On 3/30/26 14:53, Li Wang wrote:
> hugetlb_dio test uses sub-page offsets (pagesize / 2) to verify that
> hugepages used as DIO user buffers are correctly unpinned at completion.
>
> However, on filesystems with a logical block size larger than half the
> page size (e.g., 4K-sector block devices), these unaligned DIO writes
> are rejected with -EINVAL, causing the test to fail unexpectedly.
>
> Add get_dio_alignment() to query the filesystem's required DIO alignment
> via statx(STATX_DIOALIGN) and skip individual test cases whose file
> offset or write size is not a multiple of that alignment. Aligned cases
> continue to run so the core coverage is preserved.
>
> While here, open the temporary file once in main() and share the fd
> across all test cases instead of reopening it in each invocation.
>
> === Reproduce Steps ===
>
> # dd if=/dev/zero of=/tmp/test.img bs=1M count=512
> # losetup --sector-size 4096 /dev/loop0 /tmp/test.img
> # mkfs.xfs /dev/loop0
> # mkdir -p /mnt/dio_test
> # mount /dev/loop0 /mnt/dio_test
>
> // Modify test to open /mnt/dio_test and rebuild it:
> - fd = open("/tmp", O_TMPFILE | O_RDWR | O_DIRECT, 0664);
> + fd = open("/mnt/dio_test", O_TMPFILE | O_RDWR | O_DIRECT, 0664);
>
> # getconf PAGESIZE
> 4096
>
> # echo 100 >/proc/sys/vm/nr_hugepages
>
> # ./hugetlb_dio
> TAP version 13
> 1..4
> # No. Free pages before allocation : 100
> # No. Free pages after munmap : 100
> ok 1 free huge pages from 0-12288
> Bail out! Error writing to file
> : Invalid argument (22)
> # Planned tests != run tests (4 != 1)
> # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
>
> Signed-off-by: Li Wang <[email protected]>
> Suggested-by: Mike Rapoport <[email protected]>
> Suggested-by: David Hildenbrand <[email protected]>
> ---
[...]
> +static void run_dio_using_hugetlb(int fd, unsigned int start_off,
> + unsigned int end_off)
> {
> - int fd;
> char *buffer = NULL;
> char *orig_buffer = NULL;
> size_t h_pagesize = 0;
> @@ -39,10 +84,9 @@ void run_dio_using_hugetlb(unsigned int start_off,
> unsigned int end_off)
> if (!h_pagesize)
> ksft_exit_fail_msg("Unable to determine huge page size\n");
>
> - /* Open the file to DIO */
> - fd = open("/tmp", O_TMPFILE | O_RDWR | O_DIRECT, 0664);
> - if (fd < 0)
> - ksft_exit_fail_perror("Error opening file\n");
> + /* Reset file position since fd is shared across tests */
> + if (lseek(fd, 0, SEEK_SET) < 0)
> + ksft_exit_fail_perror("lseek failed\n");
>
> /* Get the free huge pages before allocation */
> free_hpage_b = get_free_hugepages();
> @@ -71,7 +115,6 @@ void run_dio_using_hugetlb(unsigned int start_off,
> unsigned int end_off)
>
> /* unmap the huge page */
> munmap(orig_buffer, h_pagesize);
> - close(fd);
>
> /* Get the free huge pages after unmap*/
> free_hpage_a = get_free_hugepages();
> @@ -87,39 +130,49 @@ void run_dio_using_hugetlb(unsigned int start_off,
> unsigned int end_off)
> "free huge pages from %u-%u\n", start_off, end_off);
> }
>
> +static void run_test(int fd, unsigned int start_off,
> + unsigned int end_off, unsigned int align)
Nit: prefer to-tab alignment in MM land.
> +{
> + if (!check_dio_alignment(start_off, end_off, align))
> + return;
Is there a reason we just perform that at the beginning of
run_dio_using_hugetlb(), avoiding run_test() entirely?
In general, LGTM, thanks!
Feel free to add my
Acked-by: David Hildenbrand (Arm) <[email protected]>
--
Cheers,
David
