iwlwifi: introduce iwl_sta_id_or_broadcast

There are now five places where we need to
look up the station ID, but the sta pointer
may be NULL due to mac80211 passing that to
indicate a certain special state.

Replace all these by a new inline function,
called iwl_sta_id_or_broadcast(), and add
documentation about when to use it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

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

@@ -567,10 +567,7 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 	hdr_len = ieee80211_hdrlen(fc);
 
 	/* Find index into station table for destination station */
-	if (!info->control.sta)
-		sta_id = priv->hw_params.bcast_sta_id;
-	else
-		sta_id = iwl_sta_id(info->control.sta);
+	sta_id = iwl_sta_id_or_broadcast(priv, info->control.sta);
 	if (sta_id == IWL_INVALID_STATION) {
 		IWL_DEBUG_DROP(priv, "Dropping - INVALID STATION: %pM\n",
 			       hdr->addr1);

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

@@ -3081,17 +3081,9 @@ static int iwl_mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 		return -EOPNOTSUPP;
 	}
 
-	if (sta) {
-		sta_id = iwl_sta_id(sta);
-
-		if (sta_id == IWL_INVALID_STATION) {
-			IWL_DEBUG_MAC80211(priv, "leave - %pM not in station map.\n",
-					   sta->addr);
+	sta_id = iwl_sta_id_or_broadcast(priv, sta);
+	if (sta_id == IWL_INVALID_STATION)
 		return -EINVAL;
-		}
-	} else {
-		sta_id = priv->hw_params.bcast_sta_id;
-	}
 
 	mutex_lock(&priv->mutex);
 	iwl_scan_cancel_timeout(priv, 100);

drivers/net/wireless/iwlwifi/iwl-sta.c

@@ -972,24 +972,16 @@ void iwl_update_tkip_key(struct iwl_priv *priv,
 	unsigned long flags;
 	int i;
 
-	if (sta) {
-		sta_id = iwl_sta_id(sta);
-
-		if (sta_id == IWL_INVALID_STATION) {
-			IWL_DEBUG_MAC80211(priv, "leave - %pM not initialised.\n",
-					   sta->addr);
-			return;
-		}
-	} else
-		sta_id = priv->hw_params.bcast_sta_id;
-
-
 	if (iwl_scan_cancel(priv)) {
 		/* cancel scan failed, just live w/ bad key and rely
 		   briefly on SW decryption */
 		return;
 	}
 
+	sta_id = iwl_sta_id_or_broadcast(priv, sta);
+	if (sta_id == IWL_INVALID_STATION)
+		return;
+
 	spin_lock_irqsave(&priv->sta_lock, flags);
 
 	priv->stations[sta_id].sta.key.tkip_rx_tsc_byte2 = (u8) iv32;

drivers/net/wireless/iwlwifi/iwl-sta.h

@@ -107,4 +107,33 @@ static inline int iwl_sta_id(struct ieee80211_sta *sta)
 
 	return ((struct iwl_station_priv_common *)sta->drv_priv)->sta_id;
 }
+
+/**
+ * iwl_sta_id_or_broadcast - return sta_id or broadcast sta
+ * @priv: iwl priv
+ * @sta: mac80211 station
+ *
+ * In certain circumstances mac80211 passes a station pointer
+ * that may be %NULL, for example during TX or key setup. In
+ * that case, we need to use the broadcast station, so this
+ * inline wraps that pattern.
+ */
+static inline int iwl_sta_id_or_broadcast(struct iwl_priv *priv,
+					  struct ieee80211_sta *sta)
+{
+	int sta_id;
+
+	if (!sta)
+		return priv->hw_params.bcast_sta_id;
+
+	sta_id = iwl_sta_id(sta);
+
+	/*
+	 * mac80211 should not be passing a partially
+	 * initialised station!
+	 */
+	WARN_ON(sta_id == IWL_INVALID_STATION);
+
+	return sta_id;
+}
 #endif /* __iwl_sta_h__ */

drivers/net/wireless/iwlwifi/iwl3945-base.c

@@ -509,10 +509,7 @@ static int iwl3945_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 	hdr_len = ieee80211_hdrlen(fc);
 
 	/* Find index into station table for destination station */
-	if (!info->control.sta)
-		sta_id = priv->hw_params.bcast_sta_id;
-	else
-		sta_id = iwl_sta_id(info->control.sta);
+	sta_id = iwl_sta_id_or_broadcast(priv, info->control.sta);
 	if (sta_id == IWL_INVALID_STATION) {
 		IWL_DEBUG_DROP(priv, "Dropping - INVALID STATION: %pM\n",
 			       hdr->addr1);
@@ -3336,18 +3333,10 @@ static int iwl3945_mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 	static_key = !iwl_is_associated(priv);
 
 	if (!static_key) {
-		if (!sta) {
-			sta_id = priv->hw_params.bcast_sta_id;
-		} else {
-			sta_id = iwl_sta_id(sta);
-			if (sta_id == IWL_INVALID_STATION) {
-				IWL_DEBUG_MAC80211(priv,
-						   "leave - %pM not in station map.\n",
-						   sta->addr);
+		sta_id = iwl_sta_id_or_broadcast(priv, sta);
+		if (sta_id == IWL_INVALID_STATION)
 			return -EINVAL;
 	}
-		}
-	}
 
 	mutex_lock(&priv->mutex);
 	iwl_scan_cancel_timeout(priv, 100);