linux/include/uapi
Kevin Brodsky 31088f6f79 uapi/linux/const.h: prefer ISO-friendly __typeof__
typeof is (still) a GNU extension, which means that it cannot be used when
building ISO C (e.g.  -std=c99).  It should therefore be avoided in uapi
headers in favour of the ISO-friendly __typeof__.

Unfortunately this issue could not be detected by
CONFIG_UAPI_HEADER_TEST=y as the __ALIGN_KERNEL() macro is not expanded in
any uapi header.

This matters from a userspace perspective, not a kernel one. uapi
headers and their contents are expected to be usable in a variety of
situations, and in particular when building ISO C applications (with
-std=c99 or similar).

This particular problem can be reproduced by trying to use the
__ALIGN_KERNEL macro directly in application code, say:

#include <linux/const.h>

int align(int x, int a)
{
	return __KERNEL_ALIGN(x, a);
}
	
and trying to build that with -std=c99.	

Link: https://lkml.kernel.org/r/20230411092747.3759032-1-kevin.brodsky@arm.com
Fixes: a79ff731a1 ("netfilter: xtables: make XT_ALIGN() usable in exported headers by exporting __ALIGN_KERNEL()")
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Reported-by: Ruben Ayrapetyan <ruben.ayrapetyan@arm.com>
Tested-by: Ruben Ayrapetyan <ruben.ayrapetyan@arm.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Tested-by: Petr Vorel <pvorel@suse.cz>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-18 16:39:34 -07:00
..
asm-generic uapi: Add missing _UAPI prefix to <asm-generic/types.h> include guard 2022-12-01 16:22:06 +01:00
drm drm-next-fixes for 6.3-rc1 2023-03-02 15:08:54 -08:00
linux uapi/linux/const.h: prefer ISO-friendly __typeof__ 2023-04-18 16:39:34 -07:00
misc habanalabs/uapi: move uapi file to drm 2023-01-26 10:56:23 +02:00
mtd
rdma RDMA/hns: Support cqe inline in user space 2023-01-09 10:45:28 -04:00
scsi scsi: mpi3mr: Replace 1-element array with flex-array 2023-02-21 22:00:50 -05:00
sound ASoC: Updates for v6.3 2023-02-16 14:32:04 +01:00
video
xen
Kbuild