diff mbox

mac80211: agg-tx: avoid sending DelBA with sta->lock held

Message ID 1427701762-27090-1-git-send-email-johannes@sipsolutions.net (mailing list archive)
State Accepted
Delegated to: Johannes Berg
Headers show

Commit Message

Johannes Berg March 30, 2015, 7:49 a.m. UTC 
From: Johannes Berg <johannes.berg@intel.com>

The rate control locking caused a potential deadlock here due to the
locks being acquired in different orders, so that change cannot yet
be applied. However, there's no fundamental reason for this code to
hold the sta->lock while transmitting frames.

Clearly it's better not to hold the lock for longer periods of time,
which can happen here since we call all the way down to the driver.
Change the code a bit to not hold it while doing that.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/agg-tx.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index a360c15cc978..668524aeb0b2 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -793,6 +793,7 @@  void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 	struct ieee80211_local *local = sdata->local;
 	struct sta_info *sta;
 	struct tid_ampdu_tx *tid_tx;
+	bool send_delba = false;
 
 	trace_api_stop_tx_ba_cb(sdata, ra, tid);
 
@@ -824,13 +825,17 @@  void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 	}
 
 	if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
-		ieee80211_send_delba(sta->sdata, ra, tid,
-			WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
+		send_delba = true;
 
 	ieee80211_remove_tid_tx(sta, tid);
 
  unlock_sta:
 	spin_unlock_bh(&sta->lock);
+
+	if (send_delba)
+		ieee80211_send_delba(sdata, ra, tid,
+			WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
+
 	mutex_unlock(&sta->ampdu_mlme.mtx);
  unlock:
 	mutex_unlock(&local->sta_mtx);