diff --git a/sys/compat/linuxkpi/common/include/linux/wait.h b/sys/compat/linuxkpi/common/include/linux/wait.h
--- a/sys/compat/linuxkpi/common/include/linux/wait.h
+++ b/sys/compat/linuxkpi/common/include/linux/wait.h
@@ -61,12 +61,14 @@
 
 typedef int wait_queue_func_t(wait_queue_t *, unsigned int, int, void *);
 
+#define WQ_FLAG_WOKEN		0x02
+
 /*
  * Many API consumers directly reference these fields and those of
  * wait_queue_head.
  */
 struct wait_queue {
-	unsigned int flags;	/* always 0 */
+	unsigned int flags;
 	void *private;
 	wait_queue_func_t *func;
 	union {
@@ -89,6 +91,9 @@
  */
 extern wait_queue_func_t autoremove_wake_function;
 extern wait_queue_func_t default_wake_function;
+extern wait_queue_func_t woken_wake_function;
+
+long wait_woken(wait_queue_t *wq, unsigned state, long timeout);
 
 #define	DEFINE_WAIT_FUNC(name, function)				\
 	wait_queue_t name = {						\
diff --git a/sys/compat/linuxkpi/common/src/linux_schedule.c b/sys/compat/linuxkpi/common/src/linux_schedule.c
--- a/sys/compat/linuxkpi/common/src/linux_schedule.c
+++ b/sys/compat/linuxkpi/common/src/linux_schedule.c
@@ -30,6 +30,7 @@
 #include <sys/signalvar.h>
 #include <sys/sleepqueue.h>
 
+#include <asm/barrier.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
@@ -182,6 +183,30 @@
 	return (wake_up_task(wq->private, state));
 }
 
+int
+woken_wake_function(wait_queue_t *wq, unsigned int state, int flags,
+    void *key)
+{
+	smp_mb();
+	wq->flags |= WQ_FLAG_WOKEN;
+
+	return (default_wake_function(wq, state, flags, key));
+}
+
+long
+wait_woken(wait_queue_t *wq, unsigned state, long timeout)
+{
+	set_task_state(current, state);
+	if (!(wq->flags & WQ_FLAG_WOKEN)) {
+		timeout = linux_schedule_timeout(timeout);
+	}
+	set_task_state(current, TASK_RUNNING);
+
+	smp_store_mb(wq->flags, wq->flags & ~WQ_FLAG_WOKEN);
+
+	return (timeout);
+}
+
 void
 linux_init_wait_entry(wait_queue_t *wq, int flags)
 {