patches/workqueue-use-locallock.patch

Subject: Use local irq lock instead of irq disable regions
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 17 Jul 2011 21:42:26 +0200

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/workqueue.c |   33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -47,6 +47,7 @@
 #include <linux/nodemask.h>
 #include <linux/moduleparam.h>
 #include <linux/uaccess.h>
+#include <linux/locallock.h>
 
 #include "workqueue_internal.h"
 
@@ -306,6 +307,8 @@ EXPORT_SYMBOL_GPL(system_unbound_wq);
 struct workqueue_struct *system_freezable_wq __read_mostly;
 EXPORT_SYMBOL_GPL(system_freezable_wq);
 
+static DEFINE_LOCAL_IRQ_LOCK(pendingb_lock);
+
 static int worker_thread(void *__worker);
 static void copy_workqueue_attrs(struct workqueue_attrs *to,
 				 const struct workqueue_attrs *from);
@@ -1063,9 +1066,9 @@ static void put_pwq_unlocked(struct pool
 		 * As both pwqs and pools are RCU protected, the
 		 * following lock operations are safe.
 		 */
-		spin_lock_irq(&pwq->pool->lock);
+		local_spin_lock_irq(pendingb_lock, &pwq->pool->lock);
 		put_pwq(pwq);
-		spin_unlock_irq(&pwq->pool->lock);
+		local_spin_unlock_irq(pendingb_lock, &pwq->pool->lock);
 	}
 }
 
@@ -1165,7 +1168,7 @@ static int try_to_grab_pending(struct wo
 	struct worker_pool *pool;
 	struct pool_workqueue *pwq;
 
-	local_irq_save(*flags);
+	local_lock_irqsave(pendingb_lock, *flags);
 
 	/* try to steal the timer if it exists */
 	if (is_dwork) {
@@ -1229,7 +1232,7 @@ static int try_to_grab_pending(struct wo
 	spin_unlock(&pool->lock);
 fail:
 	rcu_read_unlock();
-	local_irq_restore(*flags);
+	local_unlock_irqrestore(pendingb_lock, *flags);
 	if (work_is_canceling(work))
 		return -ENOENT;
 	cpu_relax();
@@ -1301,7 +1304,7 @@ static void __queue_work(int cpu, struct
 	 * queued or lose PENDING.  Grabbing PENDING and queueing should
 	 * happen with IRQ disabled.
 	 */
-	WARN_ON_ONCE(!irqs_disabled());
+	WARN_ON_ONCE_NONRT(!irqs_disabled());
 
 	debug_work_activate(work);
 
@@ -1406,14 +1409,14 @@ bool queue_work_on(int cpu, struct workq
 	bool ret = false;
 	unsigned long flags;
 
-	local_irq_save(flags);
+	local_lock_irqsave(pendingb_lock,flags);
 
 	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
 		__queue_work(cpu, wq, work);
 		ret = true;
 	}
 
-	local_irq_restore(flags);
+	local_unlock_irqrestore(pendingb_lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL(queue_work_on);
@@ -1480,14 +1483,14 @@ bool queue_delayed_work_on(int cpu, stru
 	unsigned long flags;
 
 	/* read the comment in __queue_work() */
-	local_irq_save(flags);
+	local_lock_irqsave(pendingb_lock, flags);
 
 	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
 		__queue_delayed_work(cpu, wq, dwork, delay);
 		ret = true;
 	}
 
-	local_irq_restore(flags);
+	local_unlock_irqrestore(pendingb_lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL(queue_delayed_work_on);
@@ -1522,7 +1525,7 @@ bool mod_delayed_work_on(int cpu, struct
 
 	if (likely(ret >= 0)) {
 		__queue_delayed_work(cpu, wq, dwork, delay);
-		local_irq_restore(flags);
+		local_unlock_irqrestore(pendingb_lock, flags);
 	}
 
 	/* -ENOENT from try_to_grab_pending() becomes %true */
@@ -2855,7 +2858,7 @@ static bool __cancel_work_timer(struct w
 
 	/* tell other tasks trying to grab @work to back off */
 	mark_work_canceling(work);
-	local_irq_restore(flags);
+	local_unlock_irqrestore(pendingb_lock, flags);
 
 	flush_work(work);
 	clear_work_data(work);
@@ -2900,10 +2903,10 @@ EXPORT_SYMBOL_GPL(cancel_work_sync);
  */
 bool flush_delayed_work(struct delayed_work *dwork)
 {
-	local_irq_disable();
+	local_lock_irq(pendingb_lock);
 	if (del_timer_sync(&dwork->timer))
 		__queue_work(dwork->cpu, dwork->wq, &dwork->work);
-	local_irq_enable();
+	local_unlock_irq(pendingb_lock);
 	return flush_work(&dwork->work);
 }
 EXPORT_SYMBOL(flush_delayed_work);
@@ -2934,7 +2937,7 @@ bool cancel_delayed_work(struct delayed_
 
 	set_work_pool_and_clear_pending(&dwork->work,
 					get_work_pool_id(&dwork->work));
-	local_irq_restore(flags);
+	local_unlock_irqrestore(pendingb_lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL(cancel_delayed_work);
@@ -4385,7 +4388,7 @@ unsigned int work_busy(struct work_struc
 	if (work_pending(work))
 		ret |= WORK_BUSY_PENDING;
 
-	rcu_read_lock()
+	rcu_read_lock();
 	pool = get_work_pool(work);
 	if (pool) {
 		spin_lock_irqsave(&pool->lock, flags);