iwlagn: pending frames musn't be incremented if agg is on

During my works on the transport layer I removed code that updated
a local variable (is_agg) that is needed to keep the pending_frames
count up to date. Fix this.

Also, there should be no way to have a packet with TX_CTL_AMPDU set
while the internal aggregation state machine is not in AGG_ON state.
Add a WARN_ON to ensure that.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn-tx.c

@@ -313,6 +313,9 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 		iwl_sta_modify_sleep_tx_count(priv, sta_id, 1);
 	}
 
+	if (info->flags & IEEE80211_TX_CTL_AMPDU)
+		is_agg = true;
+
 	/* irqs already disabled/saved above when locking priv->shrd->lock */
 	spin_lock(&priv->shrd->sta_lock);
 

drivers/net/wireless/iwlwifi/iwl-trans-pcie.c

@@ -1096,8 +1096,8 @@ static int iwl_trans_pcie_tx(struct iwl_trans *trans, struct sk_buff *skb,
 		hdr->seq_ctrl |= cpu_to_le16(seq_number);
 		seq_number += 0x10;
 		/* aggregation is on for this <sta,tid> */
-		if (info->flags & IEEE80211_TX_CTL_AMPDU &&
-		    tid_data->agg.state == IWL_AGG_ON) {
+		if (info->flags & IEEE80211_TX_CTL_AMPDU) {
+			WARN_ON(tid_data->agg.state != IWL_AGG_ON);
 			txq_id = tid_data->agg.txq_id;
 			is_agg = true;
 		}