mac80211: serialize rx path workers

This patch addresses the issue of serialization between
the main rx path and various reorder release timers.

<http://www.spinics.net/lists/linux-wireless/msg57214.html>

It converts the previously local "frames" queue into
a global rx queue [rx_skb_queue]. This way, everyone
(be it the main rx-path or some reorder release timeout)
can add frames to it.

Only one active rx handler worker [ieee80211_rx_handlers]
is needed. All other threads which have lost the race of
"runnning_rx_handler" can now simply "return", knowing that
the thread who had the "edge" will also take care of their
workload.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index a21d049caf19..32e7ae0dac98 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -569,6 +569,8 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
         spin_lock_init(&local->filter_lock);
         spin_lock_init(&local->queue_stop_reason_lock);
 
+        skb_queue_head_init(&local->rx_skb_queue);
+
         INIT_DELAYED_WORK(&local->scan_work, ieee80211_scan_work);
 
         ieee80211_work_init(local);
@@ -912,6 +914,7 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
                 wiphy_warn(local->hw.wiphy, "skb_queue not empty\n");
         skb_queue_purge(&local->skb_queue);
         skb_queue_purge(&local->skb_queue_unreliable);
+        skb_queue_purge(&local->rx_skb_queue);
 
         destroy_workqueue(local->workqueue);
         wiphy_unregister(local->hw.wiphy);