mac80211: always send multicast on CAB queue

If the driver advertised support for a CAB queue, then we
should put all multicast frames there, otherwise sending
them can be racy with clients going to sleep while we TX
a frame. To avoid this, always TX multicast frames on the
multicast queue.

It seems like even drivers not using the queue framework
might want to do this which would mean also moving the
IEEE80211_TX_CTL_SEND_AFTER_DTIM flag assignment, but it
also seems that drivers behave differently here so that
just moving it wouldn't be a good idea. It'd be better to
modify those drivers to use the queue framework.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 9972e07a2f9650315521560cfb48267504476200..34be9336b5d1f3ce04f716758f44e46144edd916 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -398,13 +398,14 @@ ieee80211_tx_h_multicast_ps_buf(struct ieee80211_tx_data *tx)
        if (ieee80211_has_order(hdr->frame_control))
                return TX_CONTINUE;
 
+       if (tx->local->hw.flags & IEEE80211_HW_QUEUE_CONTROL)
+               info->hw_queue = tx->sdata->vif.cab_queue;
+
        /* no stations in PS mode */
        if (!atomic_read(&ps->num_sta_ps))
                return TX_CONTINUE;
 
        info->flags |= IEEE80211_TX_CTL_SEND_AFTER_DTIM;
-       if (tx->local->hw.flags & IEEE80211_HW_QUEUE_CONTROL)
-               info->hw_queue = tx->sdata->vif.cab_queue;
 
        /* device releases frame after DTIM beacon */
        if (!(tx->local->hw.flags & IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING))