Re: [PATCH v3] selftests/mm: skip hugetlb_dio tests when DIO alignment is incompatible

[Li Wang <liwang@redhat.com>]

> >   int main(void)
> >   {
> >       ... 
> >       fd = open("/tmp", O_TMPFILE | O_RDWR | O_DIRECT, 0664);
> >       if (fd < 0)
> >           ksft_exit_skip("Unable to allocate file: %s\n", strerror(errno));
> >   
> >       if (get_dio_alignment(fd) < 0)
> 
> I would suggest that you query the alignment only once, and forward it
> to the test.

Sure thing, I declare a global variable 'dio_offset_align' to get the value
only once via get_dio_alignment(fd).

(sorry for not posting in the above email)

static unsigned int dio_offset_align;

static int get_dio_alignment(int fd)
{
	struct statx stx;
	int ret;

	ret = syscall(__NR_statx, fd, "", AT_EMPTY_PATH, STATX_DIOALIGN, &stx);
	if (ret < 0)
		return -1;

	if (!(stx.stx_mask & STATX_DIOALIGN) || !stx.stx_dio_offset_align)
		dio_offset_align = 1;
	else
		dio_offset_align = stx.stx_dio_offset_align;

	return 0;
}


-- 
Regards,
Li Wang