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 25ba24bef8f51f669ccbcc95cfcb5f1d235e39a9..995a491f73a93f6d22a5c1c2a774c76f1118bd07 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -439,8 +439,8 @@ 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;