X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fcpu.c;h=c77bc3a1c7226b504be0a50f05136662dd464a73;hb=b2a4a7ce3a995b83f59792ec9981d20ac550ccb0;hp=2011ad8d26973fae39a373aa4121ea2fd3f0b8d1;hpb=36a23fc8aa0c72ecafe7aaee0a823b03b301e1df;p=pandora-kernel.git

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 2011ad8d2697..c77bc3a1c722 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -33,17 +33,13 @@ static struct {
 	 * an ongoing cpu hotplug operation.
 	 */
 	int refcount;
-	wait_queue_head_t writer_queue;
 } cpu_hotplug;
 
-#define writer_exists() (cpu_hotplug.active_writer != NULL)
-
 void __init cpu_hotplug_init(void)
 {
 	cpu_hotplug.active_writer = NULL;
 	mutex_init(&cpu_hotplug.lock);
 	cpu_hotplug.refcount = 0;
-	init_waitqueue_head(&cpu_hotplug.writer_queue);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
@@ -65,11 +61,8 @@ void put_online_cpus(void)
 	if (cpu_hotplug.active_writer == current)
 		return;
 	mutex_lock(&cpu_hotplug.lock);
-	cpu_hotplug.refcount--;
-
-	if (unlikely(writer_exists()) && !cpu_hotplug.refcount)
-		wake_up(&cpu_hotplug.writer_queue);
-
+	if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer))
+		wake_up_process(cpu_hotplug.active_writer);
 	mutex_unlock(&cpu_hotplug.lock);
 
 }
@@ -98,8 +91,8 @@ void cpu_maps_update_done(void)
  * Note that during a cpu-hotplug operation, the new readers, if any,
  * will be blocked by the cpu_hotplug.lock
  *
- * Since cpu_maps_update_begin is always called after invoking
- * cpu_maps_update_begin, we can be sure that only one writer is active.
+ * Since cpu_hotplug_begin() is always called after invoking
+ * cpu_maps_update_begin(), we can be sure that only one writer is active.
  *
  * Note that theoretically, there is a possibility of a livelock:
  * - Refcount goes to zero, last reader wakes up the sleeping
@@ -115,19 +108,16 @@ void cpu_maps_update_done(void)
  */
 static void cpu_hotplug_begin(void)
 {
-	DECLARE_WAITQUEUE(wait, current);
-
-	mutex_lock(&cpu_hotplug.lock);
-
 	cpu_hotplug.active_writer = current;
-	add_wait_queue_exclusive(&cpu_hotplug.writer_queue, &wait);
-	while (cpu_hotplug.refcount) {
-		set_current_state(TASK_UNINTERRUPTIBLE);
+
+	for (;;) {
+		mutex_lock(&cpu_hotplug.lock);
+		if (likely(!cpu_hotplug.refcount))
+			break;
+		__set_current_state(TASK_UNINTERRUPTIBLE);
 		mutex_unlock(&cpu_hotplug.lock);
 		schedule();
-		mutex_lock(&cpu_hotplug.lock);
 	}
-	remove_wait_queue_locked(&cpu_hotplug.writer_queue, &wait);
 }
 
 static void cpu_hotplug_done(void)
@@ -136,7 +126,7 @@ static void cpu_hotplug_done(void)
 	mutex_unlock(&cpu_hotplug.lock);
 }
 /* Need to know about CPUs going up/down? */
-int __cpuinit register_cpu_notifier(struct notifier_block *nb)
+int __ref register_cpu_notifier(struct notifier_block *nb)
 {
 	int ret;
 	cpu_maps_update_begin();
@@ -149,7 +139,7 @@ int __cpuinit register_cpu_notifier(struct notifier_block *nb)
 
 EXPORT_SYMBOL(register_cpu_notifier);
 
-void unregister_cpu_notifier(struct notifier_block *nb)
+void __ref unregister_cpu_notifier(struct notifier_block *nb)
 {
 	cpu_maps_update_begin();
 	raw_notifier_chain_unregister(&cpu_chain, nb);
@@ -180,7 +170,7 @@ struct take_cpu_down_param {
 };
 
 /* Take this CPU down. */
-static int take_cpu_down(void *_param)
+static int __ref take_cpu_down(void *_param)
 {
 	struct take_cpu_down_param *param = _param;
 	int err;
@@ -199,7 +189,7 @@ static int take_cpu_down(void *_param)
 }
 
 /* Requires cpu_add_remove_lock to be held */
-static int _cpu_down(unsigned int cpu, int tasks_frozen)
+static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 {
 	int err, nr_calls = 0;
 	struct task_struct *p;
@@ -225,7 +215,7 @@ static int _cpu_down(unsigned int cpu, int tasks_frozen)
 		__raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
 					  hcpu, nr_calls, NULL);
 		printk("%s: attempt to take down CPU %u failed\n",
-				__FUNCTION__, cpu);
+				__func__, cpu);
 		err = -EINVAL;
 		goto out_release;
 	}
@@ -274,7 +264,7 @@ out_release:
 	return err;
 }
 
-int cpu_down(unsigned int cpu)
+int __ref cpu_down(unsigned int cpu)
 {
 	int err = 0;
 
@@ -305,7 +295,7 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
 	if (ret == NOTIFY_BAD) {
 		nr_calls--;
 		printk("%s: attempt to bring up CPU %u failed\n",
-				__FUNCTION__, cpu);
+				__func__, cpu);
 		ret = -EINVAL;
 		goto out_notify;
 	}