---
 arch/x86/kernel/entry_64.S     |    7 ++-----
 include/linux/rwsem-spinlock.h |    4 ++--
 include/linux/rwsem.h          |   12 ++++++++++++
 kernel/rwsem.c                 |   23 +++++++++++++++++++++--
 lib/rwsem-spinlock.c           |   14 +++++++-------
 5 files changed, 44 insertions(+), 16 deletions(-)

Index: linux-2.6/include/linux/rwsem.h
===================================================================
--- linux-2.6.orig/include/linux/rwsem.h	2008-06-17 09:29:24.527635710 -0700
+++ linux-2.6/include/linux/rwsem.h	2008-06-17 16:41:10.328885966 -0700
@@ -48,11 +48,23 @@ extern int down_write_trylock(struct rw_
 extern void up_read(struct rw_semaphore *sem);
 
 /*
+ * Release a read lock but do not run pending writers / readers
+ * immediately.
+ */
+extern void up_read_async(struct rw_semaphore *sem);
+
+/*
  * release a write lock
  */
 extern void up_write(struct rw_semaphore *sem);
 
 /*
+ * Release a write lock but do not run pending writers / readers
+ * immediately.
+ */
+extern void up_write_async(struct rw_semaphore *sem);
+
+/*
  * downgrade write lock to read lock
  */
 extern void downgrade_write(struct rw_semaphore *sem);
Index: linux-2.6/kernel/rwsem.c
===================================================================
--- linux-2.6.orig/kernel/rwsem.c	2008-06-17 09:29:24.557625153 -0700
+++ linux-2.6/kernel/rwsem.c	2008-06-17 16:55:28.268886003 -0700
@@ -74,11 +74,21 @@ void up_read(struct rw_semaphore *sem)
 {
 	rwsem_release(&sem->dep_map, 1, _RET_IP_);
 
-	__up_read(sem);
+	__up_read(sem, 0);
 }
 
 EXPORT_SYMBOL(up_read);
 
+void up_read_async(struct rw_semaphore *sem)
+{
+	rwsem_release(&sem->dep_map, 1, _RET_IP_);
+
+	__up_read(sem, 1);
+}
+
+EXPORT_SYMBOL(up_read_async);
+
+
 /*
  * release a write lock
  */
@@ -86,11 +96,20 @@ void up_write(struct rw_semaphore *sem)
 {
 	rwsem_release(&sem->dep_map, 1, _RET_IP_);
 
-	__up_write(sem);
+	__up_write(sem, 0);
 }
 
 EXPORT_SYMBOL(up_write);
 
+void up_write_async(struct rw_semaphore *sem)
+{
+	rwsem_release(&sem->dep_map, 1, _RET_IP_);
+
+	__up_write(sem, 0);
+}
+
+EXPORT_SYMBOL(up_write_async);
+
 /*
  * downgrade write lock to read lock
  */
Index: linux-2.6/include/linux/rwsem-spinlock.h
===================================================================
--- linux-2.6.orig/include/linux/rwsem-spinlock.h	2008-06-17 09:29:24.547626416 -0700
+++ linux-2.6/include/linux/rwsem-spinlock.h	2008-06-17 16:41:10.356385685 -0700
@@ -65,8 +65,8 @@ extern int __down_read_trylock(struct rw
 extern void __down_write(struct rw_semaphore *sem);
 extern void __down_write_nested(struct rw_semaphore *sem, int subclass);
 extern int __down_write_trylock(struct rw_semaphore *sem);
-extern void __up_read(struct rw_semaphore *sem);
-extern void __up_write(struct rw_semaphore *sem);
+extern void __up_read(struct rw_semaphore *sem, int async);
+extern void __up_write(struct rw_semaphore *sem, int async);
 extern void __downgrade_write(struct rw_semaphore *sem);
 
