mac80211: fix offloaded BA session traffic after hw restart

When starting an offloaded BA session it is
unknown what starting sequence number should be
used. Using last_seq worked in most cases except
after hw restart.

When hw restart is requested last_seq is
(rightfully so) kept unmodified. This ended up
with BA sessions being restarted with an aribtrary
BA window values resulting in dropped frames until
sequence numbers caught up.

Instead of last_seq pick seqno of a first Rxed
frame of a given BA session.

This fixes stalled traffic after hw restart with
offloaded BA sessions (currently only ath10k).

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index a8d862f9183c..41eb12c87240 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -835,6 +835,16 @@ static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_sub_if_data *sdata
 
         spin_lock(&tid_agg_rx->reorder_lock);
 
+        /*
+         * Offloaded BA sessions have no known starting sequence number so pick
+         * one from first Rxed frame for this tid after BA was started.
+         */
+        if (unlikely(tid_agg_rx->auto_seq)) {
+                tid_agg_rx->auto_seq = false;
+                tid_agg_rx->ssn = mpdu_seq_num;
+                tid_agg_rx->head_seq_num = mpdu_seq_num;
+        }
+
         buf_size = tid_agg_rx->buf_size;
         head_seq_num = tid_agg_rx->head_seq_num;