Re: [PATCH V2] include: linux: Regularise the use of FIELD_SIZEOF macro

From: Andrew Morton
Date: Tue Jun 11 2019 - 16:53:07 EST

On Wed, 12 Jun 2019 01:08:36 +0530 Shyam Saini <shyam.saini@xxxxxxxxxxxxxxxxxxxx> wrote:

> Currently, there are 3 different macros, namely sizeof_field, SIZEOF_FIELD
> and FIELD_SIZEOF which are used to calculate the size of a member of
> structure, so to bring uniformity in entire kernel source tree lets use
> FIELD_SIZEOF and replace all occurrences of other two macros with this.
> For this purpose, redefine FIELD_SIZEOF in include/linux/stddef.h and
> tools/testing/selftests/bpf/bpf_util.h and remove its defination from
> include/linux/kernel.h
> In favour of FIELD_SIZEOF, this patch also deprecates other two similar
> macros sizeof_field and SIZEOF_FIELD.
> For code compatibility reason, retain sizeof_field macro as a wrapper macro

As Alexey has pointed out, C structs and unions don't have fields -
they have members. So this is an opportunity to switch everything to
a new member_sizeof().

What do people think of that and how does this impact the patch footprint?