Re: [PATCH iwl-net v2] idpf: avoid compiler padding in virtchnl2_ptype struct

[Simon Horman <horms@kernel.org>]

On Thu, Jan 04, 2024 at 05:32:32PM -0800, Pavan Kumar Linga wrote:
> In the arm random config file, kconfig option 'CONFIG_AEABI' is
> disabled which results in adding the compiler flag '-mabi=apcs-gnu'.
> This causes the compiler to add padding in virtchnl2_ptype
> structure to align it to 8 bytes, resulting in the following
> size check failure:
> 
> include/linux/build_bug.h:78:41: error: static assertion failed: "(6) == sizeof(struct virtchnl2_ptype)"
>       78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
>          |                                         ^~~~~~~~~~~~~~
> include/linux/build_bug.h:77:34: note: in expansion of macro '__static_assert'
>       77 | #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
>          |                                  ^~~~~~~~~~~~~~~
> drivers/net/ethernet/intel/idpf/virtchnl2.h:26:9: note: in expansion of macro 'static_assert'
>       26 |         static_assert((n) == sizeof(struct X))
>          |         ^~~~~~~~~~~~~
> drivers/net/ethernet/intel/idpf/virtchnl2.h:982:1: note: in expansion of macro 'VIRTCHNL2_CHECK_STRUCT_LEN'
>      982 | VIRTCHNL2_CHECK_STRUCT_LEN(6, virtchnl2_ptype);
>          | ^~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Avoid the compiler padding by using "__packed" structure
> attribute for the virtchnl2_ptype struct.
> 
> Fixes: 0d7502a9b4a7 ("virtchnl: add virtchnl version 2 ops")
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202312220250.ufEm8doQ-lkp@intel.com
> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
> Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
> Signed-off-by: Pavan Kumar Linga <pavan.kumar.linga@intel.com>

Reviewed-by: Simon Horman <horms@kernel.org>