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Commit c9678821 authored by Zhenzhong Duan's avatar Zhenzhong Duan Committed by Greg Kroah-Hartman
Browse files

cpuidle: Do not unset the driver if it is there already 



commit 918c1fe9fbbe46fcf56837ff21f0ef96424e8b29 upstream.

Fix __cpuidle_set_driver() to check if any of the CPUs in the mask has
a driver different from drv already and, if so, return -EBUSY before
updating any cpuidle_drivers per-CPU pointers.

Fixes: 82467a5a ("cpuidle: simplify multiple driver support")
Cc: 3.11+ <stable@vger.kernel.org> # 3.11+
Signed-off-by: default avatarZhenzhong Duan <zhenzhong.duan@oracle.com>
[ rjw: Subject & changelog ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent aedc1c75

drivers/cpuidle/driver.c

+7 −8
Original line number Diff line number Diff line
@@ -62,24 +62,23 @@ static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) 
 * __cpuidle_set_driver - set per CPU driver variables for the given driver.

 * @drv: a valid pointer to a struct cpuidle_driver

 *

 * For each CPU in the driver's cpumask, unset the registered driver per CPU

 * to @drv.

 *

 * Returns 0 on success, -EBUSY if the CPUs have driver(s) already.

 * Returns 0 on success, -EBUSY if any CPU in the cpumask have a driver

 * different from drv already.

 */

static inline int __cpuidle_set_driver(struct cpuidle_driver *drv)

{

	int cpu;



	for_each_cpu(cpu, drv->cpumask) {

		struct cpuidle_driver *old_drv;



		if (__cpuidle_get_cpu_driver(cpu)) {

			__cpuidle_unset_driver(drv);

		old_drv = __cpuidle_get_cpu_driver(cpu);

		if (old_drv && old_drv != drv)

			return -EBUSY;

	}



	for_each_cpu(cpu, drv->cpumask)

		per_cpu(cpuidle_drivers, cpu) = drv;

	}



	return 0;

}