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Date: Mon, 14 Apr 2008 20:18:01 +0530
From: Gautham R Shenoy <ego@in.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Miles Lane <miles.lane@gmail.com>, LKML <linux-kernel@vger.kernel.org>,
       "Rafael J. Wysocki" <rjw@sisk.pl>, Ingo Molnar <mingo@elte.hu>
Subject: Re: 2.6.25-rc9 -- INFO: possible circular locking dependency
	detected
Message-ID: <20080414144801.GC20671@in.ibm.com>
Reply-To: ego@in.ibm.com
References: <a44ae5cd0804132004v2bef54fek6e9634f8bce087ab@mail.gmail.com> <1208156045.7427.16.camel@twins> <1208174767.7427.60.camel@twins> <20080414122741.GB7416@in.ibm.com> <1208176947.7427.68.camel@twins>
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On Mon, Apr 14, 2008 at 02:42:27PM +0200, Peter Zijlstra wrote:
> 
>  void __init cpu_hotplug_init(void)
>  {
> +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> +	static struct lockdep_class_key __key;
		      ^^^^^^^^^^^^^^^^^
		      should be lock_class_key.

> +
> +	lockdep_init_map(&cpu_hotplug.dep_map, "cpu_hotplug", &__key, 0);
> +#endif
>  	cpu_hotplug.active_writer = NULL;
>  	spin_lock_init(&cpu_hotplug.lock);
>  	cpu_hotplug.refcount = 0;
> @@ -54,6 +62,8 @@ void get_online_cpus(void)
>  {
>  	might_sleep();
> 
> +	cpu_hotplug_acquire_read(&cpu_hotplug.dep_map, 0, 0, _THIS_IP_);
> +
>  	spin_lock(&cpu_hotplug.lock);
>  	if (cpu_hotplug.active_writer == current)
>  		goto unlock;
> @@ -80,6 +90,8 @@ EXPORT_SYMBOL_GPL(get_online_cpus);
> 
>  void put_online_cpus(void)
>  {
> +	cpu_hotplug_release(&cpu_hotplug.lock, 1, _THIS_IP_);
> +
>  	spin_lock(&cpu_hotplug.lock);
>  	if (cpu_hotplug.active_writer == current)
>  		goto unlock;
> @@ -119,6 +131,8 @@ static void cpu_hotplug_begin(void)
>  {
>  	might_sleep();
> 
> +	cpu_hotplug_acquire(&cpu_hotplug.dep_map, 0, 0, _THIS_IP_);
> +
>  	spin_lock(&cpu_hotplug.lock);
>  	if (cpu_hotplug.refcount || cpu_hotplug.active_writer) {
>  		DEFINE_WAIT(wait);
> @@ -140,6 +154,8 @@ static void cpu_hotplug_begin(void)
> 
>  static void cpu_hotplug_done(void)
>  {
> +	cpu_hotplug_release(&cpu_hotplug.lock, 1, _THIS_IP_);
> +
>  	spin_lock(&cpu_hotplug.lock);
>  	cpu_hotplug.active_writer = NULL;
>  	if (!list_empty(&cpu_hotplug.writer_queue.task_list))
> 

-- 
Thanks and Regards
gautham