Re: [XEN PATCH 01/11] x86/efi: move variable declaration to address MISRA C:2012 Rule 2.1

[Jan Beulich]

On 03.08.2023 04:08, Stefano Stabellini wrote:
> On Wed, 2 Aug 2023, Nicola Vetrini wrote:
>> The variable declaration is moved where it's actually used, rather
>> than being declared in the switch before any clause, thus being
>> classified as unreachable code.
>>
>> No functional changes.
>>
>> Signed-off-by: Nicola Vetrini <nicola.vetr...@bugseng.com>
>> ---
>>  xen/arch/x86/efi/efi-boot.h | 5 ++---
>>  1 file changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
>> index 92f4cfe8bd..b00441b1a2 100644
>> --- a/xen/arch/x86/efi/efi-boot.h
>> +++ b/xen/arch/x86/efi/efi-boot.h
>> @@ -390,8 +390,6 @@ static void __init efi_arch_edd(void)
>>          {
>>              switch ( DevicePathType(devp.DevPath) )
>>              {
>> -                const u8 *p;
>> -
>>              case ACPI_DEVICE_PATH:
>>                  if ( state != root || boot_edd_info_nr > EDD_INFO_MAX )
>>                      break;
>> @@ -463,7 +461,8 @@ static void __init efi_arch_edd(void)
>>                  params->device_path_info_length =
>>                      sizeof(struct edd_device_params) -
>>                      offsetof(struct edd_device_params, key);
>> -                for ( p = (const u8 *)&params->key; p < &params->checksum; 
>> ++p )
>> +                for ( const u8 *p = (const u8 *)&params->key;
>> +                      p < &params->checksum; ++p )
> 
> In Xen we don't mix declaration and code. So the following is not
> something we use:
> 
>   for (int i = 0; i < 10; i++)

You're aware that we gained a couple of such uses already? I also think
that when we discussed this we said this style could be at least
okay-ish (until formalized in ./CODING_STYLE).

What I'm unhappy with here is the retaining of u8, when it could easily
become uint8_t at this occasion.

Jan