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References: <20230215-arm_pmu_m1_regression-v1-1-f5a266577c8d@jannau.net>
In-Reply-To: <20230215-arm_pmu_m1_regression-v1-1-f5a266577c8d@jannau.net>
From:   Eric Curtin <ecurtin@redhat.com>
Date:   Wed, 15 Feb 2023 11:40:15 +0000
Message-ID: <CAOgh=FwCk1qMUAqkv+aih_=6vJ0SjqyzS9-gW+v+YjEse6V0Yw@mail.gmail.com>
Subject: Re: [PATCH] arm_pmu: Invert fallback armpmu_filter() return value
To:     Janne Grunau <j@jannau.net>
Cc:     Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ravi Bangoria <ravi.bangoria@amd.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        asahi@lists.linux.dev
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On Wed, 15 Feb 2023 at 11:36, Janne Grunau <j@jannau.net> wrote:
>
> Fixes a regression in "perf: Rewrite core context handling" for arm_pmu
> based drivers without a filter function pointer as the Apple M1 PMU.
> The event is ignored if filter() returns 'true' opposite to
> filter_match(). The refactoring failed to invert the return value if
> arm_pmu has no filter() function pointer of its own.
>
> Fixes: bd2756811766 ("perf: Rewrite core context handling")
> Signed-off-by: Janne Grunau <j@jannau.net>

Makes sense we return the inverse of armpmu_filter everywhere else in the code.

Reviewed-by: Eric Curtin <ecurtin@redhat.com>

Is mise le meas/Regards,

Eric Curtin

> ---
>  drivers/perf/arm_pmu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
> index 9b593f985805..9cb22f36cf66 100644
> --- a/drivers/perf/arm_pmu.c
> +++ b/drivers/perf/arm_pmu.c
> @@ -556,7 +556,7 @@ static bool armpmu_filter(struct pmu *pmu, int cpu)
>         if (ret && armpmu->filter)
>                 return armpmu->filter(pmu, cpu);
>
> -       return ret;
> +       return !ret;
>  }
>
>  static ssize_t cpus_show(struct device *dev,
>
> ---
> base-commit: ceaa837f96adb69c0df0397937cd74991d5d821a
> change-id: 20230215-arm_pmu_m1_regression-b6dd48d0c792
>
> Best regards,
> --
> Janne Grunau <j@jannau.net>
>
>