Re: [PATCH] perf: arm_spe: remove unnecessary zero check

From: Mark Rutland
Date: Mon Mar 09 2020 - 06:52:25 EST


On Wed, Feb 26, 2020 at 12:25:06PM +0800, luanshi wrote:
> The "nr_pages" variable has been checked before, it can't be zero, so a check here would be useless.
>
> Signed-off-by: Liguang Zhang <zhangliguang@xxxxxxxxxxxxxxxxx>

As the commit message states, a done:

| /* We need at least two pages for this to work. */
| if (nr_pages < 2)
| return NULL;

... so this looks sensible to me:

Acked-by: Mark Rutland <mark.rutland@xxxxxxx>

Mark.

> ---
> drivers/perf/arm_spe_pmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
> index 4e4984a..b72c048 100644
> --- a/drivers/perf/arm_spe_pmu.c
> +++ b/drivers/perf/arm_spe_pmu.c
> @@ -831,7 +831,7 @@ static void *arm_spe_pmu_setup_aux(struct perf_event *event, void **pages,
> * parts and give userspace a fighting chance of getting some
> * useful data out of it.
> */
> - if (!nr_pages || (snapshot && (nr_pages & 1)))
> + if (snapshot && (nr_pages & 1))
> return NULL;
>
> if (cpu == -1)
> --
> 1.8.3.1
>