| Message ID | 1571795834-2027-1-git-send-email-zhenzhong.duan@oracle.com (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Headers | show |
| Series | [v2] cpuidle: not unset the driver if it already exist | expand |
On Wednesday, October 23, 2019 3:57:14 AM CET Zhenzhong Duan wrote: > __cpuidle_set_driver() check if there is an already exist driver and > unset it before return with -EBUSY. The next call will succeed as it's > just unset. > > check if any of the CPUs in the mask have a driver different from drv > already and if so return -EBUSY before updating any cpuidle_drivers > per-CPU pointers. > > Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> > --- > v2: update code logic per Rafael > > drivers/cpuidle/driver.c | 15 +++++++-------- > 1 file changed, 7 insertions(+), 8 deletions(-) > > diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c > index 80c1a83..acfce04 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; > } > Applied as 5.5 material, thanks!
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index 80c1a83..acfce04 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; }
__cpuidle_set_driver() check if there is an already exist driver and unset it before return with -EBUSY. The next call will succeed as it's just unset. check if any of the CPUs in the mask have a driver different from drv already and if so return -EBUSY before updating any cpuidle_drivers per-CPU pointers. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> --- v2: update code logic per Rafael drivers/cpuidle/driver.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)