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Message-ID: <a2310260-ba15-428e-9fd1-08abb9565b18@gmail.com>
Date:   Mon, 6 Nov 2023 20:51:03 +0530
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Subject: Re: [PATCH] drivers: gpu: Fix warning using plain integer as NULL
To:     Jani Nikula <jani.nikula@linux.intel.com>,
        alexander.deucher@amd.com, christian.koenig@amd.com,
        Xinhui.Pan@amd.com, airlied@gmail.com, daniel@ffwll.ch
Cc:     linux-kernel-mentees@lists.linuxfoundation.org,
        dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
References: <20231103155013.332367-1-singhabhinav9051571833@gmail.com>
 <87sf5jyvkt.fsf@intel.com>
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From:   Abhinav Singh <singhabhinav9051571833@gmail.com>
In-Reply-To: <87sf5jyvkt.fsf@intel.com>
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On 11/6/23 16:53, Jani Nikula wrote:
> On Fri, 03 Nov 2023, Abhinav Singh <singhabhinav9051571833@gmail.com> wrote:
>> sparse static analysis tools generate a warning with this message
>> "Using plain integer as NULL pointer". In this case this warning is
>> being shown because we are trying to intialize a pointer to NULL using
>> integer value 0.
>>
>> Signed-off-by: Abhinav Singh <singhabhinav9051571833@gmail.com>
>> ---
>>   drivers/gpu/drm/radeon/clearstate_evergreen.h | 8 ++++----
>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/radeon/clearstate_evergreen.h b/drivers/gpu/drm/radeon/clearstate_evergreen.h
>> index 63a1ffbb3ced..3b645558f133 100644
>> --- a/drivers/gpu/drm/radeon/clearstate_evergreen.h
>> +++ b/drivers/gpu/drm/radeon/clearstate_evergreen.h
>> @@ -1049,7 +1049,7 @@ static const struct cs_extent_def SECT_CONTEXT_defs[] =
>>       {SECT_CONTEXT_def_5, 0x0000a29e, 5 },
>>       {SECT_CONTEXT_def_6, 0x0000a2a5, 56 },
>>       {SECT_CONTEXT_def_7, 0x0000a2de, 290 },
>> -    { 0, 0, 0 }
>> +    { NULL, 0, 0 }
> 
> Random drive-by comment:
> 
> I'd just use {} as the sentinel.
> 
> BR,
> Jani.
> 
>>   };
>>   static const u32 SECT_CLEAR_def_1[] =
>>   {
>> @@ -1060,7 +1060,7 @@ static const u32 SECT_CLEAR_def_1[] =
>>   static const struct cs_extent_def SECT_CLEAR_defs[] =
>>   {
>>       {SECT_CLEAR_def_1, 0x0000ffc0, 3 },
>> -    { 0, 0, 0 }
>> +    { NULL, 0, 0 }
>>   };
>>   static const u32 SECT_CTRLCONST_def_1[] =
>>   {
>> @@ -1070,11 +1070,11 @@ static const u32 SECT_CTRLCONST_def_1[] =
>>   static const struct cs_extent_def SECT_CTRLCONST_defs[] =
>>   {
>>       {SECT_CTRLCONST_def_1, 0x0000f3fc, 2 },
>> -    { 0, 0, 0 }
>> +    { NULL, 0, 0 }
>>   };
>>   static const struct cs_section_def evergreen_cs_data[] = {
>>       { SECT_CONTEXT_defs, SECT_CONTEXT },
>>       { SECT_CLEAR_defs, SECT_CLEAR },
>>       { SECT_CTRLCONST_defs, SECT_CTRLCONST },
>> -    { 0, SECT_NONE }
>> +    { NULL, SECT_NONE }
>>   };
>> --
>> 2.39.2
>>
> 
Hi, Thanks for dropping by and the suggestion. I thought of using NULL 
instead of {} is because, first the warning itself says that 0 is used 
to intialize pointers with NULL, and second due this link 
https://www.spinics.net/lists/linux-sparse/msg10066.html where linus is 
talking about not using 0 NULL intialization of pointer variable and he 
thinks this is a legitimate issue and not some false positive