linux-kernel - Re: [PATCH -next 3/5] perf: Remove duplicate errbuf

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Message-ID: <eb4db7a7-d84e-7228-d564-4a31fe255331@huawei.com>
Date:   Tue, 27 Sep 2022 09:20:36 +0800
From:   Chen Zhongjin <chenzhongjin@...wei.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-perf-users@...r.kernel.org>,
        <peterz@...radead.org>, <mingo@...hat.com>, <mark.rutland@....com>,
        <alexander.shishkin@...ux.intel.com>, <jolsa@...nel.org>,
        <namhyung@...nel.org>, <irogers@...gle.com>,
        <john.garry@...wei.com>, <adrian.hunter@...el.com>,
        <ak@...ux.intel.com>, <florian.fischer@...q.space>
Subject: Re: [PATCH -next 3/5] perf: Remove duplicate errbuf

Hi,

On 2022/9/27 3:54, Arnaldo Carvalho de Melo wrote:
> Em Mon, Sep 26, 2022 at 11:14:38AM +0800, Chen Zhongjin escreveu:
>> char errbuf[BUFSIZ] is defined twice in trace__run.
>>
>> However out_error_open is not cross to other out_error path, they can
>> share one errbuf together.
>>
>> Define the errbuf[BUFSIZ] at the beginning of function, and remove the
>> redefinations of them for code cleaning.
> Have you looked at the end result in the generated code? Just out of
> curiosity.

Good question. Because it is an auto reported warning of clang I didn't 
try it.

Just tried and found no different for 'objdump -d perf' on two version.


Best,

Chen

>
> - Arnaldo
>   
>> Signed-off-by: Chen Zhongjin <chenzhongjin@...wei.com>
>> ---
>>   tools/perf/builtin-trace.c | 7 ++-----
>>   1 file changed, 2 insertions(+), 5 deletions(-)
>>
>> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
>> index 7ecd76428440..5660c0ee3507 100644
>> --- a/tools/perf/builtin-trace.c
>> +++ b/tools/perf/builtin-trace.c
>> @@ -3937,6 +3937,7 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
>>   	unsigned long before;
>>   	const bool forks = argc > 0;
>>   	bool draining = false;
>> +	char errbuf[BUFSIZ];
>>   
>>   	trace->live = true;
>>   
>> @@ -4027,8 +4028,6 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
>>   
>>   	err = bpf__apply_obj_config();
>>   	if (err) {
>> -		char errbuf[BUFSIZ];
>> -
>>   		bpf__strerror_apply_obj_config(err, errbuf, sizeof(errbuf));
>>   		pr_err("ERROR: Apply config to BPF failed: %s\n",
>>   			 errbuf);
>> @@ -4185,8 +4184,6 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
>>   	trace->evlist = NULL;
>>   	trace->live = false;
>>   	return err;
>> -{
>> -	char errbuf[BUFSIZ];
>>   
>>   out_error_sched_stat_runtime:
>>   	tracing_path__strerror_open_tp(errno, errbuf, sizeof(errbuf), "sched", "sched_stat_runtime");
>> @@ -4213,7 +4210,7 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
>>   		evsel->filter, evsel__name(evsel), errno,
>>   		str_error_r(errno, errbuf, sizeof(errbuf)));
>>   	goto out_delete_evlist;
>> -}
>> +
>>   out_error_mem:
>>   	fprintf(trace->output, "Not enough memory to run!\n");
>>   	goto out_delete_evlist;
>> -- 
>> 2.17.1