linux-kernel - Re: [PATCH 12/12] efi: make const array 'apple' static

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Message-ID: <CAKv+Gu8iMvzvSP9-YPe+ms4qVMjcQqNQ25Wa16JW_tEG7P+jtQ@mail.gmail.com>
Date:   Fri, 9 Mar 2018 07:43:37 +0000
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Joe Perches <joe@...ches.com>
Cc:     linux-efi@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Colin Ian King <colin.king@...onical.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 12/12] efi: make const array 'apple' static

On 8 March 2018 at 11:05, Joe Perches <joe@...ches.com> wrote:
> On Thu, 2018-03-08 at 08:00 +0000, Ard Biesheuvel wrote:
>> From: Colin Ian King <colin.king@...onical.com>
>>
>> Don't populate the const read-only array 'buf' on the stack but instead
>> make it static. Makes the object code smaller by 64 bytes:
>>
>> Before:
>>    text          data     bss     dec     hex filename
>>    9264             1      16    9281    2441 arch/x86/boot/compressed/eboot.o
>>
>> After:
>>    text          data     bss     dec     hex filename
>>    9200             1      16    9217    2401 arch/x86/boot/compressed/eboot.o
>>
>> (gcc version 7.2.0 x86_64)
>>
>> Signed-off-by: Colin Ian King <colin.king@...onical.com>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
>> ---
>>  arch/x86/boot/compressed/eboot.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
>> index 886a9115af62..f2251c1c9853 100644
>> --- a/arch/x86/boot/compressed/eboot.c
>> +++ b/arch/x86/boot/compressed/eboot.c
>> @@ -423,7 +423,7 @@ static void retrieve_apple_device_properties(struct boot_params *boot_params)
>>
>>  static void setup_quirks(struct boot_params *boot_params)
>>  {
>> -     efi_char16_t const apple[] = { 'A', 'p', 'p', 'l', 'e', 0 };
>> +     static efi_char16_t const apple[] = { 'A', 'p', 'p', 'l', 'e', 0 };
>
> Perhaps
>
> static const efi_char16_t apple[] ...
>
> is better.
>

Why would that be any better? I have always found the 'const'
placement after the type to be much clearer.

const void *
void const *
void * const

I.e., #2 and #3 are equivalent, and so 'const' associates to the left
not to the right, unless it is at the beginning.

Personally, I don't mind either way, but saying it is 'better' is a stretch imo