diff --git a/drivers/net/wireless/ipw2100.h b/drivers/net/wireless/ipw2100.h
index 7d390f7..55b7227 100644
--- a/drivers/net/wireless/ipw2100.h
+++ b/drivers/net/wireless/ipw2100.h
@@ -46,6 +46,7 @@
 #endif
 
 #include <linux/workqueue.h>
+#include <linux/mutex.h>
 
 struct ipw2100_priv;
 struct ipw2100_tx_packet;