diff -urN linux.orig/include/linux/wait.h linux.diff/include/linux/wait.h
--- linux.orig/include/linux/wait.h	Tue Jan 22 15:14:48 2002
+++ linux.diff/include/linux/wait.h	Tue Jan 22 15:19:39 2002
@@ -28,17 +28,20 @@
 #define WAITQUEUE_DEBUG 0
 #endif
 
+typedef struct __wait_queue wait_queue_t;
+typedef void (*wait_queue_func_t)(wait_queue_t *wait);
+
 struct __wait_queue {
 	unsigned int flags;
 #define WQ_FLAG_EXCLUSIVE	0x01
 	struct task_struct * task;
 	struct list_head task_list;
+	wait_queue_func_t func;
 #if WAITQUEUE_DEBUG
 	long __magic;
 	long __waker;
 #endif
 };
-typedef struct __wait_queue wait_queue_t;
 
 /*
  * 'dual' spinlock architecture. Can be switched between spinlock_t and
@@ -137,6 +140,7 @@
 #endif
 
 #define __WAITQUEUE_INITIALIZER(name, tsk) {				\
+	func:		NULL,						\
 	task:		tsk,						\
 	task_list:	{ NULL, NULL },					\
 			 __WAITQUEUE_DEBUG_INIT(name)}
@@ -174,6 +178,22 @@
 #endif
 	q->flags = 0;
 	q->task = p;
+	q->func = NULL;
+#if WAITQUEUE_DEBUG
+	q->__magic = (long)&q->__magic;
+#endif
+}
+
+static inline void init_waitqueue_func_entry(wait_queue_t *q,
+					wait_queue_func_t func)
+{
+#if WAITQUEUE_DEBUG
+	if (!q || !p)
+		WQ_BUG();
+#endif
+	q->flags = 0;
+	q->task = NULL;
+	q->func = func;
 #if WAITQUEUE_DEBUG
 	q->__magic = (long)&q->__magic;
 #endif
@@ -231,6 +251,20 @@
 	list_del(&old->task_list);
 }
 
+#define add_wait_queue_cond(q, wait, cond) \
+	({							\
+		unsigned long flags;				\
+		int _raced = 0;					\
+		wq_write_lock_irqsave(&(q)->lock, flags);	\
+		(wait)->flags = 0;				\
+		if (cond)					\
+			__add_wait_queue((q), (wait));		\
+		else						\
+			_raced = 1;				\
+		wq_write_unlock_irqrestore(&(q)->lock, flags);	\
+		_raced;						\
+	})
+
 #endif /* __KERNEL__ */
 
 #endif
diff -urN linux.orig/kernel/sched.c linux.diff/kernel/sched.c
--- linux.orig/kernel/sched.c	Tue Jan 22 15:14:55 2002
+++ linux.diff/kernel/sched.c	Tue Jan 22 15:28:07 2002
@@ -644,13 +644,22 @@
 static inline void __wake_up_common (wait_queue_head_t *q, unsigned int mode,
 			 	     int nr_exclusive, const int sync)
 {
-	struct list_head *tmp;
+	struct list_head *tmp, *next;
 	task_t *p;
 
-	list_for_each(tmp,&q->task_list) {
+	list_for_each_safe(tmp, next, &q->task_list) {
 		unsigned int state;
 		wait_queue_t *curr = list_entry(tmp, wait_queue_t, task_list);
+		wait_queue_func_t func;
 
+		func = curr->func;
+		if (func) {
+			unsigned flags = curr->flags;
+			func(curr);
+			if ((flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
+				break;
+			continue;
+		}
 		p = curr->task;
 		state = p->state;
 		if ((state & mode) &&