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Subject: Re: [PATCH] perf probe: Return errno when does not hit any event
To: <linux-kernel@vger.kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>
References: <1488792891-57629-1-git-send-email-wangkefeng.wang@huawei.com>
 <326abd0a-1dd5-0cf0-245a-78c3b7802515@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>
From: Kefeng Wang <wangkefeng.wang@huawei.com>
Message-ID: <be83dd50-793f-cde1-6740-e70010689aaf@huawei.com>
Date: Tue, 14 Mar 2017 21:19:47 +0800
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Hi all, any comments, thanks.

On 2017/3/7 15:33, Kefeng Wang wrote:
> + 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)
>>
> 
> 
> .
>