diff --git a/drivers/net/cxgb3/adapter.h b/drivers/net/cxgb3/adapter.h
index 8902007e8941115aeb61642186dc897e2a2d44c7..97e35c8fec6b2282cf8f67a116f6e10af976bf09 100644
--- a/drivers/net/cxgb3/adapter.h
+++ b/drivers/net/cxgb3/adapter.h
@@ -19,6 +19,7 @@
 #include <linux/interrupt.h>
 #include <linux/timer.h>
 #include <linux/cache.h>
+#include <linux/mutex.h>
 #include "t3cdev.h"
 #include <asm/semaphore.h>
 #include <asm/bitops.h>