mac80211: handle non-bufferable MMPDUs correctly

This renames the IEEE80211_TX_CTL_POLL_RESPONSE
TX flag to IEEE80211_TX_CTL_NO_PS_BUFFER and also
uses it for non-bufferable MMPDUs (all MMPDUs but
deauth, disassoc and action frames.)

Previously, mac80211 would let the MMPDU through
but not set the flag so drivers supporting some
hardware aids for avoiding the PS races would
then reject the frame.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index da18a8f..5f78567 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -322,7 +322,7 @@
 		sta_priv = (void *)info->control.sta->drv_priv;
 
 	if (sta_priv && sta_priv->asleep &&
-	    (info->flags & IEEE80211_TX_CTL_POLL_RESPONSE)) {
+	    (info->flags & IEEE80211_TX_CTL_NO_PS_BUFFER)) {
 		/*
 		 * This sends an asynchronous command to the device,
 		 * but we can rely on it being processed before the
@@ -331,6 +331,10 @@
 		 * counter.
 		 * For now set the counter to just 1 since we do not
 		 * support uAPSD yet.
+		 *
+		 * FIXME: If we get two non-bufferable frames one
+		 * after the other, we might only send out one of
+		 * them because this is racy.
 		 */
 		iwl_sta_modify_sleep_tx_count(priv, sta_id, 1);
 	}