From 693828fe92933ce4fff4c1e51365b2e6ab033b0e Mon Sep 17 00:00:00 2001 From: Rajkumar Manoharan Date: Fri, 2 Sep 2011 13:51:59 +0530 Subject: [PATCH] mac80211: stop tx before doing hw config and rate update The assumption is that during the hw config, transmission was already stopped by mac80211. Sometimes the AP can be switching b/w the ht modes due to intolerant or etc where STA is in the middle of transmission. In such scenario, buffer overflow was observed at driver side. And also before updating the rate control, the frames are continued to xmited with older rates. This patch ensures that the frames are always xmitted with updated rates and avoid buffer overflow. Signed-off-by: Rajkumar Manoharan Reviewed-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/ieee80211_i.h | 1 + net/mac80211/mlme.c | 16 ++++++++++++++++ 2 files changed, 17 insertions(+) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 5e636bc..21186e2 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -671,6 +671,7 @@ 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 fb2f0f9..ca97b80 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -1918,8 +1918,24 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata, rcu_read_unlock(); + /* + * Whenever the AP announces the HT mode change that can be + * 40MHz intolerant or etc., it would be safer to stop tx + * queues before doing hw config to avoid buffer overflow. + */ + ieee80211_stop_queues_by_reason(&sdata->local->hw, + IEEE80211_QUEUE_STOP_REASON_CHTYPE_CHANGE); + + /* flush out all packets */ + synchronize_net(); + + drv_flush(local, false); + changed |= ieee80211_enable_ht(sdata, elems.ht_info_elem, bssid, ap_ht_cap_flags); + + ieee80211_wake_queues_by_reason(&sdata->local->hw, + IEEE80211_QUEUE_STOP_REASON_CHTYPE_CHANGE); } /* Note: country IE parsing is done for us by cfg80211 */ -- 2.7.4