Re: [PATCH v2 1/2] cper, apei, mce: Pass x86 CPER through the MCA handling chain

[Ard Biesheuvel]

On Thu, 3 Sep 2020 at 09:34, Punit Agrawal <punit1.agrawal@xxxxxxxxxxxxx> wrote:
>
> Hi Smita,
>
> Smita Koralahalli Channabasappa <skoralah@xxxxxxx> writes:
>
> > On 8/31/20 12:05 AM, Punit Agrawal wrote:
> >
> >> Hi Smita,
> >>
> >> A couple of comments below -
> >>
> >> Smita Koralahalli <Smita.KoralahalliChannabasappa@xxxxxxx> writes:
> >>
> >> [...]
> >>
> >>
> >>> diff --git a/drivers/firmware/efi/cper-x86.c b/drivers/firmware/efi/cper-x86.c
> >>> index 2531de49f56c..374b8e18552a 100644
> >>> --- a/drivers/firmware/efi/cper-x86.c
> >>> +++ b/drivers/firmware/efi/cper-x86.c
> >>> @@ -1,7 +1,7 @@
> >>>   // SPDX-License-Identifier: GPL-2.0
> >>>   // Copyright (C) 2018, Advanced Micro Devices, Inc.
> >>>   -#include <linux/cper.h>
> >> Why is the include dropped? AFAICT, the definitions from there are still
> >> being used after this patch.
> >
> > Dropped because <acpi/apei.h> already includes <linux/cper.h>
>
> Generally, you want to follow the rule that if a declaration from a
> header file is being used, it should show up in the includes. The same
> applies to both source as well as header files.
>
> It doesn't matter if another include in the source file in turn ends up
> including the same header again; the #ifdef guards are there to prevent
> duplicate declarations.
>
> The rationale is that if future changes remove the usage of
> <acpi/apei.h>, the C file can still be compiled after dropping the
> include; there should be no need to then re-introduce <linux/cper.h> at
> that point.
>
> Hope that makes sense.
>

Agreed. If the code still uses declarations from linux/cper.h after
the patch, the #include should remain.