Re: [Xen-devel] [PATCH 2/2] cpufreq: Remove cpu hotplug callbacks only if they were initialized

2016-12-15 Thread Thomas Gleixner 
On Thu, 15 Dec 2016, Boris Ostrovsky wrote:

> Since cpu hotplug callbacks are requested for CPUHP_AP_ONLINE_DYN state,
> successful callback initialization will result in cpuhp_setup_state()
> returning a positive value. Therefore acpi_cpufreq_online being zero
> indicates that callbacks have not been installed.
> 
> This means that acpi_cpufreq_boost_exit() should only remove them if
> acpi_cpufreq_online is positive. Trying to call
> cpuhp_remove_state_nocalls(0) will cause a BUG().
> 
> Signed-off-by: Boris Ostrovsky 

Reviewed-by: Thomas Gleixner 

> ---
>  drivers/cpufreq/acpi-cpufreq.c |2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index 3a98702..3a2ca0f 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -930,7 +930,7 @@ static void __init acpi_cpufreq_boost_init(void)
>  
>  static void acpi_cpufreq_boost_exit(void)
>  {
> - if (acpi_cpufreq_online >= 0)
> + if (acpi_cpufreq_online > 0)
>   cpuhp_remove_state_nocalls(acpi_cpufreq_online);
>  }
>  
> -- 
> 1.7.1
> 
> 

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[Xen-devel] [PATCH 2/2] cpufreq: Remove cpu hotplug callbacks only if they were initialized

2016-12-15 Thread Boris Ostrovsky 
Since cpu hotplug callbacks are requested for CPUHP_AP_ONLINE_DYN state,
successful callback initialization will result in cpuhp_setup_state()
returning a positive value. Therefore acpi_cpufreq_online being zero
indicates that callbacks have not been installed.

This means that acpi_cpufreq_boost_exit() should only remove them if
acpi_cpufreq_online is positive. Trying to call
cpuhp_remove_state_nocalls(0) will cause a BUG().

Signed-off-by: Boris Ostrovsky 
---
 drivers/cpufreq/acpi-cpufreq.c |2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 3a98702..3a2ca0f 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -930,7 +930,7 @@ static void __init acpi_cpufreq_boost_init(void)
 
 static void acpi_cpufreq_boost_exit(void)
 {
-   if (acpi_cpufreq_online >= 0)
+   if (acpi_cpufreq_online > 0)
cpuhp_remove_state_nocalls(acpi_cpufreq_online);
 }
 
-- 
1.7.1


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