[PATCH] linux: Fix sys/mount.h usage with kernel headers

[Adhemerval Zanella Netto]

On 09/08/22 14:43, Yann Droneaud wrote:
> Hi,
> 
> Le 09/08/2022 à 19:22, Adhemerval Zanella via Libc-alpha a écrit :
>> Now that kernel exports linux/mount.h and includes it on linux/fs.h,
>> its definitions might clash with glibc exports sys/mount.h.  To avoid
>> the need to rearrange the Linux header to be always after glibc one,
>> the glibc sys/mount.h is changed to:
>>
>>    1. Undefine the macros also used as enum constants.  This covers prior
>>       inclusion of <linux/mount.h> (for instance MS_RDONLY).
>>
>>    2. Include <linux/mount.h> based on the usual __has_include check
>>       (needs to use __has_include ("linux/mount.h") to paper over GCC
>>       bugs.
>>
>>    3. Define enum fsconfig_command only if FSOPEN_CLOEXEC is not defined.
>>       (FSOPEN_CLOEXEC should be a very close proxy.)
>>
>>    4. Define struct mount_attr if MOUNT_ATTR_SIZE_VER0 is not defined.
>>       (Added in the same commit on the Linux side.)
>>
>>    5. Undefine some macros also used on linux/fs.h.
>>
>> This patch also adds some tests to check if including linux/fs.h and
>> linux/mount.h after and before sys/mount.h does work.
> 
> For the record there's a change submitted today for review:
> 
> [RFC][PATCH] uapi: Remove the inclusion of linux/mount.h from uapi/linux/fs.h  <https://lore.kernel.org/linux-api/163410.1659964655@warthog.procyon.org.uk/#r>
> 
> https://lore.kernel.org/linux-api/163410.1659964655@warthog.procyon.org.uk/

Thanks Yann, although I think we will still need to fix on glibc side
in case user do include linux/fs.h and/or linux/mount.h before 
sys/mount.h.