On Mon 09-01-17 11:47:50, Arnd Bergmann wrote:
> The backport of upstream commit 777c6e0daebb ("hotplug: Make
> register and unregister notifier API symmetric") to linux-4.4.y
> introduced a harmless warning in 'allnoconfig' builds as spotted by
> kernelci.org:
>
> kernel/cpu.c:226:13: warning: 'cpu_notify_nofail' defined but not used
> [-Wunused-function]
Is this warning really worth bothering? Does any stable rely on warning
free builds?
> So far, this is the only stable tree that is affected, as linux-4.6 and
> higher contain commit 984581728eb4 ("cpu/hotplug: Split out cpu down
> functions")
> that makes the function used in all configurations, while older longterm
> releases so far don't seem to have a backport of 777c6e0daebb.
>
> The fix for the warning is trivial: move the unused function back
> into the #ifdef section where it was before.
this looks good to me.
> Link: https://kernelci.org/build/id/586fcacb59b514049ef6c3aa/logs/
> Fixes: 1c0f4e0ebb79 ("hotplug: Make register and unregister notifier API
> symmetric") in v4.4.y
> Signed-off-by: Arnd Bergmann <a...@arndb.de>
> ---
> kernel/cpu.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index cd6d1258554e..40d20bf5de28 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -223,10 +223,6 @@ static int cpu_notify(unsigned long val, void *v)
> return __cpu_notify(val, v, -1, NULL);
> }
>
> -static void cpu_notify_nofail(unsigned long val, void *v)
> -{
> - BUG_ON(cpu_notify(val, v));
> -}
> EXPORT_SYMBOL(register_cpu_notifier);
> EXPORT_SYMBOL(__register_cpu_notifier);
>
> @@ -245,6 +241,11 @@ void __unregister_cpu_notifier(struct notifier_block *nb)
> EXPORT_SYMBOL(__unregister_cpu_notifier);
>
> #ifdef CONFIG_HOTPLUG_CPU
> +static void cpu_notify_nofail(unsigned long val, void *v)
> +{
> + BUG_ON(cpu_notify(val, v));
> +}
> +
> /**
> * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
> * @cpu: a CPU id
> --
> 2.9.0
>
--
Michal Hocko
SUSE Labs
