[PATCH] cpu hotplug: fix hotplug cpu documentation for proper usage

		return NOTIFY_OK;

	}

	static struct notifier_block foobar_cpu_notifer =

	static struct notifier_block __cpuinitdata foobar_cpu_notifer =

	{

	   .notifier_call = foobar_cpu_callback,

	};

You need to call register_cpu_notifier() from your init function.

Init functions could be of two types:

1. early init (init function called when only the boot processor is online).

2. late init (init function called _after_ all the CPUs are online).

In your init function,

For the first case, you should add the following to your init function

	register_cpu_notifier(&foobar_cpu_notifier);

For the second case, you should add the following to your init function

	register_hotcpu_notifier(&foobar_cpu_notifier);

You can fail PREPARE notifiers if something doesn't work to prepare resources.

This will stop the activity and send a following CANCELED event back.