On Thu, Dec 21, 2023 at 11:42:31AM +0530, Disha Goel wrote:
> In some distributions, __u64 is already defined in system header files,
> causing compilation errors when building xfstest.
>
> # make
> [CC] ext4_resize
> ext4_resize.c:17:28: error: conflicting types for '__u64'
> typedef unsigned long long __u64;
> ^~~~~
> In file included from /usr/include/asm/types.h:26:0,
> from /usr/include/linux/types.h:5,
> from /usr/include/linux/mount.h:4,
> from /usr/include/sys/mount.h:32,
> from ext4_resize.c:15:
> /usr/include/asm-generic/int-l64.h:30:23: note: previous declaration of '__u64' was here
> typedef unsigned long __u64;
> ^~~~~
>
> To address this issue, replace the custom definition of __u64 with the
> standard uint64_t type from <stdint.h>. uint64_t is part of the C99
> standard, offering a standardised approach for representing unsigned
> 64-bit integers. This modification enhances code consistency and
> ensures compatibility with standard types.
...but isn't consistent with the definition in the kernel uapi headers.
ioctls explicitly use __u64, not uint64_t, and there are a few arches
(apparently) where __u64 ends up an unsigned long long but uint64_t ends
up an unsigned long, and the reverse.
> Tested on various distributions on Power architecture, by successfully
> compiling xfstest. Additionally, verified the compatibility by running
> ext4/033 and ext4/056 tests, both of which use ext4_resize and
> observed successful test execution.
>
> # make
> [CC] detached_mounts_propagation
> [CC] ext4_resize
> [CC] t_readdir_3
>
> Signed-off-by: Disha Goel <disgoel@xxxxxxxxxxxxx>
> ---
> src/ext4_resize.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/src/ext4_resize.c b/src/ext4_resize.c
> index 78b66432..6e60ee5b 100644
> --- a/src/ext4_resize.c
> +++ b/src/ext4_resize.c
> @@ -14,10 +14,8 @@
> #include <sys/ioctl.h>
> #include <sys/mount.h>
Why not #include <linux/ext4.h>, which gets you both the __u64 typedef
and EXT4_IOC_RESIZE_FS?
--D
>
> -typedef unsigned long long __u64;
> -
> #ifndef EXT4_IOC_RESIZE_FS
> -#define EXT4_IOC_RESIZE_FS _IOW('f', 16, __u64)
> +#define EXT4_IOC_RESIZE_FS _IOW('f', 16, uint64_t)
> #endif
>
> #define pr_error(fmt, ...) do { \
> @@ -31,7 +29,7 @@ static void usage(void)
>
> int main(int argc, char **argv)
> {
> - __u64 new_size;
> + uint64_t new_size;
> int error, fd;
> char *mnt_dir = NULL, *tmp = NULL;
>
> --
> 2.39.1
>
>
