| From 30922a5850fc98d2bb77b852f83041ebebf12cf3 Mon Sep 17 00:00:00 2001 |
| From: Zhenzhong Duan <zhenzhong.duan@oracle.com> |
| Date: Wed, 23 Oct 2019 09:57:14 +0800 |
| Subject: [PATCH] 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: 82467a5a885d ("cpuidle: simplify multiple driver support") |
| Cc: 3.11+ <stable@vger.kernel.org> # 3.11+ |
| 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: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c |
| index dc32f34e68d9..01acd88c4193 100644 |
| --- a/drivers/cpuidle/driver.c |
| +++ b/drivers/cpuidle/driver.c |
| @@ -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; |
| } |
| -- |
| 2.7.4 |
| |