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Date:   Wed, 31 May 2023 15:54:07 +0200
From:   Andrew Jones <ajones@ventanamicro.com>
To:     Alexandre Ghiti <alexghiti@rivosinc.com>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Atish Patra <atishp@atishpatra.org>,
        Anup Patel <anup@brainfault.org>,
        Will Deacon <will@kernel.org>, Rob Herring <robh@kernel.org>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org, linux-riscv@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 01/10] perf: Fix wrong comment about default event_idx
Message-ID: <20230531-5678beb107af4b9805cbb611@orel>
References: <20230512085321.13259-1-alexghiti@rivosinc.com>
 <20230512085321.13259-2-alexghiti@rivosinc.com>
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On Fri, May 12, 2023 at 10:53:12AM +0200, Alexandre Ghiti wrote:
> event_idx default implementation returns 0, not idx + 1.

The comment was correct until commit c719f56092ad ("perf: Fix and clean
up initialization of pmu::event_idx"). I'm not sure that warrants a fixes
tag, but maybe a reference in the commit message.

> 
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> ---
>  include/linux/perf_event.h | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index d5628a7b5eaa..56fe43b20966 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -442,7 +442,8 @@ struct pmu {
>  
>  	/*
>  	 * Will return the value for perf_event_mmap_page::index for this event,
> -	 * if no implementation is provided it will default to: event->hw.idx + 1.
> +	 * if no implementation is provided it will default to 0 (see
> +	 * perf_event_idx_default).
>  	 */
>  	int (*event_idx)		(struct perf_event *event); /*optional */
>  
> -- 
> 2.37.2
>

Otherwise,

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>