diff -Naur --exclude-from diff_exclude linux-2.6.11-final-V0.7.40-00/include/linux/rcupdate.h linux-2.6.11-final-V0.7.40-00-RCU/include/linux/rcupdate.h
--- linux-2.6.11-final-V0.7.40-00/include/linux/rcupdate.h	2005-03-11 23:40:13.000000000 +0100
+++ linux-2.6.11-final-V0.7.40-00-RCU/include/linux/rcupdate.h	2005-03-19 12:47:09.000000000 +0100
@@ -85,6 +85,7 @@
  * curlist - current batch for which quiescent cycle started if any
  */
 struct rcu_data {
+	long            active_readers;
 	/* 1) quiescent state handling : */
 	long		quiescbatch;     /* Batch # for grace period */
 	int		passed_quiesc;	 /* User-mode/idle loop etc. */
@@ -115,12 +116,14 @@
 static inline void rcu_qsctr_inc(int cpu)
 {
 	struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
-	rdp->passed_quiesc = 1;
+	if(rdp->active_readers==0)
+		rdp->passed_quiesc = 1;
 }
 static inline void rcu_bh_qsctr_inc(int cpu)
 {
 	struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu);
-	rdp->passed_quiesc = 1;
+	if(rdp->active_readers==0)
+		rdp->passed_quiesc = 1;
 }
 
 static inline int __rcu_pending(struct rcu_ctrlblk *rcp,
@@ -183,29 +186,27 @@
  *
  * It is illegal to block while in an RCU read-side critical section.
  */
-#define rcu_read_lock()		preempt_disable()
+static inline void rcu_read_lock(void)
+{	
+	preempt_disable(); 
+	__get_cpu_var(rcu_data).active_readers++;
+	preempt_enable();
+}
 
 /**
  * rcu_read_unlock - marks the end of an RCU read-side critical section.
  *
  * See rcu_read_lock() for more information.
  */
-#define rcu_read_unlock()	preempt_enable()
+static inline void rcu_read_unlock(void)
+{	
+	preempt_disable(); 
+	__get_cpu_var(rcu_data).active_readers--;
+	preempt_enable();
+}
 
 #define IGNORE_LOCK(op, lock)	do { (void)(lock); op(); } while (0)
 
-#ifdef CONFIG_PREEMPT_RT
-# define rcu_read_lock_spin(lock)	spin_lock(lock)
-# define rcu_read_unlock_spin(lock)	spin_unlock(lock)
-# define rcu_read_lock_read(lock)	read_lock(lock)
-# define rcu_read_unlock_read(lock)	read_unlock(lock)
-# define rcu_read_lock_bh_read(lock)	read_lock_bh(lock)
-# define rcu_read_unlock_bh_read(lock)	read_unlock_bh(lock)
-# define rcu_read_lock_down_read(rwsem)	down_read(rwsem)
-# define rcu_read_unlock_up_read(rwsem)	up_read(rwsem)
-# define rcu_read_lock_nort()		do { } while (0)
-# define rcu_read_unlock_nort()		do { } while (0)
-#else
 # define rcu_read_lock_spin(lock)	IGNORE_LOCK(rcu_read_lock, lock)
 # define rcu_read_unlock_spin(lock)	IGNORE_LOCK(rcu_read_unlock, lock)
 # define rcu_read_lock_read(lock)	IGNORE_LOCK(rcu_read_lock, lock)
@@ -216,15 +217,10 @@
 # define rcu_read_unlock_nort()		rcu_read_unlock()
 # define rcu_read_lock_bh_read(lock)	IGNORE_LOCK(rcu_read_lock_bh, lock)
 # define rcu_read_unlock_bh_read(lock)	IGNORE_LOCK(rcu_read_unlock_bh, lock)
-#endif
 
-#ifdef CONFIG_PREEMPT_RT
-# define rcu_read_lock_sem(lock)	down(lock)
-# define rcu_read_unlock_sem(lock)	up(lock)
-#else
 # define rcu_read_lock_sem(lock)	IGNORE_LOCK(rcu_read_lock, lock)
 # define rcu_read_unlock_sem(lock)	IGNORE_LOCK(rcu_read_unlock, lock)
-#endif
+
 /*
  * So where is rcu_write_lock()?  It does not exist, as there is no
  * way for writers to lock out RCU readers.  This is a feature, not
diff -Naur --exclude-from diff_exclude linux-2.6.11-final-V0.7.40-00/Makefile linux-2.6.11-final-V0.7.40-00-RCU/Makefile
--- linux-2.6.11-final-V0.7.40-00/Makefile	2005-03-11 23:40:13.000000000 +0100
+++ linux-2.6.11-final-V0.7.40-00-RCU/Makefile	2005-03-19 12:41:09.000000000 +0100
@@ -1,7 +1,7 @@
 VERSION = 2
 PATCHLEVEL = 6
 SUBLEVEL = 11
-EXTRAVERSION = -RT-V0.7.40-00
+EXTRAVERSION = -RT-V0.7.40-00-RCU
 NAME=Woozy Numbat
 
 # *DOCUMENTATION*