diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index afa8e0a..d9724a2 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -1266,6 +1266,8 @@
 
 #define WLAN_MAX_KEY_LEN		32
 
+#define WLAN_PMKID_LEN			16
+
 /**
  * ieee80211_get_qos_ctl - get pointer to qos control bytes
  * @hdr: the frame