mac80211: fix reordering of buffered broadcast packets

commit 9ec1190d065998650fd9260dea8cf3e1f56c0e8c upstream.

If the buffered broadcast queue contains packets, letting new packets bypass
that queue can lead to heavy reordering, since the driver is probably throttling
transmission of buffered multicast packets after beacons.

Keep buffering packets until the buffer has been cleared (and no client
is in powersave mode).

Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index a17a56032a2150b8c262ac8a3c0e856bc7f19d24..6b9bf9c027a2ed8e45d28daf9774819df7f3ba28 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -435,8 +435,8 @@ ieee80211_tx_h_multicast_ps_buf(struct ieee80211_tx_data *tx)
        if (ieee80211_hw_check(&tx->local->hw, QUEUE_CONTROL))
                info->hw_queue = tx->sdata->vif.cab_queue;
 
-       /* no stations in PS mode */
-       if (!atomic_read(&ps->num_sta_ps))
+       /* no stations in PS mode and no buffered packets */
+       if (!atomic_read(&ps->num_sta_ps) && skb_queue_empty(&ps->bc_buf))
                return TX_CONTINUE;
 
        info->flags |= IEEE80211_TX_CTL_SEND_AFTER_DTIM;