Messages in this thread | | | Date | Mon, 6 Nov 2023 23:49:14 +0530 | Subject | Re: [PATCH] drivers: gpu: Fix warning using plain integer as NULL | From | Abhinav Singh <> |
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On 11/6/23 22:10, Jani Nikula wrote: > On Mon, 06 Nov 2023, Abhinav Singh <singhabhinav9051571833@gmail.com> wrote: >> 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 > > But... {} is neither of those things. It's empty initialization instead > of 0. It's valid in GCC and C23, and used all over the place in the > kernel. > > BR, > Jani. > > > If I understand correctly you want to me change from this "{ NULL, SECT_NONE }" to "{}" right? If yes, then according to what I read from some online, it is better to intialize variables especially pointer because in some cases a non initialized pointer doesnt always point to NULL. Not sure if this applies in kernel space as well. But yeah my knowledge is pretty limited in C in user space and in kernel space it is even more limited :)
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