3.16.82-rc1 review patch. If anyone has any objections, please let me know.
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From: Zhenzhong Duan zhenzhong.duan@oracle.com
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: 82467a5a885d ("cpuidle: simplify multiple driver support") Signed-off-by: Zhenzhong Duan zhenzhong.duan@oracle.com [ rjw: Subject & changelog ] Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/cpuidle/driver.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)
--- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -60,24 +60,23 @@ static inline void __cpuidle_unset_drive * __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; }