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Subject: Re: [PATCH] selftests/bpf: Fix warning comparing pointer to 0
To:     Haowen Bai <baihaowen@meizu.com>, shuah@kernel.org, ast@kernel.org,
        daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com,
        songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com,
        kpsingh@kernel.org
Cc:     linux-kselftest@vger.kernel.org, netdev@vger.kernel.org,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        Shuah Khan <skhan@linuxfoundation.org>
References: <1648087725-29435-1-git-send-email-baihaowen@meizu.com>
From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <29503ac1-69ab-a0b7-53bc-5a7522baa289@linuxfoundation.org>
Date:   Fri, 25 Mar 2022 13:55:35 -0600
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On 3/23/22 8:08 PM, Haowen Bai wrote:
> Avoid pointer type value compared with 0 to make code clear.
> 

Patch looks good to me. Please include the error/warn message
in the commit log. This gives reviewers information on how
this problem is found.

> Signed-off-by: Haowen Bai <baihaowen@meizu.com>
> ---
>   tools/testing/selftests/bpf/progs/map_ptr_kern.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/progs/map_ptr_kern.c b/tools/testing/selftests/bpf/progs/map_ptr_kern.c
> index b64df94..db388f5 100644
> --- a/tools/testing/selftests/bpf/progs/map_ptr_kern.c
> +++ b/tools/testing/selftests/bpf/progs/map_ptr_kern.c
> @@ -367,7 +367,7 @@ static inline int check_array_of_maps(void)
>   
>   	VERIFY(check_default(&array_of_maps->map, map));
>   	inner_map = bpf_map_lookup_elem(array_of_maps, &key);
> -	VERIFY(inner_map != 0);
> +	VERIFY(inner_map != NULL);
>   	VERIFY(inner_map->map.max_entries == INNER_MAX_ENTRIES);
>   
>   	return 1;
> @@ -394,7 +394,7 @@ static inline int check_hash_of_maps(void)
>   
>   	VERIFY(check_default(&hash_of_maps->map, map));
>   	inner_map = bpf_map_lookup_elem(hash_of_maps, &key);
> -	VERIFY(inner_map != 0);
> +	VERIFY(inner_map != NULL);
>   	VERIFY(inner_map->map.max_entries == INNER_MAX_ENTRIES);
>   
>   	return 1;
> 

With the change to commit log including the error/warn message and
details on how the problems is found:

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah