Re: [v4.9 PATCH 1/6] include/uapi/linux/swab.h: fix userspace breakage, use __BITS_PER_LONG for swap

[Hans-Christian Egtvedt (hegtvedt)]

On 01/08/2022 13:09, Greg KH wrote:
> On Sun, Jul 31, 2022 at 08:26:31PM +0200, Hans-Christian Noren Egtvedt wrote:
>> From: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>>
>> QEMU has a funny new build error message when I use the upstream kernel
>> headers:
>>
>>       CC      block/file-posix.o
>>     In file included from /home/cborntra/REPOS/qemu/include/qemu/timer.h:4,
>>                      from /home/cborntra/REPOS/qemu/include/qemu/timed-average.h:29,
>>                      from /home/cborntra/REPOS/qemu/include/block/accounting.h:28,
>>                      from /home/cborntra/REPOS/qemu/include/block/block_int.h:27,
>>                      from /home/cborntra/REPOS/qemu/block/file-posix.c:30:
>>     /usr/include/linux/swab.h: In function `__swab':
>>     /home/cborntra/REPOS/qemu/include/qemu/bitops.h:20:34: error: "sizeof" is not defined, evaluates to 0 [-Werror=undef]
>>        20 | #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)
>>           |                                  ^~~~~~
>>     /home/cborntra/REPOS/qemu/include/qemu/bitops.h:20:41: error: missing binary operator before token "("
>>        20 | #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)
>>           |                                         ^
>>     cc1: all warnings being treated as errors
>>     make: *** [/home/cborntra/REPOS/qemu/rules.mak:69: block/file-posix.o] Error 1
>>     rm tests/qemu-iotests/socket_scm_helper.o
>>
>> This was triggered by commit d5767057c9a ("uapi: rename ext2_swab() to
>> swab() and share globally in swab.h").  That patch is doing
>>
>>   #include <asm/bitsperlong.h>
>>
>> but it uses BITS_PER_LONG.
>>
>> The kernel file asm/bitsperlong.h provide only __BITS_PER_LONG.
>>
>> Let us use the __ variant in swap.h
>>
>> Link: http://lkml.kernel.org/r/20200213142147.17604-1-borntraeger@xxxxxxxxxx
>> Fixes: d5767057c9a ("uapi: rename ext2_swab() to swab() and share globally in swab.h")
>> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>> Cc: Yury Norov <yury.norov@xxxxxxxxx>
>> Cc: Allison Randal <allison@xxxxxxxxxxx>
>> Cc: Joe Perches <joe@xxxxxxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
>> Cc: Torsten Hilbrich <torsten.hilbrich@xxxxxxxxxxx>
>> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>> (cherry picked from commit 467d12f5c7842896d2de3ced74e4147ee29e97c8)
> 
> As you are passing on patches from others, it is usually requried that
> you too sign-off on them.  Can you fix that up on this series and resend
> it so that I can take them?

Yes, sorry, we do not add signed-off-by entries internally, so my git
config does not add it by default. Will resend the series.

-- 
Best regards, Hans-Christian Noren Egtvedt