patches/rcutiny-use-simple-waitqueue.patch

Subject: rcutiny: Use simple waitqueue
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 03 Dec 2012 16:25:21 +0100

Simple waitqueues can be handled from interrupt disabled contexts.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/rcutiny_plugin.h |   17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -26,6 +26,7 @@
 #include <linux/module.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
+#include <linux/wait-simple.h>
 
 /* Global control variables for rcupdate callback mechanism. */
 struct rcu_ctrlblk {
@@ -260,7 +261,7 @@ static void show_tiny_preempt_stats(stru
 
 /* Controls for rcu_kthread() kthread. */
 static struct task_struct *rcu_kthread_task;
-static DECLARE_WAIT_QUEUE_HEAD(rcu_kthread_wq);
+static DEFINE_SWAIT_HEAD(rcu_kthread_wq);
 static unsigned long have_rcu_kthread_work;
 
 /*
@@ -713,7 +714,7 @@ void synchronize_rcu(void)
 }
 EXPORT_SYMBOL_GPL(synchronize_rcu);
 
-static DECLARE_WAIT_QUEUE_HEAD(sync_rcu_preempt_exp_wq);
+static DEFINE_SWAIT_HEAD(sync_rcu_preempt_exp_wq);
 static unsigned long sync_rcu_preempt_exp_count;
 static DEFINE_MUTEX(sync_rcu_preempt_exp_mutex);
 
@@ -735,7 +736,7 @@ static int rcu_preempted_readers_exp(voi
  */
 static void rcu_report_exp_done(void)
 {
-	wake_up(&sync_rcu_preempt_exp_wq);
+	swait_wake(&sync_rcu_preempt_exp_wq);
 }
 
 /*
@@ -787,8 +788,8 @@ void synchronize_rcu_expedited(void)
 	} else {
 		rcu_initiate_boost();
 		local_irq_restore(flags);
-		wait_event(sync_rcu_preempt_exp_wq,
-			   !rcu_preempted_readers_exp());
+		swait_event(sync_rcu_preempt_exp_wq,
+			    !rcu_preempted_readers_exp());
 	}
 
 	/* Clean up and exit. */
@@ -858,7 +859,7 @@ static void invoke_rcu_callbacks(void)
 {
 	have_rcu_kthread_work = 1;
 	if (rcu_kthread_task != NULL)
-		wake_up(&rcu_kthread_wq);
+		swait_wake(&rcu_kthread_wq);
 }
 
 #ifdef CONFIG_RCU_TRACE
@@ -888,8 +889,8 @@ static int rcu_kthread(void *arg)
 	unsigned long flags;
 
 	for (;;) {
-		wait_event_interruptible(rcu_kthread_wq,
-					 have_rcu_kthread_work != 0);
+		swait_event_interruptible(rcu_kthread_wq,
+					  have_rcu_kthread_work != 0);
 		morework = rcu_boost();
 		local_irq_save(flags);
 		work = have_rcu_kthread_work;