diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index f82bfeb79ebb67dc73c8d85cb434ab0b0cdacb7e..d454ec8f5c6f9ed30d8610c47efdb41482fc66e4 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -1225,6 +1225,12 @@ static inline void rt2x00debug_dump_frame(struct rt2x00_dev *rt2x00dev,
 }
 #endif /* CONFIG_RT2X00_LIB_DEBUGFS */
 
+/*
+ * Utility functions.
+ */
+u32 rt2x00lib_get_bssidx(struct rt2x00_dev *rt2x00dev,
+			 struct ieee80211_vif *vif);
+
 /*
  * Interrupt context handlers.
  */
diff --git a/drivers/net/wireless/rt2x00/rt2x00dev.c b/drivers/net/wireless/rt2x00/rt2x00dev.c
index 92ff6a72a2bb422771c85788cda715ed797068c2..634b084a6527a0e6c5d5f3697c0ae05aa85c1cd6 100644
--- a/drivers/net/wireless/rt2x00/rt2x00dev.c
+++ b/drivers/net/wireless/rt2x00/rt2x00dev.c
@@ -32,6 +32,22 @@
 #include "rt2x00.h"
 #include "rt2x00lib.h"
 
+/*
+ * Utility functions.
+ */
+u32 rt2x00lib_get_bssidx(struct rt2x00_dev *rt2x00dev,
+			 struct ieee80211_vif *vif)
+{
+	/*
+	 * When in STA mode, bssidx is always 0 otherwise local_address[5]
+	 * contains the bss number, see BSS_ID_MASK comments for details.
+	 */
+	if (rt2x00dev->intf_sta_count)
+		return 0;
+	return vif->addr[5] & (rt2x00dev->ops->max_ap_intf - 1);
+}
+EXPORT_SYMBOL_GPL(rt2x00lib_get_bssidx);
+
 /*
  * Radio control handlers.
  */
diff --git a/drivers/net/wireless/rt2x00/rt2x00mac.c b/drivers/net/wireless/rt2x00/rt2x00mac.c
index 4ccf238059730cf20e589d9f567e35a3af3f189d..9db9378820bf19e8d51df0ca05cceb932c429e9a 100644
--- a/drivers/net/wireless/rt2x00/rt2x00mac.c
+++ b/drivers/net/wireless/rt2x00/rt2x00mac.c
@@ -504,15 +504,7 @@ int rt2x00mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 
 	memset(&crypto, 0, sizeof(crypto));
 
-	/*
-	 * When in STA mode, bssidx is always 0 otherwise local_address[5]
-	 * contains the bss number, see BSS_ID_MASK comments for details.
-	 */
-	if (rt2x00dev->intf_sta_count)
-		crypto.bssidx = 0;
-	else
-		crypto.bssidx = vif->addr[5] & (rt2x00dev->ops->max_ap_intf - 1);
-
+	crypto.bssidx = rt2x00lib_get_bssidx(rt2x00dev, vif);
 	crypto.cipher = rt2x00crypto_key_to_cipher(key);
 	if (crypto.cipher == CIPHER_NONE)
 		return -EOPNOTSUPP;