[LTP] [PATCH] configure.ac: fix mount_attr detection

[Cyril Hrubis]

Hi!
> Commit b857f8723f30a4b9554bf6b0ff8fa52fd07e8b60 tried to fix build with
> latest glibc which provides mount_attr in sys/mount.h. Unfortunately,
> the following build failure is still raised because sys/mount is now
> unconditionally included in include/lapi/fsmount.h:
> 
> In file included from fsconfig01.c:9:
> ../../../../include/lapi/fsmount.h:55:8: error: redefinition of 'struct mount_attr'
>    55 | struct mount_attr {
>       |        ^~~~~~~~~~
> In file included from ../../../../include/lapi/fsmount.h:14:
> /home/autobuild/autobuild/instance-4/output-1/host/armeb-buildroot-linux-gnueabi/sysroot/usr/include/sys/mount.h:210:8: note: originally defined here
>   210 | struct mount_attr
>       |        ^~~~~~~~~~
> 
> Fixes:
>  - http://autobuild.buildroot.org/results/4dbb72e1bf081afd3cd944571b9beeefc7608865
> 
> Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
> ---
>  configure.ac | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index c2b0f48e7..a6d8ac826 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -225,10 +225,10 @@ AC_CHECK_TYPES([struct __kernel_old_timeval, struct __kernel_old_timespec, struc
>  
>  AC_CHECK_TYPES([struct futex_waitv],,,[#include <linux/futex.h>])
>  AC_CHECK_TYPES([struct mount_attr],,,[
> -#ifdef HAVE_LINUX_MOUNT_H
> -# include <linux/mount.h>
> -#else
> +#ifdef HAVE_MOUNT_SETATTR
>  # include <sys/mount.h>
> +#elif HAVE_LINUX_MOUNT_H
> +# include <linux/mount.h>
>  #endif
>  ])

I wonder if we can get this whole mess of two different fallback headers
simplified. Looking at the glibc implementation it seems to include
"linux/mount.h" if it does exist. So most reasonable solution would do
the same I guess which we did before the commit you reference.

@Li Wang where does the the sys/mount.h and linux/mount.h conflict? As
far as I can tell the UAPI linux/mount.h never defined any functions,
just constants, which should be solvable without the complex ifdefs, we
just need to check for existence of the types and define them only if
missing.

-- 
Cyril Hrubis
chrubis@suse.cz