mac80211: fix locking in ieee80211_sta_tear_down_BA_sessions

Due to overlap between
commit 9e1ea3a059a3 ("mac80211: Simplify locking in ieee80211_sta_tear_down_BA_sessions()")
and the way that Luca modified
commit 8eb20ae0b4ac ("mac80211: tear down RX aggregations first")
when sending it upstream from Intel's internal tree, we get
the following warning:

WARNING: CPU: 0 PID: 5472 at net/mac80211/agg-tx.c:315 ___ieee80211_stop_tx_ba_session+0x158/0x1f0

since there's no appropriate locking around the call to
___ieee80211_stop_tx_ba_session; Sara's original just had
a call to the locked __ieee80211_stop_tx_ba_session (one
less underscore) but it looks like Luca modified both of
the calls when fixing it up for upstream, leading to the
problem at hand.

Move the locking appropriately to fix this problem.

Reported-by: Kalle Valo <kvalo@codeaurora.org>
Reported-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/ht.c b/net/mac80211/ht.c
index 167f83b853e6bd391256e15ef99439b792e18cdc..1621b6ab17ba45e63f79e85a42563781b5536dc2 100644 (file)
--- a/net/mac80211/ht.c
+++ b/net/mac80211/ht.c
@@ -291,16 +291,15 @@ void ieee80211_sta_tear_down_BA_sessions(struct sta_info *sta,
        int i;
 
        mutex_lock(&sta->ampdu_mlme.mtx);
-       for (i = 0; i <  IEEE80211_NUM_TIDS; i++) {
+       for (i = 0; i <  IEEE80211_NUM_TIDS; i++)
                ___ieee80211_stop_rx_ba_session(sta, i, WLAN_BACK_RECIPIENT,
                                                WLAN_REASON_QSTA_LEAVE_QBSS,
                                                reason != AGG_STOP_DESTROY_STA &&
                                                reason != AGG_STOP_PEER_REQUEST);
-       }
-       mutex_unlock(&sta->ampdu_mlme.mtx);
 
        for (i = 0; i <  IEEE80211_NUM_TIDS; i++)
                ___ieee80211_stop_tx_ba_session(sta, i, reason);
+       mutex_unlock(&sta->ampdu_mlme.mtx);
 
        /* stopping might queue the work again - so cancel only afterwards */
        cancel_work_sync(&sta->ampdu_mlme.work);