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Subject: Re: [PATCH] perf probe: Return errno when does not hit any event
To: <linux-kernel@vger.kernel.org>
References: <1488792891-57629-1-git-send-email-wangkefeng.wang@huawei.com>
CC: Peter Zijlstra <peterz@infradead.org>, Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>, Wang Nan <wangnan0@huawei.com>,
        <guohanjun@huawei.com>, Arnaldo Carvalho de Melo <acme@kernel.org>
From: Kefeng Wang <wangkefeng.wang@huawei.com>
Message-ID: <326abd0a-1dd5-0cf0-245a-78c3b7802515@huawei.com>
Date: Tue, 7 Mar 2017 15:33:41 +0800
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+ Arnaldo Carvalho de Melo <acme@kernel.org>

On 2017/3/6 17:34, Kefeng Wang wrote:
> On old perf, when using perf probe -d to delete an inexistent event,
> it return errno, eg,
> 
> -bash-4.3# perf probe -d xxx  || echo $?
> Info: Event "*:xxx" does not exist.
>   Error: Failed to delete events.
> 255
> 
> But now perf_del_probe_events() will always set ret = 0, different
> from previous del_perf_probe_events(). After this, it return errno
> again, eg,
> 
> -bash-4.3# ./perf probe -d xxx  || echo $?
>   Error: Failed to delete events.
> 254
> 
> And it is more appropriate to return -ENOENT instead of -EPERM.
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>  tools/perf/builtin-probe.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
> index 1fcebc3..c46b41c 100644
> --- a/tools/perf/builtin-probe.c
> +++ b/tools/perf/builtin-probe.c
> @@ -444,7 +444,8 @@ static int perf_del_probe_events(struct strfilter *filter)
>  	if (ret == -ENOENT && ret2 == -ENOENT)
>  		pr_debug("\"%s\" does not hit any event.\n", str);
>  		/* Note that this is silently ignored */
> -	ret = 0;
> +	else
> +		ret = 0;
>  
>  error:
>  	if (kfd >= 0)
>