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Subject: Re: [PATCH] selftests: vm: remove duplicated macro and use swap() to
 make code cleaner
To:     cgel.zte@gmail.com, akpm@linux-foundation.org
Cc:     shuah@kernel.org, linux-mm@kvack.org,
        linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
        "Lv Ruyi (CGEL ZTE)" <lv.ruyi@zte.com.cn>,
        Zeal Robot <zealci@zte.com.cn>,
        Shuah Khan <skhan@linuxfoundation.org>
References: <20220301014404.2052655-1-lv.ruyi@zte.com.cn>
From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <9d6ae3b1-3f36-8196-c136-fa2d07dbca5d@linuxfoundation.org>
Date:   Tue, 1 Mar 2022 08:29:18 -0700
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On 2/28/22 6:44 PM, cgel.zte@gmail.com wrote:
> From: "Lv Ruyi (CGEL ZTE)" <lv.ruyi@zte.com.cn>
> 
> The macro is duplicated, so remove one. And use swap to make code cleaner.
> 
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Lv Ruyi (CGEL ZTE) <lv.ruyi@zte.com.cn>
> ---
>   tools/testing/selftests/vm/userfaultfd.c | 13 ++-----------
>   1 file changed, 2 insertions(+), 11 deletions(-)
> 
> diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
> index ab394e6bff43..100f08362164 100644
> --- a/tools/testing/selftests/vm/userfaultfd.c
> +++ b/tools/testing/selftests/vm/userfaultfd.c
> @@ -121,9 +121,6 @@ struct uffd_stats {
>   #define swap(a, b) \
>   	do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
>   
> -#define swap(a, b) \
> -	do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
> -
>   const char *examples =
>       "# Run anonymous memory test on 100MiB region with 99999 bounces:\n"
>       "./userfaultfd anon 100 99999\n\n"
> @@ -1424,7 +1421,6 @@ static void userfaultfd_pagemap_test(unsigned int test_pgsize)
>   static int userfaultfd_stress(void)
>   {
>   	void *area;
> -	char *tmp_area;
>   	unsigned long nr;
>   	struct uffdio_register uffdio_register;
>   	struct uffd_stats uffd_stats[nr_cpus];
> @@ -1535,13 +1531,8 @@ static int userfaultfd_stress(void)
>   					    count_verify[nr], nr);
>   
>   		/* prepare next bounce */
> -		tmp_area = area_src;
> -		area_src = area_dst;
> -		area_dst = tmp_area;
> -
> -		tmp_area = area_src_alias;
> -		area_src_alias = area_dst_alias;
> -		area_dst_alias = tmp_area;
> +		swap(area_src, area_dst);
> +		swap(area_src_alias, area_dst_alias);

Where is swap() defined? Does this patch compile? I reverted a
change like this one reported by Zeal Robot recently. Let's
make sure this change compiles and runs.

>   
>   		uffd_stats_report(uffd_stats, nr_cpus);
>   	}
> 

thanks,
-- Shuah