linux-kernel - Re: [PATCH v2] perf pmu: Validate raw event with sysfs exported format bits

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Message-ID: <4677dda8-6a3b-1908-775e-3510091abda5@linux.intel.com>
Date:   Mon, 8 Mar 2021 11:12:25 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v2] perf pmu: Validate raw event with sysfs exported
 format bits

Hi Jiri,

On 3/7/2021 3:12 AM, Jiri Olsa wrote:
> actualy we do have bitmap_scnprintf, which is already doing the
> printing in a nice way.. we could use it like below, only compile
> tested
> 
> jirka
> 
> 
> ---
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 31e975b75766..37ca5eee2667 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -1818,7 +1818,7 @@ void perf_pmu__warn_invalid_config(struct perf_pmu *pmu, __u64 config,
>   {
>   	struct perf_pmu_format *format;
>   	__u64 masks = 0, bits;
> -	struct strbuf buf = STRBUF_INIT;
> +	char buf[50];
>   	unsigned int i;
>   
>   	list_for_each_entry(format, &pmu->format, list)	{
> @@ -1836,25 +1836,15 @@ void perf_pmu__warn_invalid_config(struct perf_pmu *pmu, __u64 config,
>   	 * Kernel doesn't export any valid format bits.
>   	 */
>   	if (masks == 0)
> -		goto out;
> +		return;
>   
>   	bits = config & ~masks;
>   	if (bits == 0)
> -		goto out;
> -
> -	for_each_set_bit(i, (unsigned long *)&bits, sizeof(bits) * 8)
> -		strbuf_addf(&buf, " %d", i);
> +		return;
>   
> -	if (name) {
> -		pr_warning("WARNING: event '%s' not valid (bits%s of config "
> -			   "'%llx' not supported by kernel)!\n",
> -			   name, buf.buf, config);
> -	} else {
> -		pr_warning("WARNING: event not valid (bits%s of config "
> -			   "'%llx' not supported by kernel)!\n",
> -			   buf.buf, config);
> -	}
> +	bitmap_scnprintf((unsigned long *)&bits, sizeof(bits) * 8, buf, sizeof(buf));
>   
> -out:
> -	strbuf_release(&buf);
> +	pr_warning("WARNING: event '%s' not valid (bits%s of config "
> +		   "'%llx' not supported by kernel)!\n",
> +		   name ?: "N/A", buf, config);
>   }

The bitmap_scnprintf works fine. Yes, it's really better than original 'strbuf' way, thanks!

BTW, I added "Co-developed-by: Jiri Olsa <jolsa@...hat.com>" in v3, but the patch checking shows the 
warning:

WARNING: Co-developed-by and Signed-off-by: name/email do not match
#76:
Co-developed-by: Jiri Olsa <jolsa@...hat.com>
Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>

I'm not sure if this warning is important or not, but anyway I add the line to v3. Thanks for your 
help！

Jin Yao