Re: [PATCH] kernel/watchdog: fix warning -Wunused-variable for watchdog_allowed_mask in ppc64

[Petr Mladek <pmladek@suse.com>]

On Fri 2020-08-14 19:03:30, Balamuruhan S wrote:
> In ppc64 config if `CONFIG_SOFTLOCKUP_DETECTOR` is not set then it
> warns for unused declaration of `watchdog_allowed_mask` while building,
> move the declaration inside ifdef later in the code.
> 
> ```
> kernel/watchdog.c:47:23: warning: ‘watchdog_allowed_mask’ defined but not used [-Wunused-variable]
>  static struct cpumask watchdog_allowed_mask __read_mostly;
> ```
> 
> Signed-off-by: Balamuruhan S <bala24@linux.ibm.com>
> ---
>  kernel/watchdog.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index 5abb5b22ad13..33c9b8a3d51b 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -44,7 +44,6 @@ int __read_mostly soft_watchdog_user_enabled = 1;
>  int __read_mostly watchdog_thresh = 10;
>  static int __read_mostly nmi_watchdog_available;
>  
> -static struct cpumask watchdog_allowed_mask __read_mostly;
>  
>  struct cpumask watchdog_cpumask __read_mostly;
>  unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask);
> @@ -166,6 +165,7 @@ int __read_mostly sysctl_softlockup_all_cpu_backtrace;
>  unsigned int __read_mostly softlockup_panic =
>  			CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE;
>  
> +static struct cpumask watchdog_allowed_mask __read_mostly;

I could confirm that the variable is used only in code that is built
when CONFIG_SOFTLOCKUP_DETECTOR is enabled.

Note that the problem can't be seen on x86. There the softlockup
detector is enforced together with hardloclup detector via
via HARDLOCKUP_DETECTOR_PERF.

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr