/* if bss configuration changed store the new one */
-- 
1.7.6.1