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linux/include/uapi
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Kevin Brodsky 397eb669da uapi/linux/const.h: prefer ISO-friendly __typeof__ 
[ Upstream commit 31088f6f79 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-05-11 23:00:33 +09:00
..
asm-generic signal: Deliver SIGTRAP on perf event asynchronously if blocked 2022-06-09 10:22:48 +02:00
drm drm/fourcc: Add packed 10bit YUV 4:2:0 format 2022-12-31 13:14:10 +01:00
linux uapi/linux/const.h: prefer ISO-friendly __typeof__ 2023-05-11 23:00:33 +09:00
misc habanalabs: fix resetting args in wait for CS IOCTL 2021-09-29 12:18:48 +03:00
mtd mtd: add OTP (one-time-programmable) erase ioctl 2021-03-28 19:24:54 +02:00
rdma RDMA/mlx5: Don't compare mkey tags in DEVX indirect mkey 2022-10-26 12:35:03 +02:00
scsi scsi: fc: Add EDC ELS definition 2021-08-24 22:56:33 -04:00
sound ALSA: seq: fix undefined behavior in bit shift for SNDRV_SEQ_FILTER_USE_EVENT 2022-12-31 13:14:11 +01:00
video License cleanup: add SPDX license identifier to uapi header files with a license 2017-11-02 11:20:11 +01:00
xen xen/gntdev: gntdev.h: drop a duplicated word 2020-08-03 07:46:42 +02:00
Kbuild kbuild: re-implement Makefile.headersinst without recursion 2019-06-15 19:57:02 +09:00