at76c50x-usb: avoid mutex deadlock in at76_dwork_hw_scan

http://bugzilla.kernel.org/show_bug.cgi?id=13312

at76_dwork_hw_scan holds a mutex while calling ieee80211_scan_completed,
which then calls at76_config which needs the same mutex.  This reworks
the ordering to not hold the lock while calling ieee80211_scan_completed.

Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/at76c50x-usb.c b/drivers/net/wireless/at76c50x-usb.c
index 744f4f4..8d93ca4 100644 (file)
--- a/drivers/net/wireless/at76c50x-usb.c
+++ b/drivers/net/wireless/at76c50x-usb.c
@@ -1873,18 +1873,18 @@ static void at76_dwork_hw_scan(struct work_struct *work)
        if (ret != CMD_STATUS_COMPLETE) {
                queue_delayed_work(priv->hw->workqueue, &priv->dwork_hw_scan,
                                   SCAN_POLL_INTERVAL);
        if (ret != CMD_STATUS_COMPLETE) {
                queue_delayed_work(priv->hw->workqueue, &priv->dwork_hw_scan,
                                   SCAN_POLL_INTERVAL);

-               goto exit;
+               mutex_unlock(&priv->mtx);
+               return;

        }
 
        }
 

-       ieee80211_scan_completed(priv->hw, false);
-

        if (is_valid_ether_addr(priv->bssid))
                at76_join(priv);
 
        if (is_valid_ether_addr(priv->bssid))
                at76_join(priv);
 

-       ieee80211_wake_queues(priv->hw);
-
-exit:

        mutex_unlock(&priv->mtx);
        mutex_unlock(&priv->mtx);

+
+       ieee80211_scan_completed(priv->hw, false);
+
+       ieee80211_wake_queues(priv->hw);

 }
 
 static int at76_hw_scan(struct ieee80211_hw *hw,
 }
 
 static int at76_hw_scan(struct ieee80211_hw *hw,