mac80211: temporarily disable reorder release timer

Several serve threading problems in the current
release reorder timer implementation have been
discovered.

A lengthy discussion - which lists some of the
pitfalls and possible solutions - can be found at:
 http://marc.info/?t=128635927000001

But due to the complicated nature of the subject and
the imminent advent of a new -rc cycle, it was
decided to disable the feature for the time being.

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

1 files changed, 24 insertions, 0 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index b67221def584..902b03ee8f60 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -622,6 +622,26 @@ static void ieee80211_sta_reorder_release(struct ieee80211_hw *hw,
                                                         tid_agg_rx->buf_size;
         }
 
+        /*
+         * Disable the reorder release timer for now.
+         *
+         * The current implementation lacks a proper locking scheme
+         * which would protect vital statistic and debug counters
+         * from being updated by two different but concurrent BHs.
+         *
+         * More information about the topic is available from:
+         * - thread: http://marc.info/?t=128635927000001
+         *
+         * What was wrong:
+         * =>  http://marc.info/?l=linux-wireless&m=128636170811964
+         * "Basically the thing is that until your patch, the data
+         *  in the struct didn't actually need locking because it
+         *  was accessed by the RX path only which is not concurrent."
+         *
+         * List of what needs to be fixed:
+         * => http://marc.info/?l=linux-wireless&m=128656352920957
+         *
+
         if (tid_agg_rx->stored_mpdu_num) {
                 j = index = seq_sub(tid_agg_rx->head_seq_num,
                                     tid_agg_rx->ssn) % tid_agg_rx->buf_size;
@@ -640,6 +660,10 @@ static void ieee80211_sta_reorder_release(struct ieee80211_hw *hw,
         } else {
                 del_timer(&tid_agg_rx->reorder_timer);
         }
+        */
+
+set_release_timer:
+        return;
 }
 
 /*