Re: [PATCH] arch/x86/amd: Remove set but not used variable 'active'

[Ingo Molnar <mingo@kernel.org>]

* Zheng Yongjun <zhengyongjun3@huawei.com> wrote:

> Fixes gcc '-Wunused-but-set-variable' warning:
> 
> arch/x86/events/amd/core.c: In function amd_pmu_handle_irq:
> arch/x86/events/amd/core.c:656:6: warning: variable active set but not used [-Wunused-but-set-variable]
> 
> active is never used, so remove it.
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
> ---
>  arch/x86/events/amd/core.c | 9 +--------
>  1 file changed, 1 insertion(+), 8 deletions(-)
> 
> diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
> index 64c3e70b0556..1ff652a167db 100644
> --- a/arch/x86/events/amd/core.c
> +++ b/arch/x86/events/amd/core.c
> @@ -653,14 +653,7 @@ static void amd_pmu_disable_event(struct perf_event *event)
>  static int amd_pmu_handle_irq(struct pt_regs *regs)
>  {
>  	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> -	int active, handled;
> -
> -	/*
> -	 * Obtain the active count before calling x86_pmu_handle_irq() since
> -	 * it is possible that x86_pmu_handle_irq() may make a counter
> -	 * inactive (through x86_pmu_stop).
> -	 */
> -	active = __bitmap_weight(cpuc->active_mask, X86_PMC_IDX_MAX);
> +	int handled;
>  
>  	/* Process any counter overflows */
>  	handled = x86_pmu_handle_irq(regs);

I'm sad that not only was this changelog of poor quality (you didn't 
follow title patterns, you didn't explain why the variable went unused, 
etc. etc.), you didn't even *build* the resulting file, which now 
produces a new warning on x86-64-defconfig:

  arch/x86/events/amd/core.c:655:24: warning: unused variable ‘cpuc’ [-Wunused-variable]

I fixed this up, but please be much more careful even with 'trivial' 
patches - we expect them to be perfect.

Thanks,

	Ingo