 static inline int rwsem_is_locked(struct rw_semaphore *sem)
Index: linux-2.6/lib/rwsem-spinlock.c
===================================================================
--- linux-2.6.orig/lib/rwsem-spinlock.c	2008-06-17 09:29:24.567626697 -0700
+++ linux-2.6/lib/rwsem-spinlock.c	2008-06-17 16:59:13.628885353 -0700
@@ -45,7 +45,7 @@ void __init_rwsem(struct rw_semaphore *s
  * - writers are only woken if wakewrite is non-zero
  */
 static inline struct rw_semaphore *
-__rwsem_do_wake(struct rw_semaphore *sem, int wakewrite)
+__rwsem_do_wake(struct rw_semaphore *sem, int wakewrite, int async)
 {
 	struct rwsem_waiter *waiter;
 	struct task_struct *tsk;
@@ -104,7 +104,7 @@ __rwsem_do_wake(struct rw_semaphore *sem
  * wake a single writer
  */
 static inline struct rw_semaphore *
-__rwsem_wake_one_writer(struct rw_semaphore *sem)
+__rwsem_wake_one_writer(struct rw_semaphore *sem, int async)
 {
 	struct rwsem_waiter *waiter;
 	struct task_struct *tsk;
@@ -260,14 +260,14 @@ int __down_write_trylock(struct rw_semap
 /*
  * release a read lock on the semaphore
  */
-void __up_read(struct rw_semaphore *sem)
+void __up_read(struct rw_semaphore *sem, int async)
 {
 	unsigned long flags;
 
 	spin_lock_irqsave(&sem->wait_lock, flags);
 
 	if (--sem->activity == 0 && !list_empty(&sem->wait_list))
-		sem = __rwsem_wake_one_writer(sem);
+		sem = __rwsem_wake_one_writer(sem, async);
 
 	spin_unlock_irqrestore(&sem->wait_lock, flags);
 }
@@ -275,7 +275,7 @@ void __up_read(struct rw_semaphore *sem)
 /*
  * release a write lock on the semaphore
  */
-void __up_write(struct rw_semaphore *sem)
+void __up_write(struct rw_semaphore *sem, int async)
 {
 	unsigned long flags;
 
@@ -283,7 +283,7 @@ void __up_write(struct rw_semaphore *sem
 
 	sem->activity = 0;
 	if (!list_empty(&sem->wait_list))
-		sem = __rwsem_do_wake(sem, 1);
+		sem = __rwsem_do_wake(sem, 1, async);
 
 	spin_unlock_irqrestore(&sem->wait_lock, flags);
 }
@@ -300,7 +300,7 @@ void __downgrade_write(struct rw_semapho
 
 	sem->activity = 1;
 	if (!list_empty(&sem->wait_list))
-		sem = __rwsem_do_wake(sem, 0);
+		sem = __rwsem_do_wake(sem, 0, 0);
 
 	spin_unlock_irqrestore(&sem->wait_lock, flags);
 }
Index: linux-2.6/arch/x86/kernel/entry_64.S
===================================================================
--- linux-2.6.orig/arch/x86/kernel/entry_64.S	2008-06-17 18:06:44.480136040 -0700
+++ linux-2.6/arch/x86/kernel/entry_64.S	2008-06-17 18:11:03.881774960 -0700
@@ -766,18 +766,15 @@ END(spurious_interrupt)
 	SWAPGS
 	xorl  %ebx,%ebx
 1:
-	.if \ist
-	movq	%gs:pda_data_offset, %rbp
-	.endif
 	movq %rsp,%rdi
 	movq ORIG_RAX(%rsp),%rsi
 	movq $-1,ORIG_RAX(%rsp)
 	.if \ist
-	subq	$EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)
+	subq	$EXCEPTION_STKSZ, %gs:per_cpu__init_tss + TSS_ist + (\ist - 1) * 8
 	.endif
 	call \sym
 	.if \ist
-	addq	$EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)
+	addq	$EXCEPTION_STKSZ, %gs:per_cpu__init_tss + TSS_ist + (\ist - 1) * 8
 	.endif
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	.if \irqtrace