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authorZhenzhong Duan <zhenzhong.duan@oracle.com>2019-10-23 09:57:14 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-10-24 23:22:33 +0200
commit918c1fe9fbbe46fcf56837ff21f0ef96424e8b29 (patch)
tree1379838ce6818072eff03abe646081f37b1b97ef /drivers/cpuidle
parentMerge back earlier cpuidle material for v5.5. (diff)
downloadlinux-dev-918c1fe9fbbe46fcf56837ff21f0ef96424e8b29.tar.xz
linux-dev-918c1fe9fbbe46fcf56837ff21f0ef96424e8b29.zip
cpuidle: Do not unset the driver if it is there already
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>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/driver.c15
1 files changed, 7 insertions, 8 deletions
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 80c1a830d991..9db154224999 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;
}