linux_dsm_epyc7002/drivers/idle
Srivatsa S. Bhat 07494d547e intel-idle: Fix CPU hotplug callback registration
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:

	get_online_cpus();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	register_cpu_notifier(&foobar_cpu_notifier);

	put_online_cpus();

This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).

Instead, the correct and race-free way of performing the callback
registration is:

	cpu_notifier_register_begin();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	/* Note the use of the double underscored version of the API */
	__register_cpu_notifier(&foobar_cpu_notifier);

	cpu_notifier_register_done();

Fix the intel-idle code by using this latter form of callback registration.

Cc: Len Brown <lenb@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-20 13:43:46 +01:00
..
i7300_idle.c intel_idle: Convert i7300_idle_lock to raw_spinlock 2013-02-19 08:42:47 +01:00
intel_idle.c intel-idle: Fix CPU hotplug callback registration 2014-03-20 13:43:46 +01:00
Kconfig drivers/idle: remove depends on CONFIG_EXPERIMENTAL 2013-01-21 14:52:43 -08:00
Makefile intel_idle: native hardware cpuidle driver for latest Intel processors 2010-05-28 14:26:20 -04:00