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From:   Mike Leach <mike.leach@linaro.org>
Date:   Thu, 6 Feb 2020 11:48:29 +0000
Message-ID: <CAJ9a7VjnOw_XgFXmOgE7ufB98_VNEZH7vX=8yO5qrogoBqJQXw@mail.gmail.com>
Subject: Re: [PATCH v3 5/5] perf cs-etm: Fix unsigned variable comparison to zero
To:     Leo Yan <leo.yan@linaro.org>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        linux-kernel@vger.kernel.org,
        Robert Walker <robert.walker@arm.com>,
        Coresight ML <coresight@lists.linaro.org>
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Reviewed by: Mike Leach <mike.leach@linaro.org>

On Mon, 3 Feb 2020 at 01:53, Leo Yan <leo.yan@linaro.org> wrote:
>
> The variable 'offset' in function cs_etm__sample() is u64 type, it's not
> appropriate to check it with 'while (offset > 0)'; this patch changes to
> 'while (offset)'.
>
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> ---
>  tools/perf/util/cs-etm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index dbddf1eec2be..720108bd8dba 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -945,7 +945,7 @@ static inline u64 cs_etm__instr_addr(struct cs_etm_queue *etmq,
>         if (packet->isa == CS_ETM_ISA_T32) {
>                 u64 addr = packet->start_addr;
>
> -               while (offset > 0) {
> +               while (offset) {
>                         addr += cs_etm__t32_instr_size(etmq,
>                                                        trace_chan_id, addr);
>                         offset--;
> --
> 2.17.1
>


-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